x264源代码简单分析：编码器主干部分-2

1
2
3
4
5
6
7
8
9
10
11
12
13
/* x264_encoder_encode:
*
encode one picture.
*
*pi_nal is the number of NAL units outputted in pp_nal.
*
returns the number of bytes in the returned NALs.
*
returns negative on error and zero if no NAL units returned.
*
the payloads of all output NALs are guaranteed to be sequential in memory. */
int
x264_encoder_encode( x264_t *, x264_nal_t **pp_nal, int *pi_nal, x264_picture_t *pic_in, x264_picture_t *pic_out );

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
/****************************************************************************
* x264_encoder_encode:
*
XXX: i_poc
: is the poc of the current given picture
*
i_frame : is the number of the frame being coded
*
ex:
type frame poc
*
I
0
2*0
*
P
1
2*3
*
B
2
2*1
*
B
3
2*2
*
P
4
2*6
*
B
5
2*4
*
B
6
2*5
*
* 注释和处理：雷霄骅
* http://blog.csdn.net/leixiaohua1020
* leixiaohua1020@126.com
****************************************************************************/
//编码一帧数据
int
x264_encoder_encode( x264_t *h,
x264_nal_t **pp_nal, int *pi_nal,
x264_picture_t *pic_in,
x264_picture_t *pic_out )
{
x264_t *thread_current, *thread_prev, *thread_oldest;
int i_nal_type, i_nal_ref_idc, i_global_qp;
int overhead = NALU_OVERHEAD;
#if HAVE_OPENCL
if( h->opencl.b_fatal_error )
return -1;
#endif
if( h->i_thread_frames > 1 )
{
thread_prev
= h->thread[ h->i_thread_phase ];
h->i_thread_phase = (h->i_thread_phase + 1) % h->i_thread_frames;
thread_current = h->thread[ h->i_thread_phase ];
thread_oldest
= h->thread[ (h->i_thread_phase + 1) % h->i_thread_frames ];
x264_thread_sync_context( thread_current, thread_prev );
x264_thread_sync_ratecontrol( thread_current, thread_prev, thread_oldest );
h = thread_current;
}
else
{
thread_current =
thread_oldest
= h;
}
h->i_cpb_delay_pir_offset = h->i_cpb_delay_pir_offset_next;
/* no data out */
*pi_nal = 0;
*pp_nal = NULL;
/* ------------------- Setup new frame from picture -------------------- */
if( pic_in != NULL )
{
/* 1: Copy the picture to a frame and move it to a buffer */
//步骤1
//fenc存储了编码帧
//获取一帧的空间fenc，用来存放待编码的帧
x264_frame_t *fenc = x264_frame_pop_unused( h, 0 );
if( !fenc )
return -1;
//外部像素数据传递到内部系统
//pic_in（外部结构体x264_picture_t）到fenc（内部结构体x264_frame_t）
if( x264_frame_copy_picture( h, fenc, pic_in ) < 0 )
return -1;
//宽和高都确保是16的整数倍（宏块宽度的整数倍）
if( h->param.i_width != 16 * h->mb.i_mb_width ||
h->param.i_height != 16 * h->mb.i_mb_height )
x264_frame_expand_border_mod16( h, fenc );//扩展至16整数倍
fenc->i_frame = h->frames.i_input++;
if( fenc->i_frame == 0 )
h->frames.i_first_pts = fenc->i_pts;
if( h->frames.i_bframe_delay && fenc->i_frame == h->frames.i_bframe_delay )
h->frames.i_bframe_delay_time = fenc->i_pts - h->frames.i_first_pts;
if( h->param.b_vfr_input && fenc->i_pts <= h->frames.i_largest_pts )
x264_log( h, X264_LOG_WARNING, "non-strictly-monotonic PTSn" );
h->frames.i_second_largest_pts = h->frames.i_largest_pts;
h->frames.i_largest_pts = fenc->i_pts;
if( (fenc->i_pic_struct < PIC_STRUCT_AUTO) || (fenc->i_pic_struct > PIC_STRUCT_TRIPLE) )
fenc->i_pic_struct = PIC_STRUCT_AUTO;
if( fenc->i_pic_struct == PIC_STRUCT_AUTO )
{
#if HAVE_INTERLACED
int b_interlaced = fenc->param ? fenc->param->b_interlaced : h->param.b_interlaced;
#else
int b_interlaced = 0;
#endif
if( b_interlaced )
{
int b_tff = fenc->param ? fenc->param->b_tff : h->param.b_tff;
fenc->i_pic_struct = b_tff ? PIC_STRUCT_TOP_BOTTOM : PIC_STRUCT_BOTTOM_TOP;
}
else
fenc->i_pic_struct = PIC_STRUCT_PROGRESSIVE;
}
if( h->param.rc.b_mb_tree && h->param.rc.b_stat_read )
{
if( x264_macroblock_tree_read( h, fenc, pic_in->prop.quant_offsets ) )
return -1;
}
else
x264_stack_align( x264_adaptive_quant_frame, h, fenc, pic_in->prop.quant_offsets );
if( pic_in->prop.quant_offsets_free )
pic_in->prop.quant_offsets_free( pic_in->prop.quant_offsets );
//降低分辨率处理（原来的一半），线性内插
//注意这里并不是6抽头滤波器的半像素内插
if( h->frames.b_have_lowres )
x264_frame_init_lowres( h, fenc );
/* 2: Place the frame into the queue for its slice type decision */
//步骤2
//fenc放入lookahead.next.list[]队列，等待确定帧类型
x264_lookahead_put_frame( h, fenc );
if( h->frames.i_input <= h->frames.i_delay + 1 - h->i_thread_frames )
{
/* Nothing yet to encode, waiting for filling of buffers */
pic_out->i_type = X264_TYPE_AUTO;
return 0;
}
}
else
{
//输入数据为空的时候（Flush Encoder？），不需要lookahead
/* signal kills for lookahead thread */
x264_pthread_mutex_lock( &h->lookahead->ifbuf.mutex );
h->lookahead->b_exit_thread = 1;
x264_pthread_cond_broadcast( &h->lookahead->ifbuf.cv_fill );
x264_pthread_mutex_unlock( &h->lookahead->ifbuf.mutex );
}
h->i_frame++;
/* 3: The picture is analyzed in the lookahead */
// 步骤3
//通过lookahead分析帧类型
if( !h->frames.current[0] )
x264_lookahead_get_frames( h );
if( !h->frames.current[0] && x264_lookahead_is_empty( h ) )
return x264_encoder_frame_end( thread_oldest, thread_current, pp_nal, pi_nal, pic_out );
/* ------------------- Get frame to be encoded ------------------------- */
/* 4: get picture to encode */
//从frames.current[]队列取出1帧[0]用于编码
h->fenc = x264_frame_shift( h->frames.current );
/* If applicable, wait for previous frame reconstruction to finish */
if( h->param.b_sliced_threads )
if( x264_threadpool_wait_all( h ) < 0 )
return -1;
if( h->i_frame == h->i_thread_frames - 1 )
h->i_reordered_pts_delay = h->fenc->i_reordered_pts;
if( h->reconfig )
{
x264_encoder_reconfig_apply( h, &h->reconfig_h->param );
h->reconfig = 0;
}
if( h->fenc->param )
{
x264_encoder_reconfig_apply( h, h->fenc->param );
if( h->fenc->param->param_free )
{
h->fenc->param->param_free( h->fenc->param );
h->fenc->param = NULL;
}
}
// ok to call this before encoding any frames, since the initial values of fdec have b_kept_as_ref=0
//更新参考帧队列frames.reference[].若为B帧则不更新
//重建帧fdec移植参考帧列表，新建一个fdec
if( x264_reference_update( h ) )
return -1;
h->fdec->i_lines_completed = -1;
if( !IS_X264_TYPE_I( h->fenc->i_type ) )
{
int valid_refs_left = 0;
for( int i = 0; h->frames.reference[i]; i++ )
if( !h->frames.reference[i]->b_corrupt )
valid_refs_left++;
/* No valid reference frames left: force an IDR. */
if( !valid_refs_left )
{
h->fenc->b_keyframe = 1;
h->fenc->i_type = X264_TYPE_IDR;
}
}
if( h->fenc->b_keyframe )
{
h->frames.i_last_keyframe = h->fenc->i_frame;
if( h->fenc->i_type == X264_TYPE_IDR )
{
h->i_frame_num = 0;
h->frames.i_last_idr = h->fenc->i_frame;
}
}
h->sh.i_mmco_command_count =
h->sh.i_mmco_remove_from_end = 0;
h->b_ref_reorder[0] =
h->b_ref_reorder[1] = 0;
h->fdec->i_poc =
h->fenc->i_poc = 2 * ( h->fenc->i_frame - X264_MAX( h->frames.i_last_idr, 0 ) );
/* ------------------- Setup frame context ----------------------------- */
/* 5: Init data dependent of frame type */
if( h->fenc->i_type == X264_TYPE_IDR )
{
//I与IDR区别
//注意IDR会导致参考帧列清空，而I不会
//I图像之后的图像可以引用I图像之间的图像做运动参考
/* reset ref pictures */
i_nal_type
= NAL_SLICE_IDR;
i_nal_ref_idc = NAL_PRIORITY_HIGHEST;
h->sh.i_type = SLICE_TYPE_I;
//若是IDR帧，则清空所有参考帧
x264_reference_reset( h );
h->frames.i_poc_last_open_gop = -1;
}
else if( h->fenc->i_type == X264_TYPE_I )
{
//I与IDR区别
//注意IDR会导致参考帧列清空，而I不会
//I图像之后的图像可以引用I图像之间的图像做运动参考
i_nal_type
= NAL_SLICE;
i_nal_ref_idc = NAL_PRIORITY_HIGH; /* Not completely true but for now it is (as all I/P are kept as ref)*/
h->sh.i_type = SLICE_TYPE_I;
x264_reference_hierarchy_reset( h );
if( h->param.b_open_gop )
h->frames.i_poc_last_open_gop = h->fenc->b_keyframe ? h->fenc->i_poc : -1;
}
else if( h->fenc->i_type == X264_TYPE_P )
{
i_nal_type
= NAL_SLICE;
i_nal_ref_idc = NAL_PRIORITY_HIGH; /* Not completely true but for now it is (as all I/P are kept as ref)*/
h->sh.i_type = SLICE_TYPE_P;
x264_reference_hierarchy_reset( h );
h->frames.i_poc_last_open_gop = -1;
}
else if( h->fenc->i_type == X264_TYPE_BREF )
{
//可以作为参考帧的B帧，这是个特色
i_nal_type
= NAL_SLICE;
i_nal_ref_idc = h->param.i_bframe_pyramid == X264_B_PYRAMID_STRICT ? NAL_PRIORITY_LOW : NAL_PRIORITY_HIGH;
h->sh.i_type = SLICE_TYPE_B;
x264_reference_hierarchy_reset( h );
}
else
/* B frame */
{
//最普通
i_nal_type
= NAL_SLICE;
i_nal_ref_idc = NAL_PRIORITY_DISPOSABLE;
h->sh.i_type = SLICE_TYPE_B;
}
//重建帧与编码帧的赋值...
h->fdec->i_type = h->fenc->i_type;
h->fdec->i_frame = h->fenc->i_frame;
h->fenc->b_kept_as_ref =
h->fdec->b_kept_as_ref = i_nal_ref_idc != NAL_PRIORITY_DISPOSABLE && h->param.i_keyint_max > 1;
h->fdec->mb_info = h->fenc->mb_info;
h->fdec->mb_info_free = h->fenc->mb_info_free;
h->fenc->mb_info = NULL;
h->fenc->mb_info_free = NULL;
h->fdec->i_pts = h->fenc->i_pts;
if( h->frames.i_bframe_delay )
{
int64_t *prev_reordered_pts = thread_current->frames.i_prev_reordered_pts;
h->fdec->i_dts = h->i_frame > h->frames.i_bframe_delay
? prev_reordered_pts[ (h->i_frame - h->frames.i_bframe_delay) % h->frames.i_bframe_delay ]
: h->fenc->i_reordered_pts - h->frames.i_bframe_delay_time;
prev_reordered_pts[ h->i_frame % h->frames.i_bframe_delay ] = h->fenc->i_reordered_pts;
}
else
h->fdec->i_dts = h->fenc->i_reordered_pts;
if( h->fenc->i_type == X264_TYPE_IDR )
h->i_last_idr_pts = h->fdec->i_pts;
/* ------------------- Init
----------------------------- */
/* build ref list 0/1 */
//创建参考帧列表list0和list1
x264_reference_build_list( h, h->fdec->i_poc );
/* ---------------------- Write the bitstream -------------------------- */
/* Init bitstream context */
//用于输出
if( h->param.b_sliced_threads )
{
for( int i = 0; i < h->param.i_threads; i++ )
{
bs_init( &h->thread[i]->out.bs, h->thread[i]->out.p_bitstream, h->thread[i]->out.i_bitstream );
h->thread[i]->out.i_nal = 0;
}
}
else
{
bs_init( &h->out.bs, h->out.p_bitstream, h->out.i_bitstream );
h->out.i_nal = 0;
}
if( h->param.b_aud )
{
int pic_type;
if( h->sh.i_type == SLICE_TYPE_I )
pic_type = 0;
else if( h->sh.i_type == SLICE_TYPE_P )
pic_type = 1;
else if( h->sh.i_type == SLICE_TYPE_B )
pic_type = 2;
else
pic_type = 7;
x264_nal_start( h, NAL_AUD, NAL_PRIORITY_DISPOSABLE );
bs_write( &h->out.bs, 3, pic_type );
bs_rbsp_trailing( &h->out.bs );
if( x264_nal_end( h ) )
return -1;
overhead += h->out.nal[h->out.i_nal-1].i_payload + NALU_OVERHEAD;
}
h->i_nal_type = i_nal_type;
h->i_nal_ref_idc = i_nal_ref_idc;
if( h->param.b_intra_refresh )
{
if( IS_X264_TYPE_I( h->fenc->i_type ) )
{
h->fdec->i_frames_since_pir = 0;
h->b_queued_intra_refresh = 0;
/* PIR is currently only supported with ref == 1, so any intra frame effectively refreshes
* the whole frame and counts as an intra refresh. */
h->fdec->f_pir_position = h->mb.i_mb_width;
}
else if( h->fenc->i_type == X264_TYPE_P )
{
int pocdiff = (h->fdec->i_poc - h->fref[0][0]->i_poc)/2;
float increment = X264_MAX( ((float)h->mb.i_mb_width-1) / h->param.i_keyint_max, 1 );
h->fdec->f_pir_position = h->fref[0][0]->f_pir_position;
h->fdec->i_frames_since_pir = h->fref[0][0]->i_frames_since_pir + pocdiff;
if( h->fdec->i_frames_since_pir >= h->param.i_keyint_max ||
(h->b_queued_intra_refresh && h->fdec->f_pir_position + 0.5 >= h->mb.i_mb_width) )
{
h->fdec->f_pir_position = 0;
h->fdec->i_frames_since_pir = 0;
h->b_queued_intra_refresh = 0;
h->fenc->b_keyframe = 1;
}
h->fdec->i_pir_start_col = h->fdec->f_pir_position+0.5;
h->fdec->f_pir_position += increment * pocdiff;
h->fdec->i_pir_end_col = h->fdec->f_pir_position+0.5;
/* If our intra refresh has reached the right side of the frame, we're done. */
if( h->fdec->i_pir_end_col >= h->mb.i_mb_width - 1 )
{
h->fdec->f_pir_position = h->mb.i_mb_width;
h->fdec->i_pir_end_col = h->mb.i_mb_width - 1;
}
}
}
if( h->fenc->b_keyframe )
{
//每个关键帧前面重复加上SPS和PPS
/* Write SPS and PPS */
if( h->param.b_repeat_headers )
{
/* generate sequence parameters */
x264_nal_start( h, NAL_SPS, NAL_PRIORITY_HIGHEST );
x264_sps_write( &h->out.bs, h->sps );
if( x264_nal_end( h ) )
return -1;
/* Pad AUD/SPS to 256 bytes like Panasonic */
if( h->param.i_avcintra_class )
h->out.nal[h->out.i_nal-1].i_padding = 256 - bs_pos( &h->out.bs ) / 8 - 2*NALU_OVERHEAD;
overhead += h->out.nal[h->out.i_nal-1].i_payload + h->out.nal[h->out.i_nal-1].i_padding + NALU_OVERHEAD;
/* generate picture parameters */
x264_nal_start( h, NAL_PPS, NAL_PRIORITY_HIGHEST );
x264_pps_write( &h->out.bs, h->sps, h->pps );
if( x264_nal_end( h ) )
return -1;
if( h->param.i_avcintra_class )
h->out.nal[h->out.i_nal-1].i_padding = 256 - h->out.nal[h->out.i_nal-1].i_payload - NALU_OVERHEAD;
overhead += h->out.nal[h->out.i_nal-1].i_payload + h->out.nal[h->out.i_nal-1].i_padding + NALU_OVERHEAD;
}
/* when frame threading is used, buffering period sei is written in x264_encoder_frame_end */
if( h->i_thread_frames == 1 && h->sps->vui.b_nal_hrd_parameters_present )
{
x264_hrd_fullness( h );
x264_nal_start( h, NAL_SEI, NAL_PRIORITY_DISPOSABLE );
x264_sei_buffering_period_write( h, &h->out.bs );
if( x264_nal_end( h ) )
return -1;
overhead += h->out.nal[h->out.i_nal-1].i_payload + SEI_OVERHEAD;
}
}
/* write extra sei */
//下面很大一段代码用于写入SEI（一部分是为了适配其他的解码器）==========================================
for( int i = 0; i < h->fenc->extra_sei.num_payloads; i++ )
{
x264_nal_start( h, NAL_SEI, NAL_PRIORITY_DISPOSABLE );
x264_sei_write( &h->out.bs, h->fenc->extra_sei.payloads[i].payload, h->fenc->extra_sei.payloads[i].payload_size,
h->fenc->extra_sei.payloads[i].payload_type );
if( x264_nal_end( h ) )
return -1;
overhead += h->out.nal[h->out.i_nal-1].i_payload + SEI_OVERHEAD;
if( h->fenc->extra_sei.sei_free )
{
h->fenc->extra_sei.sei_free( h->fenc->extra_sei.payloads[i].payload );
h->fenc->extra_sei.payloads[i].payload = NULL;
}
}
if( h->fenc->extra_sei.sei_free )
{
h->fenc->extra_sei.sei_free( h->fenc->extra_sei.payloads );
h->fenc->extra_sei.payloads = NULL;
h->fenc->extra_sei.sei_free = NULL;
}
//特殊的SEI信息（Avid等解码器需要）
if( h->fenc->b_keyframe )
{
/* Avid's decoder strictly wants two SEIs for AVC-Intra so we can't insert the x264 SEI */
if( h->param.b_repeat_headers && h->fenc->i_frame == 0 && !h->param.i_avcintra_class )
{
/* identify ourself */
x264_nal_start( h, NAL_SEI, NAL_PRIORITY_DISPOSABLE );
if( x264_sei_version_write( h, &h->out.bs ) )
return -1;
if( x264_nal_end( h ) )
return -1;
overhead += h->out.nal[h->out.i_nal-1].i_payload + SEI_OVERHEAD;
}
if( h->fenc->i_type != X264_TYPE_IDR )
{
int time_to_recovery = h->param.b_open_gop ? 0 : X264_MIN( h->mb.i_mb_width - 1, h->param.i_keyint_max ) + h->param.i_bframe - 1;
x264_nal_start( h, NAL_SEI, NAL_PRIORITY_DISPOSABLE );
x264_sei_recovery_point_write( h, &h->out.bs, time_to_recovery );
if( x264_nal_end( h ) )
return -1;
overhead += h->out.nal[h->out.i_nal-1].i_payload + SEI_OVERHEAD;
}
}
if( h->param.i_frame_packing >= 0 && (h->fenc->b_keyframe || h->param.i_frame_packing == 5) )
{
x264_nal_start( h, NAL_SEI, NAL_PRIORITY_DISPOSABLE );
x264_sei_frame_packing_write( h, &h->out.bs );
if( x264_nal_end( h ) )
return -1;
overhead += h->out.nal[h->out.i_nal-1].i_payload + SEI_OVERHEAD;
}
/* generate sei pic timing */
if( h->sps->vui.b_pic_struct_present || h->sps->vui.b_nal_hrd_parameters_present )
{
x264_nal_start( h, NAL_SEI, NAL_PRIORITY_DISPOSABLE );
x264_sei_pic_timing_write( h, &h->out.bs );
if( x264_nal_end( h ) )
return -1;
overhead += h->out.nal[h->out.i_nal-1].i_payload + SEI_OVERHEAD;
}
/* As required by Blu-ray. */
if( !IS_X264_TYPE_B( h->fenc->i_type ) && h->b_sh_backup )
{
h->b_sh_backup = 0;
x264_nal_start( h, NAL_SEI, NAL_PRIORITY_DISPOSABLE );
x264_sei_dec_ref_pic_marking_write( h, &h->out.bs );
if( x264_nal_end( h ) )
return -1;
overhead += h->out.nal[h->out.i_nal-1].i_payload + SEI_OVERHEAD;
}
if( h->fenc->b_keyframe && h->param.b_intra_refresh )
h->i_cpb_delay_pir_offset_next = h->fenc->i_cpb_delay;
/* Filler space: 10 or 18 SEIs' worth of space, depending on resolution */
if( h->param.i_avcintra_class )
{
/* Write an empty filler NAL to mimic the AUD in the P2 format*/
x264_nal_start( h, NAL_FILLER, NAL_PRIORITY_DISPOSABLE );
x264_filler_write( h, &h->out.bs, 0 );
if( x264_nal_end( h ) )
return -1;
overhead += h->out.nal[h->out.i_nal-1].i_payload + NALU_OVERHEAD;
/* All lengths are magic lengths that decoders expect to see */
/* "UMID" SEI */
x264_nal_start( h, NAL_SEI, NAL_PRIORITY_DISPOSABLE );
if( x264_sei_avcintra_umid_write( h, &h->out.bs ) < 0 )
return -1;
if( x264_nal_end( h ) )
return -1;
overhead += h->out.nal[h->out.i_nal-1].i_payload + SEI_OVERHEAD;
int unpadded_len;
int total_len;
if( h->param.i_height == 1080 )
{
unpadded_len = 5780;
total_len = 17*512;
}
else
{
unpadded_len = 2900;
total_len = 9*512;
}
/* "VANC" SEI */
x264_nal_start( h, NAL_SEI, NAL_PRIORITY_DISPOSABLE );
if( x264_sei_avcintra_vanc_write( h, &h->out.bs, unpadded_len ) < 0 )
return -1;
if( x264_nal_end( h ) )
return -1;
h->out.nal[h->out.i_nal-1].i_padding = total_len - h->out.nal[h->out.i_nal-1].i_payload - SEI_OVERHEAD;
overhead += h->out.nal[h->out.i_nal-1].i_payload + h->out.nal[h->out.i_nal-1].i_padding + SEI_OVERHEAD;
}
//写入SEI代码结束========================================================
/* Init the rate control */
/* FIXME: Include slice header bit cost. */
//码率控制单元初始化
x264_ratecontrol_start( h, h->fenc->i_qpplus1, overhead*8 );
i_global_qp = x264_ratecontrol_qp( h );
pic_out->i_qpplus1 =
h->fdec->i_qpplus1 = i_global_qp + 1;
if( h->param.rc.b_stat_read && h->sh.i_type != SLICE_TYPE_I )
{
x264_reference_build_list_optimal( h );
x264_reference_check_reorder( h );
}
if( h->i_ref[0] )
h->fdec->i_poc_l0ref0 = h->fref[0][0]->i_poc;
/* ------------------------ Create slice header
----------------------- */
//创建Slice Header
x264_slice_init( h, i_nal_type, i_global_qp );
/*------------------------- Weights -------------------------------------*/
//加权预测
if( h->sh.i_type == SLICE_TYPE_B )
x264_macroblock_bipred_init( h );
x264_weighted_pred_init( h );
if( i_nal_ref_idc != NAL_PRIORITY_DISPOSABLE )
h->i_frame_num++;
/* Write frame */
h->i_threadslice_start = 0;
h->i_threadslice_end = h->mb.i_mb_height;
if( h->i_thread_frames > 1 )
{
x264_threadpool_run( h->threadpool, (void*)x264_slices_write, h );
h->b_thread_active = 1;
}
else if( h->param.b_sliced_threads )
{
if( x264_threaded_slices_write( h ) )
return -1;
}
else{
//真正的编码——编码1个图像帧（注意这里“slices”后面有“s”）
if( (intptr_t)x264_slices_write( h ) )
return -1;
}
//结束的时候做一些处理，记录一些统计信息
//输出NALU
//输出重建帧
return x264_encoder_frame_end( thread_oldest, thread_current, pp_nal, pi_nal, pic_out );
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
//获取一帧的编码帧fenc或者重建帧fdec
x264_frame_t *x264_frame_pop_unused( x264_t *h, int b_fdec )
{
x264_frame_t *frame;
if( h->frames.unused[b_fdec][0] )//unused队列不为空
frame = x264_frame_pop( h->frames.unused[b_fdec] );//从unused队列取
else
frame = x264_frame_new( h, b_fdec );//分配一帧空间
if( !frame )
return NULL;
frame->b_last_minigop_bframe = 0;
frame->i_reference_count = 1;
frame->b_intra_calculated = 0;
frame->b_scenecut = 1;
frame->b_keyframe = 0;
frame->b_corrupt = 0;
frame->i_slice_count = h->param.b_sliced_threads ? h->param.i_threads : 1;
memset( frame->weight, 0, sizeof(frame->weight) );
memset( frame->f_weighted_cost_delta, 0, sizeof(frame->f_weighted_cost_delta) );
return frame;
}

1
2
3
4
5
6
7
8
9
10
11
//从队列的尾部取出一帧
x264_frame_t *x264_frame_pop( x264_frame_t **list )
{
x264_frame_t *frame;
int i = 0;
assert( list[0] );
while( list[i+1] ) i++;
frame = list[i];
list[i] = NULL;
return frame;
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
//新建一个帧
//b_fdec：取1的时候为重建帧fdec，取0的时候为编码帧fenc
static x264_frame_t *x264_frame_new( x264_t *h, int b_fdec )
{
x264_frame_t *frame;
//注意转换后只有3种colorspace：X264_CSP_NV12(对应YUV420),X264_CSP_NV16(对应YUV422),X264_CSP_I444(对应YUV444)
int i_csp = x264_frame_internal_csp( h->param.i_csp );
int i_mb_count = h->mb.i_mb_count;
int i_stride, i_width, i_lines, luma_plane_count;
int i_padv = PADV << PARAM_INTERLACED;
int align = 16;
#if ARCH_X86 || ARCH_X86_64
if( h->param.cpu&X264_CPU_CACHELINE_64 )
align = 64;
else if( h->param.cpu&X264_CPU_CACHELINE_32 || h->param.cpu&X264_CPU_AVX2 )
align = 32;
#endif
#if ARCH_PPC
int disalign = 1<<9;
#else
int disalign = 1<<10;
#endif
//给frame分配内存，并置零
CHECKED_MALLOCZERO( frame, sizeof(x264_frame_t) );
PREALLOC_INIT
/* allocate frame data (+64 for extra data for me) */
//以像素为单位的宽高
i_width
= h->mb.i_mb_width*16;
i_lines
= h->mb.i_mb_height*16;
i_stride = align_stride( i_width + 2*PADH, align, disalign );
if( i_csp == X264_CSP_NV12 || i_csp == X264_CSP_NV16 )
{
//YUV422,YUV420情况
luma_plane_count = 1;
frame->i_plane = 2;
for( int i = 0; i < 2; i++ )
{
frame->i_width[i] = i_width >> i;
frame->i_lines[i] = i_lines >> (i && i_csp == X264_CSP_NV12);
frame->i_stride[i] = i_stride;
}
}
else if( i_csp == X264_CSP_I444 )
{
//YUV444情况
luma_plane_count = 3;
frame->i_plane = 3;
for( int i = 0; i < 3; i++ )
{
frame->i_width[i] = i_width;
frame->i_lines[i] = i_lines;
frame->i_stride[i] = i_stride;
}
}
else
goto fail;
//赋值赋值赋值...
frame->i_csp = i_csp;
frame->i_width_lowres = frame->i_width[0]/2;
frame->i_lines_lowres = frame->i_lines[0]/2;
frame->i_stride_lowres = align_stride( frame->i_width_lowres + 2*PADH, align, disalign<<1 );
for( int i = 0; i < h->param.i_bframe + 2; i++ )
for( int j = 0; j < h->param.i_bframe + 2; j++ )
PREALLOC( frame->i_row_satds[i][j], i_lines/16 * sizeof(int) );
frame->i_poc = -1;
frame->i_type = X264_TYPE_AUTO;
frame->i_qpplus1 = X264_QP_AUTO;
frame->i_pts = -1;
frame->i_frame = -1;
frame->i_frame_num = -1;
frame->i_lines_completed = -1;
frame->b_fdec = b_fdec;
frame->i_pic_struct = PIC_STRUCT_AUTO;
frame->i_field_cnt = -1;
frame->i_duration =
frame->i_cpb_duration =
frame->i_dpb_output_delay =
frame->i_cpb_delay = 0;
frame->i_coded_fields_lookahead =
frame->i_cpb_delay_lookahead = -1;
frame->orig = frame;
if( i_csp == X264_CSP_NV12 || i_csp == X264_CSP_NV16 )
{
int chroma_padv = i_padv >> (i_csp == X264_CSP_NV12);
int chroma_plane_size = (frame->i_stride[1] * (frame->i_lines[1] + 2*chroma_padv));
PREALLOC( frame->buffer[1], chroma_plane_size * sizeof(pixel) );
if( PARAM_INTERLACED )
PREALLOC( frame->buffer_fld[1], chroma_plane_size * sizeof(pixel) );
}
/* all 4 luma planes allocated together, since the cacheline split code
* requires them to be in-phase wrt cacheline alignment. */
for( int p = 0; p < luma_plane_count; p++ )
{
int luma_plane_size = align_plane_size( frame->i_stride[p] * (frame->i_lines[p] + 2*i_padv), disalign );
if( h->param.analyse.i_subpel_refine && b_fdec )
{
/* FIXME: Don't allocate both buffers in non-adaptive MBAFF. */
PREALLOC( frame->buffer[p], 4*luma_plane_size * sizeof(pixel) );
if( PARAM_INTERLACED )
PREALLOC( frame->buffer_fld[p], 4*luma_plane_size * sizeof(pixel) );
}
else
{
PREALLOC( frame->buffer[p], luma_plane_size * sizeof(pixel) );
if( PARAM_INTERLACED )
PREALLOC( frame->buffer_fld[p], luma_plane_size * sizeof(pixel) );
}
}
frame->b_duplicate = 0;
if( b_fdec ) /* fdec frame */
{
//重建帧fdec
PREALLOC( frame->mb_type, i_mb_count * sizeof(int8_t) );
PREALLOC( frame->mb_partition, i_mb_count * sizeof(uint8_t) );
PREALLOC( frame->mv[0], 2*16 * i_mb_count * sizeof(int16_t) );
PREALLOC( frame->mv16x16, 2*(i_mb_count+1) * sizeof(int16_t) );
PREALLOC( frame->ref[0], 4 * i_mb_count * sizeof(int8_t) );
if( h->param.i_bframe )
{
PREALLOC( frame->mv[1], 2*16 * i_mb_count * sizeof(int16_t) );
PREALLOC( frame->ref[1], 4 * i_mb_count * sizeof(int8_t) );
}
else
{
frame->mv[1]
= NULL;
frame->ref[1] = NULL;
}
PREALLOC( frame->i_row_bits, i_lines/16 * sizeof(int) );
PREALLOC( frame->f_row_qp, i_lines/16 * sizeof(float) );
PREALLOC( frame->f_row_qscale, i_lines/16 * sizeof(float) );
if( h->param.analyse.i_me_method >= X264_ME_ESA )
PREALLOC( frame->buffer[3], frame->i_stride[0] * (frame->i_lines[0] + 2*i_padv) * sizeof(uint16_t) << h->frames.b_have_sub8x8_esa );
if( PARAM_INTERLACED )
PREALLOC( frame->field, i_mb_count * sizeof(uint8_t) );
if( h->param.analyse.b_mb_info )
PREALLOC( frame->effective_qp, i_mb_count * sizeof(uint8_t) );
}
else /* fenc frame */
{
//编码帧fenc
if( h->frames.b_have_lowres )
{
int luma_plane_size = align_plane_size( frame->i_stride_lowres * (frame->i_lines[0]/2 + 2*PADV), disalign );
PREALLOC( frame->buffer_lowres[0], 4 * luma_plane_size * sizeof(pixel) );
for( int j = 0; j <= !!h->param.i_bframe; j++ )
for( int i = 0; i <= h->param.i_bframe; i++ )
{
PREALLOC( frame->lowres_mvs[j][i], 2*h->mb.i_mb_count*sizeof(int16_t) );
PREALLOC( frame->lowres_mv_costs[j][i], h->mb.i_mb_count*sizeof(int) );
}
PREALLOC( frame->i_propagate_cost, (i_mb_count+7) * sizeof(uint16_t) );
for( int j = 0; j <= h->param.i_bframe+1; j++ )
for( int i = 0; i <= h->param.i_bframe+1; i++ )
PREALLOC( frame->lowres_costs[j][i], (i_mb_count+3) * sizeof(uint16_t) );
}
if( h->param.rc.i_aq_mode )
{
PREALLOC( frame->f_qp_offset, h->mb.i_mb_count * sizeof(float) );
PREALLOC( frame->f_qp_offset_aq, h->mb.i_mb_count * sizeof(float) );
if( h->frames.b_have_lowres )
PREALLOC( frame->i_inv_qscale_factor, (h->mb.i_mb_count+3) * sizeof(uint16_t) );
}
}
PREALLOC_END( frame->base );
if( i_csp == X264_CSP_NV12 || i_csp == X264_CSP_NV16 )
{
int chroma_padv = i_padv >> (i_csp == X264_CSP_NV12);
frame->plane[1] = frame->buffer[1] + frame->i_stride[1] * chroma_padv + PADH;
if( PARAM_INTERLACED )
frame->plane_fld[1] = frame->buffer_fld[1] + frame->i_stride[1] * chroma_padv + PADH;
}
for( int p = 0; p < luma_plane_count; p++ )
{
int luma_plane_size = align_plane_size( frame->i_stride[p] * (frame->i_lines[p] + 2*i_padv), disalign );
if( h->param.analyse.i_subpel_refine && b_fdec )
{
for( int i = 0; i < 4; i++ )
{
frame->filtered[p][i] = frame->buffer[p] + i*luma_plane_size + frame->i_stride[p] * i_padv + PADH;
frame->filtered_fld[p][i] = frame->buffer_fld[p] + i*luma_plane_size + frame->i_stride[p] * i_padv + PADH;
}
frame->plane[p] = frame->filtered[p][0];
frame->plane_fld[p] = frame->filtered_fld[p][0];
}
else
{
frame->filtered[p][0] = frame->plane[p] = frame->buffer[p] + frame->i_stride[p] * i_padv + PADH;
frame->filtered_fld[p][0] = frame->plane_fld[p] = frame->buffer_fld[p] + frame->i_stride[p] * i_padv + PADH;
}
}
if( b_fdec )
{
M32( frame->mv16x16[0] ) = 0;
frame->mv16x16++;
if( h->param.analyse.i_me_method >= X264_ME_ESA )
frame->integral = (uint16_t*)frame->buffer[3] + frame->i_stride[0] * i_padv + PADH;
}
else
{
if( h->frames.b_have_lowres )
{
int luma_plane_size = align_plane_size( frame->i_stride_lowres * (frame->i_lines[0]/2 + 2*PADV), disalign );
for( int i = 0; i < 4; i++ )
frame->lowres[i] = frame->buffer_lowres[0] + (frame->i_stride_lowres * PADV + PADH) + i * luma_plane_size;
for( int j = 0; j <= !!h->param.i_bframe; j++ )
for( int i = 0; i <= h->param.i_bframe; i++ )
memset( frame->lowres_mvs[j][i], 0, 2*h->mb.i_mb_count*sizeof(int16_t) );
frame->i_intra_cost = frame->lowres_costs[0][0];
memset( frame->i_intra_cost, -1, (i_mb_count+3) * sizeof(uint16_t) );
if( h->param.rc.i_aq_mode )
/* shouldn't really be initialized, just silences a valgrind false-positive in x264_mbtree_propagate_cost_sse2 */
memset( frame->i_inv_qscale_factor, 0, (h->mb.i_mb_count+3) * sizeof(uint16_t) );
}
}
if( x264_pthread_mutex_init( &frame->mutex, NULL ) )
goto fail;
if( x264_pthread_cond_init( &frame->cv, NULL ) )
goto fail;
#if HAVE_OPENCL
frame->opencl.ocl = h->opencl.ocl;
#endif
return frame;
fail:
x264_free( frame );
return NULL;
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
//注意转换后只有3种内部colorspace：X264_CSP_NV12(对应YUV420),X264_CSP_NV16(对应YUV422),X264_CSP_I444(对应YUV444)
static int x264_frame_internal_csp( int external_csp )
{
switch( external_csp & X264_CSP_MASK )
{
case X264_CSP_NV12:
case X264_CSP_I420:
case X264_CSP_YV12:
return X264_CSP_NV12;
case X264_CSP_NV16:
case X264_CSP_I422:
case X264_CSP_YV16:
case X264_CSP_V210:
return X264_CSP_NV16;
case X264_CSP_I444:
case X264_CSP_YV24:
case X264_CSP_BGR:
case X264_CSP_BGRA:
case X264_CSP_RGB:
return X264_CSP_I444;
default:
return X264_CSP_NONE;
}
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
//拷贝帧数据
//src（外部结构体x264_picture_t）到dst（内部结构体x264_frame_t）
int x264_frame_copy_picture( x264_t *h, x264_frame_t *dst, x264_picture_t *src )
{
int i_csp = src->img.i_csp & X264_CSP_MASK;
//注意转换后只有3种内部colorspace：X264_CSP_NV12(对应YUV420),X264_CSP_NV16(对应YUV422),X264_CSP_I444(对应YUV444)
if( dst->i_csp != x264_frame_internal_csp( i_csp ) )
{
x264_log( h, X264_LOG_ERROR, "Invalid input colorspacen" );
return -1;
}
#if HIGH_BIT_DEPTH
if( !(src->img.i_csp & X264_CSP_HIGH_DEPTH) )
{
x264_log( h, X264_LOG_ERROR, "This build of x264 requires high depth input. Rebuild to support 8-bit input.n" );
return -1;
}
#else
if( src->img.i_csp & X264_CSP_HIGH_DEPTH )
{
x264_log( h, X264_LOG_ERROR, "This build of x264 requires 8-bit input. Rebuild to support high depth input.n" );
return -1;
}
#endif
if( BIT_DEPTH != 10 && i_csp == X264_CSP_V210 )
{
x264_log( h, X264_LOG_ERROR, "v210 input is only compatible with bit-depth of 10 bitsn" );
return -1;
}
//赋值赋值赋值
dst->i_type
= src->i_type;
dst->i_qpplus1
= src->i_qpplus1;
dst->i_pts
= dst->i_reordered_pts = src->i_pts;
dst->param
= src->param;
dst->i_pic_struct = src->i_pic_struct;
dst->extra_sei
= src->extra_sei;
dst->opaque
= src->opaque;
dst->mb_info
= h->param.analyse.b_mb_info ? src->prop.mb_info : NULL;
dst->mb_info_free = h->param.analyse.b_mb_info ? src->prop.mb_info_free : NULL;
uint8_t *pix[3];
int stride[3];
if( i_csp == X264_CSP_V210 )
{
stride[0] = src->img.i_stride[0];
pix[0] = src->img.plane[0];
h->mc.plane_copy_deinterleave_v210( dst->plane[0], dst->i_stride[0],
dst->plane[1], dst->i_stride[1],
(uint32_t *)pix[0], stride[0]/sizeof(uint32_t), h->param.i_width, h->param.i_height );
}
else if( i_csp >= X264_CSP_BGR )
{
stride[0] = src->img.i_stride[0];
pix[0] = src->img.plane[0];
if( src->img.i_csp & X264_CSP_VFLIP )
{
pix[0] += (h->param.i_height-1) * stride[0];
stride[0] = -stride[0];
}
int b = i_csp==X264_CSP_RGB;
h->mc.plane_copy_deinterleave_rgb( dst->plane[1+b], dst->i_stride[1+b],
dst->plane[0], dst->i_stride[0],
dst->plane[2-b], dst->i_stride[2-b],
(pixel*)pix[0], stride[0]/sizeof(pixel), i_csp==X264_CSP_BGRA ? 4 : 3, h->param.i_width, h->param.i_height );
}
else
{
int v_shift = CHROMA_V_SHIFT;
get_plane_ptr( h, src, &pix[0], &stride[0], 0, 0, 0 );
//拷贝像素
h->mc.plane_copy( dst->plane[0], dst->i_stride[0], (pixel*)pix[0],
stride[0]/sizeof(pixel), h->param.i_width, h->param.i_height );
if( i_csp == X264_CSP_NV12 || i_csp == X264_CSP_NV16 )
{
get_plane_ptr( h, src, &pix[1], &stride[1], 1, 0, v_shift );
h->mc.plane_copy( dst->plane[1], dst->i_stride[1], (pixel*)pix[1],
stride[1]/sizeof(pixel), h->param.i_width, h->param.i_height>>v_shift );
}
else if( i_csp == X264_CSP_I420 || i_csp == X264_CSP_I422 || i_csp == X264_CSP_YV12 || i_csp == X264_CSP_YV16 )
{
int uv_swap = i_csp == X264_CSP_YV12 || i_csp == X264_CSP_YV16;
get_plane_ptr( h, src, &pix[1], &stride[1], uv_swap ? 2 : 1, 1, v_shift );
get_plane_ptr( h, src, &pix[2], &stride[2], uv_swap ? 1 : 2, 1, v_shift );
h->mc.plane_copy_interleave( dst->plane[1], dst->i_stride[1],
(pixel*)pix[1], stride[1]/sizeof(pixel),
(pixel*)pix[2], stride[2]/sizeof(pixel),
h->param.i_width>>1, h->param.i_height>>v_shift );
}
else //if( i_csp == X264_CSP_I444 || i_csp == X264_CSP_YV24 )
{
get_plane_ptr( h, src, &pix[1], &stride[1], i_csp==X264_CSP_I444 ? 1 : 2, 0, 0 );
get_plane_ptr( h, src, &pix[2], &stride[2], i_csp==X264_CSP_I444 ? 2 : 1, 0, 0 );
h->mc.plane_copy( dst->plane[1], dst->i_stride[1], (pixel*)pix[1],
stride[1]/sizeof(pixel), h->param.i_width, h->param.i_height );
h->mc.plane_copy( dst->plane[2], dst->i_stride[2], (pixel*)pix[2],
stride[2]/sizeof(pixel), h->param.i_width, h->param.i_height );
}
}
return 0;
}

1
2
3
4
5
6
7
8
9
//x264_frame_t放入x264_sync_frame_list_t队列
void x264_lookahead_put_frame( x264_t *h, x264_frame_t *frame )
{
if( h->param.i_sync_lookahead )
x264_sync_frame_list_push( &h->lookahead->ifbuf, frame );
else
x264_sync_frame_list_push( &h->lookahead->next, frame );//放入next队列
}

1
2
3
4
5
6
7
8
9
10
11
void x264_sync_frame_list_push( x264_sync_frame_list_t *slist, x264_frame_t *frame )
{
x264_pthread_mutex_lock( &slist->mutex );
while( slist->i_size == slist->i_max_size )
x264_pthread_cond_wait( &slist->cv_empty, &slist->mutex );
//放入
slist->list[ slist->i_size++ ] = frame;
x264_pthread_mutex_unlock( &slist->mutex );
x264_pthread_cond_broadcast( &slist->cv_fill );
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
//通过lookahead分析帧类型
void x264_lookahead_get_frames( x264_t *h )
{
if( h->param.i_sync_lookahead )
{
/* We have a lookahead thread, so get frames from there */
x264_pthread_mutex_lock( &h->lookahead->ofbuf.mutex );
while( !h->lookahead->ofbuf.i_size && h->lookahead->b_thread_active )
x264_pthread_cond_wait( &h->lookahead->ofbuf.cv_fill, &h->lookahead->ofbuf.mutex );
x264_lookahead_encoder_shift( h );
x264_pthread_mutex_unlock( &h->lookahead->ofbuf.mutex );
}
else
{
/* We are not running a lookahead thread, so perform all the slicetype decide on the fly */
//currect[]必须为空，next不能为空？
if( h->frames.current[0] || !h->lookahead->next.i_size )
return;
//分析lookahead->next->list帧的类型
x264_stack_align( x264_slicetype_decide, h );
//更新lookahead->last_nonb
x264_lookahead_update_last_nonb( h, h->lookahead->next.list[0] );
int shift_frames = h->lookahead->next.list[0]->i_bframes + 1;
//lookahead->next.list移动到lookahead->ofbuf.list
x264_lookahead_shift( &h->lookahead->ofbuf, &h->lookahead->next, shift_frames );
/* For MB-tree and VBV lookahead, we have to perform propagation analysis on I-frames too. */
if( h->lookahead->b_analyse_keyframe && IS_X264_TYPE_I( h->lookahead->last_nonb->i_type ) )
x264_stack_align( x264_slicetype_analyse, h, shift_frames );
//lookahead->ofbuf.list帧移动到frames->current
x264_lookahead_encoder_shift( h );
}
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
//确定帧的类型（I、B、P）
void x264_slicetype_decide( x264_t *h )
{
x264_frame_t *frames[X264_BFRAME_MAX+2];
x264_frame_t *frm;
int bframes;
int brefs;
if( !h->lookahead->next.i_size )
return;
int lookahead_size = h->lookahead->next.i_size;
//遍历next队列
for( int i = 0; i < h->lookahead->next.i_size; i++ )
{
if( h->param.b_vfr_input )
{
if( lookahead_size-- > 1 )
h->lookahead->next.list[i]->i_duration = 2 * (h->lookahead->next.list[i+1]->i_pts - h->lookahead->next.list[i]->i_pts);
else
h->lookahead->next.list[i]->i_duration = h->i_prev_duration;
}
else
h->lookahead->next.list[i]->i_duration = delta_tfi_divisor[h->lookahead->next.list[i]->i_pic_struct];
h->i_prev_duration = h->lookahead->next.list[i]->i_duration;
h->lookahead->next.list[i]->f_duration = (double)h->lookahead->next.list[i]->i_duration
* h->sps->vui.i_num_units_in_tick
/ h->sps->vui.i_time_scale;
if( h->lookahead->next.list[i]->i_frame > h->i_disp_fields_last_frame && lookahead_size > 0 )
{
h->lookahead->next.list[i]->i_field_cnt = h->i_disp_fields;
h->i_disp_fields += h->lookahead->next.list[i]->i_duration;
h->i_disp_fields_last_frame = h->lookahead->next.list[i]->i_frame;
}
else if( lookahead_size == 0 )
{
h->lookahead->next.list[i]->i_field_cnt = h->i_disp_fields;
h->lookahead->next.list[i]->i_duration = h->i_prev_duration;
}
}
if( h->param.rc.b_stat_read )
{
//b_stat_read在2pass模式的第2遍才不为0
/* Use the frame types from the first pass */
for( int i = 0; i < h->lookahead->next.i_size; i++ )
h->lookahead->next.list[i]->i_type =
x264_ratecontrol_slice_type( h, h->lookahead->next.list[i]->i_frame );
}
else if( (h->param.i_bframe && h->param.i_bframe_adaptive)
|| h->param.i_scenecut_threshold
|| h->param.rc.b_mb_tree
|| (h->param.rc.i_vbv_buffer_size && h->param.rc.i_lookahead) )
x264_slicetype_analyse( h, 0 );//分析帧的类型（I、B、P）
//===========================================================================
for( bframes = 0, brefs = 0;; bframes++ )
{
//从next队列取出1个
frm = h->lookahead->next.list[bframes];
//BREF的处理
if( frm->i_type == X264_TYPE_BREF && h->param.i_bframe_pyramid < X264_B_PYRAMID_NORMAL &&
brefs == h->param.i_bframe_pyramid )
{
//BREF改成B
frm->i_type = X264_TYPE_B;
x264_log( h, X264_LOG_WARNING, "B-ref at frame %d incompatible with B-pyramid %s n",
frm->i_frame, x264_b_pyramid_names[h->param.i_bframe_pyramid] );
}
/* pyramid with multiple B-refs needs a big enough dpb that the preceding P-frame stays available.
smaller dpb could be supported by smart enough use of mmco, but it's easier just to forbid it. */
else if( frm->i_type == X264_TYPE_BREF && h->param.i_bframe_pyramid == X264_B_PYRAMID_NORMAL &&
brefs && h->param.i_frame_reference <= (brefs+3) )
{
frm->i_type = X264_TYPE_B;
x264_log( h, X264_LOG_WARNING, "B-ref at frame %d incompatible with B-pyramid %s and %d reference framesn",
frm->i_frame, x264_b_pyramid_names[h->param.i_bframe_pyramid], h->param.i_frame_reference );
}
//Keyframe处理
if( frm->i_type == X264_TYPE_KEYFRAME )
frm->i_type = h->param.b_open_gop ? X264_TYPE_I : X264_TYPE_IDR;
/* Limit GOP size */
if( (!h->param.b_intra_refresh || frm->i_frame == 0) && frm->i_frame - h->lookahead->i_last_keyframe >= h->param.i_keyint_max )
{
if( frm->i_type == X264_TYPE_AUTO || frm->i_type == X264_TYPE_I )
frm->i_type = h->param.b_open_gop && h->lookahead->i_last_keyframe >= 0 ? X264_TYPE_I : X264_TYPE_IDR;
int warn = frm->i_type != X264_TYPE_IDR;
if( warn && h->param.b_open_gop )
warn &= frm->i_type != X264_TYPE_I;
if( warn )
{
x264_log( h, X264_LOG_WARNING, "specified frame type (%d) at %d is not compatible with keyframe intervaln", frm->i_type, frm->i_frame );
frm->i_type = h->param.b_open_gop && h->lookahead->i_last_keyframe >= 0 ? X264_TYPE_I : X264_TYPE_IDR;
}
}
if( frm->i_type == X264_TYPE_I && frm->i_frame - h->lookahead->i_last_keyframe >= h->param.i_keyint_min )
{
if( h->param.b_open_gop )
{
h->lookahead->i_last_keyframe = frm->i_frame; // Use display order
if( h->param.b_bluray_compat )
h->lookahead->i_last_keyframe -= bframes; // Use bluray order
frm->b_keyframe = 1;
}
else
frm->i_type = X264_TYPE_IDR;
}
if( frm->i_type == X264_TYPE_IDR )
{
/* Close GOP */
//设置当前帧为“上一个关键帧”
h->lookahead->i_last_keyframe = frm->i_frame;
frm->b_keyframe = 1;
if( bframes > 0 )
{
bframes--;
h->lookahead->next.list[bframes]->i_type = X264_TYPE_P;
}
}
if( bframes == h->param.i_bframe ||
!h->lookahead->next.list[bframes+1] )
{
if( IS_X264_TYPE_B( frm->i_type ) )
x264_log( h, X264_LOG_WARNING, "specified frame type is not compatible with max B-framesn" );
if( frm->i_type == X264_TYPE_AUTO
|| IS_X264_TYPE_B( frm->i_type ) )
frm->i_type = X264_TYPE_P;
}
if( frm->i_type == X264_TYPE_BREF )
brefs++;
if( frm->i_type == X264_TYPE_AUTO )
frm->i_type = X264_TYPE_B;
else if( !IS_X264_TYPE_B( frm->i_type ) ) break;
}
if( bframes )
h->lookahead->next.list[bframes-1]->b_last_minigop_bframe = 1;
h->lookahead->next.list[bframes]->i_bframes = bframes;
/* insert a bref into the sequence */
if( h->param.i_bframe_pyramid && bframes > 1 && !brefs )
{
h->lookahead->next.list[bframes/2]->i_type = X264_TYPE_BREF;
brefs++;
}
/* calculate the frame costs ahead of time for x264_rc_analyse_slice while we still have lowres */
if( h->param.rc.i_rc_method != X264_RC_CQP )
{
x264_mb_analysis_t a;
int p0, p1, b;
p1 = b = bframes + 1;
x264_lowres_context_init( h, &a );
frames[0] = h->lookahead->last_nonb;
memcpy( &frames[1], h->lookahead->next.list, (bframes+1) * sizeof(x264_frame_t*) );
if( IS_X264_TYPE_I( h->lookahead->next.list[bframes]->i_type ) )
p0 = bframes + 1;
else // P
p0 = 0;
x264_slicetype_frame_cost( h, &a, frames, p0, p1, b, 0 );
if( (p0 != p1 || bframes) && h->param.rc.i_vbv_buffer_size )
{
/* We need the intra costs for row SATDs. */
x264_slicetype_frame_cost( h, &a, frames, b, b, b, 0 );
/* We need B-frame costs for row SATDs. */
p0 = 0;
for( b = 1; b <= bframes; b++ )
{
if( frames[b]->i_type == X264_TYPE_B )
for( p1 = b; frames[p1]->i_type == X264_TYPE_B; )
p1++;
else
p1 = bframes + 1;
x264_slicetype_frame_cost( h, &a, frames, p0, p1, b, 0 );
if( frames[b]->i_type == X264_TYPE_BREF )
p0 = b;
}
}
}
/* Analyse for weighted P frames */
if( !h->param.rc.b_stat_read && h->lookahead->next.list[bframes]->i_type == X264_TYPE_P
&& h->param.analyse.i_weighted_pred >= X264_WEIGHTP_SIMPLE )
{
x264_emms();
x264_weights_analyse( h, h->lookahead->next.list[bframes], h->lookahead->last_nonb, 0 );
}
/* shift sequence to coded order.
use a small temporary list to avoid shifting the entire next buffer around */
int i_coded = h->lookahead->next.list[0]->i_frame;
if( bframes )
{
int idx_list[] = { brefs+1, 1 };
for( int i = 0; i < bframes; i++ )
{
int idx = idx_list[h->lookahead->next.list[i]->i_type == X264_TYPE_BREF]++;
frames[idx] = h->lookahead->next.list[i];
frames[idx]->i_reordered_pts = h->lookahead->next.list[idx]->i_pts;
}
frames[0] = h->lookahead->next.list[bframes];
frames[0]->i_reordered_pts = h->lookahead->next.list[0]->i_pts;
memcpy( h->lookahead->next.list, frames, (bframes+1) * sizeof(x264_frame_t*) );
}
for( int i = 0; i <= bframes; i++ )
{
h->lookahead->next.list[i]->i_coded = i_coded++;
if( i )
{
x264_calculate_durations( h, h->lookahead->next.list[i], h->lookahead->next.list[i-1], &h->i_cpb_delay, &h->i_coded_fields );
h->lookahead->next.list[0]->f_planned_cpb_duration[i-1] = (double)h->lookahead->next.list[i]->i_cpb_duration *
h->sps->vui.i_num_units_in_tick / h->sps->vui.i_time_scale;
}
else
x264_calculate_durations( h, h->lookahead->next.list[i], NULL, &h->i_cpb_delay, &h->i_coded_fields );
}
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
//分析帧的类型（I、B、P）
void x264_slicetype_analyse( x264_t *h, int intra_minigop )
{
x264_mb_analysis_t a;
x264_frame_t *frames[X264_LOOKAHEAD_MAX+3] = { NULL, };
int num_frames, orig_num_frames, keyint_limit, framecnt;
int i_mb_count = NUM_MBS;
int cost1p0, cost2p0, cost1b1, cost2p1;
// 确定最大的搜索长度
// 在我的调试当中， h->lookahead->next.i_size = 4
int i_max_search = X264_MIN( h->lookahead->next.i_size, X264_LOOKAHEAD_MAX );
int vbv_lookahead = h->param.rc.i_vbv_buffer_size && h->param.rc.i_lookahead;
/* For determinism we should limit the search to the number of frames lookahead has for sure
* in h->lookahead->next.list buffer, except at the end of stream.
* For normal calls with (intra_minigop == 0) that is h->lookahead->i_slicetype_length + 1 frames.
* And for I-frame calls (intra_minigop != 0) we already removed intra_minigop frames from there. */
if( h->param.b_deterministic )
i_max_search = X264_MIN( i_max_search, h->lookahead->i_slicetype_length + 1 - intra_minigop );
int keyframe = !!intra_minigop;
assert( h->frames.b_have_lowres );
if( !h->lookahead->last_nonb )
return;
//frames[0]指向上一次的非B帧
frames[0] = h->lookahead->last_nonb;
//frames[] 依次指向 lookahead->next链表中的帧
for( framecnt = 0; framecnt < i_max_search && h->lookahead->next.list[framecnt]->i_type == X264_TYPE_AUTO; framecnt++ )
frames[framecnt+1] = h->lookahead->next.list[framecnt];
x264_lowres_context_init( h, &a );
if( !framecnt )
{
if( h->param.rc.b_mb_tree )
x264_macroblock_tree( h, &a, frames, 0, keyframe );
return;
}
keyint_limit = h->param.i_keyint_max - frames[0]->i_frame + h->lookahead->i_last_keyframe - 1;
orig_num_frames = num_frames = h->param.b_intra_refresh ? framecnt : X264_MIN( framecnt, keyint_limit );
/* This is important psy-wise: if we have a non-scenecut keyframe,
* there will be significant visual artifacts if the frames just before
* go down in quality due to being referenced less, despite it being
* more RD-optimal. */
if( (h->param.analyse.b_psy && h->param.rc.b_mb_tree) || vbv_lookahead )
num_frames = framecnt;
else if( h->param.b_open_gop && num_frames < framecnt )
num_frames++;
else if( num_frames == 0 )
{
frames[1]->i_type = X264_TYPE_I;
return;
}
int num_bframes = 0;
int num_analysed_frames = num_frames;
int reset_start;
//通过scenecut()函数判断是否有场景切换，从而确定I帧
if( h->param.i_scenecut_threshold && scenecut( h, &a, frames, 0, 1, 1, orig_num_frames, i_max_search ) )
{
frames[1]->i_type = X264_TYPE_I;
return;
}
#if HAVE_OPENCL
x264_opencl_slicetype_prep( h, frames, num_frames, a.i_lambda );
#endif
//允许有B帧的时候
if( h->param.i_bframe )
{
if( h->param.i_bframe_adaptive == X264_B_ADAPT_TRELLIS )
{
if( num_frames > 1 )
{
char best_paths[X264_BFRAME_MAX+1][X264_LOOKAHEAD_MAX+1] = {"","P"};
int best_path_index = num_frames % (X264_BFRAME_MAX+1);
/* Perform the frametype analysis. */
for( int j = 2; j <= num_frames; j++ )
x264_slicetype_path( h, &a, frames, j, best_paths );
num_bframes = strspn( best_paths[best_path_index], "B" );
/* Load the results of the analysis into the frame types. */
for( int j = 1; j < num_frames; j++ )
frames[j]->i_type = best_paths[best_path_index][j-1] == 'B' ? X264_TYPE_B : X264_TYPE_P;
}
frames[num_frames]->i_type = X264_TYPE_P;
}
else if( h->param.i_bframe_adaptive == X264_B_ADAPT_FAST )
{
for( int i = 0; i <= num_frames-2; )
{
//i+2作为Ｐ帧编码的代价
//注：i+2始终为P帧
cost2p1 = x264_slicetype_frame_cost( h, &a, frames, i+0, i+2, i+2, 1 );
if( frames[i+2]->i_intra_mbs[2] > i_mb_count / 2 )
{
frames[i+1]->i_type = X264_TYPE_P;
frames[i+2]->i_type = X264_TYPE_P;
i += 2;
continue;
}
#if HAVE_OPENCL
if( h->param.b_opencl )
{
int b_work_done = 0;
b_work_done |= x264_opencl_precalculate_frame_cost(h, frames, a.i_lambda, i+0, i+2, i+1 );
b_work_done |= x264_opencl_precalculate_frame_cost(h, frames, a.i_lambda, i+0, i+1, i+1 );
b_work_done |= x264_opencl_precalculate_frame_cost(h, frames, a.i_lambda, i+1, i+2, i+2 );
if( b_work_done )
x264_opencl_flush( h );
}
#endif
//计算代价
//x264_slicetype_frame_cost(,,,p0,p1,b,)
//p0 b p1
//p1!=b为B帧，否则为P帧
// i + 1 作为B帧编码的代价
cost1b1 = x264_slicetype_frame_cost( h, &a, frames, i+0, i+2, i+1, 0 );
// i + 1 作为P帧编码的代价
cost1p0 = x264_slicetype_frame_cost( h, &a, frames, i+0, i+1, i+1, 0 );
// i + 2 作为P帧编码的代价
cost2p0 = x264_slicetype_frame_cost( h, &a, frames, i+1, i+2, i+2, 0 );
//如果i+1作为P帧编码的代价　+ i+2作为P帧编码的代价
//小于 i+1作为B帧编码的代价
+ i+2作为P帧编码的代价
if( cost1p0 + cost2p0 < cost1b1 + cost2p1 )
{
//那么i+1将作为P帧编码
//然后直接continue
frames[i+1]->i_type = X264_TYPE_P;
i += 1;
continue;
}
// arbitrary and untuned
#define INTER_THRESH 300
#define P_SENS_BIAS (50 - h->param.i_bframe_bias)
// i+1 将作为B帧编码
frames[i+1]->i_type = X264_TYPE_B;
int j;
for( j = i+2; j <= X264_MIN( i+h->param.i_bframe, num_frames-1 ); j++ )
{
int pthresh = X264_MAX(INTER_THRESH - P_SENS_BIAS * (j-i-1), INTER_THRESH/10);
// 预测j+1作为P帧编码代价
int pcost = x264_slicetype_frame_cost( h, &a, frames, i+0, j+1, j+1, 1 );
// 如果pcost 满足下述条件， 则确定了一个P帧，跳出循环
if( pcost > pthresh*i_mb_count || frames[j+1]->i_intra_mbs[j-i+1] > i_mb_count/3 )
break;
// 否则就是B帧
frames[j]->i_type = X264_TYPE_B;
}
// 将j帧确定为P帧
frames[j]->i_type = X264_TYPE_P;
i = j;
}
// 最后一帧确定为P帧
frames[num_frames]->i_type = X264_TYPE_P;
num_bframes = 0;
// 确定有多少个B帧
while( num_bframes < num_frames && frames[num_bframes+1]->i_type == X264_TYPE_B )
num_bframes++;
}
else
{
// 确定多少B帧
num_bframes = X264_MIN(num_frames-1, h->param.i_bframe);
// 每num_bframes + 1一个P帧， 其余皆为B帧
for( int j = 1; j < num_frames; j++ )
frames[j]->i_type = (j%(num_bframes+1)) ? X264_TYPE_B : X264_TYPE_P;
// 最后一帧为P帧
frames[num_frames]->i_type = X264_TYPE_P;
}
/* Check scenecut on the first minigop. */
// 如果B帧中， 有帧有场景切换， 则改变其为P帧
for( int j = 1; j < num_bframes+1; j++ )
if( h->param.i_scenecut_threshold && scenecut( h, &a, frames, j, j+1, 0, orig_num_frames, i_max_search ) )
{
frames[j]->i_type = X264_TYPE_P;
num_analysed_frames = j;
break;
}
reset_start = keyframe ? 1 : X264_MIN( num_bframes+2, num_analysed_frames+1 );
}
else
{
//h->param.i_bframe为 0
//则所有的帧皆为P帧
for( int j = 1; j <= num_frames; j++ )
frames[j]->i_type = X264_TYPE_P;
reset_start = !keyframe + 1;
num_bframes = 0;
}
/* Perform the actual macroblock tree analysis.
* Don't go farther than the maximum keyframe interval; this helps in short GOPs. */
if( h->param.rc.b_mb_tree )
x264_macroblock_tree( h, &a, frames, X264_MIN(num_frames, h->param.i_keyint_max), keyframe );
/* Enforce keyframe limit. */
if( !h->param.b_intra_refresh )
for( int i = keyint_limit+1; i <= num_frames; i += h->param.i_keyint_max )
{
//迫使为I帧
frames[i]->i_type = X264_TYPE_I;
reset_start = X264_MIN( reset_start, i+1 );
if( h->param.b_open_gop && h->param.b_bluray_compat )
while( IS_X264_TYPE_B( frames[i-1]->i_type ) )
i--;
}
if( vbv_lookahead )
x264_vbv_lookahead( h, &a, frames, num_frames, keyframe );
/* Restore frametypes for all frames that haven't actually been decided yet. */
for( int j = reset_start; j <= num_frames; j++ )
frames[j]->i_type = X264_TYPE_AUTO;
#if HAVE_OPENCL
x264_opencl_slicetype_end( h );
#endif
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
//一帧图像的开销
//x264_slicetype_frame_cost(,,,p0,p1,b,)
// p0 b p1
static int x264_slicetype_frame_cost( x264_t *h, x264_mb_analysis_t *a,
x264_frame_t **frames, int p0, int p1, int b,
int b_intra_penalty )
{
int i_score = 0;
int do_search[2];
const x264_weight_t *w = x264_weight_none;
x264_frame_t *fenc = frames[b];
/* Check whether we already evaluated this frame
* If we have tried this frame as P, then we have also tried
* the preceding frames as B. (is this still true?) */
/* Also check that we already calculated the row SATDs for the current frame. */
//如果已经计算过就不用算了
if( fenc->i_cost_est[b-p0][p1-b] >= 0 && (!h->param.rc.i_vbv_buffer_size || fenc->i_row_satds[b-p0][p1-b][0] != -1) )
i_score = fenc->i_cost_est[b-p0][p1-b];
else
{
int dist_scale_factor = 128;
/* For each list, check to see whether we have lowres motion-searched this reference frame before. */
do_search[0] = b != p0 && fenc->lowres_mvs[0][b-p0-1][0][0] == 0x7FFF;
do_search[1] = b != p1 && fenc->lowres_mvs[1][p1-b-1][0][0] == 0x7FFF;
if( do_search[0] )
{
if( h->param.analyse.i_weighted_pred && b == p1 )
{
x264_emms();
x264_weights_analyse( h, fenc, frames[p0], 1 );
w = fenc->weight[0];
}
fenc->lowres_mvs[0][b-p0-1][0][0] = 0;
}
if( do_search[1] ) fenc->lowres_mvs[1][p1-b-1][0][0] = 0;
if( p1 != p0 )
dist_scale_factor = ( ((b-p0) << 8) + ((p1-p0) >> 1) ) / (p1-p0);
int output_buf_size = h->mb.i_mb_height + (NUM_INTS + PAD_SIZE) * h->param.i_lookahead_threads;
int *output_inter[X264_LOOKAHEAD_THREAD_MAX+1];
int *output_intra[X264_LOOKAHEAD_THREAD_MAX+1];
output_inter[0] = h->scratch_buffer2;
output_intra[0] = output_inter[0] + output_buf_size;
#if HAVE_OPENCL
if( h->param.b_opencl )
{
x264_opencl_lowres_init(h, fenc, a->i_lambda );
if( do_search[0] )
{
x264_opencl_lowres_init( h, frames[p0], a->i_lambda );
x264_opencl_motionsearch( h, frames, b, p0, 0, a->i_lambda, w );
}
if( do_search[1] )
{
x264_opencl_lowres_init( h, frames[p1], a->i_lambda );
x264_opencl_motionsearch( h, frames, b, p1, 1, a->i_lambda, NULL );
}
if( b != p0 )
x264_opencl_finalize_cost( h, a->i_lambda, frames, p0, p1, b, dist_scale_factor );
x264_opencl_flush( h );
i_score = fenc->i_cost_est[b-p0][p1-b];
}
else
#endif
{
if( h->param.i_lookahead_threads > 1 )
{
x264_slicetype_slice_t s[X264_LOOKAHEAD_THREAD_MAX];
for( int i = 0; i < h->param.i_lookahead_threads; i++ )
{
x264_t *t = h->lookahead_thread[i];
/* FIXME move this somewhere else */
t->mb.i_me_method = h->mb.i_me_method;
t->mb.i_subpel_refine = h->mb.i_subpel_refine;
t->mb.b_chroma_me = h->mb.b_chroma_me;
s[i] = (x264_slicetype_slice_t){ t, a, frames, p0, p1, b, dist_scale_factor, do_search, w,
output_inter[i], output_intra[i] };
t->i_threadslice_start = ((h->mb.i_mb_height *
i
+ h->param.i_lookahead_threads/2) / h->param.i_lookahead_threads);
t->i_threadslice_end
= ((h->mb.i_mb_height * (i+1) + h->param.i_lookahead_threads/2) / h->param.i_lookahead_threads);
int thread_height = t->i_threadslice_end - t->i_threadslice_start;
int thread_output_size = thread_height + NUM_INTS;
memset( output_inter[i], 0, thread_output_size * sizeof(int) );
memset( output_intra[i], 0, thread_output_size * sizeof(int) );
output_inter[i][NUM_ROWS] = output_intra[i][NUM_ROWS] = thread_height;
output_inter[i+1] = output_inter[i] + thread_output_size + PAD_SIZE;
output_intra[i+1] = output_intra[i] + thread_output_size + PAD_SIZE;
x264_threadpool_run( h->lookaheadpool, (void*)x264_slicetype_slice_cost, &s[i] );
}
for( int i = 0; i < h->param.i_lookahead_threads; i++ )
x264_threadpool_wait( h->lookaheadpool, &s[i] );
}
else
{
h->i_threadslice_start = 0;
h->i_threadslice_end = h->mb.i_mb_height;
memset( output_inter[0], 0, (output_buf_size - PAD_SIZE) * sizeof(int) );
memset( output_intra[0], 0, (output_buf_size - PAD_SIZE) * sizeof(int) );
output_inter[0][NUM_ROWS] = output_intra[0][NUM_ROWS] = h->mb.i_mb_height;
//作为参数的结构体
x264_slicetype_slice_t s = (x264_slicetype_slice_t){ h, a, frames, p0, p1, b, dist_scale_factor, do_search, w,
output_inter[0], output_intra[0] };
//一个slice的开销
//输入输出参数都在s结构体中
x264_slicetype_slice_cost( &s );
}
/* Sum up accumulators */
if( b == p1 )
fenc->i_intra_mbs[b-p0] = 0;
if( !fenc->b_intra_calculated )
{
fenc->i_cost_est[0][0] = 0;
fenc->i_cost_est_aq[0][0] = 0;
}
fenc->i_cost_est[b-p0][p1-b] = 0;
fenc->i_cost_est_aq[b-p0][p1-b] = 0;
int *row_satd_inter = fenc->i_row_satds[b-p0][p1-b];
int *row_satd_intra = fenc->i_row_satds[0][0];
for( int i = 0; i < h->param.i_lookahead_threads; i++ )
{
//累加output_inter[]或output_intra[]
//这2个变量中存储了整帧的开销
if( b == p1 )
fenc->i_intra_mbs[b-p0] += output_inter[i][INTRA_MBS];
if( !fenc->b_intra_calculated )
{
//帧内编码的代价
fenc->i_cost_est[0][0] += output_intra[i][COST_EST];
fenc->i_cost_est_aq[0][0] += output_intra[i][COST_EST_AQ];
}
//帧间编码的代价
fenc->i_cost_est[b-p0][p1-b] += output_inter[i][COST_EST];
fenc->i_cost_est_aq[b-p0][p1-b] += output_inter[i][COST_EST_AQ];
if( h->param.rc.i_vbv_buffer_size )
{
int row_count = output_inter[i][NUM_ROWS];
memcpy( row_satd_inter, output_inter[i] + NUM_INTS, row_count * sizeof(int) );
if( !fenc->b_intra_calculated )
memcpy( row_satd_intra, output_intra[i] + NUM_INTS, row_count * sizeof(int) );
row_satd_inter += row_count;
row_satd_intra += row_count;
}
}
//一帧的开销
i_score = fenc->i_cost_est[b-p0][p1-b];
if( b != p1 )//B帧
i_score = (uint64_t)i_score * 100 / (120 + h->param.i_bframe_bias);
else
fenc->b_intra_calculated = 1;
fenc->i_cost_est[b-p0][p1-b] = i_score;
x264_emms();
}
}
if( b_intra_penalty )
{
// arbitrary penalty for I-blocks after B-frames
int nmb = NUM_MBS;
i_score += (uint64_t)i_score * fenc->i_intra_mbs[b-p0] / (nmb * 8);
}
//返回一帧的开销值
return i_score;
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
//一个slice的开销
static void x264_slicetype_slice_cost( x264_slicetype_slice_t *s )
{
x264_t *h = s->h;
/* Lowres lookahead goes backwards because the MVs are used as predictors in the main encode.
* This considerably improves MV prediction overall. */
/* The edge mbs seem to reduce the predictive quality of the
* whole frame's score, but are needed for a spatial distribution. */
int do_edges = h->param.rc.b_mb_tree || h->param.rc.i_vbv_buffer_size || h->mb.i_mb_width <= 2 || h->mb.i_mb_height <= 2;
int start_y = X264_MIN( h->i_threadslice_end - 1, h->mb.i_mb_height - 2 + do_edges );
int end_y = X264_MAX( h->i_threadslice_start, 1 - do_edges );
int start_x = h->mb.i_mb_width - 2 + do_edges;
int end_x = 1 - do_edges;
//逐个计算每个MB的开销
for( h->mb.i_mb_y = start_y; h->mb.i_mb_y >= end_y; h->mb.i_mb_y-- )
for( h->mb.i_mb_x = start_x; h->mb.i_mb_x >= end_x; h->mb.i_mb_x-- )
x264_slicetype_mb_cost( h, s->a, s->frames, s->p0, s->p1, s->b, s->dist_scale_factor,
s->do_search, s->w, s->output_inter, s->output_intra );
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
//一个MB的开销
static void x264_slicetype_mb_cost( x264_t *h, x264_mb_analysis_t *a,
x264_frame_t **frames, int p0, int p1, int b,
int dist_scale_factor, int do_search[2], const x264_weight_t *w,
int *output_inter, int *output_intra )
{
x264_frame_t *fref0 = frames[p0];
x264_frame_t *fref1 = frames[p1];
x264_frame_t *fenc
= frames[b];
const int b_bidir = (b < p1);
const int i_mb_x = h->mb.i_mb_x;
const int i_mb_y = h->mb.i_mb_y;
const int i_mb_stride = h->mb.i_mb_width;
const int i_mb_xy = i_mb_x + i_mb_y * i_mb_stride;
const int i_stride = fenc->i_stride_lowres;
const int i_pel_offset = 8 * (i_mb_x + i_mb_y * i_stride);
const int i_bipred_weight = h->param.analyse.b_weighted_bipred ? 64 - (dist_scale_factor>>2) : 32;
int16_t (*fenc_mvs[2])[2] = { &fenc->lowres_mvs[0][b-p0-1][i_mb_xy], &fenc->lowres_mvs[1][p1-b-1][i_mb_xy] };
int (*fenc_costs[2]) = { &fenc->lowres_mv_costs[0][b-p0-1][i_mb_xy], &fenc->lowres_mv_costs[1][p1-b-1][i_mb_xy] };
int b_frame_score_mb = (i_mb_x > 0 && i_mb_x < h->mb.i_mb_width - 1 &&
i_mb_y > 0 && i_mb_y < h->mb.i_mb_height - 1) ||
h->mb.i_mb_width <= 2 || h->mb.i_mb_height <= 2;
ALIGNED_ARRAY_16( pixel, pix1,[9*FDEC_STRIDE] );
pixel *pix2 = pix1+8;
x264_me_t m[2];
int i_bcost = COST_MAX;
int list_used = 0;
/* A small, arbitrary bias to avoid VBV problems caused by zero-residual lookahead blocks. */
int lowres_penalty = 4;
//计算只涉及一个分量
h->mb.pic.p_fenc[0] = h->mb.pic.fenc_buf;
//从低分辨率（1/2线性内插）图像中拷贝数据
h->mc.copy[PIXEL_8x8]( h->mb.pic.p_fenc[0], FENC_STRIDE, &fenc->lowres[0][i_pel_offset], i_stride, 8 );
if( p0 == p1 )
goto lowres_intra_mb;
// no need for h->mb.mv_min[]
h->mb.mv_limit_fpel[0][0] = -8*h->mb.i_mb_x - 4;
h->mb.mv_limit_fpel[1][0] = 8*( h->mb.i_mb_width - h->mb.i_mb_x - 1 ) + 4;
h->mb.mv_min_spel[0] = 4*( h->mb.mv_limit_fpel[0][0] - 8 );
h->mb.mv_max_spel[0] = 4*( h->mb.mv_limit_fpel[1][0] + 8 );
if( h->mb.i_mb_x >= h->mb.i_mb_width - 2 )
{
h->mb.mv_limit_fpel[0][1] = -8*h->mb.i_mb_y - 4;
h->mb.mv_limit_fpel[1][1] = 8*( h->mb.i_mb_height - h->mb.i_mb_y - 1 ) + 4;
h->mb.mv_min_spel[1] = 4*( h->mb.mv_limit_fpel[0][1] - 8 );
h->mb.mv_max_spel[1] = 4*( h->mb.mv_limit_fpel[1][1] + 8 );
}
#define LOAD_HPELS_LUMA(dst, src) 
{ 
(dst)[0] = &(src)[0][i_pel_offset]; 
(dst)[1] = &(src)[1][i_pel_offset]; 
(dst)[2] = &(src)[2][i_pel_offset]; 
(dst)[3] = &(src)[3][i_pel_offset]; 
}
#define LOAD_WPELS_LUMA(dst,src) 
(dst) = &(src)[i_pel_offset];
#define CLIP_MV( mv ) 
{ 
mv[0] = x264_clip3( mv[0], h->mb.mv_min_spel[0], h->mb.mv_max_spel[0] ); 
mv[1] = x264_clip3( mv[1], h->mb.mv_min_spel[1], h->mb.mv_max_spel[1] ); 
}
#define TRY_BIDIR( mv0, mv1, penalty ) 
{ 
int i_cost; 
if( h->param.analyse.i_subpel_refine <= 1 ) 
{ 
int hpel_idx1 = (((mv0)[0]&2)>>1) + ((mv0)[1]&2); 
int hpel_idx2 = (((mv1)[0]&2)>>1) + ((mv1)[1]&2); 
pixel *src1 = m[0].p_fref[hpel_idx1] + ((mv0)[0]>>2) + ((mv0)[1]>>2) * m[0].i_stride[0]; 
pixel *src2 = m[1].p_fref[hpel_idx2] + ((mv1)[0]>>2) + ((mv1)[1]>>2) * m[1].i_stride[0]; 
h->mc.avg[PIXEL_8x8]( pix1, 16, src1, m[0].i_stride[0], src2, m[1].i_stride[0], i_bipred_weight ); 
} 
else 
{ 
intptr_t stride1 = 16, stride2 = 16; 
pixel *src1, *src2; 
src1 = h->mc.get_ref( pix1, &stride1, m[0].p_fref, m[0].i_stride[0], 
(mv0)[0], (mv0)[1], 8, 8, w ); 
src2 = h->mc.get_ref( pix2, &stride2, m[1].p_fref, m[1].i_stride[0], 
(mv1)[0], (mv1)[1], 8, 8, w ); 
h->mc.avg[PIXEL_8x8]( pix1, 16, src1, stride1, src2, stride2, i_bipred_weight ); 
} 
i_cost = penalty * a->i_lambda + h->pixf.mbcmp[PIXEL_8x8]( 
m[0].p_fenc[0], FENC_STRIDE, pix1, 16 ); 
COPY2_IF_LT( i_bcost, i_cost, list_used, 3 ); 
}
//帧间编码（后面还有帧内编码）
//处理m[0]
m[0].i_pixel = PIXEL_8x8;
m[0].p_cost_mv = a->p_cost_mv;
m[0].i_stride[0] = i_stride;
m[0].p_fenc[0] = h->mb.pic.p_fenc[0];
m[0].weight = w;
m[0].i_ref = 0;
//加载1/2插值像素点
LOAD_HPELS_LUMA( m[0].p_fref, fref0->lowres );
m[0].p_fref_w = m[0].p_fref[0];
if( w[0].weightfn )
LOAD_WPELS_LUMA( m[0].p_fref_w, fenc->weighted[0] );
//双线预测，处理m[1]
if( b_bidir )
{
int16_t *mvr = fref1->lowres_mvs[0][p1-p0-1][i_mb_xy];
ALIGNED_ARRAY_8( int16_t, dmv,[2],[2] );
m[1].i_pixel = PIXEL_8x8;
m[1].p_cost_mv = a->p_cost_mv;
m[1].i_stride[0] = i_stride;
m[1].p_fenc[0] = h->mb.pic.p_fenc[0];
m[1].i_ref = 0;
m[1].weight = x264_weight_none;
LOAD_HPELS_LUMA( m[1].p_fref, fref1->lowres );
m[1].p_fref_w = m[1].p_fref[0];
dmv[0][0] = ( mvr[0] * dist_scale_factor + 128 ) >> 8;
dmv[0][1] = ( mvr[1] * dist_scale_factor + 128 ) >> 8;
dmv[1][0] = dmv[0][0] - mvr[0];
dmv[1][1] = dmv[0][1] - mvr[1];
CLIP_MV( dmv[0] );
CLIP_MV( dmv[1] );
if( h->param.analyse.i_subpel_refine <= 1 )
M64( dmv ) &= ~0x0001000100010001ULL; /* mv & ~1 */
//双向预测，其中包含了mc.avg[PIXEL_8x8]()
TRY_BIDIR( dmv[0], dmv[1], 0 );
if( M64( dmv ) )
{
int i_cost;
h->mc.avg[PIXEL_8x8]( pix1, 16, m[0].p_fref[0], m[0].i_stride[0], m[1].p_fref[0], m[1].i_stride[0], i_bipred_weight );
i_cost = h->pixf.mbcmp[PIXEL_8x8]( m[0].p_fenc[0], FENC_STRIDE, pix1, 16 );
COPY2_IF_LT( i_bcost, i_cost, list_used, 3 );
}
}
for( int l = 0; l < 1 + b_bidir; l++ )
{
if( do_search[l] )
{
int i_mvc = 0;
int16_t (*fenc_mv)[2] = fenc_mvs[l];
ALIGNED_4( int16_t mvc[4][2] );
/* Reverse-order MV prediction. */
M32( mvc[0] ) = 0;
M32( mvc[2] ) = 0;
#define MVC(mv) { CP32( mvc[i_mvc], mv ); i_mvc++; }
if( i_mb_x < h->mb.i_mb_width - 1 )
MVC( fenc_mv[1] );
if( i_mb_y < h->i_threadslice_end - 1 )
{
MVC( fenc_mv[i_mb_stride] );
if( i_mb_x > 0 )
MVC( fenc_mv[i_mb_stride-1] );
if( i_mb_x < h->mb.i_mb_width - 1 )
MVC( fenc_mv[i_mb_stride+1] );
}
#undef MVC
if( i_mvc <= 1 )
CP32( m[l].mvp, mvc[0] );
else
x264_median_mv( m[l].mvp, mvc[0], mvc[1], mvc[2] );
/* Fast skip for cases of near-zero residual.
Shortcut: don't bother except in the mv0 case,
* since anything else is likely to have enough residual to not trigger the skip. */
if( !M32( m[l].mvp ) )
{
m[l].cost = h->pixf.mbcmp[PIXEL_8x8]( m[l].p_fenc[0], FENC_STRIDE, m[l].p_fref[0], m[l].i_stride[0] );
if( m[l].cost < 64 )
{
M32( m[l].mv ) = 0;
goto skip_motionest;
}
}
//运动搜索，开销存在m[l].cost中
x264_me_search( h, &m[l], mvc, i_mvc );
m[l].cost -= a->p_cost_mv[0]; // remove mvcost from skip mbs
if( M32( m[l].mv ) )
m[l].cost += 5 * a->i_lambda;
skip_motionest:
CP32( fenc_mvs[l], m[l].mv );
*fenc_costs[l] = m[l].cost;
}
else
{
CP32( m[l].mv, fenc_mvs[l] );
m[l].cost = *fenc_costs[l];
}
//如果更小就拷贝
//帧间编码开销，存储于i_bcost
COPY2_IF_LT( i_bcost, m[l].cost, list_used, l+1 );
}
if( b_bidir && ( M32( m[0].mv ) || M32( m[1].mv ) ) )
TRY_BIDIR( m[0].mv, m[1].mv, 5 );
lowres_intra_mb:
//帧内编码
if( !fenc->b_intra_calculated )
{
ALIGNED_ARRAY_16( pixel, edge,[36] );
pixel *pix = &pix1[8+FDEC_STRIDE];
pixel *src = &fenc->lowres[0][i_pel_offset];
const int intra_penalty = 5 * a->i_lambda;
int satds[3];
int pixoff = 4 / sizeof(pixel);
/* Avoid store forwarding stalls by writing larger chunks */
memcpy( pix-FDEC_STRIDE, src-i_stride, 16 * sizeof(pixel) );
for( int i = -1; i < 8; i++ )
M32( &pix[i*FDEC_STRIDE-pixoff] ) = M32( &src[i*i_stride-pixoff] );
//8x8块的SAD/SATD计算
//x3打表计算了V，H，DC三种模式，开销存储在satds[3]数组的3个元素中
h->pixf.intra_mbcmp_x3_8x8c( h->mb.pic.p_fenc[0], pix, satds );
//帧内编码开销，存储于i_icost
int i_icost = X264_MIN3( satds[0], satds[1], satds[2] );
if( h->param.analyse.i_subpel_refine > 1 )
{
h->predict_8x8c[I_PRED_CHROMA_P]( pix );
int satd = h->pixf.mbcmp[PIXEL_8x8]( pix, FDEC_STRIDE, h->mb.pic.p_fenc[0], FENC_STRIDE );
i_icost = X264_MIN( i_icost, satd );
h->predict_8x8_filter( pix, edge, ALL_NEIGHBORS, ALL_NEIGHBORS );
for( int i = 3; i < 9; i++ )
{
h->predict_8x8[i]( pix, edge );
satd = h->pixf.mbcmp[PIXEL_8x8]( pix, FDEC_STRIDE, h->mb.pic.p_fenc[0], FENC_STRIDE );
i_icost = X264_MIN( i_icost, satd );
}
}
i_icost += intra_penalty + lowres_penalty;
//存一下
fenc->i_intra_cost[i_mb_xy] = i_icost;
int i_icost_aq = i_icost;
if( h->param.rc.i_aq_mode )
i_icost_aq = (i_icost_aq * fenc->i_inv_qscale_factor[i_mb_xy] + 128) >> 8;
output_intra[ROW_SATD] += i_icost_aq;
if( b_frame_score_mb )
{
//累加。[COST_EST]用于整帧的开销计算
output_intra[COST_EST] += i_icost;
output_intra[COST_EST_AQ] += i_icost_aq;
}
}
i_bcost += lowres_penalty;
/* forbid intra-mbs in B-frames, because it's rare and not worth checking */
/* FIXME: Should we still forbid them now that we cache intra scores? */
if( !b_bidir )
{
int i_icost = fenc->i_intra_cost[i_mb_xy];
//帧内开销比帧间更小，b_intra就会取1
int b_intra = i_icost < i_bcost;
if( b_intra )
{
//赋值给i_bcost
i_bcost = i_icost;
list_used = 0;
}
if( b_frame_score_mb )
output_inter[INTRA_MBS] += b_intra;//[INTRA_MBS]统计有多少个帧内模式的宏块
}
/* In an I-frame, we've already added the results above in the intra section. */
if( p0 != p1 )
{
int i_bcost_aq = i_bcost;
if( h->param.rc.i_aq_mode )
i_bcost_aq = (i_bcost_aq * fenc->i_inv_qscale_factor[i_mb_xy] + 128) >> 8;
output_inter[ROW_SATD] += i_bcost_aq;
if( b_frame_score_mb )
{
/* Don't use AQ-weighted costs for slicetype decision, only for ratecontrol. */
//累加。[COST_EST]用于整帧的开销计算
output_inter[COST_EST] += i_bcost;
output_inter[COST_EST_AQ] += i_bcost_aq;
}
}
//存储开销i_bcost
fenc->lowres_costs[b-p0][p1-b][i_mb_xy] = X264_MIN( i_bcost, LOWRES_COST_MASK ) + (list_used << LOWRES_COST_SHIFT);
}
#undef TRY_BIDIR

1
2
3
4
5
6
7
8
9
10
11
//从队列的头部取出一帧
x264_frame_t *x264_frame_shift( x264_frame_t **list )
{
x264_frame_t *frame = list[0];
int i;
for( i = 0; list[i]; i++ )
list[i] = list[i+1];
assert(frame);
return frame;
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
//更新参考帧队列，若为非参考B帧则不更新
//重建帧移植参考帧列表，新建一个重建帧
static inline int x264_reference_update( x264_t *h )
{
//如果不是被参考的帧
if( !h->fdec->b_kept_as_ref )
{
if( h->i_thread_frames > 1 )
{
x264_frame_push_unused( h, h->fdec );
h->fdec = x264_frame_pop_unused( h, 1 );
if( !h->fdec )
return -1;
}
return 0;
}
/* apply mmco from previous frame. */
for( int i = 0; i < h->sh.i_mmco_command_count; i++ )
for( int j = 0; h->frames.reference[j]; j++ )
if( h->frames.reference[j]->i_poc == h->sh.mmco[i].i_poc )
x264_frame_push_unused( h, x264_frame_shift( &h->frames.reference[j] ) );
/* move frame in the buffer */
//重建帧加入参考帧列表
x264_frame_push( h->frames.reference, h->fdec );
//列表满了，则要移除1帧
if( h->frames.reference[h->sps->i_num_ref_frames] )
x264_frame_push_unused( h, x264_frame_shift( h->frames.reference ) );
//重新初始化重建帧fdec
h->fdec = x264_frame_pop_unused( h, 1 );
if( !h->fdec )
return -1;
return 0;
}

1
2
3
4
5
6
7
8
9
10
//清空所有参考帧
static inline void x264_reference_reset( x264_t *h )
{
//把frames.reference[]中所有帧移动到frames.unused[]
while( h->frames.reference[0] )
x264_frame_push_unused( h, x264_frame_pop( h->frames.reference ) );
h->fdec->i_poc =
h->fenc->i_poc = 0;
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
//创建Slice Header
static inline void x264_slice_init( x264_t *h, int i_nal_type, int i_global_qp )
{
/* ------------------------ Create slice header
----------------------- */
if( i_nal_type == NAL_SLICE_IDR )
{
//I帧
//对x264_slice_header_t进行赋值
x264_slice_header_init( h, &h->sh, h->sps, h->pps, h->i_idr_pic_id, h->i_frame_num, i_global_qp );
/* alternate id */
if( h->param.i_avcintra_class )
{
switch( h->i_idr_pic_id )
{
case 5:
h->i_idr_pic_id = 3;
break;
case 3:
h->i_idr_pic_id = 4;
break;
case 4:
default:
h->i_idr_pic_id = 5;
break;
}
}
else
h->i_idr_pic_id ^= 1;
}
else
{
//非IDR帧
x264_slice_header_init( h, &h->sh, h->sps, h->pps, -1, h->i_frame_num, i_global_qp );
//参考帧列表
h->sh.i_num_ref_idx_l0_active = h->i_ref[0] <= 0 ? 1 : h->i_ref[0];
h->sh.i_num_ref_idx_l1_active = h->i_ref[1] <= 0 ? 1 : h->i_ref[1];
if( h->sh.i_num_ref_idx_l0_active != h->pps->i_num_ref_idx_l0_default_active ||
(h->sh.i_type == SLICE_TYPE_B && h->sh.i_num_ref_idx_l1_active != h->pps->i_num_ref_idx_l1_default_active) )
{
h->sh.b_num_ref_idx_override = 1;
}
}
if( h->fenc->i_type == X264_TYPE_BREF && h->param.b_bluray_compat && h->sh.i_mmco_command_count )
{
h->b_sh_backup = 1;
h->sh_backup = h->sh;
}
h->fdec->i_frame_num = h->sh.i_frame_num;
if( h->sps->i_poc_type == 0 )
{
h->sh.i_poc = h->fdec->i_poc;
if( PARAM_INTERLACED )
{
h->sh.i_delta_poc_bottom = h->param.b_tff ? 1 : -1;
h->sh.i_poc += h->sh.i_delta_poc_bottom == -1;
}
else
h->sh.i_delta_poc_bottom = 0;
h->fdec->i_delta_poc[0] = h->sh.i_delta_poc_bottom == -1;
h->fdec->i_delta_poc[1] = h->sh.i_delta_poc_bottom ==
1;
}
else
{
/* Nothing to do ? */
}
//主要对mb结构体赋初值
x264_macroblock_slice_init( h );
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
/* Fill "default" values */
//对x264_slice_header_t进行赋值
static void x264_slice_header_init( x264_t *h, x264_slice_header_t *sh,
x264_sps_t *sps, x264_pps_t *pps,
int i_idr_pic_id, int i_frame, int i_qp )
{
x264_param_t *param = &h->param;
/* First we fill all fields */
sh->sps = sps;
sh->pps = pps;
sh->i_first_mb
= 0;
sh->i_last_mb
= h->mb.i_mb_count - 1;
sh->i_pps_id
= pps->i_id;
sh->i_frame_num = i_frame;
sh->b_mbaff = PARAM_INTERLACED;
sh->b_field_pic = 0;
/* no field support for now */
sh->b_bottom_field = 0; /* not yet used */
sh->i_idr_pic_id = i_idr_pic_id;
/* poc stuff, fixed later */
sh->i_poc = 0;
sh->i_delta_poc_bottom = 0;
sh->i_delta_poc[0] = 0;
sh->i_delta_poc[1] = 0;
sh->i_redundant_pic_cnt = 0;
h->mb.b_direct_auto_write = h->param.analyse.i_direct_mv_pred == X264_DIRECT_PRED_AUTO
&& h->param.i_bframe
&& ( h->param.rc.b_stat_write || !h->param.rc.b_stat_read );
if( !h->mb.b_direct_auto_read && sh->i_type == SLICE_TYPE_B )
{
if( h->fref[1][0]->i_poc_l0ref0 == h->fref[0][0]->i_poc )
{
if( h->mb.b_direct_auto_write )
sh->b_direct_spatial_mv_pred = ( h->stat.i_direct_score[1] > h->stat.i_direct_score[0] );
else
sh->b_direct_spatial_mv_pred = ( param->analyse.i_direct_mv_pred == X264_DIRECT_PRED_SPATIAL );
}
else
{
h->mb.b_direct_auto_write = 0;
sh->b_direct_spatial_mv_pred = 1;
}
}
/* else b_direct_spatial_mv_pred was read from the 2pass statsfile */
sh->b_num_ref_idx_override = 0;
sh->i_num_ref_idx_l0_active = 1;
sh->i_num_ref_idx_l1_active = 1;
sh->b_ref_pic_list_reordering[0] = h->b_ref_reorder[0];
sh->b_ref_pic_list_reordering[1] = h->b_ref_reorder[1];
/* If the ref list isn't in the default order, construct reordering header */
for( int list = 0; list < 2; list++ )
{
if( sh->b_ref_pic_list_reordering[list] )
{
int pred_frame_num = i_frame;
for( int i = 0; i < h->i_ref[list]; i++ )
{
int diff = h->fref[list][i]->i_frame_num - pred_frame_num;
sh->ref_pic_list_order[list][i].idc = ( diff > 0 );
sh->ref_pic_list_order[list][i].arg = (abs(diff) - 1) & ((1 << sps->i_log2_max_frame_num) - 1);
pred_frame_num = h->fref[list][i]->i_frame_num;
}
}
}
sh->i_cabac_init_idc = param->i_cabac_init_idc;
sh->i_qp = SPEC_QP(i_qp);
sh->i_qp_delta = sh->i_qp - pps->i_pic_init_qp;
sh->b_sp_for_swidth = 0;
sh->i_qs_delta = 0;
int deblock_thresh = i_qp + 2 * X264_MIN(param->i_deblocking_filter_alphac0, param->i_deblocking_filter_beta);
/* If effective qp <= 15, deblocking would have no effect anyway */
if( param->b_deblocking_filter && (h->mb.b_variable_qp || 15 < deblock_thresh ) )
sh->i_disable_deblocking_filter_idc = param->b_sliced_threads ? 2 : 0;
else
sh->i_disable_deblocking_filter_idc = 1;
sh->i_alpha_c0_offset = param->i_deblocking_filter_alphac0 << 1;
sh->i_beta_offset = param->i_deblocking_filter_beta << 1;
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
//真正的编码——编码1个图像帧
//注意“slice”后面有一个“s”
//它其中又调用了一个x264_slice_write()
//这一点要区分开
static void *x264_slices_write( x264_t *h )
{
int i_slice_num = 0;
int last_thread_mb = h->sh.i_last_mb;
/* init stats */
memset( &h->stat.frame, 0, sizeof(h->stat.frame) );
h->mb.b_reencode_mb = 0;
//循环每一个slice（一幅图像可以由多个Slice构成）
while( h->sh.i_first_mb + SLICE_MBAFF*h->mb.i_mb_stride <= last_thread_mb )
{
h->sh.i_last_mb = last_thread_mb;
if( !i_slice_num || !x264_frame_new_slice( h, h->fdec ) )
{
if( h->param.i_slice_max_mbs )
{
if( SLICE_MBAFF )
{
// convert first to mbaff form, add slice-max-mbs, then convert back to normal form
int last_mbaff = 2*(h->sh.i_first_mb % h->mb.i_mb_width)
+ h->mb.i_mb_width*(h->sh.i_first_mb / h->mb.i_mb_width)
+ h->param.i_slice_max_mbs - 1;
int last_x = (last_mbaff % (2*h->mb.i_mb_width))/2;
int last_y = (last_mbaff / (2*h->mb.i_mb_width))*2 + 1;
h->sh.i_last_mb = last_x + h->mb.i_mb_stride*last_y;
}
else
{
h->sh.i_last_mb = h->sh.i_first_mb + h->param.i_slice_max_mbs - 1;
if( h->sh.i_last_mb < last_thread_mb && last_thread_mb - h->sh.i_last_mb < h->param.i_slice_min_mbs )
h->sh.i_last_mb = last_thread_mb - h->param.i_slice_min_mbs;
}
i_slice_num++;
}
else if( h->param.i_slice_count && !h->param.b_sliced_threads )
{
int height = h->mb.i_mb_height >> PARAM_INTERLACED;
int width = h->mb.i_mb_width << PARAM_INTERLACED;
i_slice_num++;
h->sh.i_last_mb = (height * i_slice_num + h->param.i_slice_count/2) / h->param.i_slice_count * width - 1;
}
}
h->sh.i_last_mb = X264_MIN( h->sh.i_last_mb, last_thread_mb );
//真正的编码——编码1个Slice
//x264_stack_align()应该是平台优化过程中内存对齐的工作
//实际上就是调用x264_slice_write()
if( x264_stack_align( x264_slice_write, h ) )
goto fail;
//注意这里对i_first_mb进行了赋值
h->sh.i_first_mb = h->sh.i_last_mb + 1;
// if i_first_mb is not the last mb in a row then go to the next mb in MBAFF order
if( SLICE_MBAFF && h->sh.i_first_mb % h->mb.i_mb_width )
h->sh.i_first_mb -= h->mb.i_mb_stride;
}
return (void *)0;
fail:
/* Tell other threads we're done, so they wouldn't wait for it */
if( h->param.b_sliced_threads )
x264_threadslice_cond_broadcast( h, 2 );
return (void *)-1;
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
//结束的时候做一些处理，记录一些统计信息
//pp_nal：输出的NALU
//pic_out：输出的重建帧
static int x264_encoder_frame_end( x264_t *h, x264_t *thread_current,
x264_nal_t **pp_nal, int *pi_nal,
x264_picture_t *pic_out )
{
char psz_message[80];
if( !h->param.b_sliced_threads && h->b_thread_active )
{
h->b_thread_active = 0;
if( (intptr_t)x264_threadpool_wait( h->threadpool, h ) )
return -1;
}
if( !h->out.i_nal )
{
pic_out->i_type = X264_TYPE_AUTO;
return 0;
}
x264_emms();
/* generate buffering period sei and insert it into place */
if( h->i_thread_frames > 1 && h->fenc->b_keyframe && h->sps->vui.b_nal_hrd_parameters_present )
{
x264_hrd_fullness( h );
x264_nal_start( h, NAL_SEI, NAL_PRIORITY_DISPOSABLE );
x264_sei_buffering_period_write( h, &h->out.bs );
if( x264_nal_end( h ) )
return -1;
/* buffering period sei must follow AUD, SPS and PPS and precede all other SEIs */
int idx = 0;
while( h->out.nal[idx].i_type == NAL_AUD ||
h->out.nal[idx].i_type == NAL_SPS ||
h->out.nal[idx].i_type == NAL_PPS )
idx++;
x264_nal_t nal_tmp = h->out.nal[h->out.i_nal-1];
memmove( &h->out.nal[idx+1], &h->out.nal[idx], (h->out.i_nal-idx-1)*sizeof(x264_nal_t) );
h->out.nal[idx] = nal_tmp;
}
//封装一帧数据对应的NALU.
//例如给NALU添加起始码0x00000001
int frame_size = x264_encoder_encapsulate_nals( h, 0 );
if( frame_size < 0 )
return -1;
/* Set output picture properties */
//pic_out为x264_picture_t类型结构体。是libx264对外的结构体
//fenc,fdec是x264_frame_t类型结构体。是libx264的内部结构体
pic_out->i_type = h->fenc->i_type;
pic_out->b_keyframe = h->fenc->b_keyframe;
pic_out->i_pic_struct = h->fenc->i_pic_struct;
pic_out->i_pts = h->fdec->i_pts;
pic_out->i_dts = h->fdec->i_dts;
if( pic_out->i_pts < pic_out->i_dts )
x264_log( h, X264_LOG_WARNING, "invalid DTS: PTS is less than DTSn" );
pic_out->opaque = h->fenc->opaque;
pic_out->img.i_csp = h->fdec->i_csp;
#if HIGH_BIT_DEPTH
pic_out->img.i_csp |= X264_CSP_HIGH_DEPTH;
#endif
pic_out->img.i_plane = h->fdec->i_plane;
//图像数据
for( int i = 0; i < pic_out->img.i_plane; i++ )
{
pic_out->img.i_stride[i] = h->fdec->i_stride[i] * sizeof(pixel);
pic_out->img.plane[i] = (uint8_t*)h->fdec->plane[i];
}
//回收用过的编码帧fenc
x264_frame_push_unused( thread_current, h->fenc );
/* ---------------------- Update encoder state ------------------------- */
/* update rc */
int filler = 0;
if( x264_ratecontrol_end( h, frame_size * 8, &filler ) < 0 )
return -1;
pic_out->hrd_timing = h->fenc->hrd_timing;
pic_out->prop.f_crf_avg = h->fdec->f_crf_avg;
/* Filler in AVC-Intra mode is written as zero bytes to the last slice
* We don't know the size of the last slice until encapsulation so we add filler to the encapsulated NAL */
if( h->param.i_avcintra_class )
{
x264_t *h0 = h->thread[0];
int ret = x264_check_encapsulated_buffer( h, h0, h->out.i_nal, frame_size, frame_size + filler );
if( ret < 0 )
return -1;
memset( h->out.nal[0].p_payload + frame_size, 0, filler );
h->out.nal[h->out.i_nal-1].i_payload += filler;
h->out.nal[h->out.i_nal-1].i_padding = filler;
frame_size += filler;
}
else
{
while( filler > 0 )
{
int f, overhead;
overhead = (FILLER_OVERHEAD - h->param.b_annexb);
if( h->param.i_slice_max_size && filler > h->param.i_slice_max_size )
{
int next_size = filler - h->param.i_slice_max_size;
int overflow = X264_MAX( overhead - next_size, 0 );
f = h->param.i_slice_max_size - overhead - overflow;
}
else
f = X264_MAX( 0, filler - overhead );
if( x264_bitstream_check_buffer_filler( h, f ) )
return -1;
x264_nal_start( h, NAL_FILLER, NAL_PRIORITY_DISPOSABLE );
x264_filler_write( h, &h->out.bs, f );
if( x264_nal_end( h ) )
return -1;
int total_size = x264_encoder_encapsulate_nals( h, h->out.i_nal-1 );
if( total_size < 0 )
return -1;
frame_size += total_size;
filler -= total_size;
}
}
/* End bitstream, set output
*/
*pi_nal = h->out.i_nal;
*pp_nal = h->out.nal;
h->out.i_nal = 0;
x264_noise_reduction_update( h );
/* ---------------------- Compute/Print statistics --------------------- */
x264_thread_sync_stat( h, h->thread[0] );
/* Slice stat */
//stat中存储了统计信息
//帧数+1 （根据类型）
h->stat.i_frame_count[h->sh.i_type]++;
//帧大小
h->stat.i_frame_size[h->sh.i_type] += frame_size;
h->stat.f_frame_qp[h->sh.i_type] += h->fdec->f_qp_avg_aq;
//统计MB个数，把不同类型的累加起来
for( int i = 0; i < X264_MBTYPE_MAX; i++ )
h->stat.i_mb_count[h->sh.i_type][i] += h->stat.frame.i_mb_count[i];
for( int i = 0; i < X264_PARTTYPE_MAX; i++ )
h->stat.i_mb_partition[h->sh.i_type][i] += h->stat.frame.i_mb_partition[i];
for( int i = 0; i < 2; i++ )
h->stat.i_mb_count_8x8dct[i] += h->stat.frame.i_mb_count_8x8dct[i];
for( int i = 0; i < 6; i++ )
h->stat.i_mb_cbp[i] += h->stat.frame.i_mb_cbp[i];
for( int i = 0; i < 4; i++ )
for( int j = 0; j < 13; j++ )
h->stat.i_mb_pred_mode[i][j] += h->stat.frame.i_mb_pred_mode[i][j];
if( h->sh.i_type != SLICE_TYPE_I )
for( int i_list = 0; i_list < 2; i_list++ )
for( int i = 0; i < X264_REF_MAX*2; i++ )
h->stat.i_mb_count_ref[h->sh.i_type][i_list][i] += h->stat.frame.i_mb_count_ref[i_list][i];
for( int i = 0; i < 3; i++ )
h->stat.i_mb_field[i] += h->stat.frame.i_mb_field[i];
if( h->sh.i_type == SLICE_TYPE_P && h->param.analyse.i_weighted_pred >= X264_WEIGHTP_SIMPLE )
{
h->stat.i_wpred[0] += !!h->sh.weight[0][0].weightfn;
h->stat.i_wpred[1] += !!h->sh.weight[0][1].weightfn || !!h->sh.weight[0][2].weightfn;
}
if( h->sh.i_type == SLICE_TYPE_B )
{
h->stat.i_direct_frames[ h->sh.b_direct_spatial_mv_pred ] ++;
if( h->mb.b_direct_auto_write )
{
//FIXME somewhat arbitrary time constants
if( h->stat.i_direct_score[0] + h->stat.i_direct_score[1] > h->mb.i_mb_count )
for( int i = 0; i < 2; i++ )
h->stat.i_direct_score[i] = h->stat.i_direct_score[i] * 9/10;
for( int i = 0; i < 2; i++ )
h->stat.i_direct_score[i] += h->stat.frame.i_direct_score[i];
}
}
else
h->stat.i_consecutive_bframes[h->fenc->i_bframes]++;
psz_message[0] = '';
double dur = h->fenc->f_duration;
h->stat.f_frame_duration[h->sh.i_type] += dur;
//需要计算PSNR
if( h->param.analyse.b_psnr )
{
//SSD（Sum of Squared Difference）即差值的平方和
int64_t ssd[3] =
{
h->stat.frame.i_ssd[0],
h->stat.frame.i_ssd[1],
h->stat.frame.i_ssd[2],
};
int luma_size = h->param.i_width * h->param.i_height;
int chroma_size = CHROMA_SIZE( luma_size );
//SSD是已经在“滤波”环节计算过的
//SSD简单换算成PSNR，调用x264_psnr()
pic_out->prop.f_psnr[0] = x264_psnr( ssd[0], luma_size );
pic_out->prop.f_psnr[1] = x264_psnr( ssd[1], chroma_size );
pic_out->prop.f_psnr[2] = x264_psnr( ssd[2], chroma_size );
//平均值
pic_out->prop.f_psnr_avg = x264_psnr( ssd[0] + ssd[1] + ssd[2], luma_size + chroma_size*2 );
//mean系列的需要累加
h->stat.f_ssd_global[h->sh.i_type]
+= dur * (ssd[0] + ssd[1] + ssd[2]);
h->stat.f_psnr_average[h->sh.i_type] += dur * pic_out->prop.f_psnr_avg;
h->stat.f_psnr_mean_y[h->sh.i_type]
+= dur * pic_out->prop.f_psnr[0];
h->stat.f_psnr_mean_u[h->sh.i_type]
+= dur * pic_out->prop.f_psnr[1];
h->stat.f_psnr_mean_v[h->sh.i_type]
+= dur * pic_out->prop.f_psnr[2];
snprintf( psz_message, 80, " PSNR Y:%5.2f U:%5.2f V:%5.2f", pic_out->prop.f_psnr[0],
pic_out->prop.f_psnr[1],
pic_out->prop.f_psnr[2] );
}
//需要计算SSIM
if( h->param.analyse.b_ssim )
{
//SSIM是已经在“滤波”环节计算过的
pic_out->prop.f_ssim = h->stat.frame.f_ssim / h->stat.frame.i_ssim_cnt;
//mean系列的需要累加
h->stat.f_ssim_mean_y[h->sh.i_type] += pic_out->prop.f_ssim * dur;
snprintf( psz_message + strlen(psz_message), 80 - strlen(psz_message),
" SSIM Y:%.5f", pic_out->prop.f_ssim );
}
psz_message[79] = '';
//Debug时候输出
x264_log( h, X264_LOG_DEBUG,
"frame=%4d QP=%.2f NAL=%d Slice:%c Poc:%-3d I:%-4d P:%-4d SKIP:%-4d size=%d bytes%sn",
h->i_frame,
h->fdec->f_qp_avg_aq,
h->i_nal_ref_idc,
h->sh.i_type == SLICE_TYPE_I ? 'I' : (h->sh.i_type == SLICE_TYPE_P ? 'P' : 'B' ),
h->fdec->i_poc,
h->stat.frame.i_mb_count_i,
h->stat.frame.i_mb_count_p,
h->stat.frame.i_mb_count_skip,
frame_size,
psz_message );
// keep stats all in one place
x264_thread_sync_stat( h->thread[0], h );
// for the use of the next frame
x264_thread_sync_stat( thread_current, h );
#ifdef DEBUG_MB_TYPE
{
static const char mb_chars[] = { 'i', 'i', 'I', 'C', 'P', '8', 'S',
'D', '<', 'X', 'B', 'X', '>', 'B', 'B', 'B', 'B', '8', 'S' };
for( int mb_xy = 0; mb_xy < h->mb.i_mb_width * h->mb.i_mb_height; mb_xy++ )
{
if( h->mb.type[mb_xy] < X264_MBTYPE_MAX && h->mb.type[mb_xy] >= 0 )
fprintf( stderr, "%c ", mb_chars[ h->mb.type[mb_xy] ] );
else
fprintf( stderr, "? " );
if( (mb_xy+1) % h->mb.i_mb_width == 0 )
fprintf( stderr, "n" );
}
}
#endif
/* Remove duplicates, must be done near the end as breaks h->fref0 array
* by freeing some of its pointers. */
for( int i = 0; i < h->i_ref[0]; i++ )
if( h->fref[0][i] && h->fref[0][i]->b_duplicate )
{
x264_frame_push_blank_unused( h, h->fref[0][i] );
h->fref[0][i] = 0;
}
if( h->param.psz_dump_yuv )
x264_frame_dump( h );
x264_emms();
return frame_size;
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
//封装一帧数据对应的NALU.
//例如给NALU添加起始码0x00000001
static int x264_encoder_encapsulate_nals( x264_t *h, int start )
{
x264_t *h0 = h->thread[0];
int nal_size = 0, previous_nal_size = 0;
if( h->param.nalu_process )
{
for( int i = start; i < h->out.i_nal; i++ )
nal_size += h->out.nal[i].i_payload;
return nal_size;
}
for( int i = 0; i < start; i++ )
previous_nal_size += h->out.nal[i].i_payload;
for( int i = start; i < h->out.i_nal; i++ )
nal_size += h->out.nal[i].i_payload;
/* Worst-case NAL unit escaping: reallocate the buffer if it's too small. */
int necessary_size = previous_nal_size + nal_size * 3/2 + h->out.i_nal * 4 + 4 + 64;
for( int i = start; i < h->out.i_nal; i++ )
necessary_size += h->out.nal[i].i_padding;
if( x264_check_encapsulated_buffer( h, h0, start, previous_nal_size, necessary_size ) )
return -1;
uint8_t *nal_buffer = h0->nal_buffer + previous_nal_size;
//一个一个NALU处理
for( int i = start; i < h->out.i_nal; i++ )
{
int old_payload_len = h->out.nal[i].i_payload;
h->out.nal[i].b_long_startcode = !i || h->out.nal[i].i_type == NAL_SPS || h->out.nal[i].i_type == NAL_PPS ||
h->param.i_avcintra_class;
//添加起始码
x264_nal_encode( h, nal_buffer, &h->out.nal[i] );
nal_buffer += h->out.nal[i].i_payload;
if( h->param.i_avcintra_class )
{
h->out.nal[i].i_padding -= h->out.nal[i].i_payload - (old_payload_len + NALU_OVERHEAD);
if( h->out.nal[i].i_padding > 0 )
{
memset( nal_buffer, 0, h->out.nal[i].i_padding );
nal_buffer += h->out.nal[i].i_padding;
h->out.nal[i].i_payload += h->out.nal[i].i_padding;
}
h->out.nal[i].i_padding = X264_MAX( h->out.nal[i].i_padding, 0 );
}
}
x264_emms();
return nal_buffer - (h0->nal_buffer + previous_nal_size);
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
/****************************************************************************
* x264_nal_encode:
****************************************************************************/
//添加起始码
void x264_nal_encode( x264_t *h, uint8_t *dst, x264_nal_t *nal )
{
uint8_t *src = nal->p_payload;
uint8_t *end = nal->p_payload + nal->i_payload;
uint8_t *orig_dst = dst;
//起始码 ============================================
//annexb格式，起始码为0x00000001
if( h->param.b_annexb )
{
if( nal->b_long_startcode )
*dst++ = 0x00;
*dst++ = 0x00;
*dst++ = 0x00;
*dst++ = 0x01;
}
else /* save room for size later */
dst += 4;//mp4格式
//NALU Header =======================================
/* nal header */
*dst++ = ( 0x00 << 7 ) | ( nal->i_ref_idc << 5 ) | nal->i_type;
dst = h->bsf.nal_escape( dst, src, end );
int size = (dst - orig_dst) - 4;
/* Write the size header for mp4/etc */
//重新回到起始码的位置，写入mp4格式的起始码（size大小，不含起始码）
if( !h->param.b_annexb )
{
/* Size doesn't include the size of the header we're writing now. */
orig_dst[0] = size>>24;
orig_dst[1] = size>>16;
orig_dst[2] = size>> 8;
orig_dst[3] = size>> 0;
}
//NALU负载大小，包含起始码
nal->i_payload = size+4;
nal->p_payload = orig_dst;
x264_emms();
}