ffmpeg使用vp8编解码

1. /*
2.  * copyright (c) 2001 Fabrice Bellard
3.  *
4.  * This file is part of FFmpeg.
5.  *
6.  * FFmpeg is free software; you can redistribute it and/or
7.  * modify it under the terms of the GNU Lesser General Public
8.  * License as published by the Free Software Foundation; either
9.  * version 2.1 of the License, or (at your option) any later version.
10.  *
11.  * FFmpeg is distributed in the hope that it will be useful,
12.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14.  * Lesser General Public License for more details.
15.  *
16.  * You should have received a copy of the GNU Lesser General Public
17.  * License along with FFmpeg; if not, write to the Free Software
18.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19.  */
20. #include <stdlib.h>
21. #include <stdio.h>
22. #include <string.h>
23.  
24. #ifdef HAVE_AV_CONFIG_H
25. #undef HAVE_AV_CONFIG_H
26. #endif
27.  
28. #include "libavcodec/avcodec.h"
29. #include "libavutil/mathematics.h"
30.  
31. #define INBUF_SIZE 4096
32. #define AUDIO_INBUF_SIZE 20480
33. #define AUDIO_REFILL_THRESH 4096
34.  
35. /*
36.  * Video encoding example
37.  */
38. static  void video_encode_example ( const  char  *filename )
39. {
40.     AVCodec  *codec ;
41.     AVCodecContext  *c = NULL ;
42.      int i , out_size , size , x , y , outbuf_size ;
43.     FILE  *f ;
44.     AVFrame  *picture ;
45.     uint8_t  *outbuf ,  *picture_buf ;
46.  
47.      printf ( "Video encodingn" ) ;
48.  
49.      /* find the mpeg1 video encoder */
50.     codec  = avcodec_find_encoder (CODEC_ID_VP8 ) ;
51.      if  ( !codec )  {
52.         fprintf (stderr ,  "codec not foundn" ) ;
53.         exit (1 ) ;
54.      }
55.  
56.     c = avcodec_alloc_context ( ) ;
57.     picture = avcodec_alloc_frame ( ) ;
58.  
59.      /* put sample parameters */
60.     c ->bit_rate  =  400000 ;
61.      /* resolution must be a multiple of two */
62.     c ->width  =  352 ;
63.     c ->height  =  288 ;
64.      /* frames per second */
65.     c ->time_base =  (AVRational ) {1 ,25 } ;
66.     c ->gop_size  =  10 ;  /* emit one intra frame every ten frames */
67.     c ->max_b_frames = 1 ;
68.     c ->pix_fmt  = PIX_FMT_YUV420P ;
69.  
70.      /* open it */
71.      if  (avcodec_open (c , codec )  <  0 )  {
72.         fprintf (stderr ,  "could not open codecn" ) ;
73.         exit (1 ) ;
74.      }
75.  
76.     f  = fopen (filename ,  "wb" ) ;
77.      if  ( !f )  {
78.         fprintf (stderr ,  "could not open %sn" , filename ) ;
79.         exit (1 ) ;
80.      }
81.  
82.      /* alloc image and output buffer */
83.     outbuf_size  =  100000 ;
84.     outbuf  = malloc (outbuf_size ) ;
85.     size  = c ->width  * c ->height ;
86.     picture_buf  = malloc ( (size  * 3 )  / 2 ) ;  /* size for YUV 420 */
87.  
88.     picture ->data [0 ]  = picture_buf ;
89.     picture ->data [1 ]  = picture ->data [0 ]  + size ;
90.     picture ->data [2 ]  = picture ->data [1 ]  + size  /  4 ;
91.     picture ->linesize [0 ]  = c ->width ;
92.     picture ->linesize [1 ]  = c ->width  /  2 ;
93.     picture ->linesize [2 ]  = c ->width  /  2 ;
94.  
95.      /* encode 1 second of video */
96.      for (i = 0 ;i < 25 ;i ++ )  {
97.         fflush (stdout ) ;
98.          /* prepare a dummy image */
99.          /* Y */
100.          for (y = 0 ;y <c ->height ;y ++ )  {
101.              for (x = 0 ;x <c ->width ;x ++ )  {
102.                 picture ->data [0 ] [y  * picture ->linesize [0 ]  + x ]  = x  + y  + i  *  3 ;
103.              }
104.          }
105.  
106.          /* Cb and Cr */
107.          for (y = 0 ;y <c ->height / 2 ;y ++ )  {
108.              for (x = 0 ;x <c ->width / 2 ;x ++ )  {
109.                 picture ->data [1 ] [y  * picture ->linesize [1 ]  + x ]  = 128  + y  + i  *  2 ;
110.                 picture ->data [2 ] [y  * picture ->linesize [2 ]  + x ]  = 64  + x  + i  *  5 ;
111.              }
112.          }
113.  
114.          /* encode the image */
115.         out_size  = avcodec_encode_video (c , outbuf , outbuf_size , picture ) ;
116.          printf ( "encoding frame %3d (size=%5d)n" , i , out_size ) ;
117.         fwrite (outbuf , 1 , out_size , f ) ;
118.      }
119.  
120.      /* get the delayed frames */
121.      /*for(; out_size; i++) {
122.         fflush(stdout);
123.  
124.         out_size = avcodec_encode_video(c, outbuf, outbuf_size, NULL);
125.         printf("write frame %3d (size=%5d)n", i, out_size);
126.         fwrite(outbuf, 1, out_size, f);
127.     }*/
128.  
129.      /* add sequence end code to have a real mpeg file */
130.      /*outbuf[0] = 0x00;
131.     outbuf[1] = 0x00;
132.     outbuf[2] = 0x01;
133.     outbuf[3] = 0xb7;
134.     fwrite(outbuf, 1, 4, f);*/
135.    
136.     fclose (f ) ;
137.     free (picture_buf ) ;
138.     free (outbuf ) ;
139.  
140.     avcodec_close (c ) ;
141.     av_free (c ) ;
142.     av_free (picture ) ;
143.      printf ( "n" ) ;
144. }
145.  
146. 原文地址
147.  
148. int main ( int argc ,  char  **argv )
149. {
150.      const  char  *filename ;
151.  
152.      /* must be called before using avcodec lib */
153.     avcodec_init ( ) ;
154.  
155.      /* register all the codecs */
156.     avcodec_register_all ( ) ;
157.  
158.     video_encode_example ( "testa.webm" ) ;
159.  
160.      return  0 ;
161. }

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