雷神simplest_ffmpeg_player解析（二）

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
static const URLProtocol * const url_protocols[] = {
    &ff_async_protocol,
    &ff_cache_protocol,
    &ff_concat_protocol,
    &ff_crypto_protocol,
    &ff_data_protocol,
    &ff_ffrtmphttp_protocol,
    &ff_file_protocol,
    &ff_ftp_protocol,
    &ff_gopher_protocol,
    &ff_hls_protocol,
    &ff_http_protocol,
    &ff_httpproxy_protocol,
    &ff_icecast_protocol,
    &ff_mmsh_protocol,
    &ff_mmst_protocol,
    &ff_md5_protocol,
    &ff_pipe_protocol,
    &ff_prompeg_protocol,
    &ff_rtmp_protocol,
    &ff_rtmpt_protocol,
    &ff_rtp_protocol,
    &ff_srtp_protocol,
    &ff_subfile_protocol,
    &ff_tee_protocol,
    &ff_tcp_protocol,
    &ff_udp_protocol,
    &ff_udplite_protocol,
    &ff_unix_protocol,
    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
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
/**
 * 最简单的FFmpeg Helloworld程序
 * Simplest FFmpeg HelloWorld
 *
 * 雷霄骅 Lei Xiaohua
 * leixiaohua1020@126.com
 * 中国传媒大学/数字电视技术
 * Communication University of China / Digital TV Technology
 * http://blog.csdn.net/leixiaohua1020
 *
 * 
 * 本程序是基于FFmpeg函数的最简单的程序。它可以打印出FFmpeg类库的下列信息：
 * Protocol:  FFmpeg类库支持的协议
 * AVFormat:  FFmpeg类库支持的封装格式
 * AVCodec:   FFmpeg类库支持的编解码器
 * AVFilter:  FFmpeg类库支持的滤镜
 * Configure: FFmpeg类库的配置信息
 * 
 * This is the simplest program based on FFmpeg API. It can show following 
 * informations about FFmpeg library:
 * Protocol:  Protocols supported by FFmpeg.
 * AVFormat:  Container format supported by FFmpeg.
 * AVCodec:   Encoder/Decoder supported by FFmpeg.
 * AVFilter:  Filters supported by FFmpeg.
 * Configure: configure information of FFmpeg.
 *
 */

#include <stdio.h>

#define __STDC_CONSTANT_MACROS

#ifdef _WIN32
//Windows
extern "C"
{
#include "libavcodec/avcodec.h"
#include "libavformat/avformat.h"
#include "libavfilter/avfilter.h"
};
#else
//Linux...
#ifdef __cplusplus
extern "C"
{
#endif
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libavfilter/avfilter.h>
#ifdef __cplusplus
};
#endif
#endif

//FIX
struct URLProtocol;
/**
 * Protocol Support Information
 * 协议支持信息（输入协议&&输出协议）
 */
char * urlprotocolinfo(){
	
	char *info=(char *)malloc(40000);

	// 将指定内存的前n个字节设置为特定的值
	memset(info,0,40000);

    // 注册复用器，编码器等(参考https://blog.csdn.net/asd501823206/article/details/96377773)
	av_register_all();

	struct URLProtocol *pup = NULL;
	//Input
	struct URLProtocol **p_temp = &pup;

	/**
	 * libavformat->protocolos.c
	
     * const char *avio_enum_protocols(void **opaque, int output)
     * {
     *     const URLProtocol **p = *opaque;
     *
     *     p = p ? p + 1 : url_protocols;
     *     *opaque = p;
     *     if (!*p) {
     *         *opaque = NULL;
     *         return NULL;
     *     }
     *     if ((output && (*p)->url_write) || (!output && (*p)->url_read))
     *         return (*p)->name;
     *     return avio_enum_protocols(opaque, output);
     * }
     *
     * Iterate through names of available protocols.
     * 迭代可用协议的名称。
     *
     * Parameters
     *      opaque	A private pointer representing current protocol. It must be a pointer to NULL on first iteration and will be updated by successive calls to avio_enum_protocols.
     *      opaque  表示当前协议的私有指针。 它必须是第一次迭代时指向NULL的指针，并将通过连续调用avio_enum_protocols进行更新。
     *
     *      output	If set to 1, iterate over output protocols, otherwise over input protocols.
     *      output  如果设置为1，则迭代输出协议，否则迭代输入协议。
     * Returns
     *      A static string containing the name of current protocol or NULL
     *      包含当前协议名称或NULL的静态字符串
     */
	avio_enum_protocols((void **)p_temp, 0);
	while ((*p_temp) != NULL){
		sprintf(info, "%s[In ][%10s]n", info, avio_enum_protocols((void **)p_temp, 0));
	}
	pup = NULL;
	//Output
	avio_enum_protocols((void **)p_temp, 1);
	while ((*p_temp) != NULL){
		sprintf(info, "%s[Out][%10s]n", info, avio_enum_protocols((void **)p_temp, 1));
	}

	return info;
}

/**
 * AVFormat Support Information
 *
 * 获取所有复用器、解复用器并打印
 */
char * avformatinfo(){

	char *info=(char *)malloc(40000);
	memset(info,0,40000);

	av_register_all();

    /**
     * libavformat->format.c中
     *
     * // head of registered input format linked list
     * static AVInputFormat* first_iformat = NULL;
     *
     * AVInputFormat *av_iformat_next(const AVInputFormat *f)
     * {
     *     if (f)
     *         return f->next;
     *     else
     *         return first_iformat;
     * }
     *
     * 当传入为null时，返回所有注册的复用器的第一个。in&out逻辑相同
     *
     * 循环调用next，打印出format->name
     */
	AVInputFormat *if_temp = av_iformat_next(NULL);
	AVOutputFormat *of_temp = av_oformat_next(NULL);
	//Input
	while(if_temp!=NULL){
		sprintf(info, "%s[In ] %10sn", info, if_temp->name);
		if_temp=if_temp->next;
	}
	//Output
	while (of_temp != NULL){
		sprintf(info, "%s[Out] %10sn", info, of_temp->name);
		of_temp = of_temp->next;
	}
	return info;
}

/**
 * AVCodec Support Information
 *
 * static AVCodec *first_avcodec = NULL;
 *
 * AVCodec *av_codec_next(const AVCodec *c)
 * {
 *     if (c)
 *         return c->next;
 *     else
 *         return first_avcodec;
 * }
 *
 * 当传入为null时，返回所有注册的编解码器的第一个
 */
char * avcodecinfo()
{
	char *info=(char *)malloc(40000);
	memset(info,0,40000);

	av_register_all();

	AVCodec *c_temp = av_codec_next(NULL);

    // 循环取下一个AVCodec
	while(c_temp!=NULL){
	    // 解码/编码
		if (c_temp->decode!=NULL){
			sprintf(info, "%s[Dec]", info);
		}
		else{
			sprintf(info, "%s[Enc]", info);
		}
		// Type：视频、音频、字幕
		switch (c_temp->type){
		case AVMEDIA_TYPE_VIDEO:
			sprintf(info, "%s[Video]", info);
			break;
		case AVMEDIA_TYPE_AUDIO:
			sprintf(info, "%s[Audio]", info);
			break;
		default:
			sprintf(info, "%s[Other]", info);
			break;
		}

        // name
		sprintf(info, "%s %10sn", info, c_temp->name);

		c_temp=c_temp->next;
	}
	return info;
}

/**
 * AVFilter Support Information
 */
char * avfilterinfo()
{
	char *info=(char *)malloc(40000);
	memset(info,0,40000);

    /**
     * 详细注册信息请查看https://blog.csdn.net/asd501823206/article/details/96377773
     */
	avfilter_register_all();

    /**
     * libavfilter->avfilter.c
     *
     * static AVFilter *first_filter;
     *
     * const AVFilter *avfilter_next(const AVFilter *prev)
     * {
     *     return prev ? prev->next : first_filter;
     * }
     *
     * 循环打印出filter->name
     */
	AVFilter *f_temp = (AVFilter *)avfilter_next(NULL);
	
	while (f_temp != NULL){
		sprintf(info, "%s[%15s]n", info, f_temp->name);
		f_temp=f_temp->next;
	}
	return info;
}

/**
 * Configuration Information
 *
 * Return the libavcodec build-time configuration. 构建时的配置信息
 */
char * configurationinfo()
{
	char *info=(char *)malloc(40000);
	memset(info,0,40000);

    // 注册复用器，编码器等(参考https://blog.csdn.net/asd501823206/article/details/96377773)
	av_register_all();

	sprintf(info, "%sn", avcodec_configuration());

	return info;
}

/**
 * 每个函数（除了avfilterinfo）都调用了av_register_all()，av_register_all()里的ff_thread_once保证了register_all只会被调用一次
 */
int main(int argc, char* argv[])
{
	char *infostr=NULL;
	infostr=configurationinfo();
	printf("n<<Configuration>>n%s",infostr);
	free(infostr);

	infostr=urlprotocolinfo();
	printf("n<<URLProtocol>>n%s",infostr);
	free(infostr);

	infostr=avformatinfo();
	printf("n<<AVFormat>>n%s",infostr);
	free(infostr);

	infostr=avcodecinfo();
	printf("n<<AVCodec>>n%s",infostr);
	free(infostr);

	infostr=avfilterinfo();
	printf("n<<AVFilter>>n%s",infostr);
	free(infostr);

	return 0;
}