使用FFmpeg新解码API解封装解码音视频(代码实例)

在ffmpeg的源代码中，有新旧版本的编解码接口调用示例，但是demux、mux然后decode、encode的联动起来的接口调用实例并没有，在使用旧版本的编解码接口在编译时会报接口弃用告警信息，所以最好尽快把原有的调用方式切换到新的编解码接口调用方式，告警信息如下：

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1. liuqideMBP:xxx liuqi$ make doc/examples/demuxing_decoding
2. CC doc/examples/demuxing_decoding.o
3. src/doc/examples/demuxing_decoding.c:73:15: warning: 'avcodec_decode_video2' is deprecated [-Wdeprecated-declarations]
4. ret = avcodec_decode_video2(video_dec_ctx, frame, got_frame, &pkt);
5.               ^
6. src/libavcodec/avcodec.h:4631:1: note: 'avcodec_decode_video2' has been explicitly marked deprecated here
7. attribute_deprecated
8. ^
9. src/libavutil/attributes.h:94:49: note: expanded from macro 'attribute_deprecated'
10. # define attribute_deprecated __attribute__((deprecated))
11.                                                 ^
12. src/doc/examples/demuxing_decoding.c:111:15: warning: 'avcodec_decode_audio4' is deprecated [-Wdeprecated-declarations]
13. ret = avcodec_decode_audio4(audio_dec_ctx, frame, got_frame, &pkt);
14.               ^
15. src/libavcodec/avcodec.h:4582:1: note: 'avcodec_decode_audio4' has been explicitly marked deprecated here
16. attribute_deprecated
17. ^
18. src/libavutil/attributes.h:94:49: note: expanded from macro 'attribute_deprecated'
19. # define attribute_deprecated __attribute__((deprecated))
20.                                                 ^
21. 2 warnings generated.
22. LD doc/examples/demuxing_decoding_g
23. ld: warning: directory not found for option '-Llibavresample'
24. STRIP doc/examples/demuxing_decoding

为了修改方便，而网上又没有只管举例的相关完整的实例，所以在这里写一个例子，供大伙参考

1. /*
2. * Copyright (c) 2017 bbs.chinaffmpeg.com 孙悟空
3. *
4. * Permission is hereby granted, free of charge, to any person obtaining a copy
5. * of this software and associated documentation files (the "Software"), to deal
6. * in the Software without restriction, including without limitation the rights
7. * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
8. * copies of the Software, and to permit persons to whom the Software is
9. * furnished to do so, subject to the following conditions:
10. *
11. * The above copyright notice and this permission notice shall be included in
12. * all copies or substantial portions of the Software.
13. *
14. * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15. * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16. * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
17. * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18. * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
19. * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
20. * THE SOFTWARE.
21. */
23. /**
24. * @file
25. * Demuxing and decoding example.
26. *
27. * Show how to use the libavformat and libavcodec API to demux and
28. * decode audio and video data.
29. * @example demuxing_decoding.c
30. */
32. #include <libavutil/imgutils.h>
33. #include <libavutil/samplefmt.h>
34. #include <libavutil/timestamp.h>
35. #include <libavformat/avformat.h>
37. static AVFormatContext *fmt_ctx = NULL;
38. static AVCodecContext *video_dec_ctx = NULL, *audio_dec_ctx;
39. static int width, height;
40. static enum AVPixelFormat pix_fmt;
41. static AVStream *video_stream = NULL, *audio_stream = NULL;
42. static const char *src_filename = NULL;
43. static const char *video_dst_filename = NULL;
44. static const char *audio_dst_filename = NULL;
45. static FILE *video_dst_file = NULL;
46. static FILE *audio_dst_file = NULL;
48. static uint8_t *video_dst_data[4] = {NULL};
49. static int video_dst_linesize[4];
50. static int video_dst_bufsize;
52. static int video_stream_idx = -1, audio_stream_idx = -1;
53. static AVFrame *frame = NULL;
54. static AVPacket pkt;
55. static int video_frame_count = 0;
56. static int audio_frame_count = 0;
58. /* Enable or disable frame reference counting. You are not supposed to support
59. * both paths in your application but pick the one most appropriate to your
60. * needs. Look for the use of refcount in this example to see what are the
61. * differences of API usage between them. */
62. static int refcount = 0;
64. static int decode_packet(int *got_frame, int cached)
65. {
66. int ret = 0;
67. int i = 0;
68. int ch = 0;
69. int data_size = 0;
70. int decoded = pkt.size;
72. *got_frame = 0;
74. if (pkt.stream_index == video_stream_idx) {
75. /* decode video frame */
76.         ret = avcodec_send_packet(video_dec_ctx, &pkt);
77. if (ret < 0) {
78.             fprintf(stderr, "Error sending a packet for decoding\n");
79. exit(1);
80. }
82. while (ret >= 0) {
83.             ret = avcodec_receive_frame(video_dec_ctx, frame);
84. if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
85.                 return ret;
86. else if (ret < 0) {
87.                 fprintf(stderr, "Error during decoding\n");
88. exit(1);
89. }
90.             printf("bbs.chinaffmpeg.com 孙悟空 video_frame%s n:%d coded_n:%d\n",
91.                    cached ? "(cached)" : "",
92.                    video_frame_count++, frame->coded_picture_number);
94. /* copy decoded frame to destination buffer:
95. * this is required since rawvideo expects non aligned data */
96.             av_image_copy(video_dst_data, video_dst_linesize,
97. (const uint8_t **)(frame->data), frame->linesize,
98.                           pix_fmt, width, height);
100. /* write to rawvideo file */
101.             fwrite(video_dst_data[0], 1, video_dst_bufsize, video_dst_file);
103.             printf("saving frame %3d\n", video_dec_ctx->frame_number);
104.             fflush(stdout);
105. }
106. } else if (pkt.stream_index == audio_stream_idx) {
107. /* decode audio frame */
108. #if 1
109. /* send the packet with the compressed data to the decoder */
110.         ret = avcodec_send_packet(audio_dec_ctx, &pkt);
111. if (ret < 0) {
112.             fprintf(stderr, "Error submitting the packet to the decoder\n");
113. exit(1);
114. }
116. /* read all the output frames (in general there may be any number of them */
117. while (ret >= 0) {
118.             ret = avcodec_receive_frame(audio_dec_ctx, frame);
119. if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
120.                 return ret;
121. else if (ret < 0) {
122.                 fprintf(stderr, "Error during decoding\n");
123. exit(1);
124. }
125.             data_size = av_get_bytes_per_sample(audio_dec_ctx->sample_fmt);
126. if (data_size < 0) {
127. /* This should not occur, checking just for paranoia */
128.                 fprintf(stderr, "Failed to calculate data size\n");
129. exit(1);
130. }
131. for (i = 0; i < frame->nb_samples; i++)
132. for (ch = 0; ch < audio_dec_ctx->channels; ch++)
133.                     fwrite(frame->data[ch] + data_size*i, 1, data_size, audio_dst_file);
134. }
136.         printf("audio_frame%s n:%d nb_samples:%d pts:%s\n",
137.                cached ? "(cached)" : "",
138.                audio_frame_count++, frame->nb_samples,
139.                av_ts2timestr(frame->pts, &audio_dec_ctx->time_base));
140. #else
141.         ret = avcodec_decode_audio4(audio_dec_ctx, frame, got_frame, &pkt);
142. if (ret < 0) {
143.             fprintf(stderr, "Error decoding audio frame (%s)\n", av_err2str(ret));
144.             return ret;
145. }
146. /* Some audio decoders decode only part of the packet, and have to be
147. * called again with the remainder of the packet data.
148. * Sample: 转自bbs.chinaffmpeg.com 孙悟空fate-suite/lossless-audio/
149.          * luckynight-partial.shn
150. * Also, some decoders might over-read the packet. */
151.         decoded = FFMIN(ret, pkt.size);
153. if (*got_frame) {
154.             size_t unpadded_linesize = frame->nb_samples * av_get_bytes_per_sample(frame->format);
155.             printf("audio_frame%s n:%d nb_samples:%d pts:%s\n",
156.                    cached ? "(cached)" : "",
157.                    audio_frame_count++, frame->nb_samples,
158.                    av_ts2timestr(frame->pts, &audio_dec_ctx->time_base));
160. /* Write the raw audio data samples of the first plane. This works
161. * fine for packed formats (e.g. AV_SAMPLE_FMT_S16). However,
162. * most audio decoders output planar audio, which uses a separate
163. * plane of audio samples for each channel (e.g. AV_SAMPLE_FMT_S16P).
164. * In other words, this code will write only the first audio channel
165. * in these cases.
166. * You should use libswresample or libavfilter to convert the frame
167. * to packed data. */
168.             fwrite(frame->extended_data[0], 1, unpadded_linesize, audio_dst_file);
169. }
170. #endif
171. }
173. /* If we use frame reference counting, we own the data and need
174. * to de-reference it when we don't use it anymore */
175. if (*got_frame && refcount)
176.         av_frame_unref(frame);
178.     return decoded;
179. }
181. static int open_codec_context(int *stream_idx,
182.                               AVCodecContext **dec_ctx, AVFormatContext *fmt_ctx, enum AVMediaType type)
183. {
184. int ret, stream_index;
185.     AVStream *st;
186.     AVCodec *dec = NULL;
187.     AVDictionary *opts = NULL;
189.     ret = av_find_best_stream(fmt_ctx, type, -1, -1, NULL, 0);
190. if (ret < 0) {
191.         fprintf(stderr, "Could not find %s stream in input file '%s'\n",
192.                 av_get_media_type_string(type), src_filename);
193.         return ret;
194. } else {
195.         stream_index = ret;
196.         st = fmt_ctx->streams[stream_index];
198. /* find decoder for the stream */
199.         dec = avcodec_find_decoder(st->codecpar->codec_id);
200. if (!dec) {
201.             fprintf(stderr, "Failed to find %s codec\n",
202.                     av_get_media_type_string(type));
203.             return AVERROR(EINVAL);
204. }
206. /* Allocate a codec context for the decoder */
207. *dec_ctx = avcodec_alloc_context3(dec);
208. if (!*dec_ctx) {
209.             fprintf(stderr, "Failed to allocate the %s codec context\n",
210.                     av_get_media_type_string(type));
211.             return AVERROR(ENOMEM);
212. }
214. /* Copy codec parameters from input stream to output codec context */
215. if ((ret = avcodec_parameters_to_context(*dec_ctx, st->codecpar)) < 0) {
216.             fprintf(stderr, "Failed to copy %s codec parameters to decoder context\n",
217.                     av_get_media_type_string(type));
218.             return ret;
219. }
221. /* Init the decoders, with or without reference counting */
222.         av_dict_set(&opts, "refcounted_frames", refcount ? "1" : "0", 0);
223. if ((ret = avcodec_open2(*dec_ctx, dec, &opts)) < 0) {
224.             fprintf(stderr, "Failed to open %s codec\n",
225.                     av_get_media_type_string(type));
226.             return ret;
227. }
228. *stream_idx = stream_index;
229. }
231.     return 0;
232. }
234. static int get_format_from_sample_fmt(const char **fmt,
235.                                       enum AVSampleFormat sample_fmt)
236. {
237. int i;
238.     struct sample_fmt_entry {
239.         enum AVSampleFormat sample_fmt; const char *fmt_be, *fmt_le;
240. } sample_fmt_entries[] = {
241. { AV_SAMPLE_FMT_U8, "u8", "u8" },
242. { AV_SAMPLE_FMT_S16, "s16be", "s16le" },
243. { AV_SAMPLE_FMT_S32, "s32be", "s32le" },
244. { AV_SAMPLE_FMT_FLT, "f32be", "f32le" },
245. { AV_SAMPLE_FMT_DBL, "f64be", "f64le" },
246. };
247. *fmt = NULL;
249. for (i = 0; i < FF_ARRAY_ELEMS(sample_fmt_entries); i++) {
250.         struct sample_fmt_entry *entry = &sample_fmt_entries[i];
251. if (sample_fmt == entry->sample_fmt) {
252. *fmt = AV_NE(entry->fmt_be, entry->fmt_le);
253.             return 0;
254. }
255. }
257.     fprintf(stderr,
258. "sample format %s is not supported as output format\n",
259.             av_get_sample_fmt_name(sample_fmt));
260.     return -1;
261. }
263. int main (int argc, char **argv)
264. {
265. int ret = 0, got_frame;
267. if (argc != 4 && argc != 5) {
268.         fprintf(stderr, "usage: %s [-refcount] input_file video_output_file audio_output_file\n"
269. "API example program to show how to read frames from an input file.\n"
270. "This program reads frames from a file, decodes them, and writes decoded\n"
271. "video frames to a rawvideo file named video_output_file, and decoded\n"
272. "audio frames to a rawaudio file named audio_output_file.\n\n"
273. "If the -refcount option is specified, the program use the\n"
274. "reference counting frame system which allows keeping a copy of\n"
275. "the data for longer than one decode call.\n"
276. "\n", argv[0]);
277. exit(1);
278. }
279. if (argc == 5 && !strcmp(argv[1], "-refcount")) {
280.         refcount = 1;
281.         argv++;
282. }
283.     src_filename = argv[1];
284.     video_dst_filename = argv[2];
285.     audio_dst_filename = argv[3];
287. /* register all formats and codecs */
288.     av_register_all();
290. /* open input file, and allocate format context */
291. if (avformat_open_input(&fmt_ctx, src_filename, NULL, NULL) < 0) {
292.         fprintf(stderr, "Could not open source file %s\n", src_filename);
293. exit(1);
294. }
296. /* retrieve stream information */
297. if (avformat_find_stream_info(fmt_ctx, NULL) < 0) {
298.         fprintf(stderr, "Could not find stream information\n");
299. exit(1);
300. }
302. if (open_codec_context(&video_stream_idx, &video_dec_ctx, fmt_ctx, AVMEDIA_TYPE_VIDEO) >= 0) {
303.         video_stream = fmt_ctx->streams[video_stream_idx];
305.         video_dst_file = fopen(video_dst_filename, "wb");
306. if (!video_dst_file) {
307.             fprintf(stderr, "Could not open destination file %s\n", video_dst_filename);
308.             ret = 1;
309.             goto end;
310. }
312. /* allocate image where the decoded image will be put */
313.         width = video_dec_ctx->width;
314.         height = video_dec_ctx->height;
315.         pix_fmt = video_dec_ctx->pix_fmt;
316.         ret = av_image_alloc(video_dst_data, video_dst_linesize,
317.                              width, height, pix_fmt, 1);
318. if (ret < 0) {
319.             fprintf(stderr, "Could not allocate raw video buffer\n");
320.             goto end;
321. }
322.         video_dst_bufsize = ret;
323. }
325. if (open_codec_context(&audio_stream_idx, &audio_dec_ctx, fmt_ctx, AVMEDIA_TYPE_AUDIO) >= 0) {
326.         audio_stream = fmt_ctx->streams[audio_stream_idx];
327.         audio_dst_file = fopen(audio_dst_filename, "wb");
328. if (!audio_dst_file) {
329.             fprintf(stderr, "Could not open destination file %s\n", audio_dst_filename);
330.             ret = 1;
331.             goto end;
332. }
333. }
335. /* dump input information to stderr */
336.     av_dump_format(fmt_ctx, 0, src_filename, 0);
338. if (!audio_stream && !video_stream) {
339.         fprintf(stderr, "Could not find audio or video stream in the input, aborting\n");
340.         ret = 1;
341.         goto end;
342. }
344.     frame = av_frame_alloc();
345. if (!frame) {
346.         fprintf(stderr, "Could not allocate frame\n");
347.         ret = AVERROR(ENOMEM);
348.         goto end;
349. }
351. /* initialize packet, set data to NULL, let the demuxer fill it */
352.     av_init_packet(&pkt);
353.     pkt.data = NULL;
354.     pkt.size = 0;
356. if (video_stream)
357.         printf("Demuxing video from file '%s' into '%s'\n", src_filename, video_dst_filename);
358. if (audio_stream)
359.         printf("Demuxing audio from file '%s' into '%s'\n", src_filename, audio_dst_filename);
361. /* read frames from the file */
362. while (av_read_frame(fmt_ctx, &pkt) >= 0) {
363.         AVPacket orig_pkt = pkt;
364. do {
365.             ret = decode_packet(&got_frame, 0);
366. if (ret < 0)
367.                 break;
368.             pkt.data += ret;
369.             pkt.size -= ret;
370. } while (pkt.size > 0);
371.         av_packet_unref(&orig_pkt);
372. }
374. /* flush cached frames */
375.     pkt.data = NULL;
376.     pkt.size = 0;
377. do {
378.         decode_packet(&got_frame, 1);
379. } while (got_frame);
381.     printf("Demuxing succeeded.\n");
383. if (video_stream) {
384.         printf("Play the output video file with the command:\n"
385. "ffplay -f rawvideo -pix_fmt %s -video_size %dx%d %s\n",
386.                av_get_pix_fmt_name(pix_fmt), width, height,
387.                video_dst_filename);
388. }
390. if (audio_stream) {
391.         enum AVSampleFormat sfmt = audio_dec_ctx->sample_fmt;
392. int n_channels = audio_dec_ctx->channels;
393. const char *fmt;
395. if (av_sample_fmt_is_planar(sfmt)) {
396. const char *packed = av_get_sample_fmt_name(sfmt);
397.             printf("Warning: the sample format the decoder produced is planar "
398. "(%s). This example will output the first channel only.\n",
399.                    packed ? packed : "?");
400.             sfmt = av_get_packed_sample_fmt(sfmt);
401.             n_channels = 2;
402. }
404. if ((ret = get_format_from_sample_fmt(&fmt, sfmt)) < 0)
405.             goto end;
407.         printf("Play the output audio file with the command:\n"
408. "ffplay -f %s -ac %d -ar %d %s\n",
409.                fmt, n_channels, audio_dec_ctx->sample_rate,
410.                audio_dst_filename);
411. }
413. end:
414.     avcodec_free_context(&video_dec_ctx);
415.     avcodec_free_context(&audio_dec_ctx);
416.     avformat_close_input(&fmt_ctx);
417. if (video_dst_file)
418.         fclose(video_dst_file);
419. if (audio_dst_file)
420.         fclose(audio_dst_file);
421.     av_frame_free(&frame);
422.     av_free(video_dst_data[0]);
424.     return ret < 0;
425. }

下面看一下编译的方式，其实我是用的ffmpeg原生的编译方式编译的make doc/examples/demuxing_decoding，在这里贴一下make -n doc/examples/demuxing_decoding的输出

点击(此处)折叠或打开

1. liuqideMBP:xxx liuqi$ make -n doc/examples/demuxing_decoding
2. printf "CC\t%s\n" doc/examples/demuxing_decoding.o; ccache gcc -I. -Isrc/ -D_ISOC99_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -I/Users/liuqi/multimedia/ffmpeg/compat/dispatch_semaphore -DPIC -DZLIB_CONST -std=c11 -Werror=partial-availability -fomit-frame-pointer -fPIC -pthread -I/usr/local/include -I/usr/local/Cellar/fontconfig/2.12.6/include -I/usr/local/opt/freetype/include/freetype2 -I/usr/local/Cellar/fribidi/0.19.7_1/include/fribidi -I/usr/local/Cellar/glib/2.54.2/include/glib-2.0 -I/usr/local/Cellar/glib/2.54.2/lib/glib-2.0/include -I/usr/local/opt/gettext/include -I/usr/local/Cellar/pcre/8.41/include -I/usr/local/opt/freetype/include/freetype2 -I/usr/local/Cellar/libbluray/1.0.1/include -I/usr/local/include -I/usr/local/Cellar/fontconfig/2.12.6/include -I/usr/local/opt/freetype/include/freetype2 -I/usr/local/opt/freetype/include/freetype2 -I/usr/local/Cellar/speex/1.2rc1/include -I/usr/local/include -I/usr/local/Cellar/x265/2.5_1/include -g -Wdeclaration-after-statement -Wall -Wdisabled-optimization -Wpointer-arith -Wredundant-decls -Wwrite-strings -Wtype-limits -Wundef -Wmissing-prototypes -Wno-pointer-to-int-cast -Wstrict-prototypes -Wempty-body -Wno-parentheses -Wno-switch -Wno-format-zero-length -Wno-pointer-sign -Wno-unused-const-variable -O3 -fno-math-errno -fno-signed-zeros -mstack-alignment=16 -Qunused-arguments -Werror=implicit-function-declaration -Werror=missing-prototypes -Werror=return-type -D_THREAD_SAFE -I/usr/local/include/SDL2 -MMD -MF doc/examples/demuxing_decoding.d -MT doc/examples/demuxing_decoding.o -c -o doc/examples/demuxing_decoding.o src/doc/examples/demuxing_decoding.c
3. printf "LD\t%s\n" doc/examples/demuxing_decoding_g; ccache gcc -Llibavcodec -Llibavdevice -Llibavfilter -Llibavformat -Llibavresample -Llibavutil -Llibpostproc -Llibswscale -Llibswresample -Wl,-dynamic,-search_paths_first -Qunused-arguments -o doc/examples/demuxing_decoding_g doc/examples/demuxing_decoding.o -lavdevice -lavfilter -lavformat -lavcodec -lpostproc -lswresample -lswscale -lavutil -framework Foundation -lm -framework AVFoundation -framework CoreVideo -framework CoreMedia -pthread -framework CoreGraphics -L/usr/local/lib -lSDL2 -framework OpenGL -framework OpenGL -pthread -lm -L/usr/local/lib -lass -framework CoreImage -framework AppKit -L/usr/local/Cellar/fontconfig/2.12.6/lib -L/usr/local/opt/freetype/lib -lfontconfig -lfreetype -L/usr/local/opt/freetype/lib -lfreetype -lm -lbz2 -L/usr/local/Cellar/libbluray/1.0.1/lib -lbluray -lz -Wl,-framework,CoreFoundation -Wl,-framework,Security -liconv -lm -llzma -lz -framework AudioToolbox -L/usr/local/lib -lfdk-aac -lmp3lame -L/usr/local/Cellar/speex/1.2rc1/lib -lspeex -L/usr/local/lib -lx264 -L/usr/local/Cellar/x265/2.5_1/lib -lx265 -pthread -framework VideoToolbox -framework CoreFoundation -framework CoreMedia -framework CoreVideo -framework CoreServices -lm -lm -lm -pthread -lm -framework VideoToolbox -framework CoreFoundation -framework CoreMedia -framework CoreVideo -framework CoreServices
4. printf "STRIP\t%s\n" doc/examples/demuxing_decoding; strip -x -o doc/examples/demuxing_decoding doc/examples/demuxing_decoding_g