2 * Copyright (c) 2001 Fabrice Bellard
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:
11 * The above copyright notice and this permission notice shall be included in
12 * all copies or substantial portions of the Software.
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
25 * libavcodec API use example.
27 * Note that libavcodec only handles codecs (mpeg, mpeg4, etc...),
28 * not file formats (avi, vob, mp4, mov, mkv, mxf, flv, mpegts, mpegps, etc...). See library 'libavformat' for the
32 #include "libavcodec/avcodec.h"
33 #include "libavutil/mathematics.h"
35 #define INBUF_SIZE 4096
36 #define AUDIO_INBUF_SIZE 20480
37 #define AUDIO_REFILL_THRESH 4096
40 * Audio encoding example
42 static void audio_encode_example(const char *filename)
45 AVCodecContext *c= NULL;
46 int frame_size, i, j, out_size, outbuf_size;
52 printf("Audio encoding\n");
54 /* find the MP2 encoder */
55 codec = avcodec_find_encoder(CODEC_ID_MP2);
57 fprintf(stderr, "codec not found\n");
61 c = avcodec_alloc_context3(codec);
63 /* put sample parameters */
65 c->sample_rate = 44100;
67 c->sample_fmt = AV_SAMPLE_FMT_S16;
70 if (avcodec_open(c, codec) < 0) {
71 fprintf(stderr, "could not open codec\n");
75 /* the codec gives us the frame size, in samples */
76 frame_size = c->frame_size;
77 samples = malloc(frame_size * 2 * c->channels);
79 outbuf = malloc(outbuf_size);
81 f = fopen(filename, "wb");
83 fprintf(stderr, "could not open %s\n", filename);
87 /* encode a single tone sound */
89 tincr = 2 * M_PI * 440.0 / c->sample_rate;
91 for(j=0;j<frame_size;j++) {
92 samples[2*j] = (int)(sin(t) * 10000);
93 samples[2*j+1] = samples[2*j];
96 /* encode the samples */
97 out_size = avcodec_encode_audio(c, outbuf, outbuf_size, samples);
98 fwrite(outbuf, 1, out_size, f);
111 static void audio_decode_example(const char *outfilename, const char *filename)
114 AVCodecContext *c= NULL;
118 uint8_t inbuf[AUDIO_INBUF_SIZE + FF_INPUT_BUFFER_PADDING_SIZE];
121 av_init_packet(&avpkt);
123 printf("Audio decoding\n");
125 /* find the mpeg audio decoder */
126 codec = avcodec_find_decoder(CODEC_ID_MP2);
128 fprintf(stderr, "codec not found\n");
132 c = avcodec_alloc_context3(codec);
135 if (avcodec_open(c, codec) < 0) {
136 fprintf(stderr, "could not open codec\n");
140 outbuf = malloc(AVCODEC_MAX_AUDIO_FRAME_SIZE);
142 f = fopen(filename, "rb");
144 fprintf(stderr, "could not open %s\n", filename);
147 outfile = fopen(outfilename, "wb");
153 /* decode until eof */
155 avpkt.size = fread(inbuf, 1, AUDIO_INBUF_SIZE, f);
157 while (avpkt.size > 0) {
158 out_size = AVCODEC_MAX_AUDIO_FRAME_SIZE;
159 len = avcodec_decode_audio3(c, (short *)outbuf, &out_size, &avpkt);
161 fprintf(stderr, "Error while decoding\n");
165 /* if a frame has been decoded, output it */
166 fwrite(outbuf, 1, out_size, outfile);
170 if (avpkt.size < AUDIO_REFILL_THRESH) {
171 /* Refill the input buffer, to avoid trying to decode
172 * incomplete frames. Instead of this, one could also use
173 * a parser, or use a proper container format through
175 memmove(inbuf, avpkt.data, avpkt.size);
177 len = fread(avpkt.data + avpkt.size, 1,
178 AUDIO_INBUF_SIZE - avpkt.size, f);
193 * Video encoding example
195 static void video_encode_example(const char *filename)
198 AVCodecContext *c= NULL;
199 int i, out_size, size, x, y, outbuf_size;
204 printf("Video encoding\n");
206 /* find the mpeg1 video encoder */
207 codec = avcodec_find_encoder(CODEC_ID_MPEG1VIDEO);
209 fprintf(stderr, "codec not found\n");
213 c = avcodec_alloc_context3(codec);
214 picture= avcodec_alloc_frame();
216 /* put sample parameters */
217 c->bit_rate = 400000;
218 /* resolution must be a multiple of two */
221 /* frames per second */
222 c->time_base= (AVRational){1,25};
223 c->gop_size = 10; /* emit one intra frame every ten frames */
225 c->pix_fmt = PIX_FMT_YUV420P;
228 if (avcodec_open(c, codec) < 0) {
229 fprintf(stderr, "could not open codec\n");
233 f = fopen(filename, "wb");
235 fprintf(stderr, "could not open %s\n", filename);
239 /* alloc image and output buffer */
240 outbuf_size = 100000;
241 outbuf = malloc(outbuf_size);
243 /* the image can be allocated by any means and av_image_alloc() is
244 * just the most convenient way if av_malloc() is to be used */
245 av_image_alloc(picture->data, picture->linesize,
246 c->width, c->height, c->pix_fmt, 1);
248 /* encode 1 second of video */
251 /* prepare a dummy image */
253 for(y=0;y<c->height;y++) {
254 for(x=0;x<c->width;x++) {
255 picture->data[0][y * picture->linesize[0] + x] = x + y + i * 3;
260 for(y=0;y<c->height/2;y++) {
261 for(x=0;x<c->width/2;x++) {
262 picture->data[1][y * picture->linesize[1] + x] = 128 + y + i * 2;
263 picture->data[2][y * picture->linesize[2] + x] = 64 + x + i * 5;
267 /* encode the image */
268 out_size = avcodec_encode_video(c, outbuf, outbuf_size, picture);
269 printf("encoding frame %3d (size=%5d)\n", i, out_size);
270 fwrite(outbuf, 1, out_size, f);
273 /* get the delayed frames */
274 for(; out_size; i++) {
277 out_size = avcodec_encode_video(c, outbuf, outbuf_size, NULL);
278 printf("write frame %3d (size=%5d)\n", i, out_size);
279 fwrite(outbuf, 1, out_size, f);
282 /* add sequence end code to have a real mpeg file */
287 fwrite(outbuf, 1, 4, f);
293 av_free(picture->data[0]);
299 * Video decoding example
302 static void pgm_save(unsigned char *buf, int wrap, int xsize, int ysize,
308 f=fopen(filename,"w");
309 fprintf(f,"P5\n%d %d\n%d\n",xsize,ysize,255);
311 fwrite(buf + i * wrap,1,xsize,f);
315 static void video_decode_example(const char *outfilename, const char *filename)
318 AVCodecContext *c= NULL;
319 int frame, got_picture, len;
322 uint8_t inbuf[INBUF_SIZE + FF_INPUT_BUFFER_PADDING_SIZE];
326 av_init_packet(&avpkt);
328 /* set end of buffer to 0 (this ensures that no overreading happens for damaged mpeg streams) */
329 memset(inbuf + INBUF_SIZE, 0, FF_INPUT_BUFFER_PADDING_SIZE);
331 printf("Video decoding\n");
333 /* find the mpeg1 video decoder */
334 codec = avcodec_find_decoder(CODEC_ID_MPEG1VIDEO);
336 fprintf(stderr, "codec not found\n");
340 c = avcodec_alloc_context3(codec);
341 picture= avcodec_alloc_frame();
343 if(codec->capabilities&CODEC_CAP_TRUNCATED)
344 c->flags|= CODEC_FLAG_TRUNCATED; /* we do not send complete frames */
346 /* For some codecs, such as msmpeg4 and mpeg4, width and height
347 MUST be initialized there because this information is not
348 available in the bitstream. */
351 if (avcodec_open(c, codec) < 0) {
352 fprintf(stderr, "could not open codec\n");
356 /* the codec gives us the frame size, in samples */
358 f = fopen(filename, "rb");
360 fprintf(stderr, "could not open %s\n", filename);
366 avpkt.size = fread(inbuf, 1, INBUF_SIZE, f);
370 /* NOTE1: some codecs are stream based (mpegvideo, mpegaudio)
371 and this is the only method to use them because you cannot
372 know the compressed data size before analysing it.
374 BUT some other codecs (msmpeg4, mpeg4) are inherently frame
375 based, so you must call them with all the data for one
376 frame exactly. You must also initialize 'width' and
377 'height' before initializing them. */
379 /* NOTE2: some codecs allow the raw parameters (frame size,
380 sample rate) to be changed at any frame. We handle this, so
381 you should also take care of it */
383 /* here, we use a stream based decoder (mpeg1video), so we
384 feed decoder and see if it could decode a frame */
386 while (avpkt.size > 0) {
387 len = avcodec_decode_video2(c, picture, &got_picture, &avpkt);
389 fprintf(stderr, "Error while decoding frame %d\n", frame);
393 printf("saving frame %3d\n", frame);
396 /* the picture is allocated by the decoder. no need to
398 snprintf(buf, sizeof(buf), outfilename, frame);
399 pgm_save(picture->data[0], picture->linesize[0],
400 c->width, c->height, buf);
408 /* some codecs, such as MPEG, transmit the I and P frame with a
409 latency of one frame. You must do the following to have a
410 chance to get the last frame of the video */
413 len = avcodec_decode_video2(c, picture, &got_picture, &avpkt);
415 printf("saving last frame %3d\n", frame);
418 /* the picture is allocated by the decoder. no need to
420 snprintf(buf, sizeof(buf), outfilename, frame);
421 pgm_save(picture->data[0], picture->linesize[0],
422 c->width, c->height, buf);
434 int main(int argc, char **argv)
436 const char *filename;
438 /* must be called before using avcodec lib */
441 /* register all the codecs */
442 avcodec_register_all();
445 audio_encode_example("/tmp/test.mp2");
446 audio_decode_example("/tmp/test.sw", "/tmp/test.mp2");
448 video_encode_example("/tmp/test.mpg");
449 filename = "/tmp/test.mpg";
454 // audio_decode_example("/tmp/test.sw", filename);
455 video_decode_example("/tmp/test%d.pgm", filename);