2 * copyright (c) 2001 Fabrice Bellard
4 * This file is part of FFmpeg.
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.
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.
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
23 * avcodec API use example.
25 * Note that this library only handles codecs (mpeg, mpeg4, etc...),
26 * not file formats (avi, vob, etc...). See library 'libavformat' for the
35 #ifdef HAVE_AV_CONFIG_H
36 #undef HAVE_AV_CONFIG_H
41 #define INBUF_SIZE 4096
44 * Audio encoding example
46 void audio_encode_example(const char *filename)
49 AVCodecContext *c= NULL;
50 int frame_size, i, j, out_size, outbuf_size;
56 printf("Audio encoding\n");
58 /* find the MP2 encoder */
59 codec = avcodec_find_encoder(CODEC_ID_MP2);
61 fprintf(stderr, "codec not found\n");
65 c= avcodec_alloc_context();
67 /* put sample parameters */
69 c->sample_rate = 44100;
73 if (avcodec_open(c, codec) < 0) {
74 fprintf(stderr, "could not open codec\n");
78 /* the codec gives us the frame size, in samples */
79 frame_size = c->frame_size;
80 samples = malloc(frame_size * 2 * c->channels);
82 outbuf = malloc(outbuf_size);
84 f = fopen(filename, "wb");
86 fprintf(stderr, "could not open %s\n", filename);
90 /* encode a single tone sound */
92 tincr = 2 * M_PI * 440.0 / c->sample_rate;
94 for(j=0;j<frame_size;j++) {
95 samples[2*j] = (int)(sin(t) * 10000);
96 samples[2*j+1] = samples[2*j];
99 /* encode the samples */
100 out_size = avcodec_encode_audio(c, outbuf, outbuf_size, samples);
101 fwrite(outbuf, 1, out_size, f);
114 void audio_decode_example(const char *outfilename, const char *filename)
117 AVCodecContext *c= NULL;
118 int out_size, size, len;
121 uint8_t inbuf[INBUF_SIZE + FF_INPUT_BUFFER_PADDING_SIZE], *inbuf_ptr;
123 printf("Audio decoding\n");
125 /* set end of buffer to 0 (this ensures that no overreading happens for damaged mpeg streams) */
126 memset(inbuf + INBUF_SIZE, 0, FF_INPUT_BUFFER_PADDING_SIZE);
128 /* find the mpeg audio decoder */
129 codec = avcodec_find_decoder(CODEC_ID_MP2);
131 fprintf(stderr, "codec not found\n");
135 c= avcodec_alloc_context();
138 if (avcodec_open(c, codec) < 0) {
139 fprintf(stderr, "could not open codec\n");
143 outbuf = malloc(AVCODEC_MAX_AUDIO_FRAME_SIZE);
145 f = fopen(filename, "rb");
147 fprintf(stderr, "could not open %s\n", filename);
150 outfile = fopen(outfilename, "wb");
156 /* decode until eof */
159 size = fread(inbuf, 1, INBUF_SIZE, f);
165 len = avcodec_decode_audio(c, (short *)outbuf, &out_size,
168 fprintf(stderr, "Error while decoding\n");
172 /* if a frame has been decoded, output it */
173 fwrite(outbuf, 1, out_size, outfile);
189 * Video encoding example
191 void video_encode_example(const char *filename)
194 AVCodecContext *c= NULL;
195 int i, out_size, size, x, y, outbuf_size;
198 uint8_t *outbuf, *picture_buf;
200 printf("Video encoding\n");
202 /* find the mpeg1 video encoder */
203 codec = avcodec_find_encoder(CODEC_ID_MPEG1VIDEO);
205 fprintf(stderr, "codec not found\n");
209 c= avcodec_alloc_context();
210 picture= avcodec_alloc_frame();
212 /* put sample parameters */
213 c->bit_rate = 400000;
214 /* resolution must be a multiple of two */
217 /* frames per second */
218 c->time_base= (AVRational){1,25};
219 c->gop_size = 10; /* emit one intra frame every ten frames */
221 c->pix_fmt = PIX_FMT_YUV420P;
224 if (avcodec_open(c, codec) < 0) {
225 fprintf(stderr, "could not open codec\n");
229 /* the codec gives us the frame size, in samples */
231 f = fopen(filename, "wb");
233 fprintf(stderr, "could not open %s\n", filename);
237 /* alloc image and output buffer */
238 outbuf_size = 100000;
239 outbuf = malloc(outbuf_size);
240 size = c->width * c->height;
241 picture_buf = malloc((size * 3) / 2); /* size for YUV 420 */
243 picture->data[0] = picture_buf;
244 picture->data[1] = picture->data[0] + size;
245 picture->data[2] = picture->data[1] + size / 4;
246 picture->linesize[0] = c->width;
247 picture->linesize[1] = c->width / 2;
248 picture->linesize[2] = c->width / 2;
250 /* encode 1 second of video */
253 /* prepare a dummy image */
255 for(y=0;y<c->height;y++) {
256 for(x=0;x<c->width;x++) {
257 picture->data[0][y * picture->linesize[0] + x] = x + y + i * 3;
262 for(y=0;y<c->height/2;y++) {
263 for(x=0;x<c->width/2;x++) {
264 picture->data[1][y * picture->linesize[1] + x] = 128 + y + i * 2;
265 picture->data[2][y * picture->linesize[2] + x] = 64 + x + i * 5;
269 /* encode the image */
270 out_size = avcodec_encode_video(c, outbuf, outbuf_size, picture);
271 printf("encoding frame %3d (size=%5d)\n", i, out_size);
272 fwrite(outbuf, 1, out_size, f);
275 /* get the delayed frames */
276 for(; out_size; i++) {
279 out_size = avcodec_encode_video(c, outbuf, outbuf_size, NULL);
280 printf("write frame %3d (size=%5d)\n", i, out_size);
281 fwrite(outbuf, 1, out_size, f);
284 /* add sequence end code to have a real mpeg file */
289 fwrite(outbuf, 1, 4, f);
301 * Video decoding example
304 void pgm_save(unsigned char *buf,int wrap, int xsize,int ysize,char *filename)
309 f=fopen(filename,"w");
310 fprintf(f,"P5\n%d %d\n%d\n",xsize,ysize,255);
312 fwrite(buf + i * wrap,1,xsize,f);
316 void video_decode_example(const char *outfilename, const char *filename)
319 AVCodecContext *c= NULL;
320 int frame, size, got_picture, len;
323 uint8_t inbuf[INBUF_SIZE + FF_INPUT_BUFFER_PADDING_SIZE], *inbuf_ptr;
326 /* set end of buffer to 0 (this ensures that no overreading happens for damaged mpeg streams) */
327 memset(inbuf + INBUF_SIZE, 0, FF_INPUT_BUFFER_PADDING_SIZE);
329 printf("Video decoding\n");
331 /* find the mpeg1 video decoder */
332 codec = avcodec_find_decoder(CODEC_ID_MPEG1VIDEO);
334 fprintf(stderr, "codec not found\n");
338 c= avcodec_alloc_context();
339 picture= avcodec_alloc_frame();
341 if(codec->capabilities&CODEC_CAP_TRUNCATED)
342 c->flags|= CODEC_FLAG_TRUNCATED; /* we dont send complete frames */
344 /* for some codecs, such as msmpeg4 and mpeg4, width and height
345 MUST be initialized there because these info are not available
349 if (avcodec_open(c, codec) < 0) {
350 fprintf(stderr, "could not open codec\n");
354 /* the codec gives us the frame size, in samples */
356 f = fopen(filename, "rb");
358 fprintf(stderr, "could not open %s\n", filename);
364 size = fread(inbuf, 1, INBUF_SIZE, f);
368 /* NOTE1: some codecs are stream based (mpegvideo, mpegaudio)
369 and this is the only method to use them because you cannot
370 know the compressed data size before analysing it.
372 BUT some other codecs (msmpeg4, mpeg4) are inherently frame
373 based, so you must call them with all the data for one
374 frame exactly. You must also initialize 'width' and
375 'height' before initializing them. */
377 /* NOTE2: some codecs allow the raw parameters (frame size,
378 sample rate) to be changed at any frame. We handle this, so
379 you should also take care of it */
381 /* here, we use a stream based decoder (mpeg1video), so we
382 feed decoder and see if it could decode a frame */
385 len = avcodec_decode_video(c, picture, &got_picture,
388 fprintf(stderr, "Error while decoding frame %d\n", frame);
392 printf("saving frame %3d\n", frame);
395 /* the picture is allocated by the decoder. no need to
397 snprintf(buf, sizeof(buf), outfilename, frame);
398 pgm_save(picture->data[0], picture->linesize[0],
399 c->width, c->height, buf);
407 /* some codecs, such as MPEG, transmit the I and P frame with a
408 latency of one frame. You must do the following to have a
409 chance to get the last frame of the video */
410 len = avcodec_decode_video(c, picture, &got_picture,
413 printf("saving last frame %3d\n", frame);
416 /* the picture is allocated by the decoder. no need to
418 snprintf(buf, sizeof(buf), outfilename, frame);
419 pgm_save(picture->data[0], picture->linesize[0],
420 c->width, c->height, buf);
432 int main(int argc, char **argv)
434 const char *filename;
436 /* must be called before using avcodec lib */
439 /* register all the codecs (you can also register only the codec
440 you wish to have smaller code */
441 avcodec_register_all();
444 audio_encode_example("/tmp/test.mp2");
445 audio_decode_example("/tmp/test.sw", "/tmp/test.mp2");
447 video_encode_example("/tmp/test.mpg");
448 filename = "/tmp/test.mpg";
453 // audio_decode_example("/tmp/test.sw", filename);
454 video_decode_example("/tmp/test%d.pgm", filename);