2 * copyright (c) 2001 Fabrice Bellard
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with this library; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 * avcodec API use example.
23 * Note that this library only handles codecs (mpeg, mpeg4, etc...),
24 * not file formats (avi, vob, etc...). See library 'libavformat' for the
33 #ifdef HAVE_AV_CONFIG_H
34 #undef HAVE_AV_CONFIG_H
39 #define INBUF_SIZE 4096
42 * Audio encoding example
44 void audio_encode_example(const char *filename)
47 AVCodecContext *c= NULL;
48 int frame_size, i, j, out_size, outbuf_size;
54 printf("Audio encoding\n");
56 /* find the MP2 encoder */
57 codec = avcodec_find_encoder(CODEC_ID_MP2);
59 fprintf(stderr, "codec not found\n");
63 c= avcodec_alloc_context();
65 /* put sample parameters */
67 c->sample_rate = 44100;
71 if (avcodec_open(c, codec) < 0) {
72 fprintf(stderr, "could not open codec\n");
76 /* the codec gives us the frame size, in samples */
77 frame_size = c->frame_size;
78 samples = malloc(frame_size * 2 * c->channels);
80 outbuf = malloc(outbuf_size);
82 f = fopen(filename, "wb");
84 fprintf(stderr, "could not open %s\n", filename);
88 /* encode a single tone sound */
90 tincr = 2 * M_PI * 440.0 / c->sample_rate;
92 for(j=0;j<frame_size;j++) {
93 samples[2*j] = (int)(sin(t) * 10000);
94 samples[2*j+1] = samples[2*j];
97 /* encode the samples */
98 out_size = avcodec_encode_audio(c, outbuf, outbuf_size, samples);
99 fwrite(outbuf, 1, out_size, f);
112 void audio_decode_example(const char *outfilename, const char *filename)
115 AVCodecContext *c= NULL;
116 int out_size, size, len;
119 uint8_t inbuf[INBUF_SIZE + FF_INPUT_BUFFER_PADDING_SIZE], *inbuf_ptr;
121 printf("Audio decoding\n");
123 /* set end of buffer to 0 (this ensures that no overreading happens for damaged mpeg streams) */
124 memset(inbuf + INBUF_SIZE, 0, FF_INPUT_BUFFER_PADDING_SIZE);
126 /* find the mpeg audio decoder */
127 codec = avcodec_find_decoder(CODEC_ID_MP2);
129 fprintf(stderr, "codec not found\n");
133 c= avcodec_alloc_context();
136 if (avcodec_open(c, codec) < 0) {
137 fprintf(stderr, "could not open codec\n");
141 outbuf = malloc(AVCODEC_MAX_AUDIO_FRAME_SIZE);
143 f = fopen(filename, "rb");
145 fprintf(stderr, "could not open %s\n", filename);
148 outfile = fopen(outfilename, "wb");
154 /* decode until eof */
157 size = fread(inbuf, 1, INBUF_SIZE, f);
163 len = avcodec_decode_audio(c, (short *)outbuf, &out_size,
166 fprintf(stderr, "Error while decoding\n");
170 /* if a frame has been decoded, output it */
171 fwrite(outbuf, 1, out_size, outfile);
187 * Video encoding example
189 void video_encode_example(const char *filename)
192 AVCodecContext *c= NULL;
193 int i, out_size, size, x, y, outbuf_size;
196 uint8_t *outbuf, *picture_buf;
198 printf("Video encoding\n");
200 /* find the mpeg1 video encoder */
201 codec = avcodec_find_encoder(CODEC_ID_MPEG1VIDEO);
203 fprintf(stderr, "codec not found\n");
207 c= avcodec_alloc_context();
208 picture= avcodec_alloc_frame();
210 /* put sample parameters */
211 c->bit_rate = 400000;
212 /* resolution must be a multiple of two */
215 /* frames per second */
216 c->time_base= (AVRational){1,25};
217 c->gop_size = 10; /* emit one intra frame every ten frames */
219 c->pix_fmt = PIX_FMT_YUV420P;
222 if (avcodec_open(c, codec) < 0) {
223 fprintf(stderr, "could not open codec\n");
227 /* the codec gives us the frame size, in samples */
229 f = fopen(filename, "wb");
231 fprintf(stderr, "could not open %s\n", filename);
235 /* alloc image and output buffer */
236 outbuf_size = 100000;
237 outbuf = malloc(outbuf_size);
238 size = c->width * c->height;
239 picture_buf = malloc((size * 3) / 2); /* size for YUV 420 */
241 picture->data[0] = picture_buf;
242 picture->data[1] = picture->data[0] + size;
243 picture->data[2] = picture->data[1] + size / 4;
244 picture->linesize[0] = c->width;
245 picture->linesize[1] = c->width / 2;
246 picture->linesize[2] = c->width / 2;
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);
299 * Video decoding example
302 void pgm_save(unsigned char *buf,int wrap, int xsize,int ysize,char *filename)
307 f=fopen(filename,"w");
308 fprintf(f,"P5\n%d %d\n%d\n",xsize,ysize,255);
310 fwrite(buf + i * wrap,1,xsize,f);
314 void video_decode_example(const char *outfilename, const char *filename)
317 AVCodecContext *c= NULL;
318 int frame, size, got_picture, len;
321 uint8_t inbuf[INBUF_SIZE + FF_INPUT_BUFFER_PADDING_SIZE], *inbuf_ptr;
324 /* set end of buffer to 0 (this ensures that no overreading happens for damaged mpeg streams) */
325 memset(inbuf + INBUF_SIZE, 0, FF_INPUT_BUFFER_PADDING_SIZE);
327 printf("Video decoding\n");
329 /* find the mpeg1 video decoder */
330 codec = avcodec_find_decoder(CODEC_ID_MPEG1VIDEO);
332 fprintf(stderr, "codec not found\n");
336 c= avcodec_alloc_context();
337 picture= avcodec_alloc_frame();
339 if(codec->capabilities&CODEC_CAP_TRUNCATED)
340 c->flags|= CODEC_FLAG_TRUNCATED; /* we dont send complete frames */
342 /* for some codecs, such as msmpeg4 and mpeg4, width and height
343 MUST be initialized there because these info are not available
347 if (avcodec_open(c, codec) < 0) {
348 fprintf(stderr, "could not open codec\n");
352 /* the codec gives us the frame size, in samples */
354 f = fopen(filename, "rb");
356 fprintf(stderr, "could not open %s\n", filename);
362 size = fread(inbuf, 1, INBUF_SIZE, f);
366 /* NOTE1: some codecs are stream based (mpegvideo, mpegaudio)
367 and this is the only method to use them because you cannot
368 know the compressed data size before analysing it.
370 BUT some other codecs (msmpeg4, mpeg4) are inherently frame
371 based, so you must call them with all the data for one
372 frame exactly. You must also initialize 'width' and
373 'height' before initializing them. */
375 /* NOTE2: some codecs allow the raw parameters (frame size,
376 sample rate) to be changed at any frame. We handle this, so
377 you should also take care of it */
379 /* here, we use a stream based decoder (mpeg1video), so we
380 feed decoder and see if it could decode a frame */
383 len = avcodec_decode_video(c, picture, &got_picture,
386 fprintf(stderr, "Error while decoding frame %d\n", frame);
390 printf("saving frame %3d\n", frame);
393 /* the picture is allocated by the decoder. no need to
395 snprintf(buf, sizeof(buf), outfilename, frame);
396 pgm_save(picture->data[0], picture->linesize[0],
397 c->width, c->height, buf);
405 /* some codecs, such as MPEG, transmit the I and P frame with a
406 latency of one frame. You must do the following to have a
407 chance to get the last frame of the video */
408 len = avcodec_decode_video(c, picture, &got_picture,
411 printf("saving last frame %3d\n", frame);
414 /* the picture is allocated by the decoder. no need to
416 snprintf(buf, sizeof(buf), outfilename, frame);
417 pgm_save(picture->data[0], picture->linesize[0],
418 c->width, c->height, buf);
430 int main(int argc, char **argv)
432 const char *filename;
434 /* must be called before using avcodec lib */
437 /* register all the codecs (you can also register only the codec
438 you wish to have smaller code */
439 avcodec_register_all();
442 audio_encode_example("/tmp/test.mp2");
443 audio_decode_example("/tmp/test.sw", "/tmp/test.mp2");
445 video_encode_example("/tmp/test.mpg");
446 filename = "/tmp/test.mpg";
451 // audio_decode_example("/tmp/test.sw", filename);
452 video_decode_example("/tmp/test%d.pgm", filename);