diff options
author | Fabrice Bellard <fabrice@bellard.org> | 2001-07-22 18:18:56 +0400 |
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committer | Fabrice Bellard <fabrice@bellard.org> | 2001-07-22 18:18:56 +0400 |
commit | de6d9b6404bfd1c589799142da5a95428f146edd (patch) | |
tree | 75ae0cbb74bdfafb6f1a40922db111a103db3bcf /libavcodec/apiexample.c | |
parent | 1b58d58ddaf8a8c766a0353885ff504babed0453 (diff) |
Initial revision
Originally committed as revision 5 to svn://svn.ffmpeg.org/ffmpeg/trunk
Diffstat (limited to 'libavcodec/apiexample.c')
-rw-r--r-- | libavcodec/apiexample.c | 407 |
1 files changed, 407 insertions, 0 deletions
diff --git a/libavcodec/apiexample.c b/libavcodec/apiexample.c new file mode 100644 index 0000000000..e7ae6e80be --- /dev/null +++ b/libavcodec/apiexample.c @@ -0,0 +1,407 @@ +/* avcodec API use example. + * + * Note that this library only handles codecs (mpeg, mpeg4, etc...), + * not file formats (avi, vob, etc...). See library 'libav' for the + * format handling + */ +#include <stdlib.h> +#include <stdio.h> +#include <string.h> +#include <math.h> + +#include "avcodec.h" + +#define INBUF_SIZE 4096 + +/* + * Audio encoding example + */ +void audio_encode_example(const char *filename) +{ + AVCodec *codec; + AVCodecContext codec_context, *c = &codec_context; + int frame_size, i, j, out_size, outbuf_size; + FILE *f; + short *samples; + float t, tincr; + UINT8 *outbuf; + + printf("Audio encoding\n"); + + /* find the MP2 encoder */ + codec = avcodec_find_encoder(CODEC_ID_MP2); + if (!codec) { + fprintf(stderr, "codec not found\n"); + exit(1); + } + + /* put default values */ + memset(c, 0, sizeof(*c)); + + /* put sample parameters */ + c->bit_rate = 64000; + c->sample_rate = 44100; + c->channels = 2; + + /* open it */ + if (avcodec_open(c, codec) < 0) { + fprintf(stderr, "could not open codec\n"); + exit(1); + } + + /* the codec gives us the frame size, in samples */ + frame_size = c->frame_size; + samples = malloc(frame_size * 2 * c->channels); + outbuf_size = 10000; + outbuf = malloc(outbuf_size); + + f = fopen(filename, "w"); + if (!f) { + fprintf(stderr, "could not open %s\n", filename); + exit(1); + } + + /* encode a single tone sound */ + t = 0; + tincr = 2 * M_PI * 440.0 / c->sample_rate; + for(i=0;i<200;i++) { + for(j=0;j<frame_size;j++) { + samples[2*j] = (int)(sin(t) * 10000); + samples[2*j+1] = samples[2*j]; + t += tincr; + } + /* encode the samples */ + out_size = avcodec_encode_audio(c, outbuf, outbuf_size, samples); + fwrite(outbuf, 1, out_size, f); + } + fclose(f); + free(outbuf); + free(samples); + + avcodec_close(c); +} + +/* + * Audio decoding. + */ +void audio_decode_example(const char *outfilename, const char *filename) +{ + AVCodec *codec; + AVCodecContext codec_context, *c = &codec_context; + int out_size, size, len; + FILE *f, *outfile; + UINT8 *outbuf; + UINT8 inbuf[INBUF_SIZE], *inbuf_ptr; + + printf("Audio decoding\n"); + + /* find the mpeg audio decoder */ + codec = avcodec_find_decoder(CODEC_ID_MP2); + if (!codec) { + fprintf(stderr, "codec not found\n"); + exit(1); + } + + /* put default values */ + memset(c, 0, sizeof(*c)); + + /* open it */ + if (avcodec_open(c, codec) < 0) { + fprintf(stderr, "could not open codec\n"); + exit(1); + } + + outbuf = malloc(AVCODEC_MAX_AUDIO_FRAME_SIZE); + + f = fopen(filename, "r"); + if (!f) { + fprintf(stderr, "could not open %s\n", filename); + exit(1); + } + outfile = fopen(outfilename, "w"); + if (!outfile) { + fprintf(stderr, "could not open %s\n", outfilename); + exit(1); + } + + /* decode until eof */ + inbuf_ptr = inbuf; + for(;;) { + size = fread(inbuf, 1, INBUF_SIZE, f); + if (size == 0) + break; + + inbuf_ptr = inbuf; + while (size > 0) { + len = avcodec_decode_audio(c, (short *)outbuf, &out_size, + inbuf_ptr, size); + if (len < 0) { + fprintf(stderr, "Error while decoding\n"); + exit(1); + } + if (out_size > 0) { + /* if a frame has been decoded, output it */ + fwrite(outbuf, 1, out_size, outfile); + } + size -= len; + inbuf_ptr += len; + } + } + + fclose(outfile); + fclose(f); + free(outbuf); + + avcodec_close(c); +} + +/* + * Video encoding example + */ +void video_encode_example(const char *filename) +{ + AVCodec *codec; + AVCodecContext codec_context, *c = &codec_context; + int i, out_size, size, x, y, outbuf_size; + FILE *f; + AVPicture picture; + UINT8 *outbuf, *picture_buf; + + printf("Video encoding\n"); + + /* find the mpeg1 video encoder */ + codec = avcodec_find_encoder(CODEC_ID_MPEG1VIDEO); + if (!codec) { + fprintf(stderr, "codec not found\n"); + exit(1); + } + + /* put default values */ + memset(c, 0, sizeof(*c)); + + /* put sample parameters */ + c->bit_rate = 400000; + /* resolution must be a multiple of two */ + c->width = 352; + c->height = 288; + /* frames per second */ + c->frame_rate = 25 * FRAME_RATE_BASE; + c->gop_size = 10; /* emit one intra frame every ten frames */ + + /* open it */ + if (avcodec_open(c, codec) < 0) { + fprintf(stderr, "could not open codec\n"); + exit(1); + } + + /* the codec gives us the frame size, in samples */ + + f = fopen(filename, "w"); + if (!f) { + fprintf(stderr, "could not open %s\n", filename); + exit(1); + } + + /* alloc image and output buffer */ + outbuf_size = 100000; + outbuf = malloc(outbuf_size); + size = c->width * c->height; + picture_buf = malloc((size * 3) / 2); /* size for YUV 420 */ + + picture.data[0] = picture_buf; + picture.data[1] = picture.data[0] + size; + picture.data[2] = picture.data[1] + size / 4; + picture.linesize[0] = c->width; + picture.linesize[1] = c->width / 2; + picture.linesize[2] = c->width / 2; + + /* encode 1 second of video */ + for(i=0;i<25;i++) { + printf("encoding frame %3d\r", i); + fflush(stdout); + /* prepare a dummy image */ + /* Y */ + for(y=0;y<c->height;y++) { + for(x=0;x<c->width;x++) { + picture.data[0][y * picture.linesize[0] + x] = x + y + i * 3; + } + } + + /* Cb and Cr */ + for(y=0;y<c->height/2;y++) { + for(x=0;x<c->width/2;x++) { + picture.data[1][y * picture.linesize[1] + x] = 128 + y + i * 2; + picture.data[2][y * picture.linesize[2] + x] = 64 + x + i * 5; + } + } + + /* encode the image */ + out_size = avcodec_encode_video(c, outbuf, outbuf_size, &picture); + fwrite(outbuf, 1, out_size, f); + } + + /* add sequence end code to have a real mpeg file */ + outbuf[0] = 0x00; + outbuf[1] = 0x00; + outbuf[2] = 0x01; + outbuf[3] = 0xb7; + fwrite(outbuf, 1, 4, f); + fclose(f); + free(picture_buf); + free(outbuf); + + avcodec_close(c); + printf("\n"); +} + +/* + * Video decoding example + */ + +void pgm_save(unsigned char *buf,int wrap, int xsize,int ysize,char *filename) +{ + FILE *f; + int i; + + f=fopen(filename,"w"); + fprintf(f,"P5\n%d %d\n%d\n",xsize,ysize,255); + for(i=0;i<ysize;i++) + fwrite(buf + i * wrap,1,xsize,f); + fclose(f); +} + +void video_decode_example(const char *outfilename, const char *filename) +{ + AVCodec *codec; + AVCodecContext codec_context, *c = &codec_context; + int frame, size, got_picture, len; + FILE *f; + AVPicture picture; + UINT8 inbuf[INBUF_SIZE], *inbuf_ptr; + char buf[1024]; + + printf("Video decoding\n"); + + /* find the mpeg1 video decoder */ + codec = avcodec_find_decoder(CODEC_ID_MPEG1VIDEO); + if (!codec) { + fprintf(stderr, "codec not found\n"); + exit(1); + } + + /* put default values */ + memset(c, 0, sizeof(*c)); + + /* for some codecs, such as msmpeg4 and opendivx, width and height + MUST be initialized there because these info are not available + in the bitstream */ + + /* open it */ + if (avcodec_open(c, codec) < 0) { + fprintf(stderr, "could not open codec\n"); + exit(1); + } + + /* the codec gives us the frame size, in samples */ + + f = fopen(filename, "r"); + if (!f) { + fprintf(stderr, "could not open %s\n", filename); + exit(1); + } + + frame = 0; + for(;;) { + size = fread(inbuf, 1, INBUF_SIZE, f); + if (size == 0) + break; + + /* NOTE1: some codecs are stream based (mpegvideo, mpegaudio) + and this is the only method to use them because you cannot + know the compressed data size before analysing it. + + BUT some other codecs (msmpeg4, opendivx) are inherently + frame based, so you must call them with all the data for + one frame exactly. You must also initialize 'width' and + 'height' before initializing them. */ + + /* NOTE2: some codecs allow the raw parameters (frame size, + sample rate) to be changed at any frame. We handle this, so + you should also take care of it */ + + /* here, we use a stream based decoder (mpeg1video), so we + feed decoder and see if it could decode a frame */ + inbuf_ptr = inbuf; + while (size > 0) { + len = avcodec_decode_video(c, &picture, &got_picture, + inbuf_ptr, size); + if (len < 0) { + fprintf(stderr, "Error while decoding frame %d\n", frame); + exit(1); + } + if (got_picture) { + printf("saving frame %3d\r", frame); + fflush(stdout); + + /* the picture is allocated by the decoder. no need to + free it */ + snprintf(buf, sizeof(buf), outfilename, frame); + pgm_save(picture.data[0], picture.linesize[0], + c->width, c->height, buf); + frame++; + } + size -= len; + inbuf_ptr += len; + } + } + + /* some codecs, such as MPEG, transmit the I and P frame with a + latency of one frame. You must do the following to have a + chance to get the last frame of the video */ + len = avcodec_decode_video(c, &picture, &got_picture, + NULL, 0); + if (got_picture) { + printf("saving frame %3d\r", frame); + fflush(stdout); + + /* the picture is allocated by the decoder. no need to + free it */ + snprintf(buf, sizeof(buf), outfilename, frame); + pgm_save(picture.data[0], picture.linesize[0], + c->width, c->height, buf); + frame++; + } + + fclose(f); + + avcodec_close(c); + printf("\n"); +} + + +int main(int argc, char **argv) +{ + const char *filename; + + /* must be called before using avcodec lib */ + avcodec_init(); + + /* register all the codecs (you can also register only the codec + you wish to have smaller code */ + avcodec_register_all(); + + if (argc <= 1) { + audio_encode_example("/tmp/test.mp2"); + audio_decode_example("/tmp/test.sw", "/tmp/test.mp2"); + + video_encode_example("/tmp/test.mpg"); + filename = "/tmp/test.mpg"; + } else { + filename = argv[1]; + } + + // audio_decode_example("/tmp/test.sw", filename); + video_decode_example("/tmp/test%d.pgm", filename); + + return 0; +} |