501 lines
13 KiB
C
501 lines
13 KiB
C
/**
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* @file apiexample.c
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* avcodec API use example.
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*
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* Note that this library only handles codecs (mpeg, mpeg4, etc...),
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* not file formats (avi, vob, etc...). See library 'libav' for the
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* format handling
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*/
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <math.h>
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#ifdef HAVE_AV_CONFIG_H
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#undef HAVE_AV_CONFIG_H
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#endif
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#include "avcodec.h"
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#define INBUF_SIZE 4096
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/*
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* Audio encoding example
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*/
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void audio_encode_example(const char *filename)
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{
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AVCodec *codec;
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AVCodecContext *c= NULL;
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int frame_size, i, j, out_size, outbuf_size;
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FILE *f;
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short *samples;
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float t, tincr;
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uint8_t *outbuf;
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printf("Audio encoding\n");
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/* find the MP2 encoder */
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codec = avcodec_find_encoder(CODEC_ID_MP2);
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if (!codec) {
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fprintf(stderr, "codec not found\n");
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exit(1);
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}
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c= avcodec_alloc_context();
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/* put sample parameters */
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c->bit_rate = 64000;
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c->sample_rate = 44100;
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c->channels = 2;
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/* open it */
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if (avcodec_open(c, codec) < 0) {
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fprintf(stderr, "could not open codec\n");
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exit(1);
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}
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/* the codec gives us the frame size, in samples */
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frame_size = c->frame_size;
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samples = malloc(frame_size * 2 * c->channels);
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outbuf_size = 10000;
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outbuf = malloc(outbuf_size);
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f = fopen(filename, "w");
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if (!f) {
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fprintf(stderr, "could not open %s\n", filename);
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exit(1);
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}
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/* encode a single tone sound */
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t = 0;
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tincr = 2 * M_PI * 440.0 / c->sample_rate;
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for(i=0;i<200;i++) {
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for(j=0;j<frame_size;j++) {
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samples[2*j] = (int)(sin(t) * 10000);
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samples[2*j+1] = samples[2*j];
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t += tincr;
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}
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/* encode the samples */
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out_size = avcodec_encode_audio(c, outbuf, outbuf_size, samples);
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fwrite(outbuf, 1, out_size, f);
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}
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fclose(f);
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free(outbuf);
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free(samples);
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avcodec_close(c);
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free(c);
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}
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/*
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* Audio decoding.
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*/
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void audio_decode_example(const char *outfilename, const char *filename)
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{
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AVCodec *codec;
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AVCodecContext *c= NULL;
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int out_size, size, len;
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FILE *f, *outfile;
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uint8_t *outbuf;
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uint8_t inbuf[INBUF_SIZE], *inbuf_ptr;
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printf("Audio decoding\n");
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/* find the mpeg audio decoder */
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codec = avcodec_find_decoder(CODEC_ID_MP2);
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if (!codec) {
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fprintf(stderr, "codec not found\n");
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exit(1);
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}
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c= avcodec_alloc_context();
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/* open it */
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if (avcodec_open(c, codec) < 0) {
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fprintf(stderr, "could not open codec\n");
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exit(1);
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}
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outbuf = malloc(AVCODEC_MAX_AUDIO_FRAME_SIZE);
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f = fopen(filename, "r");
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if (!f) {
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fprintf(stderr, "could not open %s\n", filename);
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exit(1);
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}
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outfile = fopen(outfilename, "w");
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if (!outfile) {
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free(c);
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exit(1);
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}
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/* decode until eof */
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inbuf_ptr = inbuf;
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for(;;) {
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size = fread(inbuf, 1, INBUF_SIZE, f);
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if (size == 0)
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break;
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inbuf_ptr = inbuf;
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while (size > 0) {
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len = avcodec_decode_audio(c, (short *)outbuf, &out_size,
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inbuf_ptr, size);
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if (len < 0) {
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fprintf(stderr, "Error while decoding\n");
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exit(1);
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}
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if (out_size > 0) {
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/* if a frame has been decoded, output it */
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fwrite(outbuf, 1, out_size, outfile);
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}
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size -= len;
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inbuf_ptr += len;
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}
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}
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fclose(outfile);
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fclose(f);
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free(outbuf);
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avcodec_close(c);
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free(c);
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}
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/*
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* Video encoding example
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*/
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void video_encode_example(const char *filename)
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{
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AVCodec *codec;
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AVCodecContext *c= NULL;
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int i, out_size, size, x, y, outbuf_size;
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FILE *f;
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AVFrame *picture;
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uint8_t *outbuf, *picture_buf;
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printf("Video encoding\n");
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/* find the mpeg1 video encoder */
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codec = avcodec_find_encoder(CODEC_ID_MPEG1VIDEO);
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if (!codec) {
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fprintf(stderr, "codec not found\n");
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exit(1);
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}
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c= avcodec_alloc_context();
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picture= avcodec_alloc_frame();
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/* put sample parameters */
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c->bit_rate = 400000;
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/* resolution must be a multiple of two */
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c->width = 352;
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c->height = 288;
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/* frames per second */
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c->frame_rate = 25;
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c->frame_rate_base= 1;
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c->gop_size = 10; /* emit one intra frame every ten frames */
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/* open it */
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if (avcodec_open(c, codec) < 0) {
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fprintf(stderr, "could not open codec\n");
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exit(1);
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}
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/* the codec gives us the frame size, in samples */
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f = fopen(filename, "w");
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if (!f) {
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fprintf(stderr, "could not open %s\n", filename);
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exit(1);
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}
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/* alloc image and output buffer */
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outbuf_size = 100000;
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outbuf = malloc(outbuf_size);
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size = c->width * c->height;
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picture_buf = malloc((size * 3) / 2); /* size for YUV 420 */
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picture->data[0] = picture_buf;
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picture->data[1] = picture->data[0] + size;
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picture->data[2] = picture->data[1] + size / 4;
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picture->linesize[0] = c->width;
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picture->linesize[1] = c->width / 2;
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picture->linesize[2] = c->width / 2;
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/* encode 1 second of video */
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for(i=0;i<25;i++) {
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printf("encoding frame %3d\r", i);
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fflush(stdout);
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/* prepare a dummy image */
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/* Y */
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for(y=0;y<c->height;y++) {
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for(x=0;x<c->width;x++) {
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picture->data[0][y * picture->linesize[0] + x] = x + y + i * 3;
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}
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}
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/* Cb and Cr */
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for(y=0;y<c->height/2;y++) {
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for(x=0;x<c->width/2;x++) {
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picture->data[1][y * picture->linesize[1] + x] = 128 + y + i * 2;
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picture->data[2][y * picture->linesize[2] + x] = 64 + x + i * 5;
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}
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}
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/* encode the image */
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out_size = avcodec_encode_video(c, outbuf, outbuf_size, picture);
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fwrite(outbuf, 1, out_size, f);
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}
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/* add sequence end code to have a real mpeg file */
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outbuf[0] = 0x00;
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outbuf[1] = 0x00;
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outbuf[2] = 0x01;
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outbuf[3] = 0xb7;
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fwrite(outbuf, 1, 4, f);
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fclose(f);
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free(picture_buf);
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free(outbuf);
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avcodec_close(c);
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free(c);
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free(picture);
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printf("\n");
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}
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/*
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* Video decoding example
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*/
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void pgm_save(unsigned char *buf,int wrap, int xsize,int ysize,char *filename)
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{
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FILE *f;
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int i;
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f=fopen(filename,"w");
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fprintf(f,"P5\n%d %d\n%d\n",xsize,ysize,255);
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for(i=0;i<ysize;i++)
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fwrite(buf + i * wrap,1,xsize,f);
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fclose(f);
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}
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void video_decode_example(const char *outfilename, const char *filename)
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{
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AVCodec *codec;
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AVCodecContext *c= NULL;
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int frame, size, got_picture, len;
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FILE *f;
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AVFrame *picture;
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uint8_t inbuf[INBUF_SIZE], *inbuf_ptr;
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char buf[1024];
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printf("Video decoding\n");
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/* find the mpeg1 video decoder */
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codec = avcodec_find_decoder(CODEC_ID_MPEG1VIDEO);
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if (!codec) {
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fprintf(stderr, "codec not found\n");
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exit(1);
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}
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c= avcodec_alloc_context();
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picture= avcodec_alloc_frame();
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if(codec->capabilities&CODEC_CAP_TRUNCATED)
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c->flags|= CODEC_FLAG_TRUNCATED; /* we dont send complete frames */
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/* for some codecs, such as msmpeg4 and mpeg4, width and height
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MUST be initialized there because these info are not available
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in the bitstream */
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/* open it */
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if (avcodec_open(c, codec) < 0) {
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fprintf(stderr, "could not open codec\n");
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exit(1);
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}
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/* the codec gives us the frame size, in samples */
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f = fopen(filename, "r");
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if (!f) {
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fprintf(stderr, "could not open %s\n", filename);
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exit(1);
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}
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frame = 0;
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for(;;) {
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size = fread(inbuf, 1, INBUF_SIZE, f);
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if (size == 0)
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break;
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/* NOTE1: some codecs are stream based (mpegvideo, mpegaudio)
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and this is the only method to use them because you cannot
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know the compressed data size before analysing it.
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BUT some other codecs (msmpeg4, mpeg4) are inherently frame
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based, so you must call them with all the data for one
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frame exactly. You must also initialize 'width' and
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'height' before initializing them. */
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/* NOTE2: some codecs allow the raw parameters (frame size,
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sample rate) to be changed at any frame. We handle this, so
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you should also take care of it */
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/* here, we use a stream based decoder (mpeg1video), so we
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feed decoder and see if it could decode a frame */
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inbuf_ptr = inbuf;
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while (size > 0) {
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len = avcodec_decode_video(c, picture, &got_picture,
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inbuf_ptr, size);
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if (len < 0) {
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fprintf(stderr, "Error while decoding frame %d\n", frame);
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exit(1);
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}
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if (got_picture) {
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printf("saving frame %3d\r", frame);
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fflush(stdout);
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/* the picture is allocated by the decoder. no need to
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free it */
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snprintf(buf, sizeof(buf), outfilename, frame);
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pgm_save(picture->data[0], picture->linesize[0],
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c->width, c->height, buf);
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frame++;
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}
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size -= len;
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inbuf_ptr += len;
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}
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}
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/* some codecs, such as MPEG, transmit the I and P frame with a
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latency of one frame. You must do the following to have a
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chance to get the last frame of the video */
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len = avcodec_decode_video(c, picture, &got_picture,
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NULL, 0);
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if (got_picture) {
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printf("saving frame %3d\r", frame);
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fflush(stdout);
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/* the picture is allocated by the decoder. no need to
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free it */
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snprintf(buf, sizeof(buf), outfilename, frame);
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pgm_save(picture->data[0], picture->linesize[0],
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c->width, c->height, buf);
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frame++;
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}
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fclose(f);
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avcodec_close(c);
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free(c);
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free(picture);
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printf("\n");
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}
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// simple example how the options could be used
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int options_example(int argc, char* argv[])
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{
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AVCodec* codec = avcodec_find_encoder_by_name((argc > 1) ? argv[2] : "mpeg4");
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const AVOption* c;
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AVCodecContext* avctx;
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char* def = av_malloc(5000);
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const char* col = "";
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int i = 0;
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if (!codec)
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return -1;
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c = codec->options;
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avctx = avcodec_alloc_context();
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*def = 0;
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if (c) {
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const AVOption *stack[FF_OPT_MAX_DEPTH];
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int depth = 0;
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for (;;) {
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if (!c->name) {
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if (c->help) {
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stack[depth++] = c;
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c = (const AVOption*)c->help;
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} else {
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if (depth == 0)
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break; // finished
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c = stack[--depth];
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c++;
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}
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} else {
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int t = c->type & FF_OPT_TYPE_MASK;
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printf("Config %s %s\n",
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t == FF_OPT_TYPE_BOOL ? "bool " :
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t == FF_OPT_TYPE_DOUBLE ? "double " :
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t == FF_OPT_TYPE_INT ? "integer" :
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t == FF_OPT_TYPE_STRING ? "string " :
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"unknown??", c->name);
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switch (t) {
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case FF_OPT_TYPE_BOOL:
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i += sprintf(def + i, "%s%s=%s",
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col, c->name,
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c->defval != 0. ? "on" : "off");
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break;
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case FF_OPT_TYPE_DOUBLE:
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i += sprintf(def + i, "%s%s=%f",
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col, c->name, c->defval);
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break;
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case FF_OPT_TYPE_INT:
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i += sprintf(def + i, "%s%s=%d",
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col, c->name, (int) c->defval);
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break;
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case FF_OPT_TYPE_STRING:
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if (c->defstr) {
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char* d = av_strdup(c->defstr);
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char* f = strchr(d, ',');
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if (f)
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*f = 0;
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i += sprintf(def + i, "%s%s=%s",
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col, c->name, d);
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av_free(d);
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}
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break;
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}
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col = ":";
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c++;
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}
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}
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}
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printf("Default Options: %s\n", def);
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av_free(def);
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return 0;
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}
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int main(int argc, char **argv)
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{
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const char *filename;
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/* must be called before using avcodec lib */
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avcodec_init();
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/* register all the codecs (you can also register only the codec
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you wish to have smaller code */
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avcodec_register_all();
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#ifdef OPT_TEST
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options_example(argc, argv);
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#else
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if (argc <= 1) {
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audio_encode_example("/tmp/test.mp2");
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audio_decode_example("/tmp/test.sw", "/tmp/test.mp2");
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video_encode_example("/tmp/test.mpg");
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filename = "/tmp/test.mpg";
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} else {
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filename = argv[1];
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}
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// audio_decode_example("/tmp/test.sw", filename);
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video_decode_example("/tmp/test%d.pgm", filename);
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#endif
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return 0;
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}
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