mirror of
https://github.com/FFmpeg/FFmpeg.git
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long awaited simple libavformat output API example
Originally committed as revision 2069 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Fabrice Bellard
parent
6a6362f088
commit
8de65d4f11
6
Makefile
6
Makefile
@ -25,6 +25,7 @@ endif
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endif
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PROG=ffmpeg$(EXE)
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PROGTEST=output_example$(EXE)
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ifeq ($(CONFIG_FFSERVER),yes)
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PROG+=ffserver$(EXE)
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@ -75,7 +76,7 @@ OBJS = ffmpeg.o ffserver.o cmdutils.o ffplay.o
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SRCS = $(OBJS:.o=.c) $(ASM_OBJS:.o=.s)
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FFLIBS = -L./libavformat -lavformat -L./libavcodec -lavcodec
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all: lib $(PROG) $(VHOOK)
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all: lib $(PROG) $(PROGTEST) $(VHOOK)
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lib: $(AMRLIBS)
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$(MAKE) -C libavcodec all
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@ -98,6 +99,9 @@ ffplay$(EXE): ffplay_g$(EXE)
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cp -p $< $@
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$(STRIP) $@
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output_example$(EXE): output_example.o .libs
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$(CC) $(LDFLAGS) -o $@ output_example.o $(FFLIBS) $(EXTRALIBS)
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ffplay.o: ffplay.c
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$(CC) $(CFLAGS) $(SDL_CFLAGS) -c -o $@ $<
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350
output_example.c
Normal file
350
output_example.c
Normal file
@ -0,0 +1,350 @@
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/*
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* Libavformat API example: Output a media file in any supported
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* libavformat format. The default codecs are used.
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*
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* Copyright (c) 2003 Fabrice Bellard
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include <stdlib.h>
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#include <stdio.h>
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#include <math.h>
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#include "avformat.h"
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/* 5 seconds stream duration */
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#define STREAM_DURATION 5.0
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/**************************************************************/
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/* audio output */
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float t, tincr;
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int16_t *samples;
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uint8_t *audio_outbuf;
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int audio_outbuf_size;
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int audio_input_frame_size;
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/*
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* add an audio output stream
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*/
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AVStream *add_audio_stream(AVFormatContext *oc, int codec_id)
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{
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AVCodec *codec;
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AVCodecContext *c;
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AVStream *st;
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st = av_new_stream(oc, 1);
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if (!st) {
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fprintf(stderr, "Could not alloc stream\n");
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exit(1);
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}
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/* find the MP2 encoder */
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codec = avcodec_find_encoder(codec_id);
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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 = &st->codec;
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avcodec_get_context_defaults(c);
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c->codec_type = CODEC_TYPE_AUDIO;
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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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/* init signal generator */
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t = 0;
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tincr = 2 * M_PI * 440.0 / c->sample_rate;
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audio_outbuf_size = 10000;
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audio_outbuf = malloc(audio_outbuf_size);
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/* ugly hack for PCM codecs (will be removed ASAP with new PCM
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support to compute the input frame size in samples */
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if (c->frame_size <= 1) {
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audio_input_frame_size = audio_outbuf_size / c->channels;
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switch(st->codec.codec_id) {
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case CODEC_ID_PCM_S16LE:
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case CODEC_ID_PCM_S16BE:
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case CODEC_ID_PCM_U16LE:
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case CODEC_ID_PCM_U16BE:
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audio_input_frame_size >>= 1;
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break;
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default:
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break;
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}
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} else {
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audio_input_frame_size = c->frame_size;
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}
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samples = malloc(audio_input_frame_size * 2 * c->channels);
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return st;
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}
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void write_audio_frame(AVFormatContext *oc, AVStream *st)
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{
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int j, out_size;
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AVCodecContext *c;
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c = &st->codec;
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for(j=0;j<audio_input_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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out_size = avcodec_encode_audio(c, audio_outbuf, audio_outbuf_size, samples);
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/* write the compressed frame in the media file */
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if (av_write_frame(oc, st->index, audio_outbuf, out_size) != 0) {
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fprintf(stderr, "Error while writing audio frame\n");
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exit(1);
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}
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}
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/**************************************************************/
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/* video output */
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AVFrame *picture;
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uint8_t *video_outbuf;
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int frame_count, video_outbuf_size;
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/* add a video output stream */
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AVStream *add_video_stream(AVFormatContext *oc, int codec_id)
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{
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AVCodec *codec;
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AVCodecContext *c;
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AVStream *st;
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uint8_t *picture_buf;
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int size;
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st = av_new_stream(oc, 0);
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if (!st) {
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fprintf(stderr, "Could not alloc stream\n");
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exit(1);
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}
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/* find the mpeg1 video encoder */
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codec = avcodec_find_encoder(codec_id);
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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 = &st->codec;
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avcodec_get_context_defaults(c);
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c->codec_type = CODEC_TYPE_VIDEO;
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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 = 12; /* emit one intra frame every twelve 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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/* alloc various buffers */
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picture= avcodec_alloc_frame();
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video_outbuf_size = 100000;
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video_outbuf = malloc(video_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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return st;
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}
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void write_video_frame(AVFormatContext *oc, AVStream *st)
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{
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int x, y, i, out_size;
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AVCodecContext *c;
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c = &st->codec;
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/* prepare a dummy image */
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/* Y */
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i = frame_count++;
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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, video_outbuf, video_outbuf_size, picture);
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/* write the compressed frame in the media file */
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if (av_write_frame(oc, st->index, video_outbuf, out_size) != 0) {
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fprintf(stderr, "Error while writing video frame\n");
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exit(1);
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}
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}
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/**************************************************************/
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/* media file output */
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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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AVOutputFormat *fmt;
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AVFormatContext *oc;
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AVStream *st, *audio_st, *video_st;
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int i;
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double audio_pts, video_pts;
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/* initialize libavcodec, and register all codecs and formats */
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av_register_all();
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if (argc != 2) {
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printf("usage: %s output_file\n"
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"API example program for to output media file with libavformat\n"
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"\n", argv[0]);
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exit(1);
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}
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filename = argv[1];
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/* auto detect the output format from the name. default is
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mpeg. */
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fmt = guess_format(NULL, filename, NULL);
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if (!fmt) {
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printf("Could not deduce output format from file extension: using MPEG.\n");
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fmt = guess_format("mpeg", NULL, NULL);
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}
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if (!fmt) {
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fprintf(stderr, "Could not find suitable output format\n");
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exit(1);
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}
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/* allocate the output media context */
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oc = av_mallocz(sizeof(AVFormatContext));
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if (!oc) {
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fprintf(stderr, "Memory error\n");
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exit(1);
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}
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oc->oformat = fmt;
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/* add the audio and video streams using the default format codecs
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and initialize the codecs */
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video_st = NULL;
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audio_st = NULL;
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if (fmt->video_codec != CODEC_ID_NONE) {
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video_st = add_video_stream(oc, fmt->video_codec);
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}
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if (fmt->audio_codec != CODEC_ID_NONE) {
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audio_st = add_audio_stream(oc, fmt->audio_codec);
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}
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dump_format(oc, 0, filename, 1);
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/* open the output file, if needed */
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if (!(fmt->flags & AVFMT_NOFILE)) {
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if (url_fopen(&oc->pb, filename, URL_WRONLY) < 0) {
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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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}
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/* set the output parameters (must be done even if no parameters) */
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av_set_parameters(oc, NULL);
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/* write the stream header, if any */
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av_write_header(oc);
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for(;;) {
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/* compute current audio and video time */
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if (audio_st)
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audio_pts = (double)audio_st->pts.val * oc->pts_num / oc->pts_den;
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else
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audio_pts = 0.0;
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if (video_st)
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video_pts = (double)video_st->pts.val * oc->pts_num / oc->pts_den;
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else
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video_pts = 0.0;
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if ((!audio_st || audio_pts >= STREAM_DURATION) &&
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(!video_st || video_pts >= STREAM_DURATION))
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break;
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/* write interleaved audio and video frames */
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if (!video_st || (video_st && audio_pts < video_pts)) {
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write_audio_frame(oc, audio_st);
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} else {
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write_video_frame(oc, video_st);
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}
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}
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/* close each codec */
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for(i = 0;i < oc->nb_streams; i++) {
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st = oc->streams[i];
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avcodec_close(&st->codec);
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}
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/* write the trailer, if any */
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av_write_trailer(oc);
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if (!(fmt->flags & AVFMT_NOFILE)) {
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/* close the output file */
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url_fclose(&oc->pb);
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}
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/* free the stream */
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av_free(oc);
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return 0;
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}
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