ffmpeg / output_example.c @ 8e2fd8e1
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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 <string.h> |
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#include <math.h> |
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#ifndef M_PI
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#define M_PI 3.14159265358979323846 |
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#endif
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#include "libavformat/avformat.h" |
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#include "libswscale/swscale.h" |
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#undef exit
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/* 5 seconds stream duration */
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#define STREAM_DURATION 5.0 |
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#define STREAM_FRAME_RATE 25 /* 25 images/s */ |
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#define STREAM_NB_FRAMES ((int)(STREAM_DURATION * STREAM_FRAME_RATE)) |
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#define STREAM_PIX_FMT PIX_FMT_YUV420P /* default pix_fmt */ |
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static int sws_flags = SWS_BICUBIC; |
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/**************************************************************/
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/* audio output */
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float t, tincr, tincr2;
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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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static AVStream *add_audio_stream(AVFormatContext *oc, int codec_id) |
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{ |
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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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c = st->codec; |
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c->codec_id = codec_id; |
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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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return st;
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} |
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static void open_audio(AVFormatContext *oc, AVStream *st) |
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{ |
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AVCodecContext *c; |
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AVCodec *codec; |
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c = st->codec; |
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/* find the audio encoder */
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codec = avcodec_find_encoder(c->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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/* 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 * 110.0 / c->sample_rate; |
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/* increment frequency by 110 Hz per second */
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tincr2 = 2 * M_PI * 110.0 / c->sample_rate / c->sample_rate; |
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audio_outbuf_size = 10000;
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audio_outbuf = av_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 = av_malloc(audio_input_frame_size * 2 * c->channels);
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} |
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/* prepare a 16 bit dummy audio frame of 'frame_size' samples and
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'nb_channels' channels */
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static void get_audio_frame(int16_t *samples, int frame_size, int nb_channels) |
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{ |
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int j, i, v;
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int16_t *q; |
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q = samples; |
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for(j=0;j<frame_size;j++) { |
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v = (int)(sin(t) * 10000); |
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for(i = 0; i < nb_channels; i++) |
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*q++ = v; |
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t += tincr; |
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tincr += tincr2; |
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} |
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} |
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static void write_audio_frame(AVFormatContext *oc, AVStream *st) |
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{ |
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AVCodecContext *c; |
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AVPacket pkt; |
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av_init_packet(&pkt); |
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c = st->codec; |
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get_audio_frame(samples, audio_input_frame_size, c->channels); |
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pkt.size= avcodec_encode_audio(c, audio_outbuf, audio_outbuf_size, samples); |
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if (c->coded_frame->pts != AV_NOPTS_VALUE)
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pkt.pts= av_rescale_q(c->coded_frame->pts, c->time_base, st->time_base); |
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pkt.flags |= PKT_FLAG_KEY; |
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pkt.stream_index= st->index; |
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pkt.data= audio_outbuf; |
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/* write the compressed frame in the media file */
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if (av_write_frame(oc, &pkt) != 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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static void close_audio(AVFormatContext *oc, AVStream *st) |
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{ |
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avcodec_close(st->codec); |
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av_free(samples); |
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av_free(audio_outbuf); |
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} |
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/**************************************************************/
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/* video output */
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AVFrame *picture, *tmp_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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static AVStream *add_video_stream(AVFormatContext *oc, int codec_id) |
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{ |
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AVCodecContext *c; |
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AVStream *st; |
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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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c = st->codec; |
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c->codec_id = codec_id; |
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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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/* time base: this is the fundamental unit of time (in seconds) in terms
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of which frame timestamps are represented. for fixed-fps content,
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timebase should be 1/framerate and timestamp increments should be
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identically 1. */
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c->time_base.den = STREAM_FRAME_RATE; |
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c->time_base.num = 1;
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c->gop_size = 12; /* emit one intra frame every twelve frames at most */ |
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c->pix_fmt = STREAM_PIX_FMT; |
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if (c->codec_id == CODEC_ID_MPEG2VIDEO) {
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/* just for testing, we also add B frames */
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c->max_b_frames = 2;
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} |
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if (c->codec_id == CODEC_ID_MPEG1VIDEO){
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/* Needed to avoid using macroblocks in which some coeffs overflow.
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This does not happen with normal video, it just happens here as
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the motion of the chroma plane does not match the luma plane. */
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c->mb_decision=2;
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} |
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// some formats want stream headers to be separate
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if(!strcmp(oc->oformat->name, "mp4") || !strcmp(oc->oformat->name, "mov") || !strcmp(oc->oformat->name, "3gp")) |
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c->flags |= CODEC_FLAG_GLOBAL_HEADER; |
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return st;
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} |
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static AVFrame *alloc_picture(int pix_fmt, int width, int height) |
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{ |
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AVFrame *picture; |
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uint8_t *picture_buf; |
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int size;
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picture = avcodec_alloc_frame(); |
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if (!picture)
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return NULL; |
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size = avpicture_get_size(pix_fmt, width, height); |
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picture_buf = av_malloc(size); |
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if (!picture_buf) {
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av_free(picture); |
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return NULL; |
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} |
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avpicture_fill((AVPicture *)picture, picture_buf, |
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pix_fmt, width, height); |
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return picture;
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} |
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static void open_video(AVFormatContext *oc, AVStream *st) |
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{ |
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AVCodec *codec; |
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AVCodecContext *c; |
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c = st->codec; |
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/* find the video encoder */
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codec = avcodec_find_encoder(c->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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/* open the codec */
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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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video_outbuf = NULL;
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if (!(oc->oformat->flags & AVFMT_RAWPICTURE)) {
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/* allocate output buffer */
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/* XXX: API change will be done */
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/* buffers passed into lav* can be allocated any way you prefer,
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as long as they're aligned enough for the architecture, and
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they're freed appropriately (such as using av_free for buffers
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allocated with av_malloc) */
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video_outbuf_size = 200000;
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video_outbuf = av_malloc(video_outbuf_size); |
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} |
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/* allocate the encoded raw picture */
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picture = alloc_picture(c->pix_fmt, c->width, c->height); |
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if (!picture) {
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fprintf(stderr, "Could not allocate picture\n");
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exit(1);
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} |
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/* if the output format is not YUV420P, then a temporary YUV420P
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picture is needed too. It is then converted to the required
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output format */
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tmp_picture = NULL;
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if (c->pix_fmt != PIX_FMT_YUV420P) {
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tmp_picture = alloc_picture(PIX_FMT_YUV420P, c->width, c->height); |
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if (!tmp_picture) {
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fprintf(stderr, "Could not allocate temporary picture\n");
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exit(1);
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} |
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} |
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} |
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/* prepare a dummy image */
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static void fill_yuv_image(AVFrame *pict, int frame_index, int width, int height) |
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{ |
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int x, y, i;
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i = frame_index; |
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/* Y */
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for(y=0;y<height;y++) { |
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for(x=0;x<width;x++) { |
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pict->data[0][y * pict->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<height/2;y++) { |
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for(x=0;x<width/2;x++) { |
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pict->data[1][y * pict->linesize[1] + x] = 128 + y + i * 2; |
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pict->data[2][y * pict->linesize[2] + x] = 64 + x + i * 5; |
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} |
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} |
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} |
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static void write_video_frame(AVFormatContext *oc, AVStream *st) |
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{ |
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int out_size, ret;
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AVCodecContext *c; |
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static struct SwsContext *img_convert_ctx; |
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c = st->codec; |
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if (frame_count >= STREAM_NB_FRAMES) {
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/* no more frame to compress. The codec has a latency of a few
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frames if using B frames, so we get the last frames by
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passing the same picture again */
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} else {
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if (c->pix_fmt != PIX_FMT_YUV420P) {
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/* as we only generate a YUV420P picture, we must convert it
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to the codec pixel format if needed */
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if (img_convert_ctx == NULL) { |
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img_convert_ctx = sws_getContext(c->width, c->height, |
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PIX_FMT_YUV420P, |
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c->width, c->height, |
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c->pix_fmt, |
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sws_flags, NULL, NULL, NULL); |
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if (img_convert_ctx == NULL) { |
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fprintf(stderr, "Cannot initialize the conversion context\n");
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exit(1);
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} |
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} |
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fill_yuv_image(tmp_picture, frame_count, c->width, c->height); |
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sws_scale(img_convert_ctx, tmp_picture->data, tmp_picture->linesize, |
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0, c->height, picture->data, picture->linesize);
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} else {
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fill_yuv_image(picture, frame_count, c->width, c->height); |
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} |
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} |
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if (oc->oformat->flags & AVFMT_RAWPICTURE) {
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/* raw video case. The API will change slightly in the near
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futur for that */
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AVPacket pkt; |
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av_init_packet(&pkt); |
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pkt.flags |= PKT_FLAG_KEY; |
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pkt.stream_index= st->index; |
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pkt.data= (uint8_t *)picture; |
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pkt.size= sizeof(AVPicture);
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ret = av_write_frame(oc, &pkt); |
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} else {
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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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/* if zero size, it means the image was buffered */
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if (out_size > 0) { |
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AVPacket pkt; |
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av_init_packet(&pkt); |
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if (c->coded_frame->pts != AV_NOPTS_VALUE)
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pkt.pts= av_rescale_q(c->coded_frame->pts, c->time_base, st->time_base); |
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if(c->coded_frame->key_frame)
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pkt.flags |= PKT_FLAG_KEY; |
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pkt.stream_index= st->index; |
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pkt.data= video_outbuf; |
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pkt.size= out_size; |
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/* write the compressed frame in the media file */
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ret = av_write_frame(oc, &pkt); |
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} else {
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ret = 0;
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} |
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} |
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if (ret != 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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frame_count++; |
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} |
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static void close_video(AVFormatContext *oc, AVStream *st) |
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{ |
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avcodec_close(st->codec); |
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av_free(picture->data[0]);
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av_free(picture); |
410 |
if (tmp_picture) {
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av_free(tmp_picture->data[0]);
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av_free(tmp_picture); |
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} |
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av_free(video_outbuf); |
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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 *audio_st, *video_st; |
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double audio_pts, video_pts;
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int i;
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/* initialize libavcodec, and register all codecs and formats */
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av_register_all(); |
431 |
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if (argc != 2) { |
433 |
printf("usage: %s output_file\n"
|
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"API example program to output a media file with libavformat.\n"
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"The output format is automatically guessed according to the file extension.\n"
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"Raw images can also be output by using '%%d' in the filename\n"
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"\n", argv[0]); |
438 |
exit(1);
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} |
440 |
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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); |
446 |
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); |
449 |
} |
450 |
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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} |
454 |
|
455 |
/* allocate the output media context */
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oc = avformat_alloc_context(); |
457 |
if (!oc) {
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458 |
fprintf(stderr, "Memory error\n");
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exit(1);
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} |
461 |
oc->oformat = fmt; |
462 |
snprintf(oc->filename, sizeof(oc->filename), "%s", filename); |
463 |
|
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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); |
470 |
} |
471 |
if (fmt->audio_codec != CODEC_ID_NONE) {
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audio_st = add_audio_stream(oc, fmt->audio_codec); |
473 |
} |
474 |
|
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/* set the output parameters (must be done even if no
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parameters). */
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if (av_set_parameters(oc, NULL) < 0) { |
478 |
fprintf(stderr, "Invalid output format parameters\n");
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exit(1);
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} |
481 |
|
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dump_format(oc, 0, filename, 1); |
483 |
|
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/* now that all the parameters are set, we can open the audio and
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video codecs and allocate the necessary encode buffers */
|
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if (video_st)
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open_video(oc, video_st); |
488 |
if (audio_st)
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open_audio(oc, audio_st); |
490 |
|
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/* open the output file, if needed */
|
492 |
if (!(fmt->flags & AVFMT_NOFILE)) {
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if (url_fopen(&oc->pb, filename, URL_WRONLY) < 0) { |
494 |
fprintf(stderr, "Could not open '%s'\n", filename);
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exit(1);
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} |
497 |
} |
498 |
|
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/* write the stream header, if any */
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av_write_header(oc); |
501 |
|
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for(;;) {
|
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/* compute current audio and video time */
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504 |
if (audio_st)
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audio_pts = (double)audio_st->pts.val * audio_st->time_base.num / audio_st->time_base.den;
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else
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audio_pts = 0.0; |
508 |
|
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if (video_st)
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video_pts = (double)video_st->pts.val * video_st->time_base.num / video_st->time_base.den;
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else
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video_pts = 0.0; |
513 |
|
514 |
if ((!audio_st || audio_pts >= STREAM_DURATION) &&
|
515 |
(!video_st || video_pts >= STREAM_DURATION)) |
516 |
break;
|
517 |
|
518 |
/* write interleaved audio and video frames */
|
519 |
if (!video_st || (video_st && audio_st && audio_pts < video_pts)) {
|
520 |
write_audio_frame(oc, audio_st); |
521 |
} else {
|
522 |
write_video_frame(oc, video_st); |
523 |
} |
524 |
} |
525 |
|
526 |
/* close each codec */
|
527 |
if (video_st)
|
528 |
close_video(oc, video_st); |
529 |
if (audio_st)
|
530 |
close_audio(oc, audio_st); |
531 |
|
532 |
/* write the trailer, if any */
|
533 |
av_write_trailer(oc); |
534 |
|
535 |
/* free the streams */
|
536 |
for(i = 0; i < oc->nb_streams; i++) { |
537 |
av_freep(&oc->streams[i]->codec); |
538 |
av_freep(&oc->streams[i]); |
539 |
} |
540 |
|
541 |
if (!(fmt->flags & AVFMT_NOFILE)) {
|
542 |
/* close the output file */
|
543 |
url_fclose(oc->pb); |
544 |
} |
545 |
|
546 |
/* free the stream */
|
547 |
av_free(oc); |
548 |
|
549 |
return 0; |
550 |
} |