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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 3.1415926535897931
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#endif
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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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#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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/**************************************************************/
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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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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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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 = 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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}
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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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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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void write_audio_frame(AVFormatContext *oc, AVStream *st)
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{
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    int out_size;
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    AVCodecContext *c;
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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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    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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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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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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    /* frames per second */
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    c->frame_rate = STREAM_FRAME_RATE;  
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    c->frame_rate_base = 1;
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    c->gop_size = 12; /* emit one intra frame every twelve frames at most */
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    if (c->codec_id == CODEC_ID_MPEG1VIDEO ||
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        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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    // some formats want stream headers to be seperate
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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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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 = 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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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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        video_outbuf_size = 200000;
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        video_outbuf = 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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void fill_yuv_image(AVFrame *pict, int frame_index, int width, int height)
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{
283
    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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void write_video_frame(AVFormatContext *oc, AVStream *st)
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{
305
    int out_size, ret;
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    AVCodecContext *c;
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    AVFrame *picture_ptr;
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    c = &st->codec;
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311
    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 a NULL picture */
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        picture_ptr = NULL;
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    } else {
317
        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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            fill_yuv_image(tmp_picture, frame_count, c->width, c->height);
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            img_convert((AVPicture *)picture, c->pix_fmt, 
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                        (AVPicture *)tmp_picture, PIX_FMT_YUV420P,
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                        c->width, c->height);
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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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        picture_ptr = picture;
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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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        ret = av_write_frame(oc, st->index, 
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                       (uint8_t *)picture_ptr, sizeof(AVPicture));
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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_ptr);
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        /* if zero size, it means the image was buffered */
340
        if (out_size != 0) {
341
            /* write the compressed frame in the media file */
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            /* XXX: in case of B frames, the pts is not yet valid */
343
            ret = av_write_frame(oc, st->index, video_outbuf, out_size);
344
        } else {
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            ret = 0;
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        }
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    }
348
    if (ret != 0) {
349
        fprintf(stderr, "Error while writing video frame\n");
350
        exit(1);
351
    }
352
    frame_count++;
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}
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void close_video(AVFormatContext *oc, AVStream *st)
356
{
357
    avcodec_close(&st->codec);
358
    av_free(picture->data[0]);
359
    av_free(picture);
360
    if (tmp_picture) {
361
        av_free(tmp_picture->data[0]);
362
        av_free(tmp_picture);
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    }
364
    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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379
    /* initialize libavcodec, and register all codecs and formats */
380
    av_register_all();
381
    
382
    if (argc != 2) {
383
        printf("usage: %s output_file\n"
384
               "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]);
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        exit(1);
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    }
390
    
391
    filename = argv[1];
392

    
393
    /* auto detect the output format from the name. default is
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       mpeg. */
395
    fmt = guess_format(NULL, filename, NULL);
396
    if (!fmt) {
397
        printf("Could not deduce output format from file extension: using MPEG.\n");
398
        fmt = guess_format("mpeg", NULL, NULL);
399
    }
400
    if (!fmt) {
401
        fprintf(stderr, "Could not find suitable output format\n");
402
        exit(1);
403
    }
404
    
405
    /* allocate the output media context */
406
    oc = av_mallocz(sizeof(AVFormatContext));
407
    if (!oc) {
408
        fprintf(stderr, "Memory error\n");
409
        exit(1);
410
    }
411
    oc->oformat = fmt;
412
    snprintf(oc->filename, sizeof(oc->filename), "%s", filename);
413

    
414
    /* add the audio and video streams using the default format codecs
415
       and initialize the codecs */
416
    video_st = NULL;
417
    audio_st = NULL;
418
    if (fmt->video_codec != CODEC_ID_NONE) {
419
        video_st = add_video_stream(oc, fmt->video_codec);
420
    }
421
    if (fmt->audio_codec != CODEC_ID_NONE) {
422
        audio_st = add_audio_stream(oc, fmt->audio_codec);
423
    }
424

    
425
    /* set the output parameters (must be done even if no
426
       parameters). */
427
    if (av_set_parameters(oc, NULL) < 0) {
428
        fprintf(stderr, "Invalid output format parameters\n");
429
        exit(1);
430
    }
431

    
432
    dump_format(oc, 0, filename, 1);
433

    
434
    /* now that all the parameters are set, we can open the audio and
435
       video codecs and allocate the necessary encode buffers */
436
    if (video_st)
437
        open_video(oc, video_st);
438
    if (audio_st)
439
        open_audio(oc, audio_st);
440

    
441
    /* open the output file, if needed */
442
    if (!(fmt->flags & AVFMT_NOFILE)) {
443
        if (url_fopen(&oc->pb, filename, URL_WRONLY) < 0) {
444
            fprintf(stderr, "Could not open '%s'\n", filename);
445
            exit(1);
446
        }
447
    }
448
    
449
    /* write the stream header, if any */
450
    av_write_header(oc);
451
    
452
    for(;;) {
453
        /* compute current audio and video time */
454
        if (audio_st)
455
            audio_pts = (double)audio_st->pts.val * oc->pts_num / oc->pts_den;
456
        else
457
            audio_pts = 0.0;
458
        
459
        if (video_st)
460
            video_pts = (double)video_st->pts.val * oc->pts_num / oc->pts_den;
461
        else
462
            video_pts = 0.0;
463

    
464
        if ((!audio_st || audio_pts >= STREAM_DURATION) && 
465
            (!video_st || video_pts >= STREAM_DURATION))
466
            break;
467
        
468
        /* write interleaved audio and video frames */
469
        if (!video_st || (video_st && audio_st && audio_pts < video_pts)) {
470
            write_audio_frame(oc, audio_st);
471
        } else {
472
            write_video_frame(oc, video_st);
473
        }
474
    }
475

    
476
    /* close each codec */
477
    if (video_st)
478
        close_video(oc, video_st);
479
    if (audio_st)
480
        close_audio(oc, audio_st);
481

    
482
    /* write the trailer, if any */
483
    av_write_trailer(oc);
484
    
485
    /* free the streams */
486
    for(i = 0; i < oc->nb_streams; i++) {
487
        av_freep(&oc->streams[i]);
488
    }
489

    
490
    if (!(fmt->flags & AVFMT_NOFILE)) {
491
        /* close the output file */
492
        url_fclose(&oc->pb);
493
    }
494

    
495
    /* free the stream */
496
    av_free(oc);
497

    
498
    return 0;
499
}