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ffmpeg / libavformat / flvdec.c @ 1ae7518d

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/*
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 * FLV demuxer
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 * Copyright (c) 2003 The FFmpeg Project.
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 *
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 *
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 * This demuxer will generate a 1 byte extradata for VP6F content.
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 * It is composed of:
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 *  - upper 4bits: difference between encoded width and visible width
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 *  - lower 4bits: difference between encoded height and visible height
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 */
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#include "avformat.h"
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#include "flv.h"
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static int flv_probe(AVProbeData *p)
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{
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    const uint8_t *d;
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    if (p->buf_size < 6)
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        return 0;
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    d = p->buf;
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    if (d[0] == 'F' && d[1] == 'L' && d[2] == 'V') {
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        return 50;
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    }
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    return 0;
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}
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static void flv_set_audio_codec(AVFormatContext *s, AVStream *astream, int flv_codecid) {
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    AVCodecContext *acodec = astream->codec;
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    switch(flv_codecid) {
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        //no distinction between S16 and S8 PCM codec flags
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        case FLV_CODECID_PCM_BE:
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            acodec->codec_id = acodec->bits_per_sample == 8 ? CODEC_ID_PCM_S8 : CODEC_ID_PCM_S16BE; break;
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        case FLV_CODECID_PCM_LE:
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            acodec->codec_id = acodec->bits_per_sample == 8 ? CODEC_ID_PCM_S8 : CODEC_ID_PCM_S16LE; break;
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        case FLV_CODECID_ADPCM: acodec->codec_id = CODEC_ID_ADPCM_SWF;                              break;
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        case FLV_CODECID_MP3  : acodec->codec_id = CODEC_ID_MP3      ; astream->need_parsing = 1  ; break;
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        case FLV_CODECID_NELLYMOSER_8HZ_MONO:
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            acodec->sample_rate = 8000; //in case metadata does not otherwise declare samplerate
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        case FLV_CODECID_NELLYMOSER:
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        default:
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            av_log(s, AV_LOG_INFO, "Unsupported audio codec (%x)\n", flv_codecid >> FLV_AUDIO_CODECID_OFFSET);
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            acodec->codec_tag = flv_codecid >> FLV_AUDIO_CODECID_OFFSET;
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    }
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}
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static int flv_set_video_codec(AVFormatContext *s, AVStream *vstream, int flv_codecid) {
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    AVCodecContext *vcodec = vstream->codec;
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    switch(flv_codecid) {
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        case FLV_CODECID_H263  : vcodec->codec_id = CODEC_ID_FLV1   ; break;
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        case FLV_CODECID_SCREEN: vcodec->codec_id = CODEC_ID_FLASHSV; break;
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        case FLV_CODECID_VP6   : vcodec->codec_id = CODEC_ID_VP6F   ;
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            if(vcodec->extradata_size != 1) {
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                vcodec->extradata_size = 1;
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                vcodec->extradata = av_malloc(1);
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            }
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            vcodec->extradata[0] = get_byte(&s->pb);
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            return 1; // 1 byte body size adjustment for flv_read_packet()
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        default:
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            av_log(s, AV_LOG_INFO, "Unsupported video codec (%x)\n", flv_codecid);
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            vcodec->codec_tag = flv_codecid;
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    }
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    return 0;
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}
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static int amf_get_string(ByteIOContext *ioc, char *buffer, int buffsize) {
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    int length = get_be16(ioc);
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    if(length >= buffsize) {
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        url_fskip(ioc, length);
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        return -1;
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    }
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    get_buffer(ioc, buffer, length);
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    buffer[length] = '\0';
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    return length;
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}
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static int amf_parse_object(AVFormatContext *s, AVStream *astream, AVStream *vstream, const char *key, unsigned int max_pos, int depth) {
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    AVCodecContext *acodec, *vcodec;
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    ByteIOContext *ioc;
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    AMFDataType amf_type;
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    char str_val[256];
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    double num_val;
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    num_val = 0;
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    ioc = &s->pb;
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    amf_type = get_byte(ioc);
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    switch(amf_type) {
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        case AMF_DATA_TYPE_NUMBER:
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            num_val = av_int2dbl(get_be64(ioc)); break;
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        case AMF_DATA_TYPE_BOOL:
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            num_val = get_byte(ioc); break;
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        case AMF_DATA_TYPE_STRING:
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            if(amf_get_string(ioc, str_val, sizeof(str_val)) < 0)
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                return -1;
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            break;
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        case AMF_DATA_TYPE_OBJECT: {
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            unsigned int keylen;
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            while(url_ftell(ioc) < max_pos - 2 && (keylen = get_be16(ioc))) {
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                url_fskip(ioc, keylen); //skip key string
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                if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)
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                    return -1; //if we couldn't skip, bomb out.
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            }
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            if(get_byte(ioc) != AMF_END_OF_OBJECT)
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                return -1;
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        }
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            break;
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        case AMF_DATA_TYPE_NULL:
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        case AMF_DATA_TYPE_UNDEFINED:
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        case AMF_DATA_TYPE_UNSUPPORTED:
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            break; //these take up no additional space
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        case AMF_DATA_TYPE_MIXEDARRAY:
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            url_fskip(ioc, 4); //skip 32-bit max array index
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            while(url_ftell(ioc) < max_pos - 2 && amf_get_string(ioc, str_val, sizeof(str_val)) > 0) {
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                //this is the only case in which we would want a nested parse to not skip over the object
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                if(amf_parse_object(s, astream, vstream, str_val, max_pos, depth + 1) < 0)
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                    return -1;
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            }
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            if(get_byte(ioc) != AMF_END_OF_OBJECT)
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                return -1;
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            break;
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        case AMF_DATA_TYPE_ARRAY: {
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            unsigned int arraylen, i;
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            arraylen = get_be32(ioc);
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            for(i = 0; i < arraylen && url_ftell(ioc) < max_pos - 1; i++) {
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                if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)
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                    return -1; //if we couldn't skip, bomb out.
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            }
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        }
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            break;
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        case AMF_DATA_TYPE_DATE:
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            url_fskip(ioc, 8 + 2); //timestamp (double) and UTC offset (int16)
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            break;
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        default: //unsupported type, we couldn't skip
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            return -1;
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    }
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    if(depth == 1 && key) { //only look for metadata values when we are not nested and key != NULL
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        acodec = astream ? astream->codec : NULL;
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        vcodec = vstream ? vstream->codec : NULL;
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        if(amf_type == AMF_DATA_TYPE_BOOL) {
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            if(!strcmp(key, "stereo") && acodec) acodec->channels = num_val > 0 ? 2 : 1;
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        } else if(amf_type == AMF_DATA_TYPE_NUMBER) {
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            if(!strcmp(key, "duration")) s->duration = num_val * AV_TIME_BASE;
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            else if(!strcmp(key, "width")  && vcodec && num_val > 0) vcodec->width  = num_val;
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            else if(!strcmp(key, "height") && vcodec && num_val > 0) vcodec->height = num_val;
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            else if(!strcmp(key, "audiocodecid") && acodec) flv_set_audio_codec(s, astream, (int)num_val << FLV_AUDIO_CODECID_OFFSET);
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            else if(!strcmp(key, "videocodecid") && vcodec) flv_set_video_codec(s, vstream, (int)num_val);
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            else if(!strcmp(key, "audiosamplesize") && acodec && num_val >= 0) {
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                acodec->bits_per_sample = num_val;
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                //we may have to rewrite a previously read codecid because FLV only marks PCM endianness.
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                if(num_val == 8 && (acodec->codec_id == CODEC_ID_PCM_S16BE || acodec->codec_id == CODEC_ID_PCM_S16LE))
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                    acodec->codec_id = CODEC_ID_PCM_S8;
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            }
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            else if(!strcmp(key, "audiosamplerate") && acodec && num_val >= 0) {
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                //some tools, like FLVTool2, write consistently approximate metadata sample rates
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                switch((int)num_val) {
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                    case 44000: acodec->sample_rate = 44100  ; break;
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                    case 22000: acodec->sample_rate = 22050  ; break;
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                    case 11000: acodec->sample_rate = 11025  ; break;
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                    case 5000 : acodec->sample_rate = 5512   ; break;
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                    default   : acodec->sample_rate = num_val;
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                }
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            }
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        }
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    }
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    return 0;
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}
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static int flv_read_metabody(AVFormatContext *s, unsigned int next_pos) {
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    AMFDataType type;
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    AVStream *stream, *astream, *vstream;
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    ByteIOContext *ioc;
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    int i, keylen;
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    char buffer[11]; //only needs to hold the string "onMetaData". Anything longer is something we don't want.
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    astream = NULL;
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    vstream = NULL;
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    keylen = 0;
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    ioc = &s->pb;
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    //first object needs to be "onMetaData" string
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    type = get_byte(ioc);
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    if(type != AMF_DATA_TYPE_STRING || amf_get_string(ioc, buffer, sizeof(buffer)) < 0 || strcmp(buffer, "onMetaData"))
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        return -1;
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211
    //find the streams now so that amf_parse_object doesn't need to do the lookup every time it is called.
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    for(i = 0; i < s->nb_streams; i++) {
213
        stream = s->streams[i];
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        if     (stream->codec->codec_type == CODEC_TYPE_AUDIO) astream = stream;
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        else if(stream->codec->codec_type == CODEC_TYPE_VIDEO) vstream = stream;
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    }
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    //parse the second object (we want a mixed array)
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    if(amf_parse_object(s, astream, vstream, buffer, next_pos, 0) < 0)
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        return -1;
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222
    return 0;
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}
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static int flv_read_header(AVFormatContext *s,
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                           AVFormatParameters *ap)
227
{
228
    int offset, flags;
229
    AVStream *st;
230

    
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    url_fskip(&s->pb, 4);
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    flags = get_byte(&s->pb);
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234
    if(flags & FLV_HEADER_FLAG_HASVIDEO){
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        st = av_new_stream(s, 0);
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        if (!st)
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            return AVERROR_NOMEM;
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        st->codec->codec_type = CODEC_TYPE_VIDEO;
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        av_set_pts_info(st, 24, 1, 1000); /* 24 bit pts in ms */
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    }
241
    if(flags & FLV_HEADER_FLAG_HASAUDIO){
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        st = av_new_stream(s, 1);
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        if (!st)
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            return AVERROR_NOMEM;
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        st->codec->codec_type = CODEC_TYPE_AUDIO;
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        av_set_pts_info(st, 24, 1, 1000); /* 24 bit pts in ms */
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    }
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    offset = get_be32(&s->pb);
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    url_fseek(&s->pb, offset, SEEK_SET);
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    s->start_time = 0;
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    return 0;
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}
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static int flv_read_packet(AVFormatContext *s, AVPacket *pkt)
258
{
259
    int ret, i, type, size, pts, flags, is_audio, next, pos;
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    AVStream *st = NULL;
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262
 for(;;){
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    pos = url_ftell(&s->pb);
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    url_fskip(&s->pb, 4); /* size of previous packet */
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    type = get_byte(&s->pb);
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    size = get_be24(&s->pb);
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    pts = get_be24(&s->pb);
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//    av_log(s, AV_LOG_DEBUG, "type:%d, size:%d, pts:%d\n", type, size, pts);
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    if (url_feof(&s->pb))
270
        return AVERROR_IO;
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    url_fskip(&s->pb, 4); /* reserved */
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    flags = 0;
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274
    if(size == 0)
275
        continue;
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277
    next= size + url_ftell(&s->pb);
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279
    if (type == FLV_TAG_TYPE_AUDIO) {
280
        is_audio=1;
281
        flags = get_byte(&s->pb);
282
    } else if (type == FLV_TAG_TYPE_VIDEO) {
283
        is_audio=0;
284
        flags = get_byte(&s->pb);
285
    } else {
286
        if (type == FLV_TAG_TYPE_META && size > 13+1+4)
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            flv_read_metabody(s, next);
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        else /* skip packet */
289
            av_log(s, AV_LOG_ERROR, "skipping flv packet: type %d, size %d, flags %d\n", type, size, flags);
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        url_fseek(&s->pb, next, SEEK_SET);
291
        continue;
292
    }
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294
    /* now find stream */
295
    for(i=0;i<s->nb_streams;i++) {
296
        st = s->streams[i];
297
        if (st->id == is_audio)
298
            break;
299
    }
300
    if(i == s->nb_streams){
301
        av_log(NULL, AV_LOG_ERROR, "invalid stream\n");
302
        url_fseek(&s->pb, next, SEEK_SET);
303
        continue;
304
    }
305
//    av_log(NULL, AV_LOG_DEBUG, "%d %X %d \n", is_audio, flags, st->discard);
306
    if(  (st->discard >= AVDISCARD_NONKEY && !((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY ||         is_audio))
307
       ||(st->discard >= AVDISCARD_BIDIR  &&  ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_DISP_INTER && !is_audio))
308
       || st->discard >= AVDISCARD_ALL
309
       ){
310
        url_fseek(&s->pb, next, SEEK_SET);
311
        continue;
312
    }
313
    if ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY)
314
        av_add_index_entry(st, pos, pts, size, 0, AVINDEX_KEYFRAME);
315
    break;
316
 }
317

    
318
    // if not streamed and no duration from metadata then seek to end to find the duration from the timestamps
319
    if(!url_is_streamed(&s->pb) && s->duration==AV_NOPTS_VALUE){
320
        int size;
321
        const int pos= url_ftell(&s->pb);
322
        const int fsize= url_fsize(&s->pb);
323
        url_fseek(&s->pb, fsize-4, SEEK_SET);
324
        size= get_be32(&s->pb);
325
        url_fseek(&s->pb, fsize-3-size, SEEK_SET);
326
        if(size == get_be24(&s->pb) + 11){
327
            s->duration= get_be24(&s->pb) * (int64_t)AV_TIME_BASE / 1000;
328
        }
329
        url_fseek(&s->pb, pos, SEEK_SET);
330
    }
331

    
332
    if(is_audio){
333
        if(!st->codec->sample_rate || !st->codec->bits_per_sample || (!st->codec->codec_id && !st->codec->codec_tag)) {
334
            st->codec->channels = (flags & FLV_AUDIO_CHANNEL_MASK) == FLV_STEREO ? 2 : 1;
335
            if((flags & FLV_AUDIO_CODECID_MASK) == FLV_CODECID_NELLYMOSER_8HZ_MONO)
336
                st->codec->sample_rate= 8000;
337
            else
338
                st->codec->sample_rate = (44100 << ((flags & FLV_AUDIO_SAMPLERATE_MASK) >> FLV_AUDIO_SAMPLERATE_OFFSET) >> 3);
339
            st->codec->bits_per_sample = (flags & FLV_AUDIO_SAMPLESIZE_MASK) ? 16 : 8;
340
            flv_set_audio_codec(s, st, flags & FLV_AUDIO_CODECID_MASK);
341
        }
342
    }else{
343
        size -= flv_set_video_codec(s, st, flags & FLV_VIDEO_CODECID_MASK);
344
    }
345

    
346
    ret= av_get_packet(&s->pb, pkt, size - 1);
347
    if (ret <= 0) {
348
        return AVERROR_IO;
349
    }
350
    /* note: we need to modify the packet size here to handle the last
351
       packet */
352
    pkt->size = ret;
353
    pkt->pts = pts;
354
    pkt->stream_index = st->index;
355

    
356
    if (is_audio || ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY))
357
        pkt->flags |= PKT_FLAG_KEY;
358

    
359
    return ret;
360
}
361

    
362
static int flv_read_close(AVFormatContext *s)
363
{
364
    return 0;
365
}
366

    
367
static int flv_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
368
{
369
    AVStream *st = s->streams[stream_index];
370
    int index = av_index_search_timestamp(st, timestamp, flags);
371
    if (index < 0)
372
        return -1;
373
    url_fseek(&s->pb, st->index_entries[index].pos, SEEK_SET);
374

    
375
    return 0;
376
}
377

    
378
AVInputFormat flv_demuxer = {
379
    "flv",
380
    "flv format",
381
    0,
382
    flv_probe,
383
    flv_read_header,
384
    flv_read_packet,
385
    flv_read_close,
386
    flv_read_seek,
387
    .extensions = "flv",
388
    .value = CODEC_ID_FLV1,
389
};