PeerStreamer

/*

 * FLV demuxer

 * Copyright (c) 2003 The Libav Project

 *

 * This demuxer will generate a 1 byte extradata for VP6F content.

 * It is composed of:

 *  - upper 4bits: difference between encoded width and visible width

 *  - lower 4bits: difference between encoded height and visible height

 *

 * This file is part of Libav.

 *

 * Libav is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * Libav is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with Libav; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

#include "libavutil/avstring.h"

#include "libavcodec/bytestream.h"

#include "libavcodec/mpeg4audio.h"

#include "avformat.h"

#include "avio_internal.h"

#include "flv.h"

#define KEYFRAMES_TAG            "keyframes"

#define KEYFRAMES_TIMESTAMP_TAG  "times"

#define KEYFRAMES_BYTEOFFSET_TAG "filepositions"

typedef struct {

    int wrong_dts; ///< wrong dts due to negative cts

} FLVContext;

static int flv_probe(AVProbeData *p)

{

    const uint8_t *d;

    d = p->buf;

    if (d[0] == 'F' && d[1] == 'L' && d[2] == 'V' && d[3] < 5 && d[5]==0 && AV_RB32(d+5)>8) {

        return AVPROBE_SCORE_MAX;

    }

    return 0;

}

static void flv_set_audio_codec(AVFormatContext *s, AVStream *astream, int flv_codecid) {

    AVCodecContext *acodec = astream->codec;

    switch(flv_codecid) {

        //no distinction between S16 and S8 PCM codec flags

        case FLV_CODECID_PCM:

            acodec->codec_id = acodec->bits_per_coded_sample == 8 ? CODEC_ID_PCM_U8 :

#if HAVE_BIGENDIAN

                                CODEC_ID_PCM_S16BE;

#else

                                CODEC_ID_PCM_S16LE;

#endif

            break;

        case FLV_CODECID_PCM_LE:

            acodec->codec_id = acodec->bits_per_coded_sample == 8 ? CODEC_ID_PCM_U8 : CODEC_ID_PCM_S16LE; break;

        case FLV_CODECID_AAC  : acodec->codec_id = CODEC_ID_AAC;                                    break;

        case FLV_CODECID_ADPCM: acodec->codec_id = CODEC_ID_ADPCM_SWF;                              break;

        case FLV_CODECID_SPEEX:

            acodec->codec_id = CODEC_ID_SPEEX;

            acodec->sample_rate = 16000;

            break;

        case FLV_CODECID_MP3  : acodec->codec_id = CODEC_ID_MP3      ; astream->need_parsing = AVSTREAM_PARSE_FULL; break;

        case FLV_CODECID_NELLYMOSER_8KHZ_MONO:

            acodec->sample_rate = 8000; //in case metadata does not otherwise declare samplerate

            acodec->codec_id = CODEC_ID_NELLYMOSER;

            break;

        case FLV_CODECID_NELLYMOSER_16KHZ_MONO:

            acodec->sample_rate = 16000;

            acodec->codec_id = CODEC_ID_NELLYMOSER;

            break;

        case FLV_CODECID_NELLYMOSER:

            acodec->codec_id = CODEC_ID_NELLYMOSER;

            break;

        default:

            av_log(s, AV_LOG_INFO, "Unsupported audio codec (%x)\n", flv_codecid >> FLV_AUDIO_CODECID_OFFSET);

            acodec->codec_tag = flv_codecid >> FLV_AUDIO_CODECID_OFFSET;

    }

}

static int flv_set_video_codec(AVFormatContext *s, AVStream *vstream, int flv_codecid) {

    AVCodecContext *vcodec = vstream->codec;

    switch(flv_codecid) {

        case FLV_CODECID_H263  : vcodec->codec_id = CODEC_ID_FLV1   ; break;

        case FLV_CODECID_SCREEN: vcodec->codec_id = CODEC_ID_FLASHSV; break;

        case FLV_CODECID_SCREEN2: vcodec->codec_id = CODEC_ID_FLASHSV2; break;

        case FLV_CODECID_VP6   : vcodec->codec_id = CODEC_ID_VP6F   ;

        case FLV_CODECID_VP6A  :

            if(flv_codecid == FLV_CODECID_VP6A)

                vcodec->codec_id = CODEC_ID_VP6A;

            if(vcodec->extradata_size != 1) {

                vcodec->extradata_size = 1;

                vcodec->extradata = av_malloc(1);

            }

            vcodec->extradata[0] = avio_r8(s->pb);

            return 1; // 1 byte body size adjustment for flv_read_packet()

        case FLV_CODECID_H264:

            vcodec->codec_id = CODEC_ID_H264;

            return 3; // not 4, reading packet type will consume one byte

        default:

            av_log(s, AV_LOG_INFO, "Unsupported video codec (%x)\n", flv_codecid);

            vcodec->codec_tag = flv_codecid;

    }

    return 0;

}

static int amf_get_string(AVIOContext *ioc, char *buffer, int buffsize) {

    int length = avio_rb16(ioc);

    if(length >= buffsize) {

        avio_skip(ioc, length);

        return -1;

    }

    avio_read(ioc, buffer, length);

    buffer[length] = '\0';

    return length;

}

static int parse_keyframes_index(AVFormatContext *s, AVIOContext *ioc, AVStream *vstream, int64_t max_pos) {

    unsigned int arraylen = 0, timeslen = 0, fileposlen = 0, i;

    double num_val;

    char str_val[256];

    int64_t *times = NULL;

    int64_t *filepositions = NULL;

    int ret = AVERROR(ENOSYS);

    int64_t initial_pos = avio_tell(ioc);

    while (avio_tell(ioc) < max_pos - 2 && amf_get_string(ioc, str_val, sizeof(str_val)) > 0) {

        int64_t* current_array;

        // Expect array object in context

        if (avio_r8(ioc) != AMF_DATA_TYPE_ARRAY)

            break;

        arraylen = avio_rb32(ioc);

        /*

         * Expect only 'times' or 'filepositions' sub-arrays in other case refuse to use such metadata

         * for indexing

         */

        if (!strcmp(KEYFRAMES_TIMESTAMP_TAG, str_val) && !times) {

            if (!(times = av_mallocz(sizeof(*times) * arraylen))) {

                ret = AVERROR(ENOMEM);

                goto finish;

            }

            timeslen = arraylen;

            current_array = times;

        } else if (!strcmp(KEYFRAMES_BYTEOFFSET_TAG, str_val) && !filepositions) {

            if (!(filepositions = av_mallocz(sizeof(*filepositions) * arraylen))) {

                ret = AVERROR(ENOMEM);

                goto finish;

            }

            fileposlen = arraylen;

            current_array = filepositions;

        } else // unexpected metatag inside keyframes, will not use such metadata for indexing

            break;

        for (i = 0; i < arraylen && avio_tell(ioc) < max_pos - 1; i++) {

            if (avio_r8(ioc) != AMF_DATA_TYPE_NUMBER)

                goto finish;

            num_val = av_int2dbl(avio_rb64(ioc));

            current_array[i] = num_val;

        }

        if (times && filepositions) {

            // All done, exiting at a position allowing amf_parse_object

            // to finish parsing the object

            ret = 0;

            break;

        }

    }

    if (timeslen == fileposlen)

         for(i = 0; i < arraylen; i++)

             av_add_index_entry(vstream, filepositions[i], times[i]*1000, 0, 0, AVINDEX_KEYFRAME);

    else

        av_log(s, AV_LOG_WARNING, "Invalid keyframes object, skipping.\n");

finish:

    av_freep(&times);

    av_freep(&filepositions);

    // If we got unexpected data, but successfully reset back to

    // the start pos, the caller can continue parsing

    if (ret < 0 && avio_seek(ioc, initial_pos, SEEK_SET) > 0)

        return 0;

    return ret;

}

static int amf_parse_object(AVFormatContext *s, AVStream *astream, AVStream *vstream, const char *key, int64_t max_pos, int depth) {

    AVCodecContext *acodec, *vcodec;

    AVIOContext *ioc;

    AMFDataType amf_type;

    char str_val[256];

    double num_val;

    num_val = 0;

    ioc = s->pb;

    amf_type = avio_r8(ioc);

    switch(amf_type) {

        case AMF_DATA_TYPE_NUMBER:

            num_val = av_int2dbl(avio_rb64(ioc)); break;

        case AMF_DATA_TYPE_BOOL:

            num_val = avio_r8(ioc); break;

        case AMF_DATA_TYPE_STRING:

            if(amf_get_string(ioc, str_val, sizeof(str_val)) < 0)

                return -1;

            break;

        case AMF_DATA_TYPE_OBJECT: {

            unsigned int keylen;

            if (key && !strcmp(KEYFRAMES_TAG, key) && depth == 1)

                if (parse_keyframes_index(s, ioc, vstream, max_pos) < 0)

                    return -1;

            while(avio_tell(ioc) < max_pos - 2 && (keylen = avio_rb16(ioc))) {

                avio_skip(ioc, keylen); //skip key string

                if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)

                    return -1; //if we couldn't skip, bomb out.

            }

            if(avio_r8(ioc) != AMF_END_OF_OBJECT)

                return -1;

        }

            break;

        case AMF_DATA_TYPE_NULL:

        case AMF_DATA_TYPE_UNDEFINED:

        case AMF_DATA_TYPE_UNSUPPORTED:

            break; //these take up no additional space

        case AMF_DATA_TYPE_MIXEDARRAY:

            avio_skip(ioc, 4); //skip 32-bit max array index

            while(avio_tell(ioc) < max_pos - 2 && amf_get_string(ioc, str_val, sizeof(str_val)) > 0) {

                //this is the only case in which we would want a nested parse to not skip over the object

                if(amf_parse_object(s, astream, vstream, str_val, max_pos, depth + 1) < 0)

                    return -1;

            }

            if(avio_r8(ioc) != AMF_END_OF_OBJECT)

                return -1;

            break;

        case AMF_DATA_TYPE_ARRAY: {

            unsigned int arraylen, i;

            arraylen = avio_rb32(ioc);

            for(i = 0; i < arraylen && avio_tell(ioc) < max_pos - 1; i++) {

                if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)

                    return -1; //if we couldn't skip, bomb out.

            }

        }

            break;

        case AMF_DATA_TYPE_DATE:

            avio_skip(ioc, 8 + 2); //timestamp (double) and UTC offset (int16)

            break;

        default: //unsupported type, we couldn't skip

            return -1;

    }

    if(depth == 1 && key) { //only look for metadata values when we are not nested and key != NULL

        acodec = astream ? astream->codec : NULL;

        vcodec = vstream ? vstream->codec : NULL;

        if(amf_type == AMF_DATA_TYPE_BOOL) {

            av_strlcpy(str_val, num_val > 0 ? "true" : "false", sizeof(str_val));

            av_metadata_set2(&s->metadata, key, str_val, 0);

        } else if(amf_type == AMF_DATA_TYPE_NUMBER) {

            snprintf(str_val, sizeof(str_val), "%.f", num_val);

            av_metadata_set2(&s->metadata, key, str_val, 0);

            if(!strcmp(key, "duration")) s->duration = num_val * AV_TIME_BASE;

            else if(!strcmp(key, "videodatarate") && vcodec && 0 <= (int)(num_val * 1024.0))

                vcodec->bit_rate = num_val * 1024.0;

            else if(!strcmp(key, "audiodatarate") && acodec && 0 <= (int)(num_val * 1024.0))

                acodec->bit_rate = num_val * 1024.0;

        } else if (amf_type == AMF_DATA_TYPE_STRING)

            av_metadata_set2(&s->metadata, key, str_val, 0);

    }

    return 0;

}

static int flv_read_metabody(AVFormatContext *s, int64_t next_pos) {

    AMFDataType type;

    AVStream *stream, *astream, *vstream;

    AVIOContext *ioc;

    int i;

    char buffer[11]; //only needs to hold the string "onMetaData". Anything longer is something we don't want.

    astream = NULL;

    vstream = NULL;

    ioc = s->pb;

    //first object needs to be "onMetaData" string

    type = avio_r8(ioc);

    if(type != AMF_DATA_TYPE_STRING || amf_get_string(ioc, buffer, sizeof(buffer)) < 0 || strcmp(buffer, "onMetaData"))

        return -1;

    //find the streams now so that amf_parse_object doesn't need to do the lookup every time it is called.

    for(i = 0; i < s->nb_streams; i++) {

        stream = s->streams[i];

        if     (stream->codec->codec_type == AVMEDIA_TYPE_AUDIO) astream = stream;

        else if(stream->codec->codec_type == AVMEDIA_TYPE_VIDEO) vstream = stream;

    }

    //parse the second object (we want a mixed array)

    if(amf_parse_object(s, astream, vstream, buffer, next_pos, 0) < 0)

        return -1;

    return 0;

}

static AVStream *create_stream(AVFormatContext *s, int is_audio){

    AVStream *st = av_new_stream(s, is_audio);

    if (!st)

        return NULL;

    st->codec->codec_type = is_audio ? AVMEDIA_TYPE_AUDIO : AVMEDIA_TYPE_VIDEO;

    av_set_pts_info(st, 32, 1, 1000); /* 32 bit pts in ms */

    return st;

}

static int flv_read_header(AVFormatContext *s,

                           AVFormatParameters *ap)

{

    int offset, flags;

    avio_skip(s->pb, 4);

    flags = avio_r8(s->pb);

    /* old flvtool cleared this field */

    /* FIXME: better fix needed */

    if (!flags) {

        flags = FLV_HEADER_FLAG_HASVIDEO | FLV_HEADER_FLAG_HASAUDIO;

        av_log(s, AV_LOG_WARNING, "Broken FLV file, which says no streams present, this might fail\n");

    }

    if((flags & (FLV_HEADER_FLAG_HASVIDEO|FLV_HEADER_FLAG_HASAUDIO))

             != (FLV_HEADER_FLAG_HASVIDEO|FLV_HEADER_FLAG_HASAUDIO))

        s->ctx_flags |= AVFMTCTX_NOHEADER;

    if(flags & FLV_HEADER_FLAG_HASVIDEO){

        if(!create_stream(s, 0))

            return AVERROR(ENOMEM);

    }

    if(flags & FLV_HEADER_FLAG_HASAUDIO){

        if(!create_stream(s, 1))

            return AVERROR(ENOMEM);

    }

    offset = avio_rb32(s->pb);

    avio_seek(s->pb, offset, SEEK_SET);

    avio_skip(s->pb, 4);

    s->start_time = 0;

    return 0;

}

static int flv_get_extradata(AVFormatContext *s, AVStream *st, int size)

{

    av_free(st->codec->extradata);

    st->codec->extradata = av_mallocz(size + FF_INPUT_BUFFER_PADDING_SIZE);

    if (!st->codec->extradata)

        return AVERROR(ENOMEM);

    st->codec->extradata_size = size;

    avio_read(s->pb, st->codec->extradata, st->codec->extradata_size);

    return 0;

}

static int flv_read_packet(AVFormatContext *s, AVPacket *pkt)

{

    FLVContext *flv = s->priv_data;

    int ret, i, type, size, flags, is_audio;

    int64_t next, pos;

    int64_t dts, pts = AV_NOPTS_VALUE;

    AVStream *st = NULL;

 for(;;avio_skip(s->pb, 4)){ /* pkt size is repeated at end. skip it */

    pos = avio_tell(s->pb);

    type = avio_r8(s->pb);

    size = avio_rb24(s->pb);

    dts = avio_rb24(s->pb);

    dts |= avio_r8(s->pb) << 24;

//    av_log(s, AV_LOG_DEBUG, "type:%d, size:%d, dts:%d\n", type, size, dts);

    if (s->pb->eof_reached)

        return AVERROR_EOF;

    avio_skip(s->pb, 3); /* stream id, always 0 */

    flags = 0;

    if(size == 0)

        continue;

    next= size + avio_tell(s->pb);

    if (type == FLV_TAG_TYPE_AUDIO) {

        is_audio=1;

        flags = avio_r8(s->pb);

        size--;

    } else if (type == FLV_TAG_TYPE_VIDEO) {

        is_audio=0;

        flags = avio_r8(s->pb);

        size--;

        if ((flags & 0xf0) == 0x50) /* video info / command frame */

            goto skip;

    } else {

        if (type == FLV_TAG_TYPE_META && size > 13+1+4)

            flv_read_metabody(s, next);

        else /* skip packet */

            av_log(s, AV_LOG_DEBUG, "skipping flv packet: type %d, size %d, flags %d\n", type, size, flags);

    skip:

        avio_seek(s->pb, next, SEEK_SET);

        continue;

    }

    /* skip empty data packets */

    if (!size)

        continue;

    /* now find stream */

    for(i=0;i<s->nb_streams;i++) {

        st = s->streams[i];

        if (st->id == is_audio)

            break;

    }

    if(i == s->nb_streams){

        av_log(s, AV_LOG_ERROR, "invalid stream\n");

        st= create_stream(s, is_audio);

        s->ctx_flags &= ~AVFMTCTX_NOHEADER;

    }

//    av_log(s, AV_LOG_DEBUG, "%d %X %d \n", is_audio, flags, st->discard);

    if(  (st->discard >= AVDISCARD_NONKEY && !((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY ||         is_audio))

       ||(st->discard >= AVDISCARD_BIDIR  &&  ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_DISP_INTER && !is_audio))

       || st->discard >= AVDISCARD_ALL

       ){

        avio_seek(s->pb, next, SEEK_SET);

        continue;

    }

    if ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY)

        av_add_index_entry(st, pos, dts, size, 0, AVINDEX_KEYFRAME);

    break;

 }

    // if not streamed and no duration from metadata then seek to end to find the duration from the timestamps

    if(s->pb->seekable && (!s->duration || s->duration==AV_NOPTS_VALUE)){

        int size;

        const int64_t pos= avio_tell(s->pb);

        const int64_t fsize= avio_size(s->pb);

        avio_seek(s->pb, fsize-4, SEEK_SET);

        size= avio_rb32(s->pb);

        avio_seek(s->pb, fsize-3-size, SEEK_SET);

        if(size == avio_rb24(s->pb) + 11){

            uint32_t ts = avio_rb24(s->pb);

            ts |= avio_r8(s->pb) << 24;

            s->duration = ts * (int64_t)AV_TIME_BASE / 1000;

        }

        avio_seek(s->pb, pos, SEEK_SET);

    }

    if(is_audio){

        if(!st->codec->channels || !st->codec->sample_rate || !st->codec->bits_per_coded_sample) {

            st->codec->channels = (flags & FLV_AUDIO_CHANNEL_MASK) == FLV_STEREO ? 2 : 1;

            st->codec->sample_rate = (44100 << ((flags & FLV_AUDIO_SAMPLERATE_MASK) >> FLV_AUDIO_SAMPLERATE_OFFSET) >> 3);

            st->codec->bits_per_coded_sample = (flags & FLV_AUDIO_SAMPLESIZE_MASK) ? 16 : 8;

        }

        if(!st->codec->codec_id){

            flv_set_audio_codec(s, st, flags & FLV_AUDIO_CODECID_MASK);

        }

    }else{

        size -= flv_set_video_codec(s, st, flags & FLV_VIDEO_CODECID_MASK);

    }

    if (st->codec->codec_id == CODEC_ID_AAC ||

        st->codec->codec_id == CODEC_ID_H264) {

        int type = avio_r8(s->pb);

        size--;

        if (st->codec->codec_id == CODEC_ID_H264) {

            int32_t cts = (avio_rb24(s->pb)+0xff800000)^0xff800000; // sign extension

            pts = dts + cts;

            if (cts < 0) { // dts are wrong

                flv->wrong_dts = 1;

                av_log(s, AV_LOG_WARNING, "negative cts, previous timestamps might be wrong\n");

            }

            if (flv->wrong_dts)

                dts = AV_NOPTS_VALUE;

        }

        if (type == 0) {

            if ((ret = flv_get_extradata(s, st, size)) < 0)

                return ret;

            if (st->codec->codec_id == CODEC_ID_AAC) {

                MPEG4AudioConfig cfg;

                ff_mpeg4audio_get_config(&cfg, st->codec->extradata,

                                         st->codec->extradata_size);

                st->codec->channels = cfg.channels;

                if (cfg.ext_sample_rate)

                    st->codec->sample_rate = cfg.ext_sample_rate;

                else

                    st->codec->sample_rate = cfg.sample_rate;

                av_dlog(s, "mp4a config channels %d sample rate %d\n",

                        st->codec->channels, st->codec->sample_rate);

            }

            ret = AVERROR(EAGAIN);

            goto leave;

        }

    }

    /* skip empty data packets */

    if (!size) {

        ret = AVERROR(EAGAIN);

        goto leave;

    }

    ret= av_get_packet(s->pb, pkt, size);

    if (ret < 0) {

        return AVERROR(EIO);

    }

    /* note: we need to modify the packet size here to handle the last

       packet */

    pkt->size = ret;

    pkt->dts = dts;

    pkt->pts = pts == AV_NOPTS_VALUE ? dts : pts;

    pkt->stream_index = st->index;

    if (is_audio || ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY))

        pkt->flags |= AV_PKT_FLAG_KEY;

leave:

    avio_skip(s->pb, 4);

    return ret;

}

static int flv_read_seek(AVFormatContext *s, int stream_index,

    int64_t ts, int flags)

{

    return avio_seek_time(s->pb, stream_index, ts, flags);

}

#if 0 /* don't know enough to implement this */

static int flv_read_seek2(AVFormatContext *s, int stream_index,

    int64_t min_ts, int64_t ts, int64_t max_ts, int flags)

{

    int ret = AVERROR(ENOSYS);

    if (ts - min_ts > (uint64_t)(max_ts - ts)) flags |= AVSEEK_FLAG_BACKWARD;

    if (!s->pb->seekable) {

        if (stream_index < 0) {

            stream_index = av_find_default_stream_index(s);

            if (stream_index < 0)

                return -1;

            /* timestamp for default must be expressed in AV_TIME_BASE units */

            ts = av_rescale_rnd(ts, 1000, AV_TIME_BASE,

                flags & AVSEEK_FLAG_BACKWARD ? AV_ROUND_DOWN : AV_ROUND_UP);

        }

        ret = avio_seek_time(s->pb, stream_index, ts, flags);

    }

    if (ret == AVERROR(ENOSYS))

        ret = av_seek_frame(s, stream_index, ts, flags);

    return ret;

}

#endif

AVInputFormat ff_flv_demuxer = {

    "flv",

    NULL_IF_CONFIG_SMALL("FLV format"),

    sizeof(FLVContext),

    flv_probe,

    flv_read_header,

    flv_read_packet,

    .read_seek = flv_read_seek,

#if 0

    .read_seek2 = flv_read_seek2,

#endif

    .extensions = "flv",

    .value = CODEC_ID_FLV1,

};