PeerStreamer

/*

 * MPEG1/2 demuxer

 * Copyright (c) 2000, 2001, 2002 Fabrice Bellard

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg 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.

 *

 * FFmpeg 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 FFmpeg; if not, write to the Free Software

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

 */

#include "avformat.h"

#include "internal.h"

#include "mpeg.h"

//#define DEBUG_SEEK

#undef NDEBUG

#include <assert.h>

/*********************************************/

/* demux code */

#define MAX_SYNC_SIZE 100000

static int check_pes(uint8_t *p, uint8_t *end){

    int pes1;

    int pes2=      (p[3] & 0xC0) == 0x80

                && (p[4] & 0xC0) != 0x40

                &&((p[4] & 0xC0) == 0x00 || (p[4]&0xC0)>>2 == (p[6]&0xF0));

    for(p+=3; p<end && *p == 0xFF; p++);

    if((*p&0xC0) == 0x40) p+=2;

    if((*p&0xF0) == 0x20){

        pes1= p[0]&p[2]&p[4]&1;

    }else if((*p&0xF0) == 0x30){

        pes1= p[0]&p[2]&p[4]&p[5]&p[7]&p[9]&1;

    }else

        pes1 = *p == 0x0F;

    return pes1||pes2;

}

static int mpegps_probe(AVProbeData *p)

{

    uint32_t code= -1;

    int sys=0, pspack=0, priv1=0, vid=0, audio=0, invalid=0;

    int i;

    int score=0;

    for(i=0; i<p->buf_size; i++){

        code = (code<<8) + p->buf[i];

        if ((code & 0xffffff00) == 0x100) {

            int len= p->buf[i+1] << 8 | p->buf[i+2];

            int pes= check_pes(p->buf+i, p->buf+p->buf_size);

            if(code == SYSTEM_HEADER_START_CODE) sys++;

            else if(code == PACK_START_CODE)     pspack++;

            else if((code & 0xf0) == VIDEO_ID &&  pes) vid++;

            // skip pes payload to avoid start code emulation for private

            // and audio streams

            else if((code & 0xe0) == AUDIO_ID &&  pes) {audio++; i+=len;}

            else if(code == PRIVATE_STREAM_1  &&  pes) {priv1++; i+=len;}

            else if((code & 0xf0) == VIDEO_ID && !pes) invalid++;

            else if((code & 0xe0) == AUDIO_ID && !pes) invalid++;

            else if(code == PRIVATE_STREAM_1  && !pes) invalid++;

        }

    }

    if(vid+audio > invalid)     /* invalid VDR files nd short PES streams */

        score= AVPROBE_SCORE_MAX/4;

//av_log(NULL, AV_LOG_ERROR, "%d %d %d %d %d %d len:%d\n", sys, priv1, pspack,vid, audio, invalid, p->buf_size);

    if(sys>invalid && sys*9 <= pspack*10)

        return pspack > 2 ? AVPROBE_SCORE_MAX/2+2 : AVPROBE_SCORE_MAX/4; // +1 for .mpg

    if(pspack > invalid && (priv1+vid+audio)*10 >= pspack*9)

        return pspack > 2 ? AVPROBE_SCORE_MAX/2+2 : AVPROBE_SCORE_MAX/4; // +1 for .mpg

    if((!!vid ^ !!audio) && (audio > 4 || vid > 1) && !sys && !pspack && p->buf_size>2048 && vid + audio > invalid) /* PES stream */

        return (audio > 12 || vid > 3) ? AVPROBE_SCORE_MAX/2+2 : AVPROBE_SCORE_MAX/4;

    //02-Penguin.flac has sys:0 priv1:0 pspack:0 vid:0 audio:1

    //mp3_misidentified_2.mp3 has sys:0 priv1:0 pspack:0 vid:0 audio:6

    return score;

}

typedef struct MpegDemuxContext {

    int32_t header_state;

    unsigned char psm_es_type[256];

    int sofdec;

} MpegDemuxContext;

static int mpegps_read_header(AVFormatContext *s,

                              AVFormatParameters *ap)

{

    MpegDemuxContext *m = s->priv_data;

    const char *sofdec = "Sofdec";

    int v, i = 0;

    m->header_state = 0xff;

    s->ctx_flags |= AVFMTCTX_NOHEADER;

    m->sofdec = -1;

    do {

        v = avio_r8(s->pb);

        m->header_state = m->header_state << 8 | v;

        m->sofdec++;

    } while (v == sofdec[i] && i++ < 6);

    m->sofdec = (m->sofdec == 6) ? 1 : 0;

    /* no need to do more */

    return 0;

}

static int64_t get_pts(AVIOContext *pb, int c)

{

    uint8_t buf[5];

    buf[0] = c<0 ? avio_r8(pb) : c;

    avio_read(pb, buf+1, 4);

    return ff_parse_pes_pts(buf);

}

static int find_next_start_code(AVIOContext *pb, int *size_ptr,

                                int32_t *header_state)

{

    unsigned int state, v;

    int val, n;

    state = *header_state;

    n = *size_ptr;

    while (n > 0) {

        if (pb->eof_reached)

            break;

        v = avio_r8(pb);

        n--;

        if (state == 0x000001) {

            state = ((state << 8) | v) & 0xffffff;

            val = state;

            goto found;

        }

        state = ((state << 8) | v) & 0xffffff;

    }

    val = -1;

 found:

    *header_state = state;

    *size_ptr = n;

    return val;

}

#if 0 /* unused, remove? */

/* XXX: optimize */

static int find_prev_start_code(AVIOContext *pb, int *size_ptr)

{

    int64_t pos, pos_start;

    int max_size, start_code;

    max_size = *size_ptr;

    pos_start = avio_tell(pb);

    /* in order to go faster, we fill the buffer */

    pos = pos_start - 16386;

    if (pos < 0)

        pos = 0;

    avio_seek(pb, pos, SEEK_SET);

    avio_r8(pb);

    pos = pos_start;

    for(;;) {

        pos--;

        if (pos < 0 || (pos_start - pos) >= max_size) {

            start_code = -1;

            goto the_end;

        }

        avio_seek(pb, pos, SEEK_SET);

        start_code = avio_rb32(pb);

        if ((start_code & 0xffffff00) == 0x100)

            break;

    }

 the_end:

    *size_ptr = pos_start - pos;

    return start_code;

}

#endif

/**

 * Extract stream types from a program stream map

 * According to ISO/IEC 13818-1 ('MPEG-2 Systems') table 2-35

 *

 * @return number of bytes occupied by PSM in the bitstream

 */

static long mpegps_psm_parse(MpegDemuxContext *m, AVIOContext *pb)

{

    int psm_length, ps_info_length, es_map_length;

    psm_length = avio_rb16(pb);

    avio_r8(pb);

    avio_r8(pb);

    ps_info_length = avio_rb16(pb);

    /* skip program_stream_info */

    avio_seek(pb, ps_info_length, SEEK_CUR);

    es_map_length = avio_rb16(pb);

    /* at least one es available? */

    while (es_map_length >= 4){

        unsigned char type      = avio_r8(pb);

        unsigned char es_id     = avio_r8(pb);

        uint16_t es_info_length = avio_rb16(pb);

        /* remember mapping from stream id to stream type */

        m->psm_es_type[es_id] = type;

        /* skip program_stream_info */

        avio_seek(pb, es_info_length, SEEK_CUR);

        es_map_length -= 4 + es_info_length;

    }

    avio_rb32(pb); /* crc32 */

    return 2 + psm_length;

}

/* read the next PES header. Return its position in ppos

   (if not NULL), and its start code, pts and dts.

 */

static int mpegps_read_pes_header(AVFormatContext *s,

                                  int64_t *ppos, int *pstart_code,

                                  int64_t *ppts, int64_t *pdts)

{

    MpegDemuxContext *m = s->priv_data;

    int len, size, startcode, c, flags, header_len;

    int pes_ext, ext2_len, id_ext, skip;

    int64_t pts, dts;

    int64_t last_sync= avio_tell(s->pb);

 error_redo:

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

 redo:

        /* next start code (should be immediately after) */

        m->header_state = 0xff;

        size = MAX_SYNC_SIZE;

        startcode = find_next_start_code(s->pb, &size, &m->header_state);

        last_sync = avio_tell(s->pb);

    //printf("startcode=%x pos=0x%"PRIx64"\n", startcode, avio_tell(s->pb));

    if (startcode < 0){

        if(s->pb->eof_reached)

            return AVERROR_EOF;

        //FIXME we should remember header_state

        return AVERROR(EAGAIN);

    }

    if (startcode == PACK_START_CODE)

        goto redo;

    if (startcode == SYSTEM_HEADER_START_CODE)

        goto redo;

    if (startcode == PADDING_STREAM) {

        avio_seek(s->pb, avio_rb16(s->pb), SEEK_CUR);

        goto redo;

    }

    if (startcode == PRIVATE_STREAM_2) {

        len = avio_rb16(s->pb);

        if (!m->sofdec) {

            while (len-- >= 6) {

                if (avio_r8(s->pb) == 'S') {

                    uint8_t buf[5];

                    avio_read(s->pb, buf, sizeof(buf));

                    m->sofdec = !memcmp(buf, "ofdec", 5);

                    len -= sizeof(buf);

                    break;

                }

            }

            m->sofdec -= !m->sofdec;

        }

        avio_seek(s->pb, len, SEEK_CUR);

        goto redo;

    }

    if (startcode == PROGRAM_STREAM_MAP) {

        mpegps_psm_parse(m, s->pb);

        goto redo;

    }

    /* find matching stream */

    if (!((startcode >= 0x1c0 && startcode <= 0x1df) ||

          (startcode >= 0x1e0 && startcode <= 0x1ef) ||

          (startcode == 0x1bd) || (startcode == 0x1fd)))

        goto redo;

    if (ppos) {

        *ppos = avio_tell(s->pb) - 4;

    }

    len = avio_rb16(s->pb);

    pts =

    dts = AV_NOPTS_VALUE;

    /* stuffing */

    for(;;) {

        if (len < 1)

            goto error_redo;

        c = avio_r8(s->pb);

        len--;

        /* XXX: for mpeg1, should test only bit 7 */

        if (c != 0xff)

            break;

    }

    if ((c & 0xc0) == 0x40) {

        /* buffer scale & size */

        avio_r8(s->pb);

        c = avio_r8(s->pb);

        len -= 2;

    }

    if ((c & 0xe0) == 0x20) {

        dts = pts = get_pts(s->pb, c);

        len -= 4;

        if (c & 0x10){

            dts = get_pts(s->pb, -1);

            len -= 5;

        }

    } else if ((c & 0xc0) == 0x80) {

        /* mpeg 2 PES */

#if 0 /* some streams have this field set for no apparent reason */

        if ((c & 0x30) != 0) {

            /* Encrypted multiplex not handled */

            goto redo;

        }

#endif

        flags = avio_r8(s->pb);

        header_len = avio_r8(s->pb);

        len -= 2;

        if (header_len > len)

            goto error_redo;

        len -= header_len;

        if (flags & 0x80) {

            dts = pts = get_pts(s->pb, -1);

            header_len -= 5;

            if (flags & 0x40) {

                dts = get_pts(s->pb, -1);

                header_len -= 5;

            }

        }

        if (flags & 0x3f && header_len == 0){

            flags &= 0xC0;

            av_log(s, AV_LOG_WARNING, "Further flags set but no bytes left\n");

        }

        if (flags & 0x01) { /* PES extension */

            pes_ext = avio_r8(s->pb);

            header_len--;

            /* Skip PES private data, program packet sequence counter and P-STD buffer */

            skip = (pes_ext >> 4) & 0xb;

            skip += skip & 0x9;

            if (pes_ext & 0x40 || skip > header_len){

                av_log(s, AV_LOG_WARNING, "pes_ext %X is invalid\n", pes_ext);

                pes_ext=skip=0;

            }

            avio_seek(s->pb, skip, SEEK_CUR);

            header_len -= skip;

            if (pes_ext & 0x01) { /* PES extension 2 */

                ext2_len = avio_r8(s->pb);

                header_len--;

                if ((ext2_len & 0x7f) > 0) {

                    id_ext = avio_r8(s->pb);

                    if ((id_ext & 0x80) == 0)

                        startcode = ((startcode & 0xff) << 8) | id_ext;

                    header_len--;

                }

            }

        }

        if(header_len < 0)

            goto error_redo;

        avio_seek(s->pb, header_len, SEEK_CUR);

    }

    else if( c!= 0xf )

        goto redo;

    if (startcode == PRIVATE_STREAM_1 && !m->psm_es_type[startcode & 0xff]) {

        startcode = avio_r8(s->pb);

        len--;

        if (startcode >= 0x80 && startcode <= 0xcf) {

            /* audio: skip header */

            avio_r8(s->pb);

            avio_r8(s->pb);

            avio_r8(s->pb);

            len -= 3;

            if (startcode >= 0xb0 && startcode <= 0xbf) {

                /* MLP/TrueHD audio has a 4-byte header */

                avio_r8(s->pb);

                len--;

            }

        }

    }

    if(len<0)

        goto error_redo;

    if(dts != AV_NOPTS_VALUE && ppos){

        int i;

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

            if(startcode == s->streams[i]->id &&

               !url_is_streamed(s->pb) /* index useless on streams anyway */) {

                ff_reduce_index(s, i);

                av_add_index_entry(s->streams[i], *ppos, dts, 0, 0, AVINDEX_KEYFRAME /* FIXME keyframe? */);

            }

        }

    }

    *pstart_code = startcode;

    *ppts = pts;

    *pdts = dts;

    return len;

}

static int mpegps_read_packet(AVFormatContext *s,

                              AVPacket *pkt)

{

    MpegDemuxContext *m = s->priv_data;

    AVStream *st;

    int len, startcode, i, es_type;

    enum CodecID codec_id = CODEC_ID_NONE;

    enum AVMediaType type;

    int64_t pts, dts, dummy_pos; //dummy_pos is needed for the index building to work

    uint8_t av_uninit(dvdaudio_substream_type);

 redo:

    len = mpegps_read_pes_header(s, &dummy_pos, &startcode, &pts, &dts);

    if (len < 0)

        return len;

    if(startcode == 0x1bd) {

        dvdaudio_substream_type = avio_r8(s->pb);

        avio_seek(s->pb, 3, SEEK_CUR);

        len -= 4;

    }

    /* now find stream */

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

        st = s->streams[i];

        if (st->id == startcode)

            goto found;

    }

    es_type = m->psm_es_type[startcode & 0xff];

    if(es_type > 0 && es_type != STREAM_TYPE_PRIVATE_DATA){

        if(es_type == STREAM_TYPE_VIDEO_MPEG1){

            codec_id = CODEC_ID_MPEG2VIDEO;

            type = AVMEDIA_TYPE_VIDEO;

        } else if(es_type == STREAM_TYPE_VIDEO_MPEG2){

            codec_id = CODEC_ID_MPEG2VIDEO;

            type = AVMEDIA_TYPE_VIDEO;

        } else if(es_type == STREAM_TYPE_AUDIO_MPEG1 ||

                  es_type == STREAM_TYPE_AUDIO_MPEG2){

            codec_id = CODEC_ID_MP3;

            type = AVMEDIA_TYPE_AUDIO;

        } else if(es_type == STREAM_TYPE_AUDIO_AAC){

            codec_id = CODEC_ID_AAC;

            type = AVMEDIA_TYPE_AUDIO;

        } else if(es_type == STREAM_TYPE_VIDEO_MPEG4){

            codec_id = CODEC_ID_MPEG4;

            type = AVMEDIA_TYPE_VIDEO;

        } else if(es_type == STREAM_TYPE_VIDEO_H264){

            codec_id = CODEC_ID_H264;

            type = AVMEDIA_TYPE_VIDEO;

        } else if(es_type == STREAM_TYPE_AUDIO_AC3){

            codec_id = CODEC_ID_AC3;

            type = AVMEDIA_TYPE_AUDIO;

        } else {

            goto skip;

        }

    } else if (startcode >= 0x1e0 && startcode <= 0x1ef) {

        static const unsigned char avs_seqh[4] = { 0, 0, 1, 0xb0 };

        unsigned char buf[8];

        avio_read(s->pb, buf, 8);

        avio_seek(s->pb, -8, SEEK_CUR);

        if(!memcmp(buf, avs_seqh, 4) && (buf[6] != 0 || buf[7] != 1))

            codec_id = CODEC_ID_CAVS;

        else

            codec_id = CODEC_ID_PROBE;

        type = AVMEDIA_TYPE_VIDEO;

    } else if (startcode >= 0x1c0 && startcode <= 0x1df) {

        type = AVMEDIA_TYPE_AUDIO;

        codec_id = m->sofdec > 0 ? CODEC_ID_ADPCM_ADX : CODEC_ID_MP2;

    } else if (startcode >= 0x80 && startcode <= 0x87) {

        type = AVMEDIA_TYPE_AUDIO;

        codec_id = CODEC_ID_AC3;

    } else if (  ( startcode >= 0x88 && startcode <= 0x8f)

               ||( startcode >= 0x98 && startcode <= 0x9f)) {

        /* 0x90 - 0x97 is reserved for SDDS in DVD specs */

        type = AVMEDIA_TYPE_AUDIO;

        codec_id = CODEC_ID_DTS;

    } else if (startcode >= 0xa0 && startcode <= 0xaf) {

        type = AVMEDIA_TYPE_AUDIO;

        /* 16 bit form will be handled as CODEC_ID_PCM_S16BE */

        codec_id = CODEC_ID_PCM_DVD;

    } else if (startcode >= 0xb0 && startcode <= 0xbf) {

        type = AVMEDIA_TYPE_AUDIO;

        codec_id = CODEC_ID_TRUEHD;

    } else if (startcode >= 0xc0 && startcode <= 0xcf) {

        /* Used for both AC-3 and E-AC-3 in EVOB files */

        type = AVMEDIA_TYPE_AUDIO;

        codec_id = CODEC_ID_AC3;

    } else if (startcode >= 0x20 && startcode <= 0x3f) {

        type = AVMEDIA_TYPE_SUBTITLE;

        codec_id = CODEC_ID_DVD_SUBTITLE;

    } else if (startcode >= 0xfd55 && startcode <= 0xfd5f) {

        type = AVMEDIA_TYPE_VIDEO;

        codec_id = CODEC_ID_VC1;

    } else if (startcode == 0x1bd) {

        // check dvd audio substream type

        type = AVMEDIA_TYPE_AUDIO;

        switch(dvdaudio_substream_type & 0xe0) {

        case 0xa0:  codec_id = CODEC_ID_PCM_DVD;

                    break;

        case 0x80:  if((dvdaudio_substream_type & 0xf8) == 0x88)

                         codec_id = CODEC_ID_DTS;

                    else codec_id = CODEC_ID_AC3;

                    break;

        default:    av_log(s, AV_LOG_ERROR, "Unknown 0x1bd sub-stream\n");

                    goto skip;

        }

    } else {

    skip:

        /* skip packet */

        avio_seek(s->pb, len, SEEK_CUR);

        goto redo;

    }

    /* no stream found: add a new stream */

    st = av_new_stream(s, startcode);

    if (!st)

        goto skip;

    st->codec->codec_type = type;

    st->codec->codec_id = codec_id;

    if (codec_id != CODEC_ID_PCM_S16BE)

        st->need_parsing = AVSTREAM_PARSE_FULL;

 found:

    if(st->discard >= AVDISCARD_ALL)

        goto skip;

    if ((startcode >= 0xa0 && startcode <= 0xaf) ||

        (startcode == 0x1bd && ((dvdaudio_substream_type & 0xe0) == 0xa0))) {

        int b1, freq;

        /* for LPCM, we just skip the header and consider it is raw

           audio data */

        if (len <= 3)

            goto skip;

        avio_r8(s->pb); /* emphasis (1), muse(1), reserved(1), frame number(5) */

        b1 = avio_r8(s->pb); /* quant (2), freq(2), reserved(1), channels(3) */

        avio_r8(s->pb); /* dynamic range control (0x80 = off) */

        len -= 3;

        freq = (b1 >> 4) & 3;

        st->codec->sample_rate = lpcm_freq_tab[freq];

        st->codec->channels = 1 + (b1 & 7);

        st->codec->bits_per_coded_sample = 16 + ((b1 >> 6) & 3) * 4;

        st->codec->bit_rate = st->codec->channels *

                              st->codec->sample_rate *

                              st->codec->bits_per_coded_sample;

        if (st->codec->bits_per_coded_sample == 16)

            st->codec->codec_id = CODEC_ID_PCM_S16BE;

        else if (st->codec->bits_per_coded_sample == 28)

            return AVERROR(EINVAL);

    }

    av_new_packet(pkt, len);

    avio_read(s->pb, pkt->data, pkt->size);

    pkt->pts = pts;

    pkt->dts = dts;

    pkt->pos = dummy_pos;

    pkt->stream_index = st->index;

#if 0

    av_log(s, AV_LOG_DEBUG, "%d: pts=%0.3f dts=%0.3f size=%d\n",

           pkt->stream_index, pkt->pts / 90000.0, pkt->dts / 90000.0, pkt->size);

#endif

    return 0;

}

static int64_t mpegps_read_dts(AVFormatContext *s, int stream_index,

                               int64_t *ppos, int64_t pos_limit)

{

    int len, startcode;

    int64_t pos, pts, dts;

    pos = *ppos;

#ifdef DEBUG_SEEK

    printf("read_dts: pos=0x%"PRIx64" next=%d -> ", pos, find_next);

#endif

    if (avio_seek(s->pb, pos, SEEK_SET) < 0)

        return AV_NOPTS_VALUE;

    for(;;) {

        len = mpegps_read_pes_header(s, &pos, &startcode, &pts, &dts);

        if (len < 0) {

#ifdef DEBUG_SEEK

            printf("none (ret=%d)\n", len);

#endif

            return AV_NOPTS_VALUE;

        }

        if (startcode == s->streams[stream_index]->id &&

            dts != AV_NOPTS_VALUE) {

            break;

        }

        avio_seek(s->pb, len, SEEK_CUR);

    }

#ifdef DEBUG_SEEK

    printf("pos=0x%"PRIx64" dts=0x%"PRIx64" %0.3f\n", pos, dts, dts / 90000.0);

#endif

    *ppos = pos;

    return dts;

}

AVInputFormat ff_mpegps_demuxer = {

    "mpeg",

    NULL_IF_CONFIG_SMALL("MPEG-PS format"),

    sizeof(MpegDemuxContext),

    mpegps_probe,

    mpegps_read_header,

    mpegps_read_packet,

    NULL,

    NULL, //mpegps_read_seek,

    mpegps_read_dts,

    .flags = AVFMT_SHOW_IDS|AVFMT_TS_DISCONT,

};