mpegts.c

ffmpeg的完整源代码和作者自己写的文档。不但有在Linux的工程哦

    pcr_pid = get16(&p, p_end) & 0x1fff;
    if (pcr_pid < 0)
        return;
    add_pid_to_pmt(ts, h->id, pcr_pid);
#ifdef DEBUG_SI
    av_log(ts->stream, AV_LOG_DEBUG, "pcr_pid=0x%x\n", pcr_pid);
#endif
    program_info_length = get16(&p, p_end) & 0xfff;
    if (program_info_length < 0)
        return;
    p += program_info_length;
    if (p >= p_end)
        return;
    for(;;) {
        language[0] = 0;
        st = 0;
        stream_type = get8(&p, p_end);
        if (stream_type < 0)
            break;
        pid = get16(&p, p_end) & 0x1fff;
        if (pid < 0)
            break;
        desc_list_len = get16(&p, p_end) & 0xfff;
        if (desc_list_len < 0)
            break;
        desc_list_end = p + desc_list_len;
        if (desc_list_end > p_end)
            break;
        for(;;) {
            desc_tag = get8(&p, desc_list_end);
            if (desc_tag < 0)
                break;
            if (stream_type == STREAM_TYPE_PRIVATE_DATA) {
                if((desc_tag == 0x6A) || (desc_tag == 0x7A)) {
                    /*assume DVB AC-3 Audio*/
                    stream_type = STREAM_TYPE_AUDIO_AC3;
                } else if(desc_tag == 0x7B) {
                    /* DVB DTS audio */
                    stream_type = STREAM_TYPE_AUDIO_DTS;
                }
            }
            desc_len = get8(&p, desc_list_end);
            desc_end = p + desc_len;
            if (desc_end > desc_list_end)
                break;
#ifdef DEBUG_SI
            av_log(ts->stream, AV_LOG_DEBUG, "tag: 0x%02x len=%d\n",
                   desc_tag, desc_len);
#endif
            switch(desc_tag) {
            case DVB_SUBT_DESCID:
                if (stream_type == STREAM_TYPE_PRIVATE_DATA)
                    stream_type = STREAM_TYPE_SUBTITLE_DVB;

                language[0] = get8(&p, desc_end);
                language[1] = get8(&p, desc_end);
                language[2] = get8(&p, desc_end);
                language[3] = 0;
                get8(&p, desc_end);
                comp_page = get16(&p, desc_end);
                anc_page = get16(&p, desc_end);

                break;
            case 0x0a: /* ISO 639 language descriptor */
                language[0] = get8(&p, desc_end);
                language[1] = get8(&p, desc_end);
                language[2] = get8(&p, desc_end);
                language[3] = 0;
                break;
            default:
                break;
            }
            p = desc_end;
        }
        p = desc_list_end;

#ifdef DEBUG_SI
        av_log(ts->stream, AV_LOG_DEBUG, "stream_type=%d pid=0x%x\n",
               stream_type, pid);
#endif

        /* now create ffmpeg stream */
        switch(stream_type) {
        case STREAM_TYPE_AUDIO_MPEG1:
        case STREAM_TYPE_AUDIO_MPEG2:
        case STREAM_TYPE_VIDEO_MPEG1:
        case STREAM_TYPE_VIDEO_MPEG2:
        case STREAM_TYPE_VIDEO_MPEG4:
        case STREAM_TYPE_VIDEO_H264:
        case STREAM_TYPE_VIDEO_VC1:
        case STREAM_TYPE_AUDIO_AAC:
        case STREAM_TYPE_AUDIO_AC3:
        case STREAM_TYPE_AUDIO_DTS:
        case STREAM_TYPE_SUBTITLE_DVB:
            if(ts->pids[pid]){
                assert(ts->pids[pid]->type == MPEGTS_PES);
                pes= ts->pids[pid]->u.pes_filter.opaque;
                st= pes->st;
            }else{
                pes = add_pes_stream(ts, pid, pcr_pid, stream_type);
                if (pes)
                    st = new_pes_av_stream(pes, 0);
            }
            add_pid_to_pmt(ts, h->id, pid);
            break;
        default:
            /* we ignore the other streams */
            break;
        }

        if (st) {
            if (language[0] != 0) {
                memcpy(st->language, language, 4);
            }

            if (stream_type == STREAM_TYPE_SUBTITLE_DVB) {
                st->codec->sub_id = (anc_page << 16) | comp_page;
            }
        }
    }
    /* all parameters are there */
    ts->stop_parse++;
    mpegts_close_filter(ts, filter);
}

static void pat_cb(MpegTSFilter *filter, const uint8_t *section, int section_len)
{
    MpegTSContext *ts = filter->u.section_filter.opaque;
    SectionHeader h1, *h = &h1;
    const uint8_t *p, *p_end;
    int sid, pmt_pid;

#ifdef DEBUG_SI
    av_log(ts->stream, AV_LOG_DEBUG, "PAT:\n");
    av_hex_dump_log(ts->stream, AV_LOG_DEBUG, (uint8_t *)section, section_len);
#endif
    p_end = section + section_len - 4;
    p = section;
    if (parse_section_header(h, &p, p_end) < 0)
        return;
    if (h->tid != PAT_TID)
        return;

    clear_programs(ts);
    for(;;) {
        sid = get16(&p, p_end);
        if (sid < 0)
            break;
        pmt_pid = get16(&p, p_end) & 0x1fff;
        if (pmt_pid < 0)
            break;
#ifdef DEBUG_SI
        av_log(ts->stream, AV_LOG_DEBUG, "sid=0x%x pid=0x%x\n", sid, pmt_pid);
#endif
        if (sid == 0x0000) {
            /* NIT info */
        } else {
            av_new_program(ts->stream, sid);
            ts->stop_parse--;
            mpegts_open_section_filter(ts, pmt_pid, pmt_cb, ts, 1);
            add_pat_entry(ts, sid);
            add_pid_to_pmt(ts, sid, 0); //add pat pid to program
            add_pid_to_pmt(ts, sid, pmt_pid);
        }
    }
    /* not found */
    ts->stop_parse++;

    mpegts_close_filter(ts, filter);
}

static void mpegts_set_service(MpegTSContext *ts)
{
    mpegts_open_section_filter(ts, PAT_PID,
                                                pat_cb, ts, 1);
}

static void sdt_cb(MpegTSFilter *filter, const uint8_t *section, int section_len)
{
    MpegTSContext *ts = filter->u.section_filter.opaque;
    SectionHeader h1, *h = &h1;
    const uint8_t *p, *p_end, *desc_list_end, *desc_end;
    int onid, val, sid, desc_list_len, desc_tag, desc_len, service_type;
    char *name, *provider_name;

#ifdef DEBUG_SI
    av_log(ts->stream, AV_LOG_DEBUG, "SDT:\n");
    av_hex_dump_log(ts->stream, AV_LOG_DEBUG, (uint8_t *)section, section_len);
#endif

    p_end = section + section_len - 4;
    p = section;
    if (parse_section_header(h, &p, p_end) < 0)
        return;
    if (h->tid != SDT_TID)
        return;
    onid = get16(&p, p_end);
    if (onid < 0)
        return;
    val = get8(&p, p_end);
    if (val < 0)
        return;
    for(;;) {
        sid = get16(&p, p_end);
        if (sid < 0)
            break;
        val = get8(&p, p_end);
        if (val < 0)
            break;
        desc_list_len = get16(&p, p_end) & 0xfff;
        if (desc_list_len < 0)
            break;
        desc_list_end = p + desc_list_len;
        if (desc_list_end > p_end)
            break;
        for(;;) {
            desc_tag = get8(&p, desc_list_end);
            if (desc_tag < 0)
                break;
            desc_len = get8(&p, desc_list_end);
            desc_end = p + desc_len;
            if (desc_end > desc_list_end)
                break;
#ifdef DEBUG_SI
            av_log(ts->stream, AV_LOG_DEBUG, "tag: 0x%02x len=%d\n",
                   desc_tag, desc_len);
#endif
            switch(desc_tag) {
            case 0x48:
                service_type = get8(&p, p_end);
                if (service_type < 0)
                    break;
                provider_name = getstr8(&p, p_end);
                if (!provider_name)
                    break;
                name = getstr8(&p, p_end);
                if (name) {
                    AVProgram *program = av_new_program(ts->stream, sid);
                    if(program)
                        av_set_program_name(program, provider_name, name);
                }
                break;
            default:
                break;
            }
            p = desc_end;
        }
        p = desc_list_end;
    }
}

/* scan services in a transport stream by looking at the SDT */
static void mpegts_scan_sdt(MpegTSContext *ts)
{
    mpegts_open_section_filter(ts, SDT_PID,
                                                sdt_cb, ts, 1);
}

static int64_t get_pts(const uint8_t *p)
{
    int64_t pts = (int64_t)((p[0] >> 1) & 0x07) << 30;
    pts |= (AV_RB16(p + 1) >> 1) << 15;
    pts |=  AV_RB16(p + 3) >> 1;
    return pts;
}

/* return non zero if a packet could be constructed */
static void mpegts_push_data(MpegTSFilter *filter,
                             const uint8_t *buf, int buf_size, int is_start)
{
    PESContext *pes = filter->u.pes_filter.opaque;
    MpegTSContext *ts = pes->ts;
    const uint8_t *p;
    int len, code;

    if(!ts->pkt)
        return;

    if (is_start) {
        pes->state = MPEGTS_HEADER;
        pes->data_index = 0;
    }
    p = buf;
    while (buf_size > 0) {
        switch(pes->state) {
        case MPEGTS_HEADER:
            len = PES_START_SIZE - pes->data_index;
            if (len > buf_size)
                len = buf_size;
            memcpy(pes->header + pes->data_index, p, len);
            pes->data_index += len;
            p += len;
            buf_size -= len;
            if (pes->data_index == PES_START_SIZE) {
                /* we got all the PES or section header. We can now
                   decide */
#if 0
                av_hex_dump_log(pes->stream, AV_LOG_DEBUG, pes->header, pes->data_index);
#endif
                if (pes->header[0] == 0x00 && pes->header[1] == 0x00 &&
                    pes->header[2] == 0x01) {
                    /* it must be an mpeg2 PES stream */
                    code = pes->header[3] | 0x100;
                    if (!((code >= 0x1c0 && code <= 0x1df) ||
                          (code >= 0x1e0 && code <= 0x1ef) ||
                          (code == 0x1bd) || (code == 0x1fd)))
                        goto skip;
                    if (!pes->st) {
                        /* allocate stream */
                        new_pes_av_stream(pes, code);
                    }
                    pes->state = MPEGTS_PESHEADER_FILL;
                    pes->total_size = AV_RB16(pes->header + 4);
                    /* NOTE: a zero total size means the PES size is
                       unbounded */
                    if (pes->total_size)
                        pes->total_size += 6;
                    pes->pes_header_size = pes->header[8] + 9;
                } else {
                    /* otherwise, it should be a table */
                    /* skip packet */
                skip:
                    pes->state = MPEGTS_SKIP;
                    continue;
                }
            }
            break;
            /**********************************************/
            /* PES packing parsing */
        case MPEGTS_PESHEADER_FILL:
            len = pes->pes_header_size - pes->data_index;
            if (len > buf_size)
                len = buf_size;
            memcpy(pes->header + pes->data_index, p, len);
            pes->data_index += len;
            p += len;
            buf_size -= len;
            if (pes->data_index == pes->pes_header_size) {
                const uint8_t *r;
                unsigned int flags;

                flags = pes->header[7];
                r = pes->header + 9;
                pes->pts = AV_NOPTS_VALUE;
                pes->dts = AV_NOPTS_VALUE;
                if ((flags & 0xc0) == 0x80) {
                    pes->pts = get_pts(r);
                    r += 5;
                } else if ((flags & 0xc0) == 0xc0) {
                    pes->pts = get_pts(r);
                    r += 5;
                    pes->dts = get_pts(r);
                    r += 5;
                }
                /* we got the full header. We parse it and get the payload */
                pes->state = MPEGTS_PAYLOAD;
            }
            break;
        case MPEGTS_PAYLOAD:
            if (pes->total_size) {
                len = pes->total_size - pes->data_index;
                if (len > buf_size)
                    len = buf_size;
            } else {
                len = buf_size;
            }
            if (len > 0) {
                AVPacket *pkt = ts->pkt;
                if (pes->st && av_new_packet(pkt, len) == 0) {
                    memcpy(pkt->data, p, len);
                    pkt->stream_index = pes->st->index;
                    pkt->pts = pes->pts;
                    pkt->dts = pes->dts;
                    /* reset pts values */
                    pes->pts = AV_NOPTS_VALUE;
                    pes->dts = AV_NOPTS_VALUE;
                    ts->stop_parse = 1;
                    return;
                }
            }
            buf_size = 0;
            break;
        case MPEGTS_SKIP:
            buf_size = 0;
            break;
        }
    }
}

static AVStream* new_pes_av_stream(PESContext *pes, uint32_t code)
{
    AVStream *st;
    int codec_type, codec_id;

    switch(pes->stream_type){
    case STREAM_TYPE_AUDIO_MPEG1:
    case STREAM_TYPE_AUDIO_MPEG2:
        codec_type = CODEC_TYPE_AUDIO;
        codec_id = CODEC_ID_MP3;
        break;
    case STREAM_TYPE_VIDEO_MPEG1:
    case STREAM_TYPE_VIDEO_MPEG2:
        codec_type = CODEC_TYPE_VIDEO;
        codec_id = CODEC_ID_MPEG2VIDEO;
        break;
    case STREAM_TYPE_VIDEO_MPEG4:
        codec_type = CODEC_TYPE_VIDEO;
        codec_id = CODEC_ID_MPEG4;
        break;
    case STREAM_TYPE_VIDEO_H264:
        codec_type = CODEC_TYPE_VIDEO;
        codec_id = CODEC_ID_H264;
        break;
    case STREAM_TYPE_VIDEO_VC1:
        codec_type = CODEC_TYPE_VIDEO;
        codec_id = CODEC_ID_VC1;
        break;
    case STREAM_TYPE_AUDIO_AAC:
        codec_type = CODEC_TYPE_AUDIO;
        codec_id = CODEC_ID_AAC;
        break;
    case STREAM_TYPE_AUDIO_AC3:
        codec_type = CODEC_TYPE_AUDIO;
        codec_id = CODEC_ID_AC3;
        break;
    case STREAM_TYPE_AUDIO_DTS:
        codec_type = CODEC_TYPE_AUDIO;
        codec_id = CODEC_ID_DTS;
        break;
    case STREAM_TYPE_SUBTITLE_DVB:
        codec_type = CODEC_TYPE_SUBTITLE;
        codec_id = CODEC_ID_DVB_SUBTITLE;
        break;
    default:
        if (code >= 0x1c0 && code <= 0x1df) {
            codec_type = CODEC_TYPE_AUDIO;
            codec_id = CODEC_ID_MP2;
        } else if (code == 0x1bd) {
            codec_type = CODEC_TYPE_AUDIO;
            codec_id = CODEC_ID_AC3;
        } else {
            codec_type = CODEC_TYPE_VIDEO;
            codec_id = CODEC_ID_MPEG1VIDEO;
        }
        break;
    }
    st = av_new_stream(pes->stream, pes->pid);
    if (st) {
        av_set_pts_info(st, 33, 1, 90000);
        st->priv_data = pes;
        st->codec->codec_type = codec_type;
        st->codec->codec_id = codec_id;
        st->need_parsing = AVSTREAM_PARSE_FULL;
        pes->st = st;
    }
    return st;
}


static PESContext *add_pes_stream(MpegTSContext *ts, int pid, int pcr_pid, int stream_type)
{
    MpegTSFilter *tss;
    PESContext *pes;

    /* if no pid found, then add a pid context */
    pes = av_mallocz(sizeof(PESContext));
    if (!pes)
        return 0;
    pes->ts = ts;
    pes->stream = ts->stream;
    pes->pid = pid;
    pes->pcr_pid = pcr_pid;
    pes->stream_type = stream_type;
    tss = mpegts_open_pes_filter(ts, pid, mpegts_push_data, pes);
    if (!tss) {
        av_free(pes);
        return 0;
    }
    return pes;
}

/* handle one TS packet */
static void handle_packet(MpegTSContext *ts, const uint8_t *packet)
{
    AVFormatContext *s = ts->stream;
    MpegTSFilter *tss;
    int len, pid, cc, cc_ok, afc, is_start;
    const uint8_t *p, *p_end;

    pid = AV_RB16(packet + 1) & 0x1fff;
    if(pid && discard_pid(ts, pid))
        return;
    is_start = packet[1] & 0x40;
    tss = ts->pids[pid];
    if (ts->auto_guess && tss == NULL && is_start) {