Method Write

src/brpc/ts.cpp:1084–1162

}

butil::Status TsWriter::Write(const RtmpAudioMessage& msg) {
    // ts support audio codec: aac/mp3
    if (msg.codec != FLV_AUDIO_AAC && msg.codec != FLV_AUDIO_MP3) {
        return butil::Status(EINVAL, "Unsupported codec=%s",
                            FlvAudioCodec2Str(msg.codec));
    }
    const int64_t dts = static_cast<int64_t>(msg.timestamp) * 90;
    TsMessage tsmsg;
    tsmsg.write_pcr = false;
    tsmsg.dts = dts;
    tsmsg.pts = dts;
    tsmsg.sid = TS_PES_STREAM_ID_AUDIO_COMMON;

    if (msg.codec == FLV_AUDIO_AAC) {
        RtmpAACMessage aac_msg;
        butil::Status st = aac_msg.Create(msg);
        if (!st.ok()) {
            return st;
        }
        // ignore sequence header
        if (aac_msg.packet_type == FLV_AAC_PACKET_SEQUENCE_HEADER) {
            butil::Status st2 = _aac_seq_header.Create(aac_msg.data);
            if (!st2.ok()) {
                return st2;
            }
            _has_aac_seq_header = true;
            ++_discontinuity_counter;
            return butil::Status::OK();
        }
        if (!_has_aac_seq_header) {
            return butil::Status(EINVAL, "Lack of AAC sequence header");
        }
        if (aac_msg.data.size() > 0x1fff) {
            return butil::Status(EINVAL, "Invalid AAC data_size=%" PRIu64,
                                (uint64_t)aac_msg.data.size());
        }
        
        // the frame length is the AAC raw data plus the adts header size.
        const int32_t frame_length = aac_msg.data.size() + 7;
        
        // AAC-ADTS
        // 6.2 Audio Data Transport Stream, ADTS
        // in aac-iso-13818-7.pdf, page 26.
        // fixed 7bytes header
        uint8_t adts_header[7] = {0xff, 0xf9, 0x00, 0x00, 0x00, 0x0f, 0xfc};
        // profile, 2bits
        const AACProfile aac_profile =
            AACObjectType2Profile(_aac_seq_header.aac_object);
        if (aac_profile == AAC_PROFILE_UNKNOWN) {
            return butil::Status(EINVAL, "Invalid aac_object=%d",
                                (int)_aac_seq_header.aac_object);
        }
        adts_header[2] = (aac_profile << 6) & 0xc0;
        // sampling_frequency_index 4bits
        adts_header[2] |= (_aac_seq_header.aac_sample_rate << 2) & 0x3c;
        // channel_configuration 3bits
        adts_header[2] |= (_aac_seq_header.aac_channels >> 2) & 0x01;
        adts_header[3] = (_aac_seq_header.aac_channels << 6) & 0xc0;