FFmpeg开发笔记（三十七）分析SRS对HLS协议里TS包的插帧操作

if ((ret = write_h264_sps_pps(dts, pts)) != ERROR_SUCCESS) {
    return ret;
}

if ((ret = write_h264_ipb_frame(ibps, frame_type, dts, pts)) != ERROR_SUCCESS) {
    // drop the ts message.
    if (ret == ERROR_H264_DROP_BEFORE_SPS_PPS) {
        return ERROR_SUCCESS;
    }
    return ret;
}

// h264 raw to h264 packet.
std::string sh;
if ((err = avc->mux_sequence_header(h264_sps, h264_pps, sh)) != srs_success) {
    // TODO: FIXME: Use error
    ret = srs_error_code(err);
    srs_freep(err);
    return ret;
}

// sps
if (true) {
    // 5.3.4.2.1 Syntax, ISO_IEC_14496-15-AVC-format-2012.pdf, page 16
    // numOfSequenceParameterSets, always 1
    stream.write_1bytes(uint8_t(0xe0 | 0x01));
    // sequenceParameterSetLength
    stream.write_2bytes((int16_t)sps.length());
    // sequenceParameterSetNALUnit
    stream.write_string(sps);
}

// pps
if (true) {
    // 5.3.4.2.1 Syntax, ISO_IEC_14496-15-AVC-format-2012.pdf, page 16
    // numOfPictureParameterSets, always 1
    stream.write_1bytes(0x01);
    // pictureParameterSetLength
    stream.write_2bytes((int16_t)pps.length());
    // pictureParameterSetNALUnit
    stream.write_string(pps);
}