private H264NALU Create(JT1078Package package, ReadOnlySpan <byte> naluheader, int startCodePrefix)
{
H264NALU nALU = new H264NALU();
nALU.SIM = package.SIM;
nALU.DataType = package.Label3.DataType;
nALU.LogicChannelNumber = package.LogicChannelNumber;
nALU.LastFrameInterval = package.LastFrameInterval;
nALU.LastIFrameInterval = package.LastIFrameInterval;
if (startCodePrefix == 3)
{
nALU.StartCodePrefix = H264NALU.Start1;
}
else if (startCodePrefix == 4)
{
nALU.StartCodePrefix = H264NALU.Start2;
}
nALU.NALUHeader = new NALUHeader(naluheader);
return(nALU);
}
/// <summary>
/// Identify NAL unit types and pass on the NALU, trackId, presentation and decode timestamps
/// for the NALUs to the next stream component.
/// Also, preprocess caption and sequence parameter NALUs.
/// 常用Nalu_type:
/// 0x67 (0 11 00111) SPS 非常重要 type = 7
/// 0x68 (0 11 01000) PPS 非常重要 type = 8
/// 0x65 (0 11 00101) IDR帧 关键帧(非常重要) type = 5
/// 0x61 (0 11 00001) I帧 重要 type = 1 非IDR的I帧不大常见
/// 0x41 (0 10 00001) P帧 重要 type = 1
/// 0x01 (0 00 00001) B帧 不重要 type = 1
/// 0x06 (0 00 00110) SEI 不重要 type = 6
/// <see cref="https://blog.csdn.net/huibailingyu/article/details/42879573"/>
/// </summary>
/// <param name="h264NALU"></param>
/// <returns></returns>
private void NALUTypeFilter(H264NALU h264NALU)
{
switch (h264NALU.NALUHeader.NalUnitType)
{
//IPB帧
case 1:
break;
//IDR
case 5:
break;
//SEI
case 6:
h264NALU.RawData = DiscardEmulationPreventionBytes(h264NALU.RawData);
break;
//SPS
case 7:
h264NALU.RawData = DiscardEmulationPreventionBytes(h264NALU.RawData);
ExpGolombReader h264GolombReader = new ExpGolombReader(h264NALU.RawData);
var spsInfo = h264GolombReader.ReadSPS();
break;
//PPS
case 8:
break;
//AUD
case 9:
break;
}
}