public MultiplexFrameHeader ParseMultiplexFrameHeader(int offset, Stream _stream)
{
_stream.Seek(offset, SeekOrigin.Begin);
byte[] tmp = new byte[4];
int r = _stream.Read(tmp, 0, 4); // read the start code,
if (r != 4)
{
return(null);
}
if (BitTools.FindBytePattern(tmp, frameStartCode) != 0)
{
return(null); // start code not match, return
}
MultiplexFrameHeader mfHeader = new MultiplexFrameHeader();
mfHeader.startAddr = 0x0;
// parse frame header length 1 byte.
_stream.Read(tmp, 0, 1);
mfHeader.headerLength = tmp[0];
// 再读两个字节，协议版本号5 bit, 最低版本号5 bit, 复用帧标示 6 bit
_stream.Read(tmp, 0, 2);
mfHeader.MD_ID = (uint)BitTools.MaskBits(tmp, 10, 6);
// 跳过4个字节， 包括从紧急广播提示-ESG更新序列号
_stream.Seek(4, SeekOrigin.Current);
// 读一个字节，取出 subFrame number (4 bit)
_stream.Read(tmp, 0, 1);
mfHeader.subFrameNum = (uint)BitTools.MaskBits(tmp, 4, 4);
//读取子帧长度 （3 byte）
mfHeader.subFrameLength = new int[mfHeader.subFrameNum];
for (int i = 0; i < mfHeader.subFrameNum; i++)
{
_stream.Read(tmp, 0, 3);
mfHeader.subFrameLength[i] = BitTools.MaskBits(tmp, 0, 24);
}
return(mfHeader);
}
public bool ParseNALHeader(MSF.VideoBlock vb)
{
// Need to get the SPS and PPS of the stream, the first frame must be I frame, other frames cannot be played.
if (vb.FirstIFrameIdx == -1)
{
return(false);
}
//有I帧
byte[] tmp = new byte[32];
byte[] NALStartCode = new byte[] { 0x00, 0x00, 0x01 };
List <byte[]> nals = new List <byte[]>();
Stream s = new MemoryStream(); //vb.vFrames[vb.FirstIFrameIdx]._vs;
s.Write(vb.vFrames[vb.FirstIFrameIdx]._data, 0,
(int)vb.vFrames[vb.FirstIFrameIdx].Length);
s.Seek(0, SeekOrigin.Begin);
s.Read(tmp, 0, 3);
if (BitTools.FindBytePattern(tmp, NALStartCode) != 0)
{
return(false);
}
while (true)
{
long pos = s.Position;
s.Read(tmp, 0, 32);
int nextNALidx = BitTools.FindBytePattern(tmp, NALStartCode);
if (nextNALidx == -1)
{
break;
}
byte[] nal = new byte[nextNALidx];
BitTools.CopyToBytesArray(tmp, nal, nextNALidx);
nals.Add(nal);
// rollback pos
pos += nextNALidx + 3; //跳过下一个startcode
s.Seek(pos, SeekOrigin.Begin);
}
s.Close();
vb.FirstIFrameInfo = new MSF.VideoBlock.NAL_SPS_PPS_SEI();
foreach (var v in nals)
{
switch (v[0])
{
case 0x67: //SPS http://www.eefocus.com/czzheng/blog/11-09/230262_65ff0.html
vb.FirstIFrameInfo.sps = new byte[v.Length - 1];
BitTools.CopyToBytesArray(v, 1, vb.FirstIFrameInfo.sps, v.Length - 1);
break;
case 0x68: //PPS
vb.FirstIFrameInfo.pps = new byte[v.Length - 1];
BitTools.CopyToBytesArray(v, 1, vb.FirstIFrameInfo.pps, v.Length - 1);
break;
case 0x06: // SEI
vb.FirstIFrameInfo.sei = new byte[v.Length - 1];
BitTools.CopyToBytesArray(v, 1, vb.FirstIFrameInfo.sei, v.Length - 1);
break;
default:
break;
}
}
return(true);
}
