// start reading at a byte boundary
public virtual void Read(BitReader bitReader)
{
_positionInStream = bitReader.Position;
Byte firstByte = bitReader.ReadByte();
Byte idc = (Byte)(firstByte >> 5);
if ((idc > 0) != (NALRefIDC > 0)) // if it's not as expected, then throw exception
{
throw new Exception("NALU base class: unexpected Ref IDC");
}
NALUnitType naluType = (NALUnitType)(firstByte & 0x1F);
if (naluType != NALUType)
{
throw new Exception("NALU base class: unexpected NALU type");
}
}
public CodedSliceBase(SequenceParameterSet sps, PictureParameterSet pps, Byte idc, NALUnitType naluType, uint size)
{
Nalu = new NetworkAbstractionLayerUnit(idc, naluType, size);
Header = new SliceHeader(sps, pps, Nalu);
Data = new SliceData(sps, pps, Header, Nalu);
}
/// <summary>
/// Internal method for locating next NAL unit of specific type.
/// </summary>
/// <param name="data"></param>
/// <param name="offset"></param>
/// <param name="end"></param>
/// <param name="type"></param>
/// <returns></returns>
private int FindNALUnitStart(byte[] data, int offset, int end, NALUnitType type)
{
for (int i = offset; i < end - 3; i++)
{
if (data[i] == 0 &&
data[i + 1] == 0 &&
data[i + 2] == 1 &&
(data[i + 3] & 0x1F) == (byte)type)
{
if (i > offset && data[i - 1] == 0)
i--;
return i;
}
}
return -1;
}
public NetworkAbstractionLayerUnit(byte idc, NALUnitType naluType, uint size)
: this(size)
{
NALRefIDC = idc;
NALUType = naluType;
}
public CodedSlicePartitionBorC(SequenceParameterSet sps, PictureParameterSet pps,
byte idc, NALUnitType naluType, uint size)
: base(sps, pps, (byte)0, NALUnitType.SlicePartitionA, size)
{
_pps = pps;
}
public CodedSliceWithoutPartition(SequenceParameterSet sps, PictureParameterSet pps,
Byte idc, NALUnitType naluType, uint size)
: base(sps, pps, idc, naluType, size)
{
}
public NetworkAbstractionLayerUnit(byte idc, NALUnitType naluType, uint size) : this(size)
{
NALRefIDC = idc;
NALUType = naluType;
}
public CodedSliceBase(SequenceParameterSet sps, PictureParameterSet pps, Byte idc, NALUnitType naluType, uint size)
{
Nalu = new NetworkAbstractionLayerUnit(idc, naluType, size);
Header = new SliceHeader(sps, pps, Nalu);
Data = new SliceData(sps, pps, Header, Nalu);
}
public CodedSliceWithoutPartition(SequenceParameterSet sps, PictureParameterSet pps,
Byte idc, NALUnitType naluType, uint size)
: base(sps, pps, idc, naluType, size)
{
}
void ParseThreadProc(object buffer)
{
byte[] sliceBytes = buffer as byte[];
BitReader br = new BitReader(new MemoryStream(sliceBytes));
int totalSize = _totalSize;
int offset = 0;
int state = 0;
while (totalSize > 4)
{
int naluLen = (int)br.GetUIntFromNBits(32);
if (naluLen > totalSize)
{
throw new Exception("H264 parsing: wrong byte count encountered");
}
if (naluLen > 0)
{
byte b = br.PeekByte();
byte refIDC = (byte)(b >> 5);
NALUnitType naluType = (NALUnitType)(b & 0x1F);
switch (state)
{
case 0:
AccessUnitDelimiter aud = new AccessUnitDelimiter((uint)naluLen);
aud.Read(br);
state = 1;
break;
case 1:
// either SEI or SPS (if it's an SEI, don't change state)
if (naluType == NALUnitType.SupplementalEnhancementInfo)
{
SupplementatlEnhancementMessage sei = new SupplementatlEnhancementMessage(_sps, (uint)naluLen);
sei.Read(br);
}
else if (naluType == NALUnitType.SequenceParamSet)
{
// replace _sps
_sps = new SequenceParameterSet((uint)naluLen);
_sps.Read(br);
}
else if (naluType == NALUnitType.PictureParamSet)
{
// replace _pps
_pps = new PictureParameterSet((uint)naluLen);
_pps.Read(br);
}
else if (naluType == NALUnitType.IDRSlice)
{
CodedSliceIDR idr = new CodedSliceIDR(_sps, _pps, (uint)naluLen);
idr.Read(br);
SliceType = idr.Header.SliceType;
FrameNum = idr.Header.FrameNum;
state = 2; // next should be zero or more redundant coded pictures
}
else if (naluType == NALUnitType.NonIDRSlice)
{
CodedSliceNonIDR nonIdr = new CodedSliceNonIDR(_sps, _pps, GetIDC(refIDC), (uint)naluLen);
nonIdr.Read(br);
SliceType = nonIdr.Header.SliceType;
FrameNum = nonIdr.Header.FrameNum;
state = 2; // next should be zero or more redundant coded pictures
}
else if (naluType == NALUnitType.SlicePartitionA)
{
CodedSlicePartitionA partA = new CodedSlicePartitionA(_sps, _pps, GetIDC(refIDC), (uint)naluLen);
partA.Read(br);
SliceType = partA.Header.SliceType;
FrameNum = partA.Header.FrameNum;
state = 2; // next should be zero or more redundant coded pictures
}
else if ((naluType == NALUnitType.SlicePartitionB) || (naluType == NALUnitType.SlicePartitionC))
{
CodedSlicePartitionBorC partBC = new CodedSlicePartitionBorC(_sps, _pps, GetIDC(refIDC), naluType, (uint)naluLen);
partBC.Read(br);
// FIXME: check that SliceType and FrameNum are set at this point
state = 2; // next should be zero or more redundant coded pictures
}
break;
case 2:
// either coded picture or end of sequence
break;
default:
break;
}
offset += naluLen;
totalSize -= (naluLen + 4);
}
else
{
naluLen = 0; // debugging break point
}
}
if (SampleDoneEvent != null)
{
SampleDoneEvent(this);
}
}
public CodedSlicePartitionBorC(SequenceParameterSet sps, PictureParameterSet pps,
byte idc, NALUnitType naluType, uint size)
: base(sps, pps, (byte)0, NALUnitType.SlicePartitionA, size)
{
_pps = pps;
}
