public void WriteChunk(byte[] chunk, uint timeStamp, int frameType)
{
if (chunk.Length < 4)
{
return;
}
// Reference: decode_frame from libavcodec's h264.c
if (chunk[0] == 0)
{ // Headers
if (chunk.Length < 10)
{
return;
}
int offset, spsCount, ppsCount;
offset = 8;
_nalLengthSize = (chunk[offset++] & 0x03) + 1;
spsCount = chunk[offset++] & 0x1F;
ppsCount = -1;
while (offset <= chunk.Length - 2)
{
if (spsCount == 0 && ppsCount == -1)
{
ppsCount = chunk[offset++];
continue;
}
if (spsCount > 0)
{
spsCount--;
}
else if (ppsCount > 0)
{
ppsCount--;
}
else
{
break;
}
var len = (int)BitConverterBE.ToUInt16(chunk, offset);
offset += 2;
if (offset + len > chunk.Length)
{
break;
}
_fs.Write(_startCode, 0, _startCode.Length);
_fs.Write(chunk, offset, len);
offset += len;
}
}
else
{ // Video data
var offset = 4;
if (_nalLengthSize != 2)
{
_nalLengthSize = 4;
}
while (offset <= chunk.Length - _nalLengthSize)
{
var len = _nalLengthSize == 2 ?
(int)BitConverterBE.ToUInt16(chunk, offset) :
(int)BitConverterBE.ToUInt32(chunk, offset);
offset += _nalLengthSize;
if (offset + len > chunk.Length)
{
break;
}
_fs.Write(_startCode, 0, _startCode.Length);
_fs.Write(chunk, offset, len);
offset += len;
}
}
}
public void WriteChunk(byte[] chunk, uint timeStamp)
{
if (chunk.Length < 1)
{
return;
}
if (chunk[0] == 0)
{ // Header
if (chunk.Length < 3)
{
return;
}
var bits = (ulong)BitConverterBE.ToUInt16(chunk, 1) << 48;
_aacProfile = BitHelper.Read(ref bits, 5) - 1;
_sampleRateIndex = BitHelper.Read(ref bits, 4);
_channelConfig = BitHelper.Read(ref bits, 4);
if (_aacProfile == 4) // HE-AAC
{
_aacProfile = 1; // Uses LC profile + SBR
}
if (_aacProfile < 0 || _aacProfile > 3)
{
throw new Exception("Unsupported AAC profile.");
}
if (_sampleRateIndex > 12)
{
throw new Exception("Invalid AAC sample rate index.");
}
if (_channelConfig > 6)
{
throw new Exception("Invalid AAC channel configuration.");
}
}
else
{ // Audio data
var dataSize = chunk.Length - 1;
ulong bits = 0;
// Reference: WriteADTSHeader from FAAC's bitstream.c
BitHelper.Write(ref bits, 12, 0xFFF);
BitHelper.Write(ref bits, 1, 0);
BitHelper.Write(ref bits, 2, 0);
BitHelper.Write(ref bits, 1, 1);
BitHelper.Write(ref bits, 2, _aacProfile);
BitHelper.Write(ref bits, 4, _sampleRateIndex);
BitHelper.Write(ref bits, 1, 0);
BitHelper.Write(ref bits, 3, _channelConfig);
BitHelper.Write(ref bits, 1, 0);
BitHelper.Write(ref bits, 1, 0);
BitHelper.Write(ref bits, 1, 0);
BitHelper.Write(ref bits, 1, 0);
BitHelper.Write(ref bits, 13, 7 + dataSize);
BitHelper.Write(ref bits, 11, 0x7FF);
BitHelper.Write(ref bits, 2, 0);
_fs.Write(BitConverterBE.GetBytes(bits), 1, 7);
_fs.Write(chunk, 1, dataSize);
}
}
