private void ParseMP3Frames(byte[] buff)
{
var MPEG1BitRate = new[] { 0, 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 0 };
var MPEG2XBitRate = new[] { 0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160, 0 };
var MPEG1SampleRate = new[] { 44100, 48000, 32000, 0 };
var MPEG20SampleRate = new[] { 22050, 24000, 16000, 0 };
var MPEG25SampleRate = new[] { 11025, 12000, 8000, 0 };
var offset = 0;
var length = buff.Length;
while (length >= 4)
{
ulong header;
int mpegVersion, layer, bitRate, sampleRate, padding, channelMode;
int frameLen;
header = (ulong)BitConverterBE.ToUInt32(buff, offset) << 32;
if (BitHelper.Read(ref header, 11) != 0x7FF)
{
break;
}
mpegVersion = BitHelper.Read(ref header, 2);
layer = BitHelper.Read(ref header, 2);
BitHelper.Read(ref header, 1);
bitRate = BitHelper.Read(ref header, 4);
sampleRate = BitHelper.Read(ref header, 2);
padding = BitHelper.Read(ref header, 1);
BitHelper.Read(ref header, 1);
channelMode = BitHelper.Read(ref header, 2);
if (mpegVersion == 1 || layer != 1 || bitRate == 0 || bitRate == 15 || sampleRate == 3)
{
break;
}
bitRate = (mpegVersion == 3 ? MPEG1BitRate[bitRate] : MPEG2XBitRate[bitRate]) * 1000;
if (mpegVersion == 3)
{
sampleRate = MPEG1SampleRate[sampleRate];
}
else if (mpegVersion == 2)
{
sampleRate = MPEG20SampleRate[sampleRate];
}
else
{
sampleRate = MPEG25SampleRate[sampleRate];
}
frameLen = GetFrameLength(mpegVersion, bitRate, sampleRate, padding);
if (frameLen > length)
{
break;
}
var isVBRHeaderFrame = false;
if (_frameOffsets.Count == 0)
{
// Check for an existing VBR header just to be safe (I haven't seen any in FLVs)
var o = offset + GetFrameDataOffset(mpegVersion, channelMode);
if (BitConverterBE.ToUInt32(buff, o) == 0x58696E67)
{ // "Xing"
isVBRHeaderFrame = true;
_delayWrite = false;
_hasVBRHeader = true;
}
}
if (isVBRHeaderFrame)
{
}
else if (_firstBitRate == 0)
{
_firstBitRate = bitRate;
_mpegVersion = mpegVersion;
_sampleRate = sampleRate;
_channelMode = channelMode;
_firstFrameHeader = BitConverterBE.ToUInt32(buff, offset);
}
else if (!_isVBR && bitRate != _firstBitRate)
{
_isVBR = true;
if (_hasVBRHeader)
{
}
else if (_delayWrite)
{
WriteVBRHeader(true);
_writeVBRHeader = true;
_delayWrite = false;
}
else
{
_warnings.Add("Detected VBR too late, cannot add VBR header.");
}
}
_frameOffsets.Add(_totalFrameLength + (uint)offset);
offset += frameLen;
length -= frameLen;
}
_totalFrameLength += (uint)buff.Length;
}
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);
}
}
public void WriteChunk(byte[] chunk, uint timeStamp)
{
var subModeSizes = new[] { 0, 43, 119, 160, 220, 300, 364, 492, 79 };
var wideBandSizes = new[] { 0, 36, 112, 192, 352 };
var inBandSignalSizes = new[] { 1, 1, 4, 4, 4, 4, 4, 4, 8, 8, 16, 16, 32, 32, 64, 64 };
var frameStart = -1;
var frameEnd = 0;
var offset = 0;
var length = chunk.Length * 8;
int x;
while (length - offset >= 5)
{
x = BitHelper.Read(chunk, ref offset, 1);
if (x != 0)
{
// wideband frame
x = BitHelper.Read(chunk, ref offset, 3);
if (x < 1 || x > 4)
{
goto Error;
}
offset += wideBandSizes[x] - 4;
}
else
{
x = BitHelper.Read(chunk, ref offset, 4);
if (x >= 1 && x <= 8)
{
// narrowband frame
if (frameStart != -1)
{
WriteFramePacket(chunk, frameStart, frameEnd);
}
frameStart = frameEnd;
offset += subModeSizes[x] - 5;
}
else if (x == 15)
{
// terminator
break;
}
else if (x == 14)
{
// in-band signal
if (length - offset < 4)
{
goto Error;
}
x = BitHelper.Read(chunk, ref offset, 4);
offset += inBandSignalSizes[x];
}
else if (x == 13)
{
// custom in-band signal
if (length - offset < 5)
{
goto Error;
}
x = BitHelper.Read(chunk, ref offset, 5);
offset += x * 8;
}
else
{
goto Error;
}
}
frameEnd = offset;
}
if (offset > length)
{
goto Error;
}
if (frameStart != -1)
{
WriteFramePacket(chunk, frameStart, frameEnd);
}
return;
Error:
throw new Exception("Invalid Speex data.");
}
private void GetFrameSize(byte[] chunk)
{
if (_codecID == 2)
{
// Reference: flv_h263_decode_picture_header from libavcodec's h263.c
if (chunk.Length < 10)
{
return;
}
if (chunk[0] != 0 || chunk[1] != 0)
{
return;
}
var x = BitConverterBE.ToUInt64(chunk, 2);
int format;
if (BitHelper.Read(ref x, 1) != 1)
{
return;
}
BitHelper.Read(ref x, 5);
BitHelper.Read(ref x, 8);
format = BitHelper.Read(ref x, 3);
switch (format)
{
case 0:
_width = BitHelper.Read(ref x, 8);
_height = BitHelper.Read(ref x, 8);
break;
case 1:
_width = BitHelper.Read(ref x, 16);
_height = BitHelper.Read(ref x, 16);
break;
case 2:
_width = 352;
_height = 288;
break;
case 3:
_width = 176;
_height = 144;
break;
case 4:
_width = 128;
_height = 96;
break;
case 5:
_width = 320;
_height = 240;
break;
case 6:
_width = 160;
_height = 120;
break;
default:
return;
}
}
else if (_codecID == 4 || _codecID == 5)
{
// Reference: vp6_parse_header from libavcodec's vp6.c
var skip = _codecID == 4 ? 1 : 4;
if (chunk.Length < skip + 8)
{
return;
}
var x = BitConverterBE.ToUInt64(chunk, skip);
var deltaFrameFlag = BitHelper.Read(ref x, 1);
var quant = BitHelper.Read(ref x, 6);
var separatedCoeffFlag = BitHelper.Read(ref x, 1);
var subVersion = BitHelper.Read(ref x, 5);
var filterHeader = BitHelper.Read(ref x, 2);
var interlacedFlag = BitHelper.Read(ref x, 1);
if (deltaFrameFlag != 0)
{
return;
}
if (separatedCoeffFlag != 0 || filterHeader == 0)
{
BitHelper.Read(ref x, 16);
}
_height = BitHelper.Read(ref x, 8) * 16;
_width = BitHelper.Read(ref x, 8) * 16;
// chunk[0] contains the width and height (4 bits each, respectively) that should
// be cropped off during playback, which will be non-zero if the encoder padded
// the frames to a macroblock boundary. But if you use this adjusted size in the
// AVI header, DirectShow seems to ignore it, and it can cause stride or chroma
// alignment problems with VFW if the width/height aren't multiples of 4.
if (!_isAlphaWriter)
{
var cropX = chunk[0] >> 4;
var cropY = chunk[0] & 0x0F;
if ((cropX != 0 || cropY != 0) && !_isAlphaWriter)
{
_warnings.Add(String.Format("Suggested cropping: {0} pixels from right, {1} pixels from bottom.", cropX, cropY));
}
}
}
}
