private uint ReadUInt32()
{
byte[] x = new byte[4];
_fs.Read(x, 0, 4);
_fileOffset += 4;
return(BitConverterBE.ToUInt32(x, 0));
}
private void ParseMP3Frames(byte[] buff)
{
int[] MPEG1BitRate = new int[] { 0, 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 0 };
int[] MPEG2XBitRate = new int[] { 0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160, 0 };
int[] MPEG1SampleRate = new int[] { 44100, 48000, 32000, 0 };
int[] MPEG20SampleRate = new int[] { 22050, 24000, 16000, 0 };
int[] MPEG25SampleRate = new int[] { 11025, 12000, 8000, 0 };
int offset = 0;
int 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;
}
bool isVBRHeaderFrame = false;
if (_frameOffsets.Count == 0)
{
// Check for an existing VBR header just to be safe (I haven't seen any in FLVs)
int 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;
}
