private static bool IsValidHeader(byte[] headerBytes, Mp3Frame frame)
{
if (headerBytes[0] != 255 || (headerBytes[1] & 224) != 224)
{
return(false);
}
frame.MpegVersion = (MpegVersion)((headerBytes[1] & 24) >> 3);
if (frame.MpegVersion == MpegVersion.Reserved)
{
return(false);
}
frame.MpegLayer = (MpegLayer)((headerBytes[1] & 6) >> 1);
if (frame.MpegLayer == MpegLayer.Reserved)
{
return(false);
}
int num = (frame.MpegLayer == MpegLayer.Layer1) ? 0 : ((frame.MpegLayer == MpegLayer.Layer2) ? 1 : 2);
frame.CrcPresent = ((headerBytes[1] & 1) == 0);
frame.BitRateIndex = (headerBytes[2] & 240) >> 4;
if (frame.BitRateIndex == 15)
{
return(false);
}
int num2 = (frame.MpegVersion == MpegVersion.Version1) ? 0 : 1;
frame.BitRate = Mp3Frame.bitRates[num2, num, frame.BitRateIndex] * 1000;
if (frame.BitRate == 0)
{
return(false);
}
int num3 = (headerBytes[2] & 12) >> 2;
if (num3 == 3)
{
return(false);
}
if (frame.MpegVersion == MpegVersion.Version1)
{
frame.SampleRate = Mp3Frame.sampleRatesVersion1[num3];
}
else if (frame.MpegVersion == MpegVersion.Version2)
{
frame.SampleRate = Mp3Frame.sampleRatesVersion2[num3];
}
else
{
frame.SampleRate = Mp3Frame.sampleRatesVersion25[num3];
}
bool flag = (headerBytes[2] & 2) == 2;
byte arg_123_0 = headerBytes[2];
frame.ChannelMode = (ChannelMode)((headerBytes[3] & 192) >> 6);
frame.ChannelExtension = (headerBytes[3] & 48) >> 4;
if (frame.ChannelExtension != 0 && frame.ChannelMode != ChannelMode.JointStereo)
{
return(false);
}
frame.Copyright = ((headerBytes[3] & 8) == 8);
byte arg_167_0 = headerBytes[3];
byte arg_16B_0 = headerBytes[3];
int num4 = flag ? 1 : 0;
frame.SampleCount = Mp3Frame.samplesPerFrame[num2, num];
int num5 = frame.SampleCount / 8;
if (frame.MpegLayer == MpegLayer.Layer1)
{
frame.FrameLength = (num5 * frame.BitRate / frame.SampleRate + num4) * 4;
}
else
{
frame.FrameLength = num5 * frame.BitRate / frame.SampleRate + num4;
}
return(frame.FrameLength <= 16384);
}
public static Mp3Frame LoadFromStream(Stream input)
{
return(Mp3Frame.LoadFromStream(input, true));
}
private Mp3FileReader(Stream inputStream, Mp3FileReader.FrameDecompressorBuilder frameDecompressorBuilder, bool ownInputStream)
{
if (inputStream == null)
{
throw new ArgumentNullException("inputStream");
}
if (frameDecompressorBuilder == null)
{
throw new ArgumentNullException("frameDecompressorBuilder");
}
this.ownInputStream = ownInputStream;
try
{
this.mp3Stream = inputStream;
this.Id3v2Tag = Id3v2Tag.ReadTag(this.mp3Stream);
this.dataStartPosition = this.mp3Stream.Position;
Mp3Frame mp3Frame = Mp3Frame.LoadFromStream(this.mp3Stream);
if (mp3Frame == null)
{
throw new InvalidDataException("Invalid MP3 file - no MP3 Frames Detected");
}
double num = (double)mp3Frame.BitRate;
this.xingHeader = XingHeader.LoadXingHeader(mp3Frame);
if (this.xingHeader != null)
{
this.dataStartPosition = this.mp3Stream.Position;
}
Mp3Frame mp3Frame2 = Mp3Frame.LoadFromStream(this.mp3Stream);
if (mp3Frame2 != null && (mp3Frame2.SampleRate != mp3Frame.SampleRate || mp3Frame2.ChannelMode != mp3Frame.ChannelMode))
{
this.dataStartPosition = mp3Frame2.FileOffset;
mp3Frame = mp3Frame2;
}
this.mp3DataLength = this.mp3Stream.Length - this.dataStartPosition;
this.mp3Stream.Position = this.mp3Stream.Length - 128L;
byte[] array = new byte[128];
this.mp3Stream.Read(array, 0, 128);
if (array[0] == 84 && array[1] == 65 && array[2] == 71)
{
this.Id3v1Tag = array;
this.mp3DataLength -= 128L;
}
this.mp3Stream.Position = this.dataStartPosition;
this.Mp3WaveFormat = new Mp3WaveFormat(mp3Frame.SampleRate, (mp3Frame.ChannelMode == ChannelMode.Mono) ? 1 : 2, mp3Frame.FrameLength, (int)num);
this.CreateTableOfContents();
this.tocIndex = 0;
num = (double)this.mp3DataLength * 8.0 / this.TotalSeconds();
this.mp3Stream.Position = this.dataStartPosition;
this.Mp3WaveFormat = new Mp3WaveFormat(mp3Frame.SampleRate, (mp3Frame.ChannelMode == ChannelMode.Mono) ? 1 : 2, mp3Frame.FrameLength, (int)num);
this.decompressor = frameDecompressorBuilder(this.Mp3WaveFormat);
this.waveFormat = this.decompressor.OutputFormat;
this.bytesPerSample = this.decompressor.OutputFormat.BitsPerSample / 8 * this.decompressor.OutputFormat.Channels;
this.bytesPerDecodedFrame = 1152 * this.bytesPerSample;
this.decompressBuffer = new byte[this.bytesPerDecodedFrame * 2];
}
catch (Exception)
{
if (ownInputStream)
{
inputStream.Dispose();
}
throw;
}
}
public override int Read(byte[] sampleBuffer, int offset, int numBytes)
{
int i = 0;
object obj = this.repositionLock;
lock (obj)
{
if (this.decompressLeftovers != 0)
{
int num = Math.Min(this.decompressLeftovers, numBytes);
Array.Copy(this.decompressBuffer, this.decompressBufferOffset, sampleBuffer, offset, num);
this.decompressLeftovers -= num;
if (this.decompressLeftovers == 0)
{
this.decompressBufferOffset = 0;
}
else
{
this.decompressBufferOffset += num;
}
i += num;
offset += num;
}
int num2 = this.tocIndex;
if (this.repositionedFlag)
{
this.decompressor.Reset();
this.tocIndex = Math.Max(0, this.tocIndex - 3);
this.mp3Stream.Position = this.tableOfContents[this.tocIndex].FilePosition;
this.repositionedFlag = false;
}
while (i < numBytes)
{
Mp3Frame mp3Frame = this.ReadNextFrame(true);
if (mp3Frame == null)
{
break;
}
int num3 = this.decompressor.DecompressFrame(mp3Frame, this.decompressBuffer, 0);
if (this.tocIndex > num2 && num3 != 0)
{
if (this.tocIndex == num2 + 1 && num3 == this.bytesPerDecodedFrame * 2)
{
Array.Copy(this.decompressBuffer, this.bytesPerDecodedFrame, this.decompressBuffer, 0, this.bytesPerDecodedFrame);
num3 = this.bytesPerDecodedFrame;
}
int num4 = Math.Min(num3 - this.decompressBufferOffset, numBytes - i);
Array.Copy(this.decompressBuffer, this.decompressBufferOffset, sampleBuffer, offset, num4);
if (num4 + this.decompressBufferOffset < num3)
{
this.decompressBufferOffset = num4 + this.decompressBufferOffset;
this.decompressLeftovers = num3 - this.decompressBufferOffset;
}
else
{
this.decompressBufferOffset = 0;
this.decompressLeftovers = 0;
}
offset += num4;
i += num4;
}
}
}
this.position += (long)i;
return(i);
}
public static XingHeader LoadXingHeader(Mp3Frame frame)
{
XingHeader xingHeader = new XingHeader();
xingHeader.frame = frame;
int num;
if (frame.MpegVersion == MpegVersion.Version1)
{
if (frame.ChannelMode != ChannelMode.Mono)
{
num = 36;
}
else
{
num = 21;
}
}
else
{
if (frame.MpegVersion != MpegVersion.Version2)
{
return(null);
}
if (frame.ChannelMode != ChannelMode.Mono)
{
num = 21;
}
else
{
num = 13;
}
}
if (frame.RawData[num] == 88 && frame.RawData[num + 1] == 105 && frame.RawData[num + 2] == 110 && frame.RawData[num + 3] == 103)
{
xingHeader.startOffset = num;
num += 4;
int arg_9E_0 = XingHeader.ReadBigEndian(frame.RawData, num);
num += 4;
if ((arg_9E_0 & 1) != 0)
{
xingHeader.framesOffset = num;
num += 4;
}
if ((arg_9E_0 & 2) != 0)
{
xingHeader.bytesOffset = num;
num += 4;
}
if ((arg_9E_0 & 4) != 0)
{
xingHeader.tocOffset = num;
num += 100;
}
if ((arg_9E_0 & 8) != 0)
{
xingHeader.vbrScale = XingHeader.ReadBigEndian(frame.RawData, num);
num += 4;
}
xingHeader.endOffset = num;
return(xingHeader);
}
return(null);
}