public void AddFrame(
MpegVersion version,
MpegLayer layer,
bool hasCRC,
int frameSizeOffset,
int frameSize)
{
Add(new Mp3Frame(BuildFrame(
version,
layer,
hasCRC,
frameSizeOffset,
frameSize)));
}
public void AddFreeFrame(
MpegVersion version,
MpegLayer layer,
bool hasCRC,
int frameSizeOffset,
int frameSize)
{
byte[] buf = BuildFrame(
version,
layer,
hasCRC,
frameSizeOffset,
frameSize);
buf[2] &= 0x0F;
Add(new Mp3Frame(buf));
}
private void GetLayer(params bool[] twoBits)
{
if (twoBits[0] && twoBits[1])
{
this.mpegLayer = MpegLayer.I;
}
else if (twoBits[0] && !twoBits[1])
{
this.mpegLayer = MpegLayer.II;
}
else if (!twoBits[0] && twoBits[1])
{
this.mpegLayer = MpegLayer.III;
}
else if (!twoBits[0] && !twoBits[1])
{
this.mpegLayer = MpegLayer.Reserved;
}
}
private static int GetSamplesPerFrame(MpegVersion mpegVersion, MpegLayer mpegLayer)
{
int tmpSamplesPerFrame = 0;
switch (mpegVersion)
{
// MPEG-1
case MpegVersion.Mpeg1:
if (mpegLayer == MpegLayer.Layer1)
{
tmpSamplesPerFrame = 384;
}
else if (mpegLayer == MpegLayer.Layer2 ||
mpegLayer == MpegLayer.Layer3)
{
tmpSamplesPerFrame = 1152;
}
break;
// MPEG-2/2.5
case MpegVersion.Mpeg2:
case MpegVersion.Mpeg25:
if (mpegLayer == MpegLayer.Layer1)
{
tmpSamplesPerFrame = 384;
}
else if (mpegLayer == MpegLayer.Layer2)
{
tmpSamplesPerFrame = 1152;
}
else if (mpegLayer == MpegLayer.Layer3)
{
tmpSamplesPerFrame = 576;
}
break;
} // end switch (ID)
return(tmpSamplesPerFrame);
}
/// <summary>Reads an MP3Frame from a stream</summary>
/// <remarks>http://mpgedit.org/mpgedit/mpeg_format/mpeghdr.htm
/// has some good info</remarks>
public Mp3Frame(Stream input)
{
BinaryReader reader = new BinaryReader(input);
// try for a header
long headerStartPosition = input.Position;
byte[] headerBytes = reader.ReadBytes(4);
// Added -jam to play wrapped mp3 files via RIFF
headerBytes = CheckForRiff(input, reader, headerBytes);
if ((headerBytes[0] == 0xFF) && ((headerBytes[1] & 0xE0) == 0xE0))
{
// TODO: could do with a bitstream class here
mpegVersion = (MpegVersion)((headerBytes[1] & 0x18) >> 3);
if (mpegVersion == MpegVersion.Reserved)
{
throw new FormatException("Unsupported MPEG Version");
}
layer = (MpegLayer)((headerBytes[1] & 0x06) >> 1);
if (layer != MpegLayer.Layer3)
{
throw new FormatException("Not an MP3");
}
crcPresent = (headerBytes[1] & 0x01) == 0x00;
int bitRateIndex = (headerBytes[2] & 0xF0) >> 4;
bitRate = (mpegVersion == MpegVersion.Version1) ? bitRatesLayer3Version1[bitRateIndex] :
bitRatesLayer3Version2[bitRateIndex];
int sampleFrequencyIndex = (headerBytes[2] & 0x0C) >> 2;
if (mpegVersion == MpegVersion.Version1)
sampleRate = sampleRatesVersion1[sampleFrequencyIndex];
else if (mpegVersion == MpegVersion.Version2)
sampleRate = sampleRatesVersion2[sampleFrequencyIndex];
else // mpegVersion == MpegVersion.Version25
sampleRate = sampleRatesVersion25[sampleFrequencyIndex];
bool padding = (headerBytes[2] & 0x02) == 0x02;
bool privateBit = (headerBytes[2] & 0x01) == 0x01;
channelMode = (ChannelMode) ((headerBytes[3] & 0xC0) >> 6);
int channelExtension = (headerBytes[3] & 0x30) >> 4;
bool copyright = (headerBytes[3] & 0x08) == 0x80;
bool original = (headerBytes[3] & 0x04) == 0x80;
int emphasis = (headerBytes[3] & 0x03);
frameLengthInBytes = (144 * 1000 * bitRate) / sampleRate + ((padding) ? 1 : 0);
}
else
{
input.Position = headerStartPosition;
throw new FormatException("Not a recognised MP3 block");
}
if (crcPresent)
crc = reader.ReadInt16();
long dataStartPosition = input.Position;
input.Position = headerStartPosition;
rawData = reader.ReadBytes(frameLengthInBytes);
}
/// <summary>
/// Initializes a new instance of the <see cref="Mpeg"/> class.
/// </summary>
/// <param name="path">The full path of the file.</param>
/// <param name="calculateBitrate">if set to <c>true</c> the bitrate will be calculated before the constructor returns.</param>
public Mpeg(string path, bool calculateBitrate)
{
_fileName = path;
using (FileStream stream = File.Open(path, FileMode.Open, FileAccess.Read, FileShare.Read))
{
int tmpID3v2TagSize = ID3v2.GetTagSize(stream);
stream.Seek(tmpID3v2TagSize, SeekOrigin.Begin);
byte[] tmpFrameHeader = new byte[4];
bool acceptNullSamples = false;
while (true)
{
int tmpByte = stream.ReadByte(); // keep as ReadByte
while (tmpByte != 0xFF && tmpByte != -1)
{
tmpByte = stream.ReadByte(); // keep as ReadByte
}
if (tmpByte == -1)
{
if (acceptNullSamples)
{
throw new InvalidDataException(string.Format("'{0}': Can't find frame sync", path));
}
stream.Seek(tmpID3v2TagSize, SeekOrigin.Begin);
acceptNullSamples = true;
continue;
}
tmpFrameHeader[0] = (byte)tmpByte;
// Get frame header
if (stream.Read(tmpFrameHeader, 1, 3) != 3)
{
throw new InvalidDataException(string.Format("'{0}': Invalid MPEG file; end of stream reached", path));
}
// No sync
if ((tmpFrameHeader[1] >> 5) != 0x07 ||
((tmpFrameHeader[1] >> 1) & 0x03) == 0) // 2/18/05 - ignore reserved layer
{
stream.Seek(-3, SeekOrigin.Current);
}
else if (tmpFrameHeader[1] == 0xFF ||
((tmpFrameHeader[1] >> 3) & 0x03) == 1) // 2/19/05 - more bad data
{
stream.Seek(-3, SeekOrigin.Current);
}
else
{
int tmpMpegID = (tmpFrameHeader[1] >> 3) & 0x03;
int tmpLayerNum = (tmpFrameHeader[1] >> 1) & 0x03;
int tmpFrequency = GetFrequency((MpegVersion)tmpMpegID, (tmpFrameHeader[2] >> 2) & 0x03);
// Check for invalid frequency
if (tmpFrequency == 0)
{
stream.Seek(-3, SeekOrigin.Current);
continue;
}
int tmpSamplesPerFrame = GetSamplesPerFrame((MpegVersion)tmpMpegID, (MpegLayer)tmpLayerNum);
int tmpUsesPadding = (tmpFrameHeader[2] >> 1) & 0x01;
double tmpFrameSizeConst = 125.0 * tmpSamplesPerFrame / tmpFrequency;
int tmpPaddingSize = (tmpLayerNum == 3 ? 4 : 1);
int tmpBitrateIndex = tmpFrameHeader[2] >> 4;
// Check for invalid values
if (tmpBitrateIndex < 1 || tmpBitrateIndex > 14 || tmpLayerNum == 0)
{
stream.Seek(-3, SeekOrigin.Current);
continue;
}
int tmpFrameBitrate = GetBitrate((MpegVersion)tmpMpegID, (MpegLayer)tmpLayerNum, tmpBitrateIndex);
int tmpFrameSize = (int)(tmpFrameBitrate * tmpFrameSizeConst) + (tmpUsesPadding * tmpPaddingSize);
_headerOffset = stream.Position - 4;
if (tmpFrameSize < 8)
{
stream.Seek(-3, SeekOrigin.Current);
continue;
}
// 7/21/05 - Check for 0x00 or 0xFF at end of last frame
// this sucks for tracks that start with silence
if (_headerOffset >= 1 && !acceptNullSamples) // if (ftell(fp) >= 5)
{
stream.Seek(-5, SeekOrigin.Current);
byte tmpLastByte = stream.Read1();
stream.Seek(4, SeekOrigin.Current);
if (tmpFrameBitrate != 320 && (tmpLastByte == 0x00 || tmpLastByte == 0xFF))
{
// 7/31/05
// may be a valid frame - skip its contents to prevent false sync
long tmpNewPosition = _headerOffset + tmpFrameSize;
if (tmpFrameSize == 0)
tmpNewPosition++;
stream.Seek(tmpNewPosition, SeekOrigin.Begin);
continue;
}
}
/*if (BR == 0 || FrameSizeConst == 0)
{
startpos = HeaderOffset+1;
fseek(fp, startpos, SEEK_SET);
continue;
}*/
stream.Seek(_headerOffset + tmpFrameSize, SeekOrigin.Begin);
if (stream.Read1() == 0xFF)
{
fh1 = stream.Read1();
fh2 = stream.Read1();
if (tmpFrameHeader[1] == fh1 &&
(tmpFrameHeader[2] & 0x0D) == (fh2 & 0x0D))
{
// header found
break;
}
}
stream.Seek(_headerOffset + 1, SeekOrigin.Begin);
continue;
}
}
_mpegVersion = (MpegVersion)((tmpFrameHeader[1] >> 3) & 0x03);
_mpegLayer = (MpegLayer)((tmpFrameHeader[1] >> 1) & 0x03);
_frequency = GetFrequency(_mpegVersion, (tmpFrameHeader[2] >> 2) & 0x03);
if (_frequency == 0)
{
throw new InvalidDataException(String.Format("'{0}'; cannot determine frequency", path));
}
_isPrivate = ((tmpFrameHeader[2] & 0x01) == 0x01);
_samplesPerFrame = GetSamplesPerFrame(_mpegVersion, _mpegLayer);
_frameSizeConst = 125.0 * _samplesPerFrame / _frequency;
_paddingSizeConst = (_mpegLayer == MpegLayer.Layer1 ? 4 : 1);
_isCopyright = (((tmpFrameHeader[3] >> 3) & 0x01) == 0x01);
_isOriginal = (((tmpFrameHeader[3] >> 2) & 0x01) == 0x01);
//tmpModeExtension = (FH[3] >> 4) & 0x03; // not interested, only used in joint-stereo
//_mpegEmphasis = (MpegEmphasis)(tmpFrameHeader[3] & 0x03);
if ((tmpFrameHeader[3] >> 6) == 3) _channels = 1; // Single Channel
else _channels = 2;
// Read LAME Info Tag
bool tmpHasLameInfoTag = false;
stream.Seek(tmpID3v2TagSize + 36, SeekOrigin.Begin);
Byte[] buf = stream.Read(4);
if (ByteUtils.Compare(buf, INFO_MARKER)) // CBR
{
tmpHasLameInfoTag = true;
_isVBR = false;
}
else if (ByteUtils.Compare(buf, XING_MARKER)) // VBR
{
tmpHasLameInfoTag = true;
_isVBR = true;
}
if (tmpHasLameInfoTag)
{
stream.Seek(4, SeekOrigin.Current);
int tmpFrames = stream.ReadInt32();
uint tmpBytes = (uint)stream.ReadInt32();
if (tmpFrames > 256 && tmpBytes > 50000)
{
decimal tmpBitrate = tmpBytes / 125.0m / (tmpFrames * _samplesPerFrame / (decimal)_frequency);
if (tmpBitrate <= 320 && tmpBitrate >= 32)
{
_frames = tmpFrames;
_bitrate = tmpBitrate;
_totalSeconds = (tmpBytes / 125.0m) / _bitrate;
}
}
}
// TODO: Take these 2 lines out
/*fs.Position = 0;
CalculateBitrate(fs, null);*/
if (calculateBitrate)
{
if (_bitrate == 0 || _isVBR == null || _frames == 0 || _totalSeconds == 0)
{
stream.Position = 0;
CalculateBitrate(stream, null);
}
}
}
}
private static int GetSamplesPerFrame(MpegVersion mpegVersion, MpegLayer mpegLayer)
{
int tmpSamplesPerFrame = 0;
switch (mpegVersion)
{
// MPEG-1
case MpegVersion.Mpeg1:
if (mpegLayer == MpegLayer.Layer1) tmpSamplesPerFrame = 384;
else if (mpegLayer == MpegLayer.Layer2 ||
mpegLayer == MpegLayer.Layer3) tmpSamplesPerFrame = 1152;
break;
// MPEG-2/2.5
case MpegVersion.Mpeg2:
case MpegVersion.Mpeg25:
if (mpegLayer == MpegLayer.Layer1) tmpSamplesPerFrame = 384;
else if (mpegLayer == MpegLayer.Layer2) tmpSamplesPerFrame = 1152;
else if (mpegLayer == MpegLayer.Layer3) tmpSamplesPerFrame = 576;
break;
} // end switch (ID)
return tmpSamplesPerFrame;
}
private static int GetBitrate(MpegVersion mpegVersion, MpegLayer mpegLayer, int bitrateIndex)
{
return BitrateTable[(int)mpegVersion][(int)mpegLayer - 1][bitrateIndex - 1];
}
public byte[] BuildFrame(
MpegVersion version,
MpegLayer layer,
bool hasCRC,
int frameSizeOffset,
int frameSize)
{
byte[] buf = Slush.DomainObjects.Mp3.Test.Mp3FrameTest.BuildFrame(
version,
layer,
hasCRC,
frameSizeOffset,
frameSize);
if (UseRandom)
{
for (int i = 6; i < buf.Length; i++)
{
buf[i] = (byte)random.Next();
}
}
return buf;
}
private static int?GetBitrate(byte three, MpegVersion version, MpegLayer layer)
{
if (version == MpegVersion.MPEG1)
{
if (layer == MpegLayer.Layer1)
{
if (CompBit(three, 1, 4, false, false, false, false))
{
return(null);
}
if (CompBit(three, 1, 4, false, false, false, true))
{
return(32);
}
if (CompBit(three, 1, 4, false, false, true, false))
{
return(64);
}
if (CompBit(three, 1, 4, false, false, true, true))
{
return(96);
}
if (CompBit(three, 1, 4, false, true, false, false))
{
return(128);
}
if (CompBit(three, 1, 4, false, true, false, true))
{
return(160);
}
if (CompBit(three, 1, 4, false, true, true, false))
{
return(192);
}
if (CompBit(three, 1, 4, false, true, true, true))
{
return(224);
}
if (CompBit(three, 1, 4, true, false, false, false))
{
return(256);
}
if (CompBit(three, 1, 4, true, false, false, true))
{
return(288);
}
if (CompBit(three, 1, 4, true, false, true, false))
{
return(320);
}
if (CompBit(three, 1, 4, true, false, true, true))
{
return(352);
}
if (CompBit(three, 1, 4, true, true, false, false))
{
return(384);
}
if (CompBit(three, 1, 4, true, true, false, true))
{
return(416);
}
if (CompBit(three, 1, 4, true, true, true, false))
{
return(448);
}
if (CompBit(three, 1, 4, true, true, true, true))
{
return(null);
}
}
else if (layer == MpegLayer.Layer2)
{
if (CompBit(three, 1, 4, false, false, false, false))
{
return(null);
}
if (CompBit(three, 1, 4, false, false, false, true))
{
return(32);
}
if (CompBit(three, 1, 4, false, false, true, false))
{
return(45);
}
if (CompBit(three, 1, 4, false, false, true, true))
{
return(56);
}
if (CompBit(three, 1, 4, false, true, false, false))
{
return(64);
}
if (CompBit(three, 1, 4, false, true, false, true))
{
return(80);
}
if (CompBit(three, 1, 4, false, true, true, false))
{
return(96);
}
if (CompBit(three, 1, 4, false, true, true, true))
{
return(112);
}
if (CompBit(three, 1, 4, true, false, false, false))
{
return(128);
}
if (CompBit(three, 1, 4, true, false, false, true))
{
return(160);
}
if (CompBit(three, 1, 4, true, false, true, false))
{
return(192);
}
if (CompBit(three, 1, 4, true, false, true, true))
{
return(224);
}
if (CompBit(three, 1, 4, true, true, false, false))
{
return(256);
}
if (CompBit(three, 1, 4, true, true, false, true))
{
return(320);
}
if (CompBit(three, 1, 4, true, true, true, false))
{
return(384);
}
if (CompBit(three, 1, 4, true, true, true, true))
{
return(null);
}
}
else if (layer == MpegLayer.Layer3)
{
if (CompBit(three, 1, 4, false, false, false, false))
{
return(null);
}
if (CompBit(three, 1, 4, false, false, false, true))
{
return(32);
}
if (CompBit(three, 1, 4, false, false, true, false))
{
return(40);
}
if (CompBit(three, 1, 4, false, false, true, true))
{
return(45);
}
if (CompBit(three, 1, 4, false, true, false, false))
{
return(56);
}
if (CompBit(three, 1, 4, false, true, false, true))
{
return(64);
}
if (CompBit(three, 1, 4, false, true, true, false))
{
return(80);
}
if (CompBit(three, 1, 4, false, true, true, true))
{
return(96);
}
if (CompBit(three, 1, 4, true, false, false, false))
{
return(112);
}
if (CompBit(three, 1, 4, true, false, false, true))
{
return(128);
}
if (CompBit(three, 1, 4, true, false, true, false))
{
return(160);
}
if (CompBit(three, 1, 4, true, false, true, true))
{
return(192);
}
if (CompBit(three, 1, 4, true, true, false, false))
{
return(224);
}
if (CompBit(three, 1, 4, true, true, false, true))
{
return(256);
}
if (CompBit(three, 1, 4, true, true, true, false))
{
return(320);
}
if (CompBit(three, 1, 4, true, true, true, true))
{
return(null);
}
}
}
return(null);
}
/// <summary>checks if the four bytes represent a valid header,
/// if they are, will parse the values into local properties
/// </summary>
private bool IsValidHeader(byte[] headerBytes)
{
if ((headerBytes[0] == 0xFF) && ((headerBytes[1] & 0xE0) == 0xE0))
{
// TODO: could do with a bitstream class here
mpegVersion = (MpegVersion)((headerBytes[1] & 0x18) >> 3);
if (mpegVersion == MpegVersion.Reserved)
{
//throw new FormatException("Unsupported MPEG Version");
return false;
}
layer = (MpegLayer)((headerBytes[1] & 0x06) >> 1);
if (layer == MpegLayer.Reserved)
{
return false;
}
int layerIndex = this.layer == MpegLayer.Layer1 ? 0 : this.layer == MpegLayer.Layer2 ? 1: 2;
crcPresent = (headerBytes[1] & 0x01) == 0x00;
int bitRateIndex = (headerBytes[2] & 0xF0) >> 4;
if (bitRateIndex == 15)
{
// invalid index
return false;
}
int versionIndex = this.mpegVersion == Wave.MpegVersion.Version1 ? 0 : 1;
this.bitRate = bitRates[versionIndex, layerIndex, bitRateIndex] * 1000;
if (bitRate == 0)
{
return false;
}
int sampleFrequencyIndex = (headerBytes[2] & 0x0C) >> 2;
if (sampleFrequencyIndex == 3)
{
return false;
}
if (mpegVersion == MpegVersion.Version1)
sampleRate = sampleRatesVersion1[sampleFrequencyIndex];
else if (mpegVersion == MpegVersion.Version2)
sampleRate = sampleRatesVersion2[sampleFrequencyIndex];
else // mpegVersion == MpegVersion.Version25
sampleRate = sampleRatesVersion25[sampleFrequencyIndex];
bool padding = (headerBytes[2] & 0x02) == 0x02;
bool privateBit = (headerBytes[2] & 0x01) == 0x01;
channelMode = (ChannelMode)((headerBytes[3] & 0xC0) >> 6);
int channelExtension = (headerBytes[3] & 0x30) >> 4;
bool copyright = (headerBytes[3] & 0x08) == 0x08;
bool original = (headerBytes[3] & 0x04) == 0x04;
int emphasis = (headerBytes[3] & 0x03);
int nPadding = padding ? 1 : 0;
this.samplesInFrame = samplesPerFrame[versionIndex, layerIndex];
int coefficient = this.samplesInFrame / 8;
if (this.layer == MpegLayer.Layer1)
{
this.frameLengthInBytes = (coefficient * bitRate / sampleRate + nPadding) * 4;
}
else
{
frameLengthInBytes = (coefficient * bitRate) / sampleRate + nPadding;
}
if (this.frameLengthInBytes > MaxFrameLength)
{
return false;
}
return true;
}
return false;
}
/// <summary>Reads an MP3Frame from a stream</summary>
/// <remarks>http://mpgedit.org/mpgedit/mpeg_format/mpeghdr.htm
/// has some good info</remarks>
public Mp3Frame(Stream input)
{
BinaryReader reader = new BinaryReader(input);
// try for a header
long headerStartPosition = input.Position;
byte[] headerBytes = reader.ReadBytes(4);
if ((headerBytes[0] == 0xFF) && ((headerBytes[1] & 0xE0) == 0xE0))
{
// TODO: could do with a bitstream class here
mpegVersion = (MpegVersion)((headerBytes[1] & 0x18) >> 3);
if (mpegVersion == MpegVersion.Reserved)
{
throw new FormatException("Unsupported MPEG Version");
}
layer = (MpegLayer)((headerBytes[1] & 0x06) >> 1);
if (layer != MpegLayer.Layer3)
{
throw new FormatException("Not an MP3");
}
crcPresent = (headerBytes[1] & 0x01) == 0x00;
int bitRateIndex = (headerBytes[2] & 0xF0) >> 4;
bitRate = (mpegVersion == MpegVersion.Version1) ? bitRatesLayer3Version1[bitRateIndex] :
bitRatesLayer3Version2[bitRateIndex];
int sampleFrequencyIndex = (headerBytes[2] & 0x0C) >> 2;
if (mpegVersion == MpegVersion.Version1)
{
sampleRate = sampleRatesVersion1[sampleFrequencyIndex];
}
else if (mpegVersion == MpegVersion.Version2)
{
sampleRate = sampleRatesVersion2[sampleFrequencyIndex];
}
else // mpegVersion == MpegVersion.Version25
{
sampleRate = sampleRatesVersion25[sampleFrequencyIndex];
}
bool padding = (headerBytes[2] & 0x02) == 0x02;
bool privateBit = (headerBytes[2] & 0x01) == 0x01;
channelMode = (ChannelMode)((headerBytes[3] & 0xC0) >> 6);
int channelExtension = (headerBytes[3] & 0x30) >> 4;
bool copyright = (headerBytes[3] & 0x08) == 0x80;
bool original = (headerBytes[3] & 0x04) == 0x80;
int emphasis = (headerBytes[3] & 0x03);
frameLengthInBytes = (144 * 1000 * bitRate) / sampleRate + ((padding) ? 1 : 0);
}
else
{
input.Position = headerStartPosition;
throw new FormatException("Not a recognised MP3 block");
}
if (crcPresent)
{
crc = reader.ReadInt16();
}
long dataStartPosition = input.Position;
input.Position = headerStartPosition;
rawData = reader.ReadBytes(frameLengthInBytes);
}
/// <summary>
/// Initializes a new instance of the <see cref="Mpeg"/> class.
/// </summary>
/// <param name="path">The full path of the file.</param>
/// <param name="calculateBitrate">if set to <c>true</c> the bitrate will be calculated before the constructor returns.</param>
public Mpeg(string path, bool calculateBitrate)
{
_fileName = path;
using (FileStream stream = File.Open(path, FileMode.Open, FileAccess.Read, FileShare.Read))
{
int tmpID3v2TagSize = ID3v2.GetTagSize(stream);
stream.Seek(tmpID3v2TagSize, SeekOrigin.Begin);
byte[] tmpFrameHeader = new byte[4];
bool acceptNullSamples = false;
while (true)
{
int tmpByte = stream.ReadByte(); // keep as ReadByte
while (tmpByte != 0xFF && tmpByte != -1)
{
tmpByte = stream.ReadByte(); // keep as ReadByte
}
if (tmpByte == -1)
{
if (acceptNullSamples)
{
throw new InvalidDataException(string.Format("'{0}': Can't find frame sync", path));
}
stream.Seek(tmpID3v2TagSize, SeekOrigin.Begin);
acceptNullSamples = true;
continue;
}
tmpFrameHeader[0] = (byte)tmpByte;
// Get frame header
if (stream.Read(tmpFrameHeader, 1, 3) != 3)
{
throw new InvalidDataException(string.Format("'{0}': Invalid MPEG file; end of stream reached", path));
}
// No sync
if ((tmpFrameHeader[1] >> 5) != 0x07 ||
((tmpFrameHeader[1] >> 1) & 0x03) == 0) // 2/18/05 - ignore reserved layer
{
stream.Seek(-3, SeekOrigin.Current);
}
else if (tmpFrameHeader[1] == 0xFF ||
((tmpFrameHeader[1] >> 3) & 0x03) == 1) // 2/19/05 - more bad data
{
stream.Seek(-3, SeekOrigin.Current);
}
else
{
int tmpMpegID = (tmpFrameHeader[1] >> 3) & 0x03;
int tmpLayerNum = (tmpFrameHeader[1] >> 1) & 0x03;
int tmpFrequency = GetFrequency((MpegVersion)tmpMpegID, (tmpFrameHeader[2] >> 2) & 0x03);
// Check for invalid frequency
if (tmpFrequency == 0)
{
stream.Seek(-3, SeekOrigin.Current);
continue;
}
int tmpSamplesPerFrame = GetSamplesPerFrame((MpegVersion)tmpMpegID, (MpegLayer)tmpLayerNum);
int tmpUsesPadding = (tmpFrameHeader[2] >> 1) & 0x01;
double tmpFrameSizeConst = 125.0 * tmpSamplesPerFrame / tmpFrequency;
int tmpPaddingSize = (tmpLayerNum == 3 ? 4 : 1);
int tmpBitrateIndex = tmpFrameHeader[2] >> 4;
// Check for invalid values
if (tmpBitrateIndex < 1 || tmpBitrateIndex > 14 || tmpLayerNum == 0)
{
stream.Seek(-3, SeekOrigin.Current);
continue;
}
int tmpFrameBitrate = GetBitrate((MpegVersion)tmpMpegID, (MpegLayer)tmpLayerNum, tmpBitrateIndex);
int tmpFrameSize = (int)(tmpFrameBitrate * tmpFrameSizeConst) + (tmpUsesPadding * tmpPaddingSize);
_headerOffset = stream.Position - 4;
if (tmpFrameSize < 8)
{
stream.Seek(-3, SeekOrigin.Current);
continue;
}
// 7/21/05 - Check for 0x00 or 0xFF at end of last frame
// this sucks for tracks that start with silence
if (_headerOffset >= 1 && !acceptNullSamples) // if (ftell(fp) >= 5)
{
stream.Seek(-5, SeekOrigin.Current);
byte tmpLastByte = stream.Read1();
stream.Seek(4, SeekOrigin.Current);
if (tmpFrameBitrate != 320 && (tmpLastByte == 0x00 || tmpLastByte == 0xFF))
{
// 7/31/05
// may be a valid frame - skip its contents to prevent false sync
long tmpNewPosition = _headerOffset + tmpFrameSize;
if (tmpFrameSize == 0)
{
tmpNewPosition++;
}
stream.Seek(tmpNewPosition, SeekOrigin.Begin);
continue;
}
}
/*if (BR == 0 || FrameSizeConst == 0)
* {
* startpos = HeaderOffset+1;
* fseek(fp, startpos, SEEK_SET);
* continue;
* }*/
stream.Seek(_headerOffset + tmpFrameSize, SeekOrigin.Begin);
if (stream.Read1() == 0xFF)
{
fh1 = stream.Read1();
fh2 = stream.Read1();
if (tmpFrameHeader[1] == fh1 &&
(tmpFrameHeader[2] & 0x0D) == (fh2 & 0x0D))
{
// header found
break;
}
}
stream.Seek(_headerOffset + 1, SeekOrigin.Begin);
continue;
}
}
_mpegVersion = (MpegVersion)((tmpFrameHeader[1] >> 3) & 0x03);
_mpegLayer = (MpegLayer)((tmpFrameHeader[1] >> 1) & 0x03);
_frequency = GetFrequency(_mpegVersion, (tmpFrameHeader[2] >> 2) & 0x03);
if (_frequency == 0)
{
throw new InvalidDataException(String.Format("'{0}'; cannot determine frequency", path));
}
_isPrivate = ((tmpFrameHeader[2] & 0x01) == 0x01);
_samplesPerFrame = GetSamplesPerFrame(_mpegVersion, _mpegLayer);
_frameSizeConst = 125.0 * _samplesPerFrame / _frequency;
_paddingSizeConst = (_mpegLayer == MpegLayer.Layer1 ? 4 : 1);
_isCopyright = (((tmpFrameHeader[3] >> 3) & 0x01) == 0x01);
_isOriginal = (((tmpFrameHeader[3] >> 2) & 0x01) == 0x01);
//tmpModeExtension = (FH[3] >> 4) & 0x03; // not interested, only used in joint-stereo
//_mpegEmphasis = (MpegEmphasis)(tmpFrameHeader[3] & 0x03);
if ((tmpFrameHeader[3] >> 6) == 3)
{
_channels = 1; // Single Channel
}
else
{
_channels = 2;
}
// Read LAME Info Tag
bool tmpHasLameInfoTag = false;
stream.Seek(tmpID3v2TagSize + 36, SeekOrigin.Begin);
Byte[] buf = stream.Read(4);
if (ByteUtils.Compare(buf, INFO_MARKER)) // CBR
{
tmpHasLameInfoTag = true;
_isVBR = false;
}
else if (ByteUtils.Compare(buf, XING_MARKER)) // VBR
{
tmpHasLameInfoTag = true;
_isVBR = true;
}
if (tmpHasLameInfoTag)
{
stream.Seek(4, SeekOrigin.Current);
int tmpFrames = stream.ReadInt32();
uint tmpBytes = (uint)stream.ReadInt32();
if (tmpFrames > 256 && tmpBytes > 50000)
{
decimal tmpBitrate = tmpBytes / 125.0m / (tmpFrames * _samplesPerFrame / (decimal)_frequency);
if (tmpBitrate <= 320 && tmpBitrate >= 32)
{
_frames = tmpFrames;
_bitrate = tmpBitrate;
_totalSeconds = (tmpBytes / 125.0m) / _bitrate;
}
}
}
// TODO: Take these 2 lines out
/*fs.Position = 0;
* CalculateBitrate(fs, null);*/
if (calculateBitrate)
{
if (_bitrate == 0 || _isVBR == null || _frames == 0 || _totalSeconds == 0)
{
stream.Position = 0;
CalculateBitrate(stream, null);
}
}
}
}
private static int GetBitrate(MpegVersion mpegVersion, MpegLayer mpegLayer, int bitrateIndex)
{
return(BitrateTable[(int)mpegVersion][(int)mpegLayer - 1][bitrateIndex - 1]);
}
/// <summary>checks if the four bytes represent a valid header,
/// if they are, will parse the values into local properties
/// </summary>
private bool IsValidHeader(byte[] headerBytes)
{
if ((headerBytes[0] == 0xFF) && ((headerBytes[1] & 0xE0) == 0xE0))
{
// TODO: could do with a bitstream class here
mpegVersion = (MpegVersion)((headerBytes[1] & 0x18) >> 3);
if (mpegVersion == MpegVersion.Reserved)
{
//throw new FormatException("Unsupported MPEG Version");
return(false);
}
layer = (MpegLayer)((headerBytes[1] & 0x06) >> 1);
if (layer == MpegLayer.Reserved)
{
return(false);
}
int layerIndex = this.layer == MpegLayer.Layer1 ? 0 : this.layer == MpegLayer.Layer2 ? 1: 2;
crcPresent = (headerBytes[1] & 0x01) == 0x00;
int bitRateIndex = (headerBytes[2] & 0xF0) >> 4;
if (bitRateIndex == 15)
{
// invalid index
return(false);
}
int versionIndex = this.mpegVersion == Wave.MpegVersion.Version1 ? 0 : 1;
this.bitRate = bitRates[versionIndex, layerIndex, bitRateIndex] * 1000;
if (bitRate == 0)
{
return(false);
}
int sampleFrequencyIndex = (headerBytes[2] & 0x0C) >> 2;
if (sampleFrequencyIndex == 3)
{
return(false);
}
if (mpegVersion == MpegVersion.Version1)
{
sampleRate = sampleRatesVersion1[sampleFrequencyIndex];
}
else if (mpegVersion == MpegVersion.Version2)
{
sampleRate = sampleRatesVersion2[sampleFrequencyIndex];
}
else // mpegVersion == MpegVersion.Version25
{
sampleRate = sampleRatesVersion25[sampleFrequencyIndex];
}
bool padding = (headerBytes[2] & 0x02) == 0x02;
bool privateBit = (headerBytes[2] & 0x01) == 0x01;
channelMode = (ChannelMode)((headerBytes[3] & 0xC0) >> 6);
int channelExtension = (headerBytes[3] & 0x30) >> 4;
bool copyright = (headerBytes[3] & 0x08) == 0x08;
bool original = (headerBytes[3] & 0x04) == 0x04;
int emphasis = (headerBytes[3] & 0x03);
int nPadding = padding ? 1 : 0;
this.samplesInFrame = samplesPerFrame[versionIndex, layerIndex];
int coefficient = this.samplesInFrame / 8;
if (this.layer == MpegLayer.Layer1)
{
this.frameLengthInBytes = (coefficient * bitRate / sampleRate + nPadding) * 4;
}
else
{
frameLengthInBytes = (coefficient * bitRate) / sampleRate + nPadding;
}
if (this.frameLengthInBytes > MaxFrameLength)
{
return(false);
}
return(true);
}
return(false);
}
private void GetLayer(params bool[] twoBits)
{
if (twoBits[0] && twoBits[1]) this.mpegLayer = MpegLayer.I;
else if (twoBits[0] && !twoBits[1]) this.mpegLayer = MpegLayer.II;
else if (!twoBits[0] && twoBits[1]) this.mpegLayer = MpegLayer.III;
else if (!twoBits[0] && !twoBits[1]) this.mpegLayer = MpegLayer.Reserved;
}
