public static int GetTotalLength(MpegAudioVersion version, MpegAudioLayer layer, int bitRateID, int sampleRateID)
{
int sampleCount = MpegAudioSpecification.GetSampleCount(version, layer);
int dataRate = MpegAudioSpecification.GetBitRate(version, layer, bitRateID) * 1000 / 8;
int sampleRate = MpegAudioSpecification.GetSamplingRate(version, sampleRateID);
return(sampleCount * dataRate / sampleRate);
}
public static int GetSlotLength(MpegAudioLayer layer)
{
switch (layer)
{
case MpegAudioLayer.I: return(4);
case MpegAudioLayer.II: return(1);
case MpegAudioLayer.III: return(1);
default: throw new InvalidOperationException();
}
}
public static MpegAudioJoinMode GetJoinMode(MpegAudioLayer layer, int joinID)
{
switch (layer)
{
case MpegAudioLayer.I:
case MpegAudioLayer.II:
return(MpegAudioJoinMode.IntensityStereo);
case MpegAudioLayer.III:
return((MpegAudioJoinMode)joinID);
default: throw new InvalidOperationException();
}
}
public static MpegAudioJoinBands GetJoinBands(MpegAudioLayer layer, int joinID)
{
switch (layer)
{
case MpegAudioLayer.I:
case MpegAudioLayer.II:
return((MpegAudioJoinBands)joinID);
case MpegAudioLayer.III:
return(MpegAudioJoinBands.Dynamic);
default: throw new InvalidOperationException();
}
}
protected MpegAudioFrame(BinaryReader reader)
{
if (reader == null)
{
throw new ArgumentNullException("reader");
}
BitField header = BitField.FromBytes(reader.ReadBytes(4));
if (header.Length != 32)
{
throw new InvalidDataException(string.Format("Incorrect header length '{0}', expected '32'.", header.Bits.Count()));
}
if (header[0, 11].Value != 0x07FF)
{
throw new InvalidDataException(string.Format("Incorrect sync '{0}', expected '11111111111'.", header[0, 11]));
}
this.version = (MpegAudioVersion)header[11, 13].Value;
if (version == MpegAudioVersion.Reserved)
{
throw new InvalidDataException(string.Format("Incorrect version '{0}'.", version));
}
this.layer = (MpegAudioLayer)header[13, 15].Value;
if (layer == MpegAudioLayer.Reserved)
{
throw new InvalidDataException(string.Format("Incorrect layer '{0}'.", layer));
}
this.hasErrorProtection = !header[15];
this.bitRateID = header[16, 20].Value;
if (bitRateID == 0 || bitRateID == 15)
{
throw new InvalidDataException(string.Format("Incorrect bit rate ID '{0}'.", bitRateID));
}
this.sampleRateID = header[20, 22].Value;
if (sampleRateID == 3)
{
throw new InvalidDataException(string.Format("Incorrect sample rate ID '{0}'.", sampleRateID));
}
this.hasPadding = header[22];
this.privateBit = header[23];
this.channelMode = (MpegAudioChannelMode)header[24, 26].Value;
this.joinID = header[26, 28].Value;
this.isCopyrighted = header[28];
this.isOriginal = header[29];
this.emphasis = (MpegAudioEmphasis)header[30, 32].Value;
this.checksum = hasErrorProtection ? reader.ReadUInt16() : (ushort)0;
}
protected MpegAudioFrame
(
MpegAudioVersion version,
MpegAudioLayer layer,
bool hasErrorProtection,
int bitRateID,
int sampleRateID,
bool hasPadding,
bool privateBit,
MpegAudioChannelMode channelMode,
int joinID,
bool isCopyrighted,
bool isOriginal,
MpegAudioEmphasis emphasis,
ushort checksum
)
{
if (version == MpegAudioVersion.Reserved)
{
throw new ArgumentException(string.Format("Incorrect version '{0}'.", version));
}
if (layer == MpegAudioLayer.Reserved)
{
throw new ArgumentException(string.Format("Incorrect layer '{0}'.", layer));
}
if (bitRateID <= 0 || bitRateID >= 15)
{
throw new ArgumentException(string.Format("Incorrect bit rate ID '{0}'.", bitRateID));
}
if (sampleRateID < 0 || sampleRateID >= 3)
{
throw new ArgumentException(string.Format("Incorrect sample rate ID '{0}'.", sampleRateID));
}
this.version = version;
this.layer = layer;
this.hasErrorProtection = hasErrorProtection;
this.bitRateID = bitRateID;
this.sampleRateID = sampleRateID;
this.hasPadding = hasPadding;
this.privateBit = privateBit;
this.channelMode = channelMode;
this.joinID = joinID;
this.isCopyrighted = isCopyrighted;
this.isOriginal = isOriginal;
this.emphasis = emphasis;
this.checksum = checksum;
}
protected MpegAudioMetaDataFrame
(
MpegAudioVersion version,
MpegAudioLayer layer,
bool hasErrorProtection,
int bitRateID,
int sampleRateID,
bool hasPadding,
bool privateBit,
MpegAudioChannelMode channelMode,
int joinID,
bool isCopyrighted,
bool isOriginal,
MpegAudioEmphasis emphasis,
ushort checksum
)
: base(version, layer, hasErrorProtection, bitRateID, sampleRateID, hasPadding, privateBit, channelMode, joinID, isCopyrighted, isOriginal, emphasis, checksum)
{
}
public static int GetSampleCount(MpegAudioVersion version, MpegAudioLayer layer)
{
switch (layer)
{
case MpegAudioLayer.I: return(0x180);
case MpegAudioLayer.II: return(0x480);
case MpegAudioLayer.III:
switch (version)
{
case MpegAudioVersion.Mpeg1: return(0x480);
case MpegAudioVersion.Mpeg2: return(0x240);
case MpegAudioVersion.Mpeg25: return(0x240);
default: throw new InvalidOperationException();
}
default: throw new InvalidOperationException();
}
}
public static int GetBitRate(MpegAudioVersion version, MpegAudioLayer layer, int value)
{
if (value <= 0 || value >= 15)
{
throw new ArgumentOutOfRangeException("value");
}
switch (version)
{
case MpegAudioVersion.Mpeg1:
switch (layer)
{
case MpegAudioLayer.I: return(version1Layer1Bitrates[value]);
case MpegAudioLayer.II: return(version1Layer2Bitrates[value]);
case MpegAudioLayer.III: return(version1Layer3Bitrates[value]);
default: throw new ArgumentOutOfRangeException("layer");
}
case MpegAudioVersion.Mpeg2:
case MpegAudioVersion.Mpeg25:
switch (layer)
{
case MpegAudioLayer.I: return(version2Layer1Bitrates[value]);
case MpegAudioLayer.II: return(version2Layer2Bitrates[value]);
case MpegAudioLayer.III: return(version2Layer3Bitrates[value]);
default: throw new ArgumentOutOfRangeException("layer");
}
default: throw new ArgumentOutOfRangeException("version");
}
}
public MpegAudioFrameType(MpegAudioVersion version, MpegAudioLayer layer, int sampleRateID, int channelCount)
{
if (version == MpegAudioVersion.Reserved)
{
throw new ArgumentOutOfRangeException("version");
}
if (layer == MpegAudioLayer.Reserved)
{
throw new ArgumentOutOfRangeException("layer");
}
if (sampleRateID < 0 || sampleRateID >= 3)
{
throw new ArgumentOutOfRangeException("sampleRateID");
}
if (channelCount < 1 || channelCount > 2)
{
throw new ArgumentOutOfRangeException("channelCount");
}
this.version = version;
this.layer = layer;
this.sampleRateID = sampleRateID;
this.channelCount = channelCount;
}
