/// <summary>
/// Initializes a new instance of the MpegFrame class.
/// </summary>
/// <remarks>
/// <para>
/// This class is a partial implementation of an MPEG audio frame. The primary purpose of this class is to represent an Mpeg 1 Layer 3
/// file or MP3 file for short. Many of the features not explicitly needed
/// for audio rendering are omitted from the implementation.
/// </para>
/// <para>
/// Data on this format is readily discoverable in many books as well as by
/// searching for "MP3 Frame" in your favorite search engine. As always,
/// Wikipedia is well stocked in all of these areas as well.
/// </para>
/// </remarks>
/// <param name="frameHeader">Byte array containing 4 bytes representing an MPEG Layer 3 header.</param>
public MpegFrame(byte[] frameHeader)
{
if (frameHeader == null)
{
throw new ArgumentNullException("frameHeader");
}
if (frameHeader.Length != 4)
{
throw new ArgumentException("Invalid frame header length.");
}
// Sync
int value = BitTools.MaskBits(frameHeader, 0, 11);
if (value != SyncValue)
{
throw new ArgumentException("Invalid sync value.");
}
this.Version = ParseVersion(frameHeader);
this.Layer = ParseLayer(frameHeader);
this.IsProtected = BitTools.MaskBits(frameHeader, 15, 1) == 1 ? false : true;
this.BitrateIndex = BitTools.MaskBits(frameHeader, 16, 4);
this.SamplingRateIndex = BitTools.MaskBits(frameHeader, 20, 2);
this.Padding = BitTools.MaskBits(frameHeader, 22, 1);
//// Private Bit = BitTools.MaskBits(_mp3FrameHeader,8,1); //USELESS
this.Channels = ParseChannel(frameHeader);
//// Joint Mode = ParseJoitMode(_mp3FrameHeader); //Not used by Mp3MSS
//// CopyRight = BitTools.MaskBits(_mp3FrameHeader,3,1); //Not used by Mp3MSS
//// Original = BitTools.MaskBits(_mp3FrameHeader,2,1); //Not used by Mp3MSS
//// Emphasis = ParseEmphasis(_mp3FrameHeader); //Not used by Mp3MSS
this.BitRate = MpegFrame.CalculateBitRate(this.Version, this.Layer, this.BitrateIndex);
this.SamplingRate = MpegFrame.LookupSamplingRate(this.Version, this.SamplingRateIndex);
this.FrameSize = MpegFrame.CalculateFrameSize(this.Version, this.Layer, this.BitRate, this.SamplingRate, this.Padding);
this.NumberOfChannels = (this.Channels == Channel.SingleChannel) ? 1 : 2;
if ((this.Version == -1) || (this.Layer == -1) ||
(this.BitrateIndex < 0) || (this.BitrateIndex >= 15) ||
(this.SamplingRateIndex < 0) || (this.SamplingRateIndex >= 3))
{
throw new ArgumentException("Invalid header values");
}
// Add in the bytes we already read
if (this.FrameSize <= 0)
{
throw new InvalidOperationException("MpegFrame's FrameSize must be greater than zero.");
}
}
/// <summary>
/// Determines whether the specified Object is equal to the current Object
/// </summary>
/// <param name="obj">The object to compare with the current object.</param>
/// <returns>true if the specified Object is equal to the current Object; otherwise, false.</returns>
public override bool Equals(object obj)
{
MpegFrame other = obj as MpegFrame;
if (other == null)
{
return(false);
}
return((this.Version == other.Version) &&
(this.Layer == other.Layer) &&
(this.SamplingRate == other.SamplingRate) &&
(this.Channels == other.Channels));
}
