public AudioFile Read(string fileName, out ArrayList ID3Frames)
{
AudioFile audioFile = new AudioFile();
byte[] vs = File.ReadAllBytes(fileName + ".mp3");
int index = 0;
//Load ID3
readID3(vs, ref index);
Console.WriteLine("ID3v2." + ID3Ver + " Header Loaded");
//Start Reading Frames
AudioFileFormat format = new AudioFileFormat();
byte[] audioData;
while (index < vs.Length)
{
//TODO: Implement MP3 File Reading
//Read Frame Header
byte[] headerBytes = new byte[4];
Array.Copy(vs, index, headerBytes, 0, 4);
index += 4;
MP3FrameHeader header = ReadFrameHeader(headerBytes);
if (format.BitsPerSample != header.bps)
{
format.BitsPerSample = (ushort)header.bps;
}
if (format.SampleRate != header.sampleRate)
{
format.SampleRate = header.sampleRate;
}
if (format.nChannels != header.channels)
{
format.nChannels = (ushort)header.channels;
}
if (header.prot)
{
index += 2;
}
int bound = header.channelMode == 0b0 ? 4 : header.channelMode == 0b01 ? 8 : header.channelMode == 0b10 ? 12 : header.channelMode == 0b11 ? 16 : -1;
}
ID3Frames = frames;
return(audioFile);
}
private MP3FrameHeader ReadFrameHeader(byte[] headerBytes)
{
MP3FrameHeader frameHeader = new MP3FrameHeader();
BitArray header = new BitArray(headerBytes);
int headerIndex = 11;
int MPEGId = BitTools.BitArrayToInt(header, ref headerIndex, 2);
if (MPEGId == 0)
{
throw new FileLoadException("MPEG-2.5 Not Supported");
}
else if (MPEGId == 2)
{
throw new FileLoadException("MPEG-2 Not Supported");
}
else if (MPEGId != 3)
{
throw new FileLoadException("Invalid Version ID");
}
frameHeader.MPEGId = MPEGId;
int MPEGLayr = BitTools.BitArrayToInt(header, ref headerIndex, 2);
//0 = res, 1 = Layer 3, 2 = Layer 2, 3 = Layer 1
frameHeader.MPEGLayr = MPEGLayr;
frameHeader.prot = header.Get(headerIndex++);
uint bitrate = 0;
if (MPEGId == 2)
{
bitrate = bitrateIndex[3 - MPEGLayr][BitTools.BitArrayToInt(header, ref headerIndex, 4)];
}
else if (MPEGId == 2 || MPEGId == 0)
{
if (MPEGLayr == 1)
{
bitrate = bitrateIndex[4][BitTools.BitArrayToInt(header, ref headerIndex, 4)];
}
else
{
bitrate = bitrateIndex[5][BitTools.BitArrayToInt(header, ref headerIndex, 4)];
}
}
bitrate *= 1000;
frameHeader.bitrate = bitrate;
uint sampleRate = 0;
switch (MPEGId)
{
case 0:
sampleRate = samplerateIndex[3][BitTools.BitArrayToInt(header, ref headerIndex, 2)];
break;
case 2:
sampleRate = samplerateIndex[0][BitTools.BitArrayToInt(header, ref headerIndex, 2)];
break;
case 3:
sampleRate = samplerateIndex[1][BitTools.BitArrayToInt(header, ref headerIndex, 2)];
break;
}
frameHeader.sampleRate = sampleRate;
frameHeader.pad = header.Get(headerIndex++);
headerIndex++;
int channelMode = BitTools.BitArrayToInt(header, ref headerIndex, 2);
if (channelMode == 1)
{
frameHeader.MSS = header.Get(headerIndex++);
frameHeader.IS = header.Get(headerIndex++);
}
else
{
headerIndex += 2;
}
frameHeader.channelMode = channelMode;
headerIndex += 2;
frameHeader.emph = BitTools.BitArrayToInt(header, ref headerIndex, 2);
int bitsPerSample = 0;
if (channelMode == 1 || channelMode == 3)
{
bitsPerSample = (int)(bitrate / (sampleRate * 2));
}
else if (channelMode == 0 || channelMode == 2)
{
bitsPerSample = (int)(bitrate / sampleRate);
}
frameHeader.bps = bitsPerSample;
if (channelMode == 0b11)
{
frameHeader.channels = 1;
}
else
{
frameHeader.channels = 2;
}
return(frameHeader);
}
