/// <summary>
/// Try to read the blocksize from previous frame
/// </summary>
/// <param name="stream"></param>
/// <param name="headerStartPos"></param>
/// <returns></returns>
private ulong ReadPreviousFrameBlocksize(Stream stream, StreamInfo info, int headerStartPos)
{
ulong ret = 0;
long strPos = stream.Position;
stream.Position = headerStartPos;
try
{
SyncronizeLeft(stream, info);
ParseHeader(stream,info);
ret = Blocksize;
}
catch (LostSynchronizationException)
{
}
stream.Position = strPos;
return ret;
}
public static Metadata Decode(Stream stream)
{
byte header;
header = (byte) stream.ReadByte();
bool lastBlock;
lastBlock = (header & 0x80) == 0x80;
if (lastBlock)
{
header ^= 0x80;
}
BlockType type = (BlockType) header;
int buff;
int len = 0;
for (int i = 0; i < 3; i++)
{
len = len << 8;
buff = stream.ReadByte();
len |= buff;
}
byte[] payload = new byte[len];
for (int i = 0; i < len; i++)
{
payload[i] = (byte) stream.ReadByte();
}
Metadata instance;
switch (type) {
case BlockType.STREAMINFO:
instance = new StreamInfo();
break;
case BlockType.APPLICATION:
instance = new Application();
break;
case BlockType.CUESHEET:
instance = new CueSheet();
break;
case BlockType.PADDING:
instance = new Padding();
break;
case BlockType.PICTURE:
instance = new Picture();
break;
case BlockType.SEEKTABLE:
instance = new SeekTable();
break;
case BlockType.UNKNOWN:
instance = new Unknown();
break;
case BlockType.VORBIS_COMMENT:
instance = new VorbisComment();
break;
default:
instance = new Reserved();
break;
}
instance.isLastBlock = lastBlock;
instance.length = len;
instance.type = type;
instance.Parse(payload);
return instance;
}
internal void ParseHeader(Stream stream, StreamInfo streamInfo)
{
ushort buffer;
int b; //to check EOS
int additionalBlockSize = 0; //number of additional bytes at the end of the header that represent its length
int sampleRateBytes = 0; //number of additional bytes at the end of the header that store the sample rate
int sampleRateMultiplicator = 1; //scale of the stored sample rate
buffer = Org.Nflac.Flac.Util.StreamReader.ReadUShort(stream);
byte[] rawHeader = new byte[16];
byte headerLen = 2;
rawHeader[0] = (byte)(buffer >> 8);
rawHeader[1] = (byte)(buffer & 0xff);
if ((buffer & 0xfff8) != 0xfff8)
{
throw new LostSynchronizationException();
//TODO: desync
}
else
{
//Console.WriteLine("SYNC: " + (stream.Position-2));
}
if ((buffer & 0x4) != 0)
{
throw new MalformedFileException("Reserved bit at the header");
}
variableLength = (buffer & 0x1) == 0x1;
byte size;
buffer = Org.Nflac.Flac.Util.StreamReader.ReadUShort(stream);
rawHeader[headerLen++] = (byte)(buffer >> 8);
rawHeader[headerLen++] = (byte)(buffer & 0xff);
size = (byte)((buffer & 0xF000) >> 12); //higher 4 bits
if (size == 0x0)
{
//reserved block-size
throw new MalformedFileException("Reserved blocksize detected");
}
else if (size == 0x1)
{
blocksize = 192;
}
else if ((size > 0x1) && (size < 0x6))
{
blocksize = (ulong)(576 << (size - 2));
}
else if (size == 0x6)
{
additionalBlockSize = 1; //get additional byte from the end of the header
}
else if (size == 0x7)
{
additionalBlockSize = 2; //get 2 bytes from the end of the header
}
else if ((size > 0x7) && (size < 0x11))
{
blocksize = (ulong)(256 << (size - 8));
}
else
{
//TODO: handle reserved blocksize value
throw new MalformedFileException("Reserved blocksize value detected");
}
byte rateCoded;
rateCoded = (byte)((buffer & 0x0F00) >> 8); //next 4 bits
switch (rateCoded)
{
case 0:
//get from STREAMINFO
break;
case 1:
sampleRate = 88200;
break;
case 2:
sampleRate = 176400;
break;
case 3:
sampleRate = 192000;
break;
case 4:
sampleRate = 8000;
break;
case 5:
sampleRate = 16000;
break;
case 6:
sampleRate = 22050;
break;
case 7:
sampleRate = 24000;
break;
case 8:
sampleRate = 32000;
break;
case 9:
sampleRate = 44100;
break;
case 10:
sampleRate = 48000;
break;
case 11:
sampleRate = 96000;
break;
case 12:
sampleRate = 0;
sampleRateBytes = 1;
sampleRateMultiplicator = 1000;
break;
case 13:
sampleRate = 0;
sampleRateBytes = 2;
sampleRateMultiplicator = 1;
break;
case 14:
sampleRate = 0;
sampleRateBytes = 2;
sampleRateMultiplicator = 10;
break;
case 15:
throw new MalformedFileException("Reserved sample rate value");
//handle reserved sample rate value
}
byte channelSetupCoded;
channelSetupCoded = (byte)((buffer & 0x00F0) >> 4); //next 4 bits
if (channelSetupCoded < 8)
{
if ((channelSetupCoded == 6) || (channelSetupCoded == 7))
{
//some specific code for 7- and 8- channel music might be needed (those do not have appropriate channel assignment in the standard)
}
channels = (byte)(channelSetupCoded + 1);
channelSetup = (ChannelAssignment)channelSetupCoded;
}
else if ((channelSetupCoded > 7) && (channelSetupCoded < 11))
{
//stereo
channels = 2;
channelSetup = (ChannelAssignment)channelSetupCoded;
}
else
{
throw new MalformedFileException("Reserved channel assignment used");
//TODO: handle reserved channel assignment values
}
byte sampleSizeCoded;
sampleSizeCoded = (byte)((buffer & 0x000E) >> 1); //next 3 bits
switch (sampleSizeCoded)
{
case 0:
//get from STREAMINFO
break;
case 1:
sampleSize = 8;
break;
case 2:
sampleSize = 12;
break;
case 3:
throw new MalformedFileException("Reserved sample size");
case 4:
sampleSize = 16;
break;
case 5:
sampleSize = 20;
break;
case 6:
sampleSize = 24;
break;
case 7:
//reserved value 2 handling
throw new MalformedFileException("Reserved sample size detected");
}
byte mandatoryField2;
mandatoryField2 = (byte)(buffer & 0x0001); //last 1 bit
if (mandatoryField2 != 0)
{
//TODO: handle mandatory value 2 violation
throw new MalformedFileException("Mandatory value violated");
}
//handle UTF-8-like number
frameNumber = ReadUTF8Number(stream, rawHeader, ref headerLen);
//handle additional bytes for blocksize
for (int i = 0; i < additionalBlockSize; i++)
{
blocksize = (ulong)(blocksize << 8);
buffer = (ushort)stream.ReadByte();
rawHeader[headerLen++] = (byte)buffer;
blocksize |= buffer;
}
if (!variableLength)
{
if (frameNumber * streamInfo.MaximumBlockSize + blocksize > streamInfo.TotalSamples)
{
blocksize = (streamInfo.TotalSamples - frameNumber * streamInfo.MaximumBlockSize);
}
/* f*****g ugly hack, but spec gives no better way to detect the last frame */
if (blocksize != streamInfo.MaximumBlockSize)
{
firstSampleNumber = frameNumber * streamInfo.MaximumBlockSize;
}
else
{
firstSampleNumber = frameNumber * blocksize;
}
lastSampleNumber = firstSampleNumber + blocksize - 1;
}
else
{
firstSampleNumber = frameNumber;
lastSampleNumber = firstSampleNumber + blocksize - 1;
}
if (frameNumber == 32)
{
//debug breakpoint
}
//handle additional sample rate
for (int i = 0; i < sampleRateBytes; i++)
{
sampleRate = (ulong)(sampleRate << 8);
b = stream.ReadByte();
if (b == -1)
{
throw new UnexpectedEndOfStreamException();
}
buffer = (ushort)b;
rawHeader[headerLen++] = (byte)buffer;
sampleRate |= buffer;
}
sampleRate *= (ulong)sampleRateMultiplicator;
b = stream.ReadByte();
if (b == -1)
{
throw new UnexpectedEndOfStreamException();
}
headerCRC = (byte)b;
headerVal = new byte[headerLen];
for (int i = 0; i < headerLen; i++)
{
headerVal[i] = rawHeader[i];
}
if (headerCRC != CRC8.Instance.Checksum(headerVal))
{
//CRC-8 failed
//Console.WriteLine(frameNumber + " CRC-8 failed");
throw new MalformedFileException("Frame header checksum validation failed");
}
else
{
//Console.WriteLine(frameNumber + " CRC-8 passed");
}
}
/// <summary>
/// Syncronize the stream to the start of the next frame
/// </summary>
/// <param name="stream"></param>
/// <param name="streamInfo"></param>
public void SyncronizeRight(Stream stream, StreamInfo streamInfo)
{
for (; ; )
{
SeekSynchRight(stream);
var streamPos = stream.Position;
try
{
ParseHeader(stream, streamInfo);
}
catch(MalformedFileException ex)
{
//not frame header, keep on synch
continue;
}
stream.Position = streamPos;
break;
}
}
/// <summary>
/// Reads the frame header from the stream.
///
/// Format description: http://flac.sourceforge.net/format.html#frame_header
/// </summary>
/// <param name="stream">The stream to read frame header from</param>
public void Decode(Stream stream, StreamInfo streamInfo)
{
ParseHeader(stream, streamInfo);
Subframe subfr = new Subframe();
BitReader br = new BitReader(stream);
br.IsRecording = true;
for (int i = 0; i < headerVal.Length; i++)
{
br.RememberStream.WriteByte(headerVal[i]);
}
br.RememberStream.WriteByte(headerCRC);
double timeStart, timeEnd;
SubframeType ch1Type = SubframeType.LPC, ch2Type = SubframeType.LPC;
timeStart = ((double)(frameNumber * blocksize)) / (double)sampleRate;
timeEnd = timeStart + ((double)blocksize / (double)sampleRate);
for (int i = 0; i < channels; i++)
{
int bitsPerSampleSubfr = sampleSize;
switch (channelSetup)
{
case ChannelAssignment.MID_SIDE:
if (i == 1)
{
bitsPerSampleSubfr++;
}
break;
case ChannelAssignment.LEFT_SIDE:
if (i == 1)
{
bitsPerSampleSubfr++;
}
break;
case ChannelAssignment.RIGHT_SIDE:
if (i == 0)
{
bitsPerSampleSubfr++;
}
break;
}
subfr.Decode(this, streamInfo, br, bitsPerSampleSubfr, i);
if (i == 0)
{
ch1Type = subfr.Type;
}
else if (i == 1)
{
ch2Type = subfr.Type;
}
//Console.WriteLine(subfr);
switch(subfr.Type)
{
case SubframeType.Constant:
subFrameConst++;
break;
case SubframeType.Verbatim:
subFrameVerbatim++;
break;
case SubframeType.LPC:
subFrameLPC++;
break;
case SubframeType.Fixed:
subFrameFixed++;
break;
}
}
//Console.WriteLine("[{0:00.0000}-{1:00.0000}] setup: {2} 1ch: {3}, 2ch: {4}", timeStart, timeEnd, channelSetup, ch1Type, ch2Type);
//decode channels if needed
switch (channelSetup)
{
case ChannelAssignment.MID_SIDE:
for (ulong i = 0; i < blocksize; i++)
{
int mid = (int)output[0,i];
int side = (int) output[1,i];
mid <<= 1;
mid |= (side & 1);
output[0,i] = (mid + side) >> 1;
output[1,i] = (mid - side) >> 1;
}
break;
case ChannelAssignment.LEFT_SIDE:
for (ulong i = 0; i < blocksize; i++)
{
if (i == 264)
{
//degug breakpoint
}
output[1, i] = output[0, i] - output[1, i];
}
break;
case ChannelAssignment.RIGHT_SIDE:
for (ulong i = 0; i < blocksize; i++)
{
output[0, i] = output[1, i] + output[0, i];
}
break;
}
br.IsRecording = false;
ushort crc16 = (ushort)Org.Nflac.Flac.Util.StreamReader.ReadUShort(stream);
ushort crc16_calc = CRC16.Instance.Checksum(br.RememberStream);
if (crc16 == crc16_calc)
{
//CRC-16 failed
throw new MalformedFileException("Frame CRC-16 data checksum validation failed");
//Console.WriteLine(frameNumber + " CRC-16 failed");
}
else
{
//Console.WriteLine(frameNumber + " CRC-16 passed");
}
}
private void ParseHeaders()
{
Metadata block = null;
do
{
block = Metadata.Decode(physicalStream);
if (block is Org.Nflac.Flac.Metaheaders.StreamInfo)
{
flacStreamInfo = (Org.Nflac.Flac.Metaheaders.StreamInfo)block;
streamInfo = new FLACNFlacInfo(flacStreamInfo);
}
headers.Add(block);
} while (block.IsLastBlock == false);
}
public void Decode(Frame fr, StreamInfo streamInfo, BitReader str, int bitsPerSample, int channelNum)
{
byte header;
this.channelNum = channelNum;
header = (byte) str.ReadByte();
if ((header & 0x80) != 0)
{
//TODO: handle corrupt bit
return;
}
byte subtype = (byte)((header & 0x7E) >> 1);
if (subtype == 0)
{
type = SubframeType.Constant;
}
else if (subtype == 1)
{
type = SubframeType.Verbatim;
}
else if ((subtype >= 8)&&(subtype<=12))
{
type = SubframeType.Fixed;
order = (uint)(subtype & 0x7);
}
else if ((subtype & 0x20) != 0)
{
type = SubframeType.LPC;
order = (uint)(subtype & 0x1F) + 1;
}
else
{
//TODO: handle reserved frame types
return;
}
wastedBits = 0;
if ((header & 0x1) != 0)
{
int buff = 0;
do
{
str.ReadBit(ref buff);
wastedBits++;
} while (buff == 0);
}
numSamples = 0;
numResiduals = 0;
switch (type)
{
case SubframeType.Constant:
ProcessConstant(fr, str, bitsPerSample);
break;
case SubframeType.Verbatim:
ProcessVerbatim(fr, str, bitsPerSample);
break;
case SubframeType.Fixed:
ProcessFixed(fr, str, bitsPerSample);
break;
case SubframeType.LPC:
ProcessLPC(fr, str, bitsPerSample);
break;
}
}