unsafe void decode_metadata()
{
byte x;
int i, id;
//bool first = true;
byte[] FLAC__STREAM_SYNC_STRING = new byte[] { (byte)'f', (byte)'L', (byte)'a', (byte)'C' };
byte[] ID3V2_TAG_ = new byte[] { (byte)'I', (byte)'D', (byte)'3' };
for (i = id = 0; i < 4;)
{
if (_IO.Read(_framesBuffer, 0, 1) == 0)
{
throw new Exception("FLAC stream not found");
}
x = _framesBuffer[0];
if (x == FLAC__STREAM_SYNC_STRING[i])
{
//first = true;
i++;
id = 0;
continue;
}
if (id < 3 && x == ID3V2_TAG_[id])
{
id++;
i = 0;
if (id == 3)
{
if (!skip_bytes(3))
{
throw new Exception("FLAC stream not found");
}
int skip = 0;
for (int j = 0; j < 4; j++)
{
if (0 == _IO.Read(_framesBuffer, 0, 1))
{
throw new Exception("FLAC stream not found");
}
skip <<= 7;
skip |= ((int)_framesBuffer[0] & 0x7f);
}
if (!skip_bytes(skip))
{
throw new Exception("FLAC stream not found");
}
}
continue;
}
id = 0;
if (x == 0xff) /* MAGIC NUMBER for the first 8 frame sync bits */
{
do
{
if (_IO.Read(_framesBuffer, 0, 1) == 0)
{
throw new Exception("FLAC stream not found");
}
x = _framesBuffer[0];
} while (x == 0xff);
if (x >> 2 == 0x3e) /* MAGIC NUMBER for the last 6 sync bits */
{
//_IO.Position -= 2;
// state = frame
throw new Exception("headerless file unsupported");
}
}
throw new Exception("FLAC stream not found");
}
do
{
fill_frames_buffer();
fixed(byte *buf = _framesBuffer)
{
BitReader bitreader = new BitReader(buf, _framesBufferOffset, _framesBufferLength - _framesBufferOffset);
bool is_last = bitreader.readbit() != 0;
MetadataType type = (MetadataType)bitreader.readbits(7);
int len = (int)bitreader.readbits(24);
if (type == MetadataType.StreamInfo)
{
const int FLAC__STREAM_METADATA_STREAMINFO_MIN_BLOCK_SIZE_LEN = 16; /* bits */
const int FLAC__STREAM_METADATA_STREAMINFO_MAX_BLOCK_SIZE_LEN = 16; /* bits */
const int FLAC__STREAM_METADATA_STREAMINFO_MIN_FRAME_SIZE_LEN = 24; /* bits */
const int FLAC__STREAM_METADATA_STREAMINFO_MAX_FRAME_SIZE_LEN = 24; /* bits */
const int FLAC__STREAM_METADATA_STREAMINFO_SAMPLE_RATE_LEN = 20; /* bits */
const int FLAC__STREAM_METADATA_STREAMINFO_CHANNELS_LEN = 3; /* bits */
const int FLAC__STREAM_METADATA_STREAMINFO_BITS_PER_SAMPLE_LEN = 5; /* bits */
const int FLAC__STREAM_METADATA_STREAMINFO_TOTAL_SAMPLES_LEN = 36; /* bits */
const int FLAC__STREAM_METADATA_STREAMINFO_MD5SUM_LEN = 128; /* bits */
min_block_size = bitreader.readbits(FLAC__STREAM_METADATA_STREAMINFO_MIN_BLOCK_SIZE_LEN);
max_block_size = bitreader.readbits(FLAC__STREAM_METADATA_STREAMINFO_MAX_BLOCK_SIZE_LEN);
min_frame_size = bitreader.readbits(FLAC__STREAM_METADATA_STREAMINFO_MIN_FRAME_SIZE_LEN);
max_frame_size = bitreader.readbits(FLAC__STREAM_METADATA_STREAMINFO_MAX_FRAME_SIZE_LEN);
int sample_rate = (int)bitreader.readbits(FLAC__STREAM_METADATA_STREAMINFO_SAMPLE_RATE_LEN);
int channels = 1 + (int)bitreader.readbits(FLAC__STREAM_METADATA_STREAMINFO_CHANNELS_LEN);
int bits_per_sample = 1 + (int)bitreader.readbits(FLAC__STREAM_METADATA_STREAMINFO_BITS_PER_SAMPLE_LEN);
pcm = new AudioPCMConfig(bits_per_sample, channels, sample_rate);
_sampleCount = (long)bitreader.readbits64(FLAC__STREAM_METADATA_STREAMINFO_TOTAL_SAMPLES_LEN);
bitreader.skipbits(FLAC__STREAM_METADATA_STREAMINFO_MD5SUM_LEN);
}
else if (type == MetadataType.Seektable)
{
int num_entries = len / 18;
seek_table = new SeekPoint[num_entries];
for (int e = 0; e < num_entries; e++)
{
seek_table[e].number = bitreader.read_long();
seek_table[e].offset = bitreader.read_long();
seek_table[e].framesize = (int)bitreader.read_ushort();
}
}
if (_framesBufferLength < 4 + len)
{
_IO.Position += 4 + len - _framesBufferLength;
_framesBufferLength = 0;
}
else
{
_framesBufferLength -= 4 + len;
_framesBufferOffset += 4 + len;
}
if (is_last)
{
break;
}
}
} while (true);
first_frame_offset = _IO.Position - _framesBufferLength;
}
private void ParseHeaders()
{
const long maxFileSize = 0x7FFFFFFEL;
const uint fccRIFF = 0x46464952;
const uint fccWAVE = 0x45564157;
const uint fccFormat = 0x20746D66;
const uint fccData = 0x61746164;
uint lenRIFF;
bool foundFormat, foundData;
if (_br.ReadUInt32() != fccRIFF)
{
throw new Exception("Not a valid RIFF file.");
}
lenRIFF = _br.ReadUInt32();
if (_br.ReadUInt32() != fccWAVE)
{
throw new Exception("Not a valid WAVE file.");
}
_largeFile = false;
foundFormat = false;
foundData = false;
long pos = 12;
do
{
uint ckID, ckSize, ckSizePadded;
long ckEnd;
ckID = _br.ReadUInt32();
ckSize = _br.ReadUInt32();
ckSizePadded = (ckSize + 1U) & ~1U;
pos += 8;
ckEnd = pos + (long)ckSizePadded;
if (ckID == fccFormat)
{
foundFormat = true;
uint fmtTag = _br.ReadUInt16();
int _channelCount = _br.ReadInt16();
int _sampleRate = _br.ReadInt32();
_br.ReadInt32(); // bytes per second
int _blockAlign = _br.ReadInt16();
int _bitsPerSample = _br.ReadInt16();
int _channelMask = 0;
pos += 16;
if (fmtTag == 0xFFFEU && ckSize >= 34) // WAVE_FORMAT_EXTENSIBLE
{
_br.ReadInt16(); // CbSize
_br.ReadInt16(); // ValidBitsPerSample
_channelMask = _br.ReadInt32();
fmtTag = _br.ReadUInt16();
pos += 10;
}
if (fmtTag != 1) // WAVE_FORMAT_PCM
{
throw new Exception("WAVE format tag not WAVE_FORMAT_PCM.");
}
pcm = new AudioPCMConfig(_bitsPerSample, _channelCount, _sampleRate, (AudioPCMConfig.SpeakerConfig)_channelMask);
if (pcm.BlockAlign != _blockAlign)
{
throw new Exception("WAVE has strange BlockAlign");
}
}
else if (ckID == fccData)
{
foundData = true;
_dataOffset = pos;
if (!_IO.CanSeek || _IO.Length <= maxFileSize)
{
if (ckSize == 0 || ckSize >= 0x7fffffff)
{
_dataLen = -1;
}
else
{
_dataLen = (long)ckSize;
}
}
else
{
_largeFile = true;
_dataLen = _IO.Length - pos;
}
}
if ((foundFormat & foundData) || _largeFile)
{
break;
}
if (_IO.CanSeek)
{
_IO.Seek(ckEnd, SeekOrigin.Begin);
}
else
{
_br.ReadBytes((int)(ckEnd - pos));
}
pos = ckEnd;
} while (true);
if ((foundFormat & foundData) == false || pcm == null)
{
throw new Exception("Format or data chunk not found.");
}
if (pcm.ChannelCount <= 0)
{
throw new Exception("Channel count is invalid.");
}
if (pcm.SampleRate <= 0)
{
throw new Exception("Sample rate is invalid.");
}
if ((pcm.BitsPerSample <= 0) || (pcm.BitsPerSample > 32))
{
throw new Exception("Bits per sample is invalid.");
}
if (pos != _dataOffset)
{
Position = 0;
}
}
public AudioBuffer(IAudioSource source, int _size)
{
pcm = source.PCM;
size = _size;
}
public AudioBuffer(AudioPCMConfig _pcm, byte[] _bytes, int _length)
{
pcm = _pcm;
Prepare(_bytes, _length);
}
public AudioBuffer(AudioPCMConfig _pcm, int[,] _samples, int _length)
{
pcm = _pcm;
// assert _samples.GetLength(1) == pcm.ChannelCount
Prepare(_samples, _length);
}
public AudioBuffer(AudioPCMConfig _pcm, int _size)
{
pcm = _pcm;
size = _size;
length = 0;
}
