private static bool IsEncoded(int stream, SyncWord syncWord)
{
const int framesToCheck = 5;
const int bytesPerSample = 4;
const int bytesPerWord = 2;
const int channelCount = 2;
long streamLength = Bass.BASS_ChannelGetLength(stream);
long currentPosition = 0;
if (streamLength > 0)
{
currentPosition = Bass.BASS_ChannelGetPosition(stream);
if (currentPosition != 0)
Bass.BASS_ChannelSetPosition(stream, 0);
}
SyncFifoBuffer syncFifoBuffer = new SyncFifoBuffer(syncWord);
float[] readBuffer = new float[channelCount];
int lastSyncWordPosition = -1;
int lastFrameSize = -1;
int frameCount = 0;
bool result = false;
bool endOfStream = false;
int sampleIndex = 0;
int maxSampleIndex = (syncWord.MaxFrameSize / bytesPerWord) * framesToCheck + syncWord.WordLength;
while (!result && !endOfStream && sampleIndex < maxSampleIndex)
{
int bytesRead = Bass.BASS_ChannelGetData(stream, readBuffer, readBuffer.Length * bytesPerSample);
endOfStream = bytesRead <= 0;
if (!endOfStream)
{
int samplesRead = bytesRead / bytesPerSample;
int readSample = 0;
while (!result && readSample < samplesRead)
{
// Convert float value to word
UInt16 word = (UInt16)(readBuffer[readSample] * 32768);
// Add word to fifo buffer
syncFifoBuffer.Write(word);
// Check Sync word
if (syncFifoBuffer.IsMatch())
{
int newSyncWordPosition = (sampleIndex - syncWord.WordLength + 1) * bytesPerWord;
if (lastSyncWordPosition != -1)
{
int thisFrameSize = newSyncWordPosition - lastSyncWordPosition;
if (lastFrameSize != -1)
{
if (thisFrameSize != lastFrameSize)
break;
}
lastFrameSize = thisFrameSize;
frameCount++;
}
lastSyncWordPosition = newSyncWordPosition;
result = (frameCount == framesToCheck);
}
sampleIndex++;
readSample++;
}
}
else
endOfStream = true;
}
if (streamLength > 0)
Bass.BASS_ChannelSetPosition(stream, currentPosition);
return result;
}
private static bool SyncToWord(int stream, SyncWord syncWord)
{
const int bytesPerSample = 4;
const int bytesPerWord = 2;
const int channelCount = 2;
long streamLength = Bass.BASS_ChannelGetLength(stream);
long currentPosition = 0;
if (streamLength > 0)
currentPosition = Bass.BASS_ChannelGetPosition(stream);
SyncFifoBuffer syncFifoBuffer = new SyncFifoBuffer(syncWord);
float[] readBuffer = new float[channelCount];
bool result = false;
bool endOfStream = false;
int sampleIndex = 0;
int maxSampleIndex = (syncWord.MaxFrameSize / bytesPerWord) + syncWord.WordLength;
while (!result && !endOfStream && sampleIndex < maxSampleIndex)
{
// For float streams we get one float value for each 16bit word
int bytesRead = Bass.BASS_ChannelGetData(stream, readBuffer, readBuffer.Length * bytesPerSample);
endOfStream = bytesRead <= 0;
if (!endOfStream)
{
int samplesRead = bytesRead / bytesPerSample;
int readSample = 0;
while (!result && readSample < samplesRead)
{
// Convert float value to word
UInt16 word = (UInt16)(readBuffer[readSample] * 32768);
// Add word to fifo buffer
syncFifoBuffer.Write(word);
// Check Sync word
if (syncFifoBuffer.IsMatch())
{
long pos = currentPosition + (sampleIndex - syncWord.WordLength + 1) * bytesPerWord;
//Log.Debug("PureAudio: Sync to next frame: changing position from {0} to {1}", currentPosition, pos);
Bass.BASS_ChannelSetPosition(stream, pos);
result = true;
}
sampleIndex++;
readSample++;
}
}
}
if (!result && streamLength > 0)
Bass.BASS_ChannelSetPosition(stream, currentPosition);
return result;
}
