/// <summary>
/// Resamples input data to output data according to the configuration of the resampler.
///
/// The input and output data is expected to be interleaved with the number of channels
/// supplied in the constructor.
///
/// All data sizes are byte sizes. E.g. to get the number of output samples, divide the
/// output length by 4 (to get the number of float samples) and then by the number of
/// channels to get the number of samples for a single channel.
/// </summary>
/// <param name="input">a byte array of interleaved float samples</param>
/// <param name="inputOffset">the byte offset in the input array</param>
/// <param name="inputLength">the byte length available in the input array</param>
/// <param name="output">a byte array of interleaved float samples</param>
/// <param name="outputOffset">the byte offset in the output array</param>
/// <param name="outputLength">the byte length available in the output array</param>
/// <param name="endOfInput">set to true if there is no more input data</param>
/// <param name="inputLengthUsed">the number of bytes read</param>
/// <param name="outputLengthGenerated">the number of bytes output</param>
/// <exception cref="SoxrException">if an error happens during processing, see error message for details</exception>
public void Process(byte[] input, int inputOffset, int inputLength,
byte[] output, int outputOffset, int outputLength,
bool endOfInput, out int inputLengthUsed, out int outputLengthGenerated)
{
// Only 32-bit float samples are supported
int sampleBlockByteSize = 4 * channels;
UIntPtr ilen = new UIntPtr((uint)(inputLength / sampleBlockByteSize));
UIntPtr olen = new UIntPtr((uint)(outputLength / sampleBlockByteSize));
UIntPtr idone = UIntPtr.Zero;
UIntPtr odone = UIntPtr.Zero;
if (outputLength == 0 && output.Length == 0)
{
output = new byte[1];
}
unsafe
{
fixed(byte *inputBytes = &input[inputOffset], outputBytes = &output[outputOffset])
{
SoxrError error = InteropWrapper.soxr_process(soxr,
endOfInput ? null : inputBytes, ilen, out idone,
outputBytes, olen, out odone);
if (error != SoxrError.Zero)
{
throw new SoxrException("Processing failed: " + GetError(error));
}
}
}
inputLengthUsed = (int)(idone.ToUInt32() * sampleBlockByteSize);
outputLengthGenerated = (int)(odone.ToUInt32() * sampleBlockByteSize);
}
/// <summary>
/// Creates a new resampler with the supplied quality parameters.
///
/// Can be used to create a variable-rate resampler by supplying SOXR_HQ as recipe
/// and SOXR_VR as flag. For a variable resampler, inputRate/outputRate must equate
/// to the maximum IO ratio that will be set by calling SetRatio. To set the initial
/// ratio, call SetRatio with a transitionLength of 0 on the created instance.
/// </summary>
/// <param name="inputRate"></param>
/// <param name="outputRate"></param>
/// <param name="channels"></param>
/// <param name="qualityRecipe"></param>
/// <param name="qualityFlags"></param>
/// <exception cref="SoxrException">when parameters are incorrect; see error message for details</exception>
public SoxResampler(double inputRate, double outputRate, int channels,
QualityRecipe qualityRecipe, QualityFlags qualityFlags)
{
if (inputRate <= 0 || outputRate <= 0 || channels <= 0)
{
throw new SoxrException("one or more parameters are invalid (zero or negative)");
}
SoxrError error = SoxrError.Zero;
// Apply the default configuration as per soxr.c
InteropWrapper.SoxrIoSpec ioSpec = InteropWrapper.soxr_io_spec(Datatype.SOXR_FLOAT32_I, Datatype.SOXR_FLOAT32_I);
InteropWrapper.SoxrQualitySpec qSpec = InteropWrapper.soxr_quality_spec(qualityRecipe, qualityFlags);
InteropWrapper.SoxrRuntimeSpec rtSpec = InteropWrapper.soxr_runtime_spec(1);
if (qualityFlags == QualityFlags.SOXR_VR)
{
if (qualityRecipe != QualityRecipe.SOXR_HQ)
{
throw new SoxrException("Invalid parameters: variable rate resampling only works with the HQ recipe");
}
variableRate = true;
maxRatio = inputRate / outputRate;
}
soxr = InteropWrapper.soxr_create(inputRate, outputRate, (uint)channels,
out error, ref ioSpec, ref qSpec, ref rtSpec);
if (error != SoxrError.Zero)
{
throw new SoxrException(GetError(error));
}
this.channels = channels;
}
/// <summary>
/// Clear internal state (e.g. buffered data) for a fresh resampling session,
/// but keeping the same configuration.
///
/// Warning: Clearing clears too much of the internal state, which seems to be
/// a bug: http://sourceforge.net/p/soxr/discussion/general/thread/15725968/
/// In variable rate mode, clearing works if the ratio is set afterwards. Without
/// setting the rate it is zero, leading to an exception at the next Process call.
/// In fixed rate mode, a new resampler should be instantiated instead of clearing,
/// because this class does not permit setting the ratio in fixed mode.
/// </summary>
/// <exception cref="SoxrException">when clearing fails, see error message for details</exception>
public void Clear()
{
SoxrError error = InteropWrapper.soxr_clear(soxr);
if (error != SoxrError.Zero)
{
throw new SoxrException("Cannot clear state: " + GetError(error));
}
}
/// <summary>
/// Deletes the current resampler instance and frees its memory.
/// To be called on destruction.
/// </summary>
private void Delete()
{
// Check if an instance is existing and only delete it if this is the case, avoiding
// an exception if called multiple times (i.e. by Dispose and the destructor).
if (soxr != SoxrInstance.Zero)
{
InteropWrapper.soxr_delete(soxr);
soxr = SoxrInstance.Zero;
}
}
/// <summary>
/// Transitions to a new resampling ratio for variable-rate resampling over the given length.
/// Set the length to 0 for an instant change.
/// The ratio is the factor that the input rate must be multiplied with to get the output rate.
/// </summary>
/// <param name="ratio">the new resampling ratio</param>
/// <param name="transitionLength">the length over which to linearly transition to the new ratio</param>
/// <exception cref="SoxrException">when the resampler is not configured for variable-rate resampling</exception>
public void SetRatio(double ratio, int transitionLength)
{
if (!variableRate)
{
throw new SoxrException("Illegal call: set_io_ratio only works in variable-rate resampling mode");
}
else if (ratio > maxRatio)
{
throw new SoxrException("Ratio exceeds max bound specified in constructor");
}
SoxrError error = InteropWrapper.soxr_set_io_ratio(soxr, 1.0 / ratio, new UIntPtr((uint)transitionLength));
if (error != SoxrError.Zero)
{
throw new SoxrException("Error changing IO ratio: " + GetError(error));
}
}
/// <summary>
/// Returns the most recent error message.
/// </summary>
public string GetError()
{
SoxrError ptr = InteropWrapper.soxr_error(soxr);
return(GetError(ptr));
}
public double GetOutputDelay()
{
return(InteropWrapper.soxr_delay(soxr));
}