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Set asio buffer size #914

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Set asio buffer size #914

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98 changes: 86 additions & 12 deletions NAudio.Asio/ASIODriverExt.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -28,7 +28,6 @@ public class AsioDriverExt
private int numberOfOutputChannels;
private int numberOfInputChannels;
private AsioFillBufferCallback fillBufferCallback;
private int bufferSize;
private int outputChannelOffset;
private int inputChannelOffset;
public Action ResetRequestCallback;
Expand Down Expand Up @@ -169,10 +168,12 @@ public AsioFillBufferCallback FillBufferCallback
/// <summary>
/// Creates the buffers for playing.
/// </summary>
/// <param name="numberOfOutputChannels">The number of outputs channels.</param>
/// <param name="numberOfInputChannels">The number of input channel.</param>
/// <param name="useMaxBufferSize">if set to <c>true</c> [use max buffer size] else use Prefered size</param>
public int CreateBuffers(int numberOfOutputChannels, int numberOfInputChannels, bool useMaxBufferSize)
/// <param name="numberOfOutputChannels"></param>
/// <param name="numberOfInputChannels"></param>
/// <param name="bufferSize"></param>
/// <returns></returns>
/// <exception cref="ArgumentException"></exception>
public int CreateBuffers(int numberOfOutputChannels, int numberOfInputChannels, int bufferSize = -1)
{
if (numberOfOutputChannels < 0 || numberOfOutputChannels > capability.NbOutputChannels)
{
Expand Down Expand Up @@ -213,17 +214,30 @@ public int CreateBuffers(int numberOfOutputChannels, int numberOfInputChannels,
bufferInfos[totalIndex].pBuffer1 = IntPtr.Zero;
}

if (useMaxBufferSize)
bool bufferSizeWentWrong = false;
try
{
// use the drivers maximum buffer size
bufferSize = capability.BufferMaxSize;
bufferSize = EnsureBufferSize(bufferSize);
CreateAsioBuffer(nbTotalChannels, bufferSize);
}
else
catch
{
bufferSizeWentWrong = true;
}

if (bufferSizeWentWrong)
{
// use the drivers preferred buffer size
bufferSize = capability.BufferPreferredSize;
CreateAsioBuffer(nbTotalChannels, bufferSize);
}

// Check if outputReady is supported
isOutputReadySupported = (driver.OutputReady() == AsioError.ASE_OK);
return bufferSize;
}

private void CreateAsioBuffer(int nbTotalChannels, int bufferSize)
{
unsafe
{
fixed (AsioBufferInfo* infos = &bufferInfos[0])
Expand All @@ -234,9 +248,57 @@ public int CreateBuffers(int numberOfOutputChannels, int numberOfInputChannels,
driver.CreateBuffers(pOutputBufferInfos, nbTotalChannels, bufferSize, ref callbacks);
}
}
}

// Check if outputReady is supported
isOutputReadySupported = (driver.OutputReady() == AsioError.ASE_OK);
private int EnsureBufferSize(int bufferSize)
{
// If a preference was not submitted than go for the preferred size
if (bufferSize == -1)
bufferSize = capability.BufferPreferredSize;
else if (bufferSize < capability.BufferMinSize)
bufferSize = capability.BufferMinSize;
else if (bufferSize > capability.BufferMaxSize)
bufferSize = capability.BufferMaxSize;
else
{
/* BUFFER GRANULARITY
* Calculating a supported buffer size can be made by starting from the minimum supported
* size (capability.BufferMinSize) and adding each time the value of granularity (capability.BufferGranularity).
* With a minimum of 8 and a granularity of 16 we got this possible values:
* 8, 24, 40, 56, 72, 88, 104, etc.. until max size is reached (capability.BufferMaxSize)
*/

// If the requested buffer size is not supported by granularity we choose the closest value supported
if ((bufferSize - capability.BufferMinSize) % capability.BufferGranularity != 0)
{
int prevBS = -1,
nextBs = -1;
for (int bs = capability.BufferMinSize; bs < capability.BufferMaxSize; bs += capability.BufferGranularity)
if (bs > bufferSize)
{
nextBs = bs;
prevBS = bs - capability.BufferGranularity;
break;
}
if (prevBS == -1 && nextBs == -1)
bufferSize = capability.BufferPreferredSize;
else if (prevBS == -1 && nextBs > 0)
bufferSize = nextBs;
else if (prevBS > 0 && nextBs == -1)
bufferSize = prevBS;
else
{
int diffPrev = bufferSize - prevBS,
diffNext = nextBs - bufferSize;
if (diffPrev == diffNext)
bufferSize = nextBs;
else if (diffPrev < diffNext)
bufferSize = diffPrev;
else if (diffPrev > diffNext)
bufferSize = diffNext;
}
}
}
return bufferSize;
}

Expand Down Expand Up @@ -284,6 +346,18 @@ private void BuildCapabilities()
driver.GetBufferSize(out capability.BufferMinSize, out capability.BufferMaxSize, out capability.BufferPreferredSize, out capability.BufferGranularity);
}

/// <summary>
/// Gets the size of the buffer.
/// </summary>
/// <param name="minSize">Size of the min.</param>
/// <param name="maxSize">Size of the max.</param>
/// <param name="preferredSize">Size of the preferred.</param>
/// <param name="granularity">The granularity.</param>
public void GetBufferSize(out int minSize, out int maxSize, out int preferredSize, out int granularity)
{
driver.GetBufferSize(out minSize, out maxSize, out preferredSize, out granularity);
}

/// <summary>
/// Callback called by the AsioDriver on fill buffer demand. Redirect call to external callback.
/// </summary>
Expand Down
25 changes: 20 additions & 5 deletions NAudio.Asio/AsioOut.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -29,6 +29,8 @@ public class AsioOut : IWavePlayer
private readonly SynchronizationContext syncContext;
private bool isInitialized;

public int PreferredBufferSize { get { return driver is null ? -1 : driver.Capabilities.BufferPreferredSize; } }

/// <summary>
/// Playback Stopped
/// </summary>
Expand Down Expand Up @@ -234,10 +236,14 @@ public void Init(IWaveProvider waveProvider)
/// <summary>
/// Initialises to play, with optional recording
/// </summary>
/// <param name="waveProvider">Source wave provider - set to null for record only</param>
/// <param name="recordChannels">Number of channels to record</param>
/// <param name="recordOnlySampleRate">Specify sample rate here if only recording, ignored otherwise</param>
public void InitRecordAndPlayback(IWaveProvider waveProvider, int recordChannels, int recordOnlySampleRate)
/// <param name="waveProvider"></param>
/// <param name="recordChannels"></param>
/// <param name="recordOnlySampleRate"></param>
/// <param name="bufferSize"></param>
/// <exception cref="InvalidOperationException"></exception>
/// <exception cref="NotSupportedException"></exception>
/// <exception cref="ArgumentException"></exception>
public void InitRecordAndPlayback(IWaveProvider waveProvider, int recordChannels, int recordOnlySampleRate, int bufferSize = -1)
{
if (isInitialized)
{
Expand Down Expand Up @@ -293,8 +299,12 @@ public void InitRecordAndPlayback(IWaveProvider waveProvider, int recordChannels
driver.FillBufferCallback = driver_BufferUpdate;

this.NumberOfInputChannels = recordChannels;
UpdateBufferSize(waveProvider, bufferSize);
}
public void UpdateBufferSize(IWaveProvider waveProvider, int bufferSize = -1)
{
// Used Prefered size of ASIO Buffer
nbSamples = driver.CreateBuffers(NumberOfOutputChannels, NumberOfInputChannels, false);
nbSamples = driver.CreateBuffers(NumberOfOutputChannels, NumberOfInputChannels, bufferSize);
driver.SetChannelOffset(ChannelOffset, InputChannelOffset); // will throw an exception if channel offset is too high

if (waveProvider != null)
Expand Down Expand Up @@ -410,6 +420,11 @@ public int PlaybackLatency
/// </summary>
public int DriverOutputChannelCount => driver.Capabilities.NbOutputChannels;

public void GetBufferSize(out int minSize, out int maxSize, out int preferredSize, out int granularity)
{
driver.GetBufferSize(out minSize, out maxSize, out preferredSize, out granularity);
}

/// <summary>
/// The number of samples per channel, per buffer.
/// </summary>
Expand Down