Adrian Stanculescu Adrian Stanculescu - 1 year ago 430
C# Question

Naudio Asio Record and Playback simultaneously on multiple channels

I have an usb audio board that supports asio driver with 4 inputs and 4 outputs.
I want to send and receive data simultaneously.
But currently I can receive and send data only to one channels at a time. I cannot figure out how to set it in asioOut class from Naudio c# library.

I have to threads

It is possible to have one AudioAvailable event for each channel? Similar to waveIn / waveOut classes.
How can I achive this?

Here is my code:

int sampleRate = 44100;
int channels = 4;

buffWaveProvider = new BufferedWaveProvider(new NAudio.Wave.WaveFormat(sampleRate, 32, channels));
asioOut = new AsioOut(radioForm.driverName);
asioOut.ChannelOffset = OUTdevID;
asioOut.InputChannelOffset = INdevId;
asioOut.AudioAvailable += OnAsioOutAudioAvailable;
asioOut.InitRecordAndPlayback(buffWaveProvider, channels, sampleRate);

for AudioAvailable event I have to send for each input channel the inputstream on different multicast address:

public void OnAsioOutAudioAvailable(object sender, AsioAudioAvailableEventArgs e)
if (speakersOn && e.InputBuffers.Length != 0 && !monitorRequest)
byte[] buf = new byte[e.SamplesPerBuffer*4];
for (int i = 0; i < e.InputBuffers.Length; i++)
Marshal.Copy(e.InputBuffers[i], buf, 0, e.SamplesPerBuffer*4);
e.WrittenToOutputBuffers = true;
udp4VoiceSend.Send(buf, buf.Length);

Is there a way to access input buffers for each channel?
enter image description here

For the outputs I've checked the naudio source code and I saw I can set the number of output channels to waveProvider.WaveFormat.Channels. So I suppose that when calling InitRecordAndPlayback method the IWaveProvider buffer should have 4 channels.

None of stackoverflow post about this subject helped me. I've tried them all.

NAudio Asio Record and Playback

How to record and playback with NAudio using AsioOut

NAudio AsioOut + Sockets



I've checked the Naudio Demo Project, Asio Recording Panel and seems that I can listen to only one channel at a time:
enter image description here

The naudio driver class creates 4 input and 4 output buffers as expected, but I'm not able to access them.
enter image description here

In AsioRecordingPanel file if asioOut object listens to 1 channel and user wants to change channel the object is disposed.

enter image description here

Is a library limitation or a driver limitation?

When I add samples to asio buffer it's possible to send data directly to an output channel?

if (Main.buffWaveProvider != null)
Main.buffWaveProvider.AddSamples(data, 0, dataLen);


Answer Source

Here's a simple example I created that is accessing both the input and output ASIO buffers and performing low-level manipulation of the samples.

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