padpo | Linter for gettext files | Translation library

Sometimes, I need to send data the device

You always need to write data to the output. Generally you need to write at least numFrames, maybe more. If you don't have any valid data to send then write zeros. Warning: in your else block you are calling memset() but not writing to the stream.

->setFramesPerCallback(1024);

Do you need 1024 specifically? Is that for an FFT? If not then AAudio can optimize the callbacks better if the FramesPerCallback is not specified.

In all the Oboe examples, the callback is registered on the output stream, and the reading is blocking. Does this have an importance?

Actually the read is NON-blocking. Whatever stream does not have the callback should be non-blocking. Use a timeoutNanos=0.

It is important to use the output stream for the callback if you want low latency. That is because the output stream can only provide low latency mode with callbacks and not with direct write()s. But an input stream can provide low latency with both callback and with read()s.

Once the streams are stabilized then you can read or write the same number of frames in each callback. But before it is stable, you may need to to read or write extra frames.

With an output callback you should drain the input for a while so that it is running close to empty.

With an input callback you should fill the output for a while so that it is running close to full.

write(this->agcData, numFrames, 1);

Your 1 nanosecond timeout is very small. But Oboe will still block. You should use a timeoutNanos of 0 for non-blocking mode.