Distorted audio on simple ASIO loop through

[thestk]

Distorted audio on simple ASIO loop through

[garyscavone]

Hi James,

I suggest using the programs in the “tests” directory to test things. That would at least rule out problems with the code.

—gary

On Sep 24, 2014, at 2:54 AM, James Heliker [email protected] wrote:

Hello -

I am currently testing RtAudio in hopes to use it on a project, and am getting unexpected results!

Given my code below (hooked up to a known-good ASIO device), I would expect my output to be essentially a copy of my input; that said it is very distorted and only somewhat recognizable with all the static / noise. Using Audacity or other known-good software I can run the same test on my hardware with no audible problems.

My setup is very simple:

audioDriver->openStream(&parameters, &parameters, RTAUDIO_SINT16, sampleRate, &bufferFrames, &input, NULL, &options);
audioDriver->startStream();

And my callback is very simple too:

int input(void *outputBuffer, void *inputBuffer, unsigned int nBufferFrames,
double streamTime, RtAudioStreamStatus status, void *userData)
{

if (status)
std::cout << "input: " << status << std::endl;
memcpy(outputBuffer, inputBuffer, nBufferFrames);
return 0;
}

Any insight you could offer would be so appreciated!! Sorry if this is the wrong place to post a question / issue of this nature.

Kind Regards,

• James Heliker
—
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[radarsat1]

memcpy(outputBuffer, inputBuffer, nBufferFrames);

If you look at, e.g., record.cpp, you'll see a line like,

bufferBytes = frames * iData->channels * sizeof( MY_TYPE );

In other words, memcpy should take the number of bytes as the 3rd parameter, but you are passing it the number of frames. Since you are using type RTAUDIO_SINT16, then outputBuffer and inputBuffer point to signed short, and your line should be,

memcpy(outputBuffer, inputBuffer, nBufferFrames * sizeof(short));

Without this, the second half of every buffer would be random values, and therefore the audio would sound crunchy and weird. Don't forget to also consider the number of channels.

[radarsat1]

Closing because no response in several months.