QAudioInput start delay

Mark Durkot

Hello guys,

I'm using QAudioInput for my app. I do real time sound processing. I'm also using build in microphone.
But when I call audioInput->start() for the first time since the program started I get a delay by starting the QAudioInput. On my computer (iMac 2019 running Mojave (10.14.6)) the delay is about 5 sec. But the audioInput->start() takes forever to start sampling on a MacBook Pro (mid 2012 also running Mojave). I have to say it just doesn't start :))).
Here is my code how I initialize the QAudioInput

format_.setSampleRate(SampelRate);
format_.setChannelCount(1);
format_.setSampleSize(16);
format_.setSampleType(QAudioFormat::SignedInt);
format_.setByteOrder(QAudioFormat::LittleEndian);
format_.setCodec("audio/pcm");

QAudioDeviceInfo inputInfo(QAudioDeviceInfo::defaultInputDevice());
if (!inputInfo.isFormatSupported(format_)) {
    format_ = inputInfo.nearestFormat(format_);
}
audioInput_ = new QAudioInput(QAudioDeviceInfo::defaultInputDevice(), format_, this);

And this is how I connect readReady() signal to my slot

inputDevice_ = audioInput_->start();
connect(inputDevice_, SIGNAL(readyRead()), this, SLOT(readMore()));

So back to my computer where I have 5 sec delay. I checked the state of the audioInput right after I started it, it says "IdleState". After approximately 5 sec it switches to "ActiveState" and I start getting data from microphone.

I couldn't find any answer on the internet so I'm asking this by you guys. I don't know if it's the problem of the device, my code, or the QAudioInput.

I would be very thankful of any help of you!
Mark :)

SGaist

Hi,

Since you want to do real-time audio, I would rather go with a library that has less latency.

I remember having had good results with PortAudio.

Mark Durkot

This post is deleted!

Mark Durkot

@SGaist
Hi,
I very appreciate your answer! Thank you so much, I'm gonna try PortAudio as soon as I get back to my project! And tell you how it went)
Thank you:)

Best regards
Mark