Audio samples don't work on Android
Hello, so my app records audio and does audio processing on it.
It works perfectly on Desktop, but on Mobile I don't seem to get any correct floating point audio samples.
I use a chart to show the value of all samples and the Android version seems to only receive values of value 0 and negative values, but nothing that makes sense.
Here are screenshots of what I mean:
As you can see, on Desktop the audio samples are good.
However, on mobile I only get weird values (values <= 0):
When I try the audio example app from Qt, that does similar audio processing, I get correct samples on Android as well. But this example app uses integer samples. I need the floating point samples though.
Here is my code for setting up the audio recording:
m_format.setSampleRate(SAMPLE_RATE); // mono sound m_format.setChannelCount(1); // aubio requires float m_format.setSampleType(QAudioFormat::SampleType::Float); // floats have a size of 32 bit m_format.setSampleSize(sizeof(float) * 8); m_format.setCodec("audio/pcm"); m_rec = new QAudioInput(m_format, this);
Any idea what could be wrong with floating point samples on Android?
If you need the full source code, it's available here: https://github.com/magnus-gross/quickpitch
OK, I found the problem. Qt doesn't support float samples on Android at all and changes the format to integer samples, even if you explicitly specify floating point samples. The
isFormatSupportedmethod to check for these cases.
I now proceeded to write a int to float conversion method and it works well now.