How to record software generated audio ??

[Gianluca]

Dear all,
I'm trying to encode and to save as AAC audio file a stream generated via software by my app.
My first idea was to use the QMediaRecorder for that, but I cannot find a way to use it setting as audio input my generated stream. It seems that supports only hardware input devices :-S
So, there is no way to use Qt Multimedia module to create apps for generating musics ??

Thanks,
Gianluca.

[raven-worx]

take a look at QAudioInput and QAudioOutput classes

[Gianluca]

I did !
But they are not useful for what I need to do.
They are low-level access to the audio streams... but again, they allow to attach an hardware device to a software buffer... and they do not encode nothing.

What I need is to encode an audio stream generated from me and not from an hardware device.

[raven-worx]

sure you can write a stream to a file using these classes. See "this example":http://qt-project.org/doc/qt-5/qaudioinput.html#details in the docs. You just have to worry about the supported codecs.

Alternatively "this":https://github.com/visore/QAudioCoder might also be interesting for you.

[Gianluca]

I'll take a look to the github project.

And for what concern the example you posted... in the example the audio stream comes from the hardware device and it's not what I need.

I'll try to explain in more details what I need:

• there is a C++ method that generate an audio stream of data (RAW audio, suppose PCM 16bit unsigned)
• I want to connect this stream of data to one of the multimedia classes for encode it into AAC and saving on the disk in MP4 format.

From what I saw in the multimedia classes, the audio stream was always coming from an hardware device and not from a buffer or a QIODevice.
So, I'm wondering what I miss.

Another scenario similar to what I need:
suppose you need to convert a file from AAC/MP4 to Vorbis/Ogg
So, digging into the multimedia documentation there is the QAudioDecoder that allow you to load and decode the AAC/MP4 file ... but then ?!?!
What multimedia class allow you to write the decoded audio into Vorbis/Ogg ?!?! QMediaRecorder ?!?! but how to connect to QAudioDecoder ?!?!