Using AudioDataOutput unsynchronized

[Ian Monroe]

On Sun, Feb 20, 2011 at 07:15, Sergey Vlasov <sergey.vlsv at gmail.com> wrote:
> Hello,
> I'm developing a small audio application and I use Phonon as its backend for
> playback and more. I want to draw audio graph (waveform) of the file and I
> need to access to raw PCM audio samples. I can do that with
> Phonon::AudioDataOutput but I have two problems.
> First, it doesn't emit dataReady() signal unless I create an extra path from
> it to Phonon::AudioOutput. Why is there such a limitation? Especially when
> playback gets so unacceptably full of pops and clicks. AudioDataOutput is
> not supposed to be used to alter audio data during playback (isn't
> Phonon::Effect for that?). If it's meant to be used for visualizing purpose
> only then why to put it in between of MediaObject and AudioOutput and thus
> cause huge glitches due to overhead?
> Second, how can I make it to output audio data full speed that is
> asynchronously and without output to sound card? That would solve the first
> problem too.
> I guess that's just a bad design for AudioDataOutput and it's not going to
> change. So I wonder if someone out there knows of some unofficial Phonon
> class or a patch to AudioDataOutput that could allow me to do that? I'm
> aware of QtMultimedia but it works only with wave files while with Phonon I
> can read pretty much any audio format.

What backend do you use?