Patch (rather for discussion): sonic and samplerate implementation

[Andrei Kholodnyi]

On Sat, Dec 4, 2010 at 2:30 PM, Bohdan R. Rau <ethanak at polip.com> wrote:
> Yes, of course! But I had audio effect function working, and as my version
> of generic module needs this function - I decided to publish it at first :)
>
> Also - you said there is nobody who wants to work on sonic integration -
> now you have :D

Yes, this is just great, thank much for that.
Here are my remarks.

Since Bill has proposed to integrate libsonic,
I'd say the first step would be to grab sonic src and put it under
e.g. src/libs/sonic

The next step would be to add sonic (rate) support to spd.

Sonic functionality shall be generic to all modules, i.e. I do not
expect any modifications in ivona.c,
but rather in module_utils.c.
For those modules that do not provide a rate change it shall be called
constantly
and for the modules which supports it, it shall be some criteria when
this function shall be called,
E.g. it shall be called when people want to listen 3.5X rate.
However for that we need a little bit more coding, e.g. provide
absolute rate to the apps,
or calculate it internally based on min/max rate module settings.

Function spd_audio_effect you have implemented should probably pass
AudioTrack instead of samples.

Then we can apply pitch settings. However we need some modifications there.
At the moment source code just flooded with #ifdef HAVE_SAMPLERATE

I'm not sure about a contract, how can we control it from speechd API?