Re: [Libvisual-devel] VisAudio overhaul proposal.

[Dennis S. <sy...@yo...>]

On Tue, 2005-03-08 at 15:15 +0200, Vitaly V. Bursov wrote:
> I think it would be nice to have an "audio filter" stack, tree or
> whatever and some "control" api (on/off, value from a range)

Audio filter stack ? what do you mean ?

> > 	Audio energy registration, calculation (already done).
> > 	normalized spectrum (logified).
> > 	Internally, use floats to represent audio. (from 0.0 to 1.0 or -1.0 to
> > 1.0 ?)
> > 	Use floats to represent the spectrum (from 0.0 to 1.0)
> > 	Have conversion code to go from short audio to float.
> there's K7 (semi) optimized verions within scivi

That is neat!, will look at it.

> I don't think it's good idea to use fixed single frequency...
> Anyway, does it matter?

Well the more we generalise the less the Actor plugin has to think.
And keep in mind, more than one actor can connect to one VisAudio.

> > 	How large do we want our buffers ?
> Large buffer means high latency. Small buffer (upto 64 bytes) measns low
> latency.

True, how many samples of how many bytes are pushed out a second ? :)

> Personally I believe buffer should be variable in size. It will be
> useful if we're going to use "audio filters".

What do you want to do with these audio filters ?, what we could
also do is take a non naieve approach, where a processed VisAudio
is rather a VisAudioPool that negotiates with the different
actors. However this does not make things easier, and I think we should
keep goal focused, proof me wrong tho :)

> What about audio frame timestamping?

GOOD one, putting that on the list. We need that anyway, to use it for
the Beat Detection. Maybe we should keep a general sample history,
of which a [3][size] buffer can be derived ?

> How to guarantee (do our's best) to synchronize video with audio?
> Hard video processing requires some time...

This is hard, I haven't put much thought into this, but timestamping
should help right ? :)

Cheers,
Dennis