[pulseaudio-discuss] Support for audio envelopes

[Tanu Kaskinen]

On Thu, 2012-07-19 at 14:35 -0300, Flavio Ceolin wrote:
> Hi floks,
> 
> I'm trying to implement support for audio envelopes on pulse audio and
> several doubts come to me. First i've checked that we already had
> support for it, but it was removed. So my first doubt is, there were
> problems with this code or it was removed just because no one was using ?

There were problems with the code. I don't remember what exactly was
broken, though. But at least I didn't like the concurrency handling: I
really dislike doing inter-thread communication by using shared
variables. Instead, message passing should be used, in my opinion.

> For purpose tests, i've re-applied the old code (doing just the necessary
> things to compile). So far so good, it was pretty easy. Now i've other
> questions:
> 
> 1) Should evenlopes be applied in source too, or just in the sink ?

Probably also in sources, but I think you don't need to care about
sources at this point. Once it's done for sinks, then we can copy it to
sources.

> 2) How an application should use this code, AFAIK this code is not being
>    exported.

What's your use case? If we are talking about sink volume ramping, I
don't see the need for a client interface at all, because it should be
done automatically by the server.

> Besides these points, i would enjoy any kind of tip/idea related with
> this subject.

You'll need to keep rewinds in mind. That is, if a rewind affects the
envelope, you need to update the envelope state accordingly.

-- 
Tanu