[pulseaudio-discuss] [PATCH 12/13] loopback: Validate the rate parameter

[Tanu Kaskinen]

On Fri, 2015-12-18 at 09:10 +0100, Georg Chini wrote:
> On 18.12.2015 09:07, Tanu Kaskinen wrote:
> > Good that you asked, because it got me thinking about this a bit more,
> > and I'm starting to think that it's not worth it after all. Adding
> > another resampler would in many situations mean that the audio would
> > get resampled twice (or three times, if we count the source ouput
> > resampler, but that's beside the point). That doesn't seem like a good
> > idea due to the extra cpu load.
> >
> > Something that could be considered is to have separate "nominal rate"
> > and "real rate" stored in pa_sink_input, so that the small rate tweaks
> > that module-loopback applies wouldn't be visible where they don't need
> > to be visible, and pa_sample_rate_valid() wouldn't have to accept rates
> > higher than PA_RATE_MAX.
> >
> > (If you anyway want to see code that does resampling, grep for
> > "pa_resampler_run".)
> 
> Wouldn't it avoid additional resampling when you set the sink_input rate
> to the sink rate?

Yes, but I fear that would require replicating the
pa_sink_input.render_memblockq buffer and some of its rewinding logic
in the loopback module to deal with stream moves. I don't think it's
worth it.

-- 
Tanu