[pulseaudio-discuss] [WIP] Passthrough support

[Arun Raghavan]

On Tue, 2011-03-15 at 01:36 +0530, Arun Raghavan wrote:
> On Mon, 2011-03-14 at 14:57 -0500, pl bossart wrote:
> > >> Other things I noticed: the volume is much higher in passthrough mode,
> > >> maybe we need to find a way to set the volume on the headset to match
> > >> the volume used for PCM. Also I heard some high-frequency modulations,
> > >> typically coding noise, maybe there's still something fishy during the
> > >> mp3 decode part.
> > >
> > > I get this sort of thing on, as far as I can tell, one channel as well.
> > > I figured the decoder on the CSR chip wasn't that great.
> > 
> > Looks to me that the quality is slightly worse than with the initial
> > patches, but it's of course a very subjective assessment since I need
> > to reinstall pulse/gstreamer to check the differences instead of doing
> > an A/B test. Can you check and make sure the payloader doesn't
> > skip/change any bytes? If you dump what is actually sent to the
> > headset and compare to the initial file, you shouldn't have any
> > deltas.
> 
> Yep, I did that before I pushed out the code (verified a few frames by
> hand, but I'll do something more extensive in the morning). I'm still
> seeing the setconf error, but now that it's at least clear it's
> connecting to the wrong seid, I'm hoping to get this fixed.

Turns out this was very likely a bluez problem. I've sent in a patch [1]
that at least gets things working for me. I also see the high-pitched
pops and clicks (these very definitely weren't there with your
payloader) - should get that pinned down before long.

I pushed your change along with a fix for the assert you saw to my tree
as well.

Cheers,
Arun

[1] http://thread.gmane.org/gmane.linux.bluez.kernel/11715