[pulseaudio-discuss] Does pulseaudio resample when source and sink sample rate / bits are identical?

Colin Guthrie gmane at colin.guthr.ie
Sat Jul 16 14:43:08 PDT 2011

'Twas brillig, and Joshua Redstone at 16/07/11 21:35 did gyre and gimble:
> Yeah, I'm using TCP because the source audio is generated on a different
> machine from the one that has the USB sound card.

OK, well I guess that explains that :D

> I have a laptop with an internet music player on it, and I have a settop
> PC (pretty wimpy)  that has a USB audio card connected to my stereo.
> I run the music player on my laptop because I want to control the audio
> from my laptop, and running the player on the settop and using vnc/nx is
> way to slow.

Yup that all makes sense :)

> So maybe the pulseaudio isn't doing any resampling work and is just
> churning to copy bytes around.  Is there any optimizations I should have
> set up?  In my /etc/pulse/default.pa <http://default.pa> I have:
>    load-module module-native-protocol-tcp
> auth-ip-acl=; port=8675

Seems fine to me.

> On the whole, I'm pretty happy with the setup.  I'm trying to become an
> audio-snob :) and so wanted to make sure all my audio bits from the
> music player were getting to the sound card
> without unnecessary transformations.

You can check with "pacmd list-sink-inputs" It should tell you the
resample method chosen for any given input. There was a bug that
prevented this from being cleared out so the info might be a bit bogus
at times for some streams, but I don't think that problem will show up.

It should say:

	resample method: (null)

Or similar if no resampling is being done.



Colin Guthrie

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