[pulseaudio-discuss] Channel Mapping

Lennart Poettering lennart at poettering.net
Mon Jun 9 11:34:40 PDT 2008

On Mon, 09.06.08 19:28, Another Sillyname (anothersname at googlemail.com) wrote:

> Hi
> I've read from assorted sources that accurate channel mapping of a AC3
> stream through a A52encode to then produce output just doesn't work
> correctly?
> Is this still the case or is there a method to be able to work out
> which channel in the original stream should map to which channel on
> the output then be able to configure pulseaudio to output correctly?
> At the moment the front left/right appear to be coming out the rear
> and the centre seems to be coming from the left/right front
> speakers........rear and woofer sounds don't appear at all!!

I am not sure about your specific setup. But PA allows you to specify
an explicit channel map for an alsa sink. Also, PA takes negotiates
the channel map with its clients.

So, which client are you using? If you access PA through ALSA, then I
guess I can only say I am sorry: ALSA does not support negotiating
channel maps. For ALSA you need to *know* the channel map of a


Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net         ICQ# 11060553
http://0pointer.net/lennart/           GnuPG 0x1A015CC4

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