[pulseaudio-discuss] observations using 9.15 test2

Lennart Poettering lennart at poettering.net
Sun Feb 15 11:46:44 PST 2009

On Sun, 15.02.09 19:21, Florian Demmer (florian at demmer.org) wrote:

> i installed test2 to get spdif working primarily, but also found this
> behavior:
> channel order/map wrong with module-detect:

module-detect shouldn't really be used unless you are running PA
on systems where HAL is not supported. That said, it would be good if
it work properly on normal systems as well. 

> - when using module-detect hw:0 is detected with 6channels. when playing
> 2ch audio, rear-left and rear-right are used (tested by muting one
> channel after the other)

module-detect tells the ALSA modules to open the device in raw
(i.e. hw:xxx) mode. Which is a really bad idea. Fixed in ra571565.

> - when using module-hal-detect front:0 is detected which is only 2ch

Which is the right thing if you set default-sample-channels to 2.

> - when manually configuring hw:0 with the following line:
> load-module module-alsa-sink device=hw:0 channels=6
> channel_map=rear-left,rear-right,front-left,front-right,front-center,lfe
> front-left and front-right are used correctly

The correct way to do this is this:

"load-module module-alsa-sink device_id=0 channels=6"

or something like this.

> about the new profile detection:
> - with hal-detect (detect lists 0 cards, that's by design i guess?)

list 0 cards? what do you mean? Where does it list 0 cards?

> - why is there no "output-analog-surround-51+output-iec958-stereo"!?
> only with input-iec958!

We only check for one output plus one input. We don't check for two
simultaneously usable outputs.

Some cards do support using spdif and analog at the same time
independantly. Some cards do not, however do support multiple opens,
resulting in mixed audio. Since we cannot distuingish these two cases
we only access the card for playback in one way at a time.

Quite frankly I don't think allowing SPIDF and analog output at the
same time would be of much realistic use, however it would confuse the

> - i can configure analog and digital output manually using:
> load-module module-alsa-sink device=surround51:CARD=Intel,DEV=0
> sink_name=analog_out
> load-module module-alsa-sink device=iec958:CARD=Intel,DEV=0
> sink_name=digital_out
> .. and both outputs work (at least in stereo)

Lucky you.  That works on your card, but won't work on others. And on
even other cards this will work but have a different effect than you
might expect (i.e. both sinks are always mixed). See above.

> - also why is the digital out only detected as 2ch? (manually configuring
> to 6ch results in error)
> .. is this an alsa limitiation? pulseaudio detection problem?
> (hardware?)

SPDIF PCM is generally only Stereo. Multichannel audio is only
possible when passing encoded audio (AC3...) over SPDIF.

> module-combine does not work anymore:
> E: module-combine.c: failed to parse module arguments
> E: module.c: Failed to load  module "module-combine" (argument:
> "sink_name=combined master=analog_out slaves=digital_out"):
> initialization failed.
> E: main.c: Module load failed.
> E: main.c: Failed to initialize daemon.
> configured with:
> load-module module-combine sink_name=combined master=analog_out
> slaves=digital_out
> (other sinks as above)
> .. did the parameterlist change?

Hmm, no, not really. Do you know if that worked in .13?

Thanks for testing!


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

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