audio device settings & downmixing

[cybmole]

could someone please explain how vlc audio device 5.1 settigns interacts with stereo speakers / stereo settigns in windows vista.

I have VLC set to use waveout, so when it encouters an AVi or MKV with a choce of audio steams then it defaults to the 5.1 oprion, not the stereo option.
But I only have stereo speackers and only use analogue out, not HDMI or SPDIF.
but in most cases, the movie still sounds fine, which suggests that downmixing is happening somewhere. I can only recell one instance ( the movie CUBE) where I had to deliberately select sereo output in order to hear dialogue properly. I think that movie file had only 5:1 DTS, not normal 5:1 , which may be why that one behaved ofddly

in fact, for most movies, the sound seems better on the 5:1 settings than on the stereo setting ??? - though occasionaly in quiet dialogue sections, I notice a faint low frequence noise on the soundtrack - like the noise which video/audio interference in VHS playback would sometimes cause

I know that most actual DVD players, and also the PowerDVD software, will automatically downmix 5:1 into 2 channel when setup for 2 channel output ( that may even be part of the DVD spec) - so does VLC do the same ?

PS It seems from searching here that I can't make audio device stereo the default unless I also use directx in place of waveout. I've not done enough listening tests to determine if directx and wave out sounds any different - I use waveout as my default because of a different bug I encountered on a different PC a while back with VLC+directX (an audio starving bug with some avi files).

I was also searching through VLC options for an LFE filter, like the one in powerdvd, which coud limit/eliminate subsonic noise (intended for dedicated woofers) from the downmixed stereo audio track, is there one anywhere ?

[VLC_help]

It seems from searching here that I can't make audio device stereo the default unless I also use directx in place of waveout.

Waveout audio output module doesn't have option to force the output. It should use same option as your Windows Speaker setup is set.

I was also searching through VLC options for an LFE filter, like the one in powerdvd, which coud limit/eliminate subsonic noise (intended for dedicated woofers) from the downmixed stereo audio track, is there one anywhere ?

VLC doesn't have filter like that.

[cybmole]

It seems from searching here that I can't make audio device stereo the default unless I also use directx in place of waveout.

Waveout audio output module doesn't have option to force the output. It should use same option as your Windows Speaker setup is set.

I was also searching through VLC options for an LFE filter, like the one in powerdvd, which coud limit/eliminate subsonic noise (intended for dedicated woofers) from the downmixed stereo audio track, is there one anywhere ?

VLC doesn't have filter like that.

OK thanks - can you explain what downmixing takes place when 5:1 is active, with only stereo sound setting in windows ?

[VLC_help]

I would guess the exact algorithm is in http://git.videolan.org/?p=vlc.git;a=bl ... ea;hb=HEAD