Re: Re: CMI8738-MC6 surround40 plugin on 4 SP systems]

[Takashi Iwai <tiwai@suse.de>]

At Tue, 4 Nov 2003 19:35:37 -0500,
Marcel wrote:
> 
> * Takashi Iwai (tiwai@suse.de) wrote:
> > At Fri, 31 Oct 2003 12:39:18 -0500,
> > Marcel wrote:
> > > 
> > > * Takashi Iwai (tiwai@suse.de) wrote:
> > > > At Thu, 30 Oct 2003 12:42:39 -0500,
> > > > Marcel wrote:
> > > > > 
> > > > > 
> > > > > I've been trying to finetune my cmipci for several weeks now.   And this is
> > > > > the best way I've been able to get transparent operation with various audio
> > > > > material: stereo, mono, 4.0, 5.1.  The main problem being no surround sound
> > > > > iif "Exchange DAC" setting was not set, and sound on the rear speakers only
> > > > > if it was.
> > > > 
> > > > ah, this might be true.
> > > > does it happen both on 4.0 and 5.1 outputs?
> > > > i don't remember that it's necessary for 5.1 at the last time i
> > > > tested.
> > > 
> > > With surround40 plugin, 4 speakers, yes it's needed for both 4.0 and 5.1
> > > material.  Applications such as mplayer or xine will remix 5.1 material to
> > > 4 channels.  For 6 speakers systems, I really don't know.
> > 
> > could you try surround51 and check whether it somehow works?
> 
> I tried.  It's ok with stereo material.  With 5.1 material, xine refuses to
> use it because I have 4 speakers only.  Mplayer will use it but 2 channels
> only.  Seems there is no way to force applications to use 6 channels when I
> got only 4 speakers.  "Mplayer -ao alsa9:surround51 -channels 6" gives an
> error.  And I don't have any 5.1 sound file in wav or mp3 format for aplay
> or alsaplayer to try.  Never been able to locate some.  But I suspect it
> will fail too.  I think you'll need someone with 6 physical speakers to have
> this verified.
> 
> > 
> > > > perhaps we should simply remove this control from user and handle
> > > > internally for the MC6 chip.
> > > > 
> > > 
> > > I agree.  Its usage is confusing and may results in improper operation
> > 
> > how about the attached patch?
> 
> Great job!  If I understand how it works, the mixer setting is gone for the
> 8738-MC[46] chipsets, and still there for plain 8[37]38.  Works very well
> here, no more confusion.  Multi-channel sound is enabled automatically. 
> Front material is always in front, and surround material always in rear.
> 
> Adjustment is unconventional, but straightforward for surround material:
> 
> 1 - Master at 0.
> 2 - Adjust rear volume with PCM near maximum required.
> 3 - Increase front volume with Master to obtain rear-front balance.
> 4 - Decrease PCM to lower volume on all 4 speakers.
> 
> Unusual, but that's the way its operates.

hmm, it seems there is something wrong in the SB-style mixer code.
perhaps we need to put some delay.

anyway, the changes are now applied to cvs.

> One more control that deserves to go in mixer: "3D Control Switch".  It
> doesn't work, never did, does nothing at all.

well, it works for the older model.
it's a 3D-enhancement and not really 3d thing.
i'm not sure whether this doesn't work for all new models (> 037), so
it still remains there.  we can remove it later after confirming that
all new chips don't support this.


Takashi


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