[alsa-devel] ALSA patch Nvidia 8 channel hdmi audio

Thu Jun 4 08:29:25 CEST 2009

At Thu, 4 Jun 2009 14:05:52 +0800,
Wei Ni wrote:
> 
> Yes, my test wav file is from Windows.
> 
> I had used different player to test with my test wav file.
> The mplayer has no mapping problem, but other players map channels
> wrong.
> As you said, it seems that is caused by the difference of the ALSA and
> Windows.

I guess mplayer corrects the channel mapping automatically.

> Unfortunately, our nvidia codec doesn't support channel-slot assignment
> yet.

OK.

> How could we fix this problems, do you have any suggestions?

It's a bit difficult issue right now.  Usually we could "fix" the
channel mapping in alsa-lib configuration.  But, HD-audio has currently
a single alsa-lib configuration, and others may use the right channel
mapping.

I don't remember how is the case of Intel HDMI...  Can anyone check?
If it also suffers from the same problem, the channel conversion rule
can be put in hdmi configuration statically as a temporary workaround.

We need a proper API to inform / change the channel mapping, anyway.
Then it'll be better adjustable...

thanks,

Takashi

> Thanks
> Wei. 
> 
> -----Original Message-----
> From: Takashi Iwai [mailto:tiwai at suse.de] 
> Sent: Wednesday, June 03, 2009 7:02 PM
> To: Wei Ni
> Cc: Alan Alan; Peer Chen; Marek Vasut; alsa-devel at alsa-project.org
> Subject: Re: [alsa-devel] ALSA patch Nvidia 8 channel hdmi audio
> 
> At Wed, 3 Jun 2009 18:25:09 +0800,
> Wei Ni wrote:
> > 
> > Hi, Alan
> > 
> > I reproduced this problems with speaker-test. The channels are wrong
> > mapped.
> > 
> > It's strange that if use mplayer to run, it looks ok.
> > 
> > I'm looking this problems, and try to find the root cause.
> 
> Actually, from historical reasons, the standard ALSA channel mapping
> for 5.1 is
>     FL/FR/RL/RR/C/LFE
> while Windows sets FL/FR/C/LFE/RL/RR.  If you play a WAV file assuming
> the latter channel assignment, it will be played like that.
> 
> Does the nvidia codec support channel-slot assignment (verb 0x734)?
> If yes, we can assign the channels freely to fix this...
> 
> 
> thanks,
> 
> Takashi
> 
> 
> > 
> >  
> > 
> > Thanks
> > 
> >  
> > 
> > From: Alan Alan [mailto:alanwww1 at gmail.com] 
> > Sent: Wednesday, June 03, 2009 4:00 PM
> > To: Wei Ni
> > Cc: Marek Vasut; alsa-devel at alsa-project.org; Peer Chen
> > Subject: Re: ALSA patch Nvidia 8 channel hdmi audio
> > 
> >  
> > 
> > Hello Wei !
> > 
> > Thanks for replying.
> > I tested it with speaker-test and xbmc babylon. Both had problems with
> > channel mapping.
> > I used this command:
> > 
> > speaker-test -Dhdmi -c6
> > or
> > speaker-test -Dhdmi -c8
> > 
> > alternatively you could try 
> > 
> > speaker-test -Dhw:0,3 -c6
> > 
> > 
> > I had to rund Xorg first and have the command from an xterm, becasue
> > from a normal terminal it would not work.
> > I think that is normal as a limitation of hdmi.
> > 
> > What about the support for 24bits 192khz sound ?
> > 
> > speaker-test -Dhdmi -c6  -r192000 does not work.
> > 
> > Thanks for working on this.
> > 
> > 
> > 
> > 
> > 
> > 2009/6/3 Wei Ni <wni at nvidia.com>
> > 
> > Hi, Marek and Alan
> > I'm a Nvidia engineer and develop this patch file.
> > 
> > I used mplayer to test. The channels are mapped good.
> > Running mplayer -ao alsa:device=hw=0.3 6ch.wav
> > 
> > I tried to use speaker-test to test, but I can't get the hdmi device
> > name.
> > I used speaker-test -Dsurround51:NVidia -c6, the sound output from the
> > analog jack.
> > Which device name should I use?
> > 
> > I use aplay -l, it show
> > **** List of PLAYBACK Hardware Devices ****
> > card 0: NVidia [HDA NVidia], device 0: ALC1200 Analog [ALC1200 Analog]
> >  Subdevices: 1/1
> >  Subdevice #0: subdevice #0
> > card 0: NVidia [HDA NVidia], device 1: ALC1200 Digital [ALC1200
> Digital]
> >  Subdevices: 1/1
> >  Subdevice #0: subdevice #0
> > card 0: NVidia [HDA NVidia], device 3: NVIDIA HDMI [NVIDIA HDMI]
> >  Subdevices: 1/1
> >  Subdevice #0: subdevice #0
> > 
> > Thanks
> > Wei.
> > 
> > 
> > -----Original Message-----
> > From: Marek Vasut [mailto:marek.vasut at gmail.com]
> > Sent: Wednesday, June 03, 2009 8:01 AM
> > To: Alan Alan
> > Cc: alsa-devel at alsa-project.org; Wei Ni
> > Subject: Re: ALSA patch Nvidia 8 channel hdmi audio
> > 
> > On Wednesday 03 of June 2009 00:30:04 Alan Alan wrote:
> > > Thank's for the info.
> > > How can i contact him ?
> > 
> > He and alsa-devel mailing list are both in CC already, please preserve
> > them
> > there or fix your mailer.
> > >
> > >
> > > 2009/6/3 Marek Vasut <marek.vasut at gmail.com>
> > >
> > > > I'm not the author of the patch, CCing alsa-devel and the original
> > > > author.
> > > >
> > > > On Tuesday 02 of June 2009 23:58:26 Alan Alan wrote:
> > > > > Hi Marek !
> > > > >
> > > > > I just read your emailing with nvidia devs about alsa supporting
> 8
> > > >
> > > > channel
> > > >
> > > > > lpcm over hdmi.
> > > > >
> > > > > I checked it out an i have to tell it is working awsome, except
> > for a
> > > > > few bugs:
> > > > >
> > > > > The channels are wrong mapped. Running a speakertest -Dhdmi -c6
> > gives
> > > > > the following result (first where it should sound)
> > > > > FL - FL
> > > > > C - RL
> > > > > FR - FR
> > > > > RR - LFE
> > > > > RL - C
> > > > >
> > > > > The other thing i realized that playback is limited to 16 bits
> 48
> > khz.
> > > > > I think the minimum which is supported by nvidia hardware is
> > 24bits 96
> > > > > (or 192) khz.
> > > > > Why not ?
> > > > >
> > > > > Could you contact the devs as i don't know how to reach them.
> > > > >
> > > > > ps.: Mybe my build methot was not 100% ok ? I used 1.020 Alsa
> with
> > the
> > > > > oatched nvidia.c file. Anyway the amplifier shows multichannel
> > LPCM and
> > > > > that's great news.
> > 
> > 
> > 
> > 
> >
> ------------------------------------------------------------------------
> > -----------
> > This email message is for the sole use of the intended recipient(s)
> and
> > may contain
> > confidential information.  Any unauthorized review, use, disclosure or
> > distribution
> > is prohibited.  If you are not the intended recipient, please contact
> > the sender by
> > reply email and destroy all copies of the original message.
> >
> ------------------------------------------------------------------------
> > -----------
> > 
> >  
> > 
> > _______________________________________________
> > Alsa-devel mailing list
> > Alsa-devel at alsa-project.org
> > http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
> > 
> 