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

Wu Fengguang fengguang.wu at intel.com
Fri Jun 5 06:28:29 CEST 2009 

On Thu, Jun 04, 2009 at 08:29:25AM +0200, Takashi Iwai wrote:
> 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?

The codecs I tested - G35/G45/GM45 - does not support the channel-slot
assignment. I guess future hardwares may support that.

Thanks,
Fengguang

> 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...
>
> > -----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.
> > > 
> > > 
> > > 
> > > 
> > >
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