[alsa-devel] Juli@ ICE1724 and 24 bit audio

[Demian Martin]

Pavel:
Thanks for all your help and work on this project.

I'm using the Juli@ card because it supports 176.4KHz. The only other
candidates are much more expensive and bring their own problems.

I'm using Xine set for dolby/dts passthrough which seems to send the audio
data at its native rate. The resampling is bypassed (Dolby Digital would be
trashed otherwise). 

I will try playing the files from the command line when I am next in front
of the system, tomorrow.

This is the Asound.conf:
Asound.conf  (/etc)

pcm.asym_spdif {

       type asym

       playback.pcm "plughw:0,1"

       capture.pcm "plughw:0"

}


pcm.!default asym_spdif

Demian Martin
PDS

> -----Original Message-----
> From: Pavel Hofman [mailto:pavel.hofman at insite.cz]
> Sent: Monday, February 09, 2009 12:27 PM
> To: Demian Martin
> Cc: alsa-devel at alsa-project.org; pavel.hofman at insite.cz
> Subject: Re: [alsa-devel] Juli@ ICE1724 and 24 bit audio
> 
> Demian Martin napsal(a):
> > I have the driver working fine for sample rates from 44.1K to 196K
> however
> > it seems to be truncating the data to 16 bits. I wasn't sure until I
> started
> > testing with the HRx 176.4K 24 bit files that have an embedded HDCD flag
> in
> > the LSB. The files work OK on Windoze systems (with a lot of low level
> > settings tweaked) and they play fine but the flag isn't detected by a
> system
> > that can detect them. Further looking at the data stream with a scope it
> > seems the last 8 bits aren't changing. Is there anything I can do to
> control
> > the driver to confirm this problem or change the playback settings to
> make
> > it work?
> >
> >
> 
> How do you play the files? Do you use the hw or plug:hw device? IIRC,
> the standard-setup dmix resampler is 16-bit only.
> 
> I did tests with SPDIF OUT/IN and found it bit-perfect, for 24bit too.
> 
> Regular ICE1724 cards do not output 176.4kHz SPDIF, only 88.2kHz. But
> Juli is not affected by that bug.
> 
> Regards,
> 
> 
> Pavel.