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

[Vedran Miletić]

Yeah, ALSA's documentation is actually quite lacking on many fronts
and is mostly scattered around various wikis and mailing lists.

But I guess it is as it is, complaining about it won't fix it.

On 2/9/09, Demian Martin <demianm_1 at yahoo.com> wrote:
> Thanks, I'll try that. I guess this e-mail will serve as more documentation
> on that feature (bug). I had not seen that factoid anywhere.
>
> Demian Martin
> PDS
>
>
>> -----Original Message-----
>> From: Vedran Miletić [mailto:rivanvx at gmail.com]
>> Sent: Monday, February 09, 2009 1:39 PM
>> To: Demian Martin
>> Cc: Pavel Hofman; alsa-devel at alsa-project.org
>> Subject: Re: [alsa-devel] Juli@ ICE1724 and 24 bit audio
>>
>> The plughw part is what makese it resample to 16-bit. You should just use
>> hw.
>>
>> On Mon, Feb 9, 2009 at 10:29 PM, Demian Martin <demianm_1 at yahoo.com>
>> wrote:
>> > 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.
>> >
>> > _______________________________________________
>> > Alsa-devel mailing list
>> > Alsa-devel at alsa-project.org
>> > http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
>> >
>>
>>
>>
>> --
>> Vedran Miletić
>
>


-- 
Vedran Miletić