On Tue, Nov 30, 2010 at 1:59 AM, Clemens Ladisch <clemens@email-addr-hidden> wrote:
> Mark Rages wrote:
>> I would like to play some audio sampled at 96 kHz. But I don't appear
>> to have this enabled:
>>
>> markrages@email-addr-hidden-desktop:~$ cat /proc/asound/card*/codec#0 | grep rates
>> rates [0x7f]: 8000 11025 16000 22050 32000 44100 48000
>> rates [0x60]: 44100 48000
>> rates [0x7f]: 8000 11025 16000 22050 32000 44100 48000
>>
>> But the same file lists "Codec: Analog Devices AD1986A". I looked up
>> the datasheet, and the AD1986A is able to support 96 kHz sampling with
>> "Double rate audio".
>
> "Double rate audio" is a special AC'97 mode that reuses some surround
> channels to transport more samples for the two front channels. (AC'97
> doesn't have enough bandwidth for more channels at 96 kHz.)
>
> HDA assumes that all DACs can run at the same sample rate. However, it
> looks as if this chip is just an AC'97 core that also has a HDA frontend,
> so it cannot run all DACs at 96 kHz, so it completely disallows 96 kHz
> when connected to a HDA controller.
>
> (All HDA controllers would support 96 kHz playback, but as for AC'97,
> only the Intel driver has double-rate support.)
>
Excellent answer. Thank you.
Regards,
Mark
markrages@email-addr-hidden
-- Mark Rages, Engineer Midwest Telecine LLC markrages@email-addr-hidden _______________________________________________ Linux-audio-user mailing list Linux-audio-user@email-addr-hidden http://lists.linuxaudio.org/listinfo/linux-audio-userReceived on Tue Nov 30 20:15:07 2010
This archive was generated by hypermail 2.1.8 : Tue Nov 30 2010 - 20:15:07 EET