External Sound Card

External Sound Card

[John Dey]

I am looking for a external sound card that has spdif (7.1) 
functioning.  The driver Soundblaster nx usb seems like it is under 
active development.  The alsa documentation page says that spdif is not 
working.  Is the documentation page out of date or is someone working 
on that capability?  If spdif capability is not in the near future, can 
someone suggest a sound device (spdif capable) that I could look at.  
Thanks.

John 

Re: External Sound Card

[Clemens Ladisch]

John Dey wrote:
> I am looking for a external sound card that has spdif (7.1) 
> functioning.

7.1 encoding is done in software, not in hardware.
I don't know of any 7.1 encoder for Linux.

ALSA has the a52 plugin that can do 5.1 encoding for any sound
card that has SPDIF, but you'd have to compile it with the ffmpeg
library to get it to work.


HTH
Clemens

Re: External Sound Card

[John Dey]

Clemens,

Thanks for your response.  The 5.1 or 7.1 capability is not as 
important to me as having 6 or 8 independent jack channels  to connect 
4 or 8 channels from an application (ambiosonics from aeolus).  Without 
adding the a52 plugin would I see more than 2 outputs in qjackctl?  
With the plugin would I see 6 outputs?


On Oct 30, 2007, at 1:19 PM, Clemens Ladisch wrote:s

> John Dey wrote:
>> I am looking for a external sound card that has spdif (7.1)
>> functioning.
>
> 7.1 encoding is done in software, not in hardware.
> I don't know of any 7.1 encoder for Linux.
>
> ALSA has the a52 plugin that can do 5.1 encoding for any sound
> card that has SPDIF, but you'd have to compile it with the ffmpeg
> library to get it to work.
>
>
> HTH
> Clemens
> _______________________________________________
> Alsa-devel mailing list
> Alsa-devel@alsa-project.org
> http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
>

Re: External Sound Card

[Clemens Ladisch]

John Dey wrote:
> Thanks for your response.  The 5.1 or 7.1 capability is not as
> important to me as having 6 or 8 independent jack channels  to connect
> 4 or 8 channels from an application (ambiosonics from aeolus).  Without
> adding the a52 plugin would I see more than 2 outputs in qjackctl?

No; SPDIF has been designed to transport two channels.  The only way to
get the data of more channels through SPDIF is to compress it with some
algorithm like AC-3/DD/DTS.

> With the plugin would I see 6 outputs?

Yes.


HTH
Clemens