Re: [linux-audio-user] Java Ambisonic b-format player

From: Jesse Chappell <jesse@email-addr-hidden>
Date: Sun Dec 04 2005 - 01:57:40 EET

On 12/3/05, John Ouzts <jouzts@email-addr-hidden> wrote:

> The success of this player has created a problem for me, however. I
> normally feed the S/PDIF output of my RME Digi96 PAD into my Panasonic
> SA-XR70 digital receiver. Now I need to feed at least four channels,
> not just a stereo pair, to the receiver, which has HDMI inputs for
> multi-channel for DVD-Audio players. (Ever heard of a sound card with
> an HDMI output?) My current theory is that I need to use the ADAT 8
> channel output of the Digi96 to feed some sort of external converter
> that will make a 4 channel MPEG2, DTS or AC3 feed into a single S/PDIF
> or Toslink cable for me, since I don't want to go to analog only to be
> converted to digital again to feed the Panasonic's digital power amps.

Well, you can also convert the multichannel (4 in your case) output in
software to AC3 using ac3jack ( http://essej.net/ac3jack/ ). That is
if the java app can be made to use JACK. The Java sound stuff appears
to use ALSA, so you might have to use the alsa-jack plugin in some
fashion to do this. Let the ALSA masters comment more on that one.

ac3jack uses the ffmpeg lib to do the AC3 encoding, and the quality is
OK, not stellar.
If you are interested in this route, I have some implementation
updates that make it easier to use and more efficient (for streaming
directly to a spdif output in realtime). Let me know, and I'll
expedite that project.

As a PS, I found the following comment in the docs for javasound that
carelessly lump JACK into the category with all the other sound
servers.
[ Excerpted from http://www.jsresources.org/faq_misc.html#no_daemons ]
    "In Florian's and my opinion, mixing daemons like artsd, esd,
JACK, rplay, NAS, yiff, ... are hacks
      that work around a shortcoming of the device drivers. We feel
that mixing should be done
      either by the soundcard hardware or in software by the device driver."

They clearly don't understand the full implications of what JACK is :)

jlc
Received on Sun Dec 4 04:15:05 2005

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