[mythtv-users] Re: MythTV & Jack

[Ross Campbell]

> On 9/7/05, Mark Knecht <markknecht at gmail.com> wrote:
> >    Anyone here using Jack as your audio interface for MythTV? If so,
> > would you mind sharing how you did it?

Mark,

I suspect that few of the people here know what jack is and why they
would even want to try to get this working.

As a musician, I'm interested in jack for MIDI-in/out/through because
of it's ultra-low latency, but far and away the best MIDI tools are
currently on Windows and MacOS :( . Most people would never notice or
need ASIO-like ultra low latency sound, but when you use your computer
as a software synth for an external MIDI keyboard... trust me - 75
milliseconds delay from keypress to sound is unacceptable.

Jack FAQ: http://jackit.sourceforge.net/docs/faq.php

How does JACK compare to ALSA:

ALSA: both a HAL and a user-space library for audio under Linux. ALSA
is used to provide the default audio i/o driver for JACK. ALSA is a
very powerful audio API, but it does not provide a callback-based API
or offer any solutions for inter-application communication, though it
has been discussed and is theoretically possible.


So, the real question is:  Why would a mythtv user/developer care
about using JACK for sound in MythTV?

The main benefits for MythTV I can see would be to have access to a
JACK plugins for sound enhancement. (if anyone else sees other
benefits I missed, please do tell :)

I could envision taking advantage of LADSPA plugins (
http://www.ladspa.org/ ) to provide graphic equalizers, different
sound environment settings (living room, concert hall, outdoors,
etc...), extra stereo separation, reverb?, high and low filters, noise
cancellation using an external mic?, and the list goes on.

If many mythtv systems eventually have a MIC and camera for mythPhone
use, I could also see a desire to have more audio/video processing
abilities - maybe the ability to have mythPhone in a PiP with your
buddy while you watch the same show? Maybe the ability to filter voice
out of music files so that people could sing karaoke over the real
music?

Anyway, JACK could be interesting for mythtv - I'm eager to know how
far anyone else gets.

-Ross