[pulseaudio-discuss] digital devices (spdif)

[Jens Peters]

Hello there,

Before I begin I want to say that pulseaudio is really one of the coolest 
peaces of software on Linux I have seen in the last years. It took me 
some time to get the whole picture and where to place pulse exactly, but 
once I got it the setup was quite easy (using Ubuntu  8.10 with Gnome and 
a Vanilla KDE4 and of course pavucontrol). For the record, I'm using an 
Intel HDA (Realtek ACL889A) card onboard and I use the digital output, 
connected to and external AC3/DTS decoder (Teufel decoderstation3) and 
headphones/microphone in the front.

I wonder actually if there are any decisions made regarding AC3/DTS pass-
through and may be life encoding. The only outsider regarding sound 
output is AC3/DTS where I talk directly to alsa (mplayer -ao alsa -ac 
hwac3,hwdts,). It would be very cool if I could do something like mplayer 
-ao pulse -ac hwac3,hwdts,. The stream would show up in pulse control and 
I can imagine that even moving the stream to another (digital) output 
could realized. Obviously any other normal output on a digital output 
would have been muted/discarded when pass-through output is started (At 
the moment I have to make sure that there is no active output before 
starting pass-through output). A second pass-through stream should also 
be muted/discarded until the output is free again. (Actually I guess this 
is the same work-flow as on Windows). I read somewhere that a big 
showstopper for this is the detection of digital devices. Why not just 
adding a module parameter for that, because I guess that most users, 
including me, already have to add the digital output by hand, so e.g.: 
load-module module-alsa-sink device=iec958:0 capabilities=spdif,..
until hal/alsa gives some more information.

Additionally having a post-processing module like ladspa for live 
encoding like the windows counterparts Dolby Digital Live of even better 
DTS Connect would made pulse the _real_ audio control software imho. But 
I already read about license issues, I don't know what possibilities are 
there :(  

Just to be sure: these are actually my ideas and nothing more :) (and not 
at all meant as criticism or offensive). And if everything has been said 
earlier then there is no need to respond either..

Regards,
jens