Re: [Fresco-devel] multimedia lib (was: List archives in mbox?)

On Sat, 2002-10-05 at 03:16, Iain Hallam wrote:
> e-mails so that I can search them offline (I was actually looking for 
> info on whether Fresco has any plans for a DirectX/Quicktime-like 
> multimedia library). So far, I can look at individual e-mails, and flat 
<snip>

Well, I've just come back from the LinuxDay in Luxemburg where we met up
with a guy from the X.org. They're currently developing MAS, which they
will release by january under the X (MIT) License. 

Their site isn't real clear on everything, but they have some docs on
there. There's a developers mailing list somewhere too (it was mentioned
in the presentation), but I haven't been able to find it. 

In general, I'm pretty impressed with what they've managed to achieve:
- It's a system that allows you to set up and network a collection of
plugins, sources, sinks - devices in their terminology. It's very
flexible.
- It's can deal with all kinds of data (audio, video), metadata and
control streams.
- It's network oriented, using (but not limited to) the RTP protocol.
You can have "devices" running on different machines thus distributing
the load, and possibly making use of various hardware. It's
peer-to-peer, so they're buzzword compliant. The capabalities of the
hardware are also exposed and accesible over the network (things like
mixers for instance)
- They can do n-way conferencing out of the box using their flexible
network topology. It'd be cool for them to write a "device" that bridges
to the H323 protocol, so you'd get communication with phones and
netmeeting out of the box.
- It's extremely performant, and handles very low latencies. It's not
built thesame way as JACK, but then it also has a way broader scope -
dealing with network, video, etc etc. 
- It's supposed to scale up to professional applications. That's why
they've been evangelizing it to the big guys (SUN and others) out there.
It's also supposed to be very high quality - I couldn't verify that, bu
it seems they have paid alot of attention to 
- It's going to be included in the next iteration of the X spec (R6.7?)
but won't have any X dependencies. There will be ways of making it work
with X, even an X extention to tunnel the streams thru the X protocol.
- All it depends on is C89 (and currently C++ for their RTP library, but
they'll eventually rework even that). It's intended to be brought to all
Unixes and even (gasp) Windows.
- The design allows it to be applied for non-realtime purposes, like
audio or video editors. 

Finally - they have working code. It's even working quite well, and they
also have a bunch of GTK2 based GUI tools. Some things need some work,
like their video support.

How does this fit with Fresco? Well, obviously eventually we'll need
something like this, and since Fresco will truly be network transparent,
we better have something that works over the network too. Now the big
issue for us is that it's "out of band", in the sense that we'd only be
using CORBA for setting up the network, not for actually transfering
data or control information.
People might disagree with this approach, because there are facilities
in some CORBA ORBs to deal with streaming and such, so it should in
theory be possible without taking this approach. 
(BTW, even the MAS guys seem to prefer to set up an out of band
connection when using it in combination with X (they have the X
extention only as a fallback)).


Some (other) links:

- http://www.mediaapplicationserver.net/
- Gstreamer (http://www.gstreamer.net/) - same principle except for less
of an emphasis on the network part. Also, it has a glib2 (and libxml2)
dependency. It's getting quite mature. I've heard they 
- Jack (http://jackit.sf.net/) - really geared for low latency local
audio applications. 
- http://uci.sf.net/ http://mcf.sf.net/ http://codecs.org/ 


By the way: I think it's too early to discuss all this for Fresco. But
it was interesting, and just thought I'd mention it to everyone. 


Take care,

-- Mourad