[gst-devel] Re: Distributed pipelines and modular synthesis ramble

[Owen Fraser-Green]

Hi,

Dan George wrote:
> Check out this paper regarding CORBA and AV streaming. Section 4 addresses
> performance.
<snip>
> http://www.cs.wustl.edu/~schmidt/PDF/av_chapter.pdf

Yes, I think this looks like a very promising solution. I recall reading 
Erik Walthinsen wished to see all the gst objects wrapped as bonobo 
components. The only problem is that ORBit doesn't support the A/V Streams 
Service at the moment and hence it can't be interfaced through bonobo 
either. I'm trying to dig up some information on implementing it in ORBit 
at the moment e.g. looking through the TAO implementation described in the 
pdf.

Wim Taymans wrote:
> - state changes. how do we handle them on remote pipelines? the scheduler
>   changes could make it possible to propagate the state change along with 
> the
>   data?
> - intermachine connections could be handled with a custom element or with
>   something standard like RTP, SCTP?

I think by using CORBA/bonobo to do the distribution for us will take care 
of these two concerns because it will be effectively become the same as a 
conventional pipeline on a single machine. Also we could then make do 
without the custom element.

Conrad Parker wrote:
> RTP/RTCP provide the following:
> 
> - RTP packets have sequence numbers and a 32-bit timestamp (payload
> dependent, ie. GStreamer could define it how it likes)
> - RTCP [RTP Control Protocol, used for delivery monitoring] has
> 64-bit NTP timestamps, and is used to report back the network delay and
> packet loss. ie. this handles your first two concerns

Yes, I agree that RTP seems like the most sensible protocol for the 
transport of the streams and A/V Streams allows one to do that. I would 
guess CORBA encapsulates the stream data in it's own control protocol 
though but I'm not too clear on the details yet.

Anyway, this seems like a good solution to the GNOME project as a whole 
because it just involves enhancing other core GNOME components rather than 
implementing a whole new set of distrubeted object mechanisms.

Regards,
Owen

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     Owen  Fraser-Green             "Hard work never killed anyone,
     owen at discobabe.net              but why give it a chance?"
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