[Kdenlive-devel] moved here from kde-multimedia (was Re: Multimedia Frameworks)

[Rolf Dubitzky]

On Monday 28 October 2002 03:11 pm, Jason Wood wrote:
> On Monday 28 Oct 2002 11:15 am, Rolf Dubitzky wrote:
> > > > I don't like the idea of threads for a number of reasons : Firstly,
> > > > if the Cutter crashes, it will take the GUI with it. Secondly, we
> > > > would still have to allow the Cutter to run as a seperate process so
> > > > that it could be run remotely or for batch processing anyway.
> > > > Thirdly, it would really screw up my idea of having a scheduler for
> > > > multiple cutters distributed on multiiple computers ;-)
> >
> > Ok, I don't want to get envolved with multiple computers too much,
> > because that's my major. But if we want to test this on a 500+ PC cluster
> > at some point I can do it. But using a PC cluster to render a movie is
> > trivial. The task is intrinsicly parallel if you can make the cutter read
> > a XML file and launch it with gst-launch. You just have to tell everybody
> > which frames to render and have a seriealizer in the end. That's what I
> > do all day ;-)
>
> I think the main problem with video rendering over a network is more a case
> of bandwidth - To edit at DV quality, you are looking at 3 Meg/second AV
> files, (30 Meg/s or more for some of the more "professional" codecs ) which
> I think could quite easily saturate the network.

Possible, most likely, if you can afford a cluster than you can afford 
network. I am a physicist and we do numbercrunching in High Energy Physics, 
bandwidth is a big problem for us, but it's not the network, it's the 
fileservers. We just add some more GBit connections to the NFS toasters if it 
becomes a problem. In video editing, you will not handle a lot of data (we 
deal with aprox. 120 Terabyte of data right now). It should be easy to 
distribute the data before you render. just put a disk in your batchnode and 
copy the files over. When done, copy the output. This will add some network 
traffic before you really start rendering. 
 Now, _interactive_ videoediting on a cluster is just .. errh.. well.. I don't 
think that makes sense, just buy a big box if you need power. Building a 
interactive cluster is highly non-trivial, believe me, it requires some real 
good reason, and video editing is just not a reason good enough.

> However, I should point out that I am not at this moment in time really
> looking into network rendering - but I don't want to have to rework the
> entire code base when it comes round to implementing it.

If you keep the renderer as an application, that can be used from the 
kommandline, using some .dv data and an XML description of what to do with 
it, then you will have no problem in distributing on a cluster.

Cheers,
Rolf

***************************************************************
 Rolf Dubitzky  
 e-mail: Rolf.Dubitzky at Physik.TU-Dresden.de
 s-mail see http://hep.phy.tu-dresden.de/~dubitzky/
***************************************************************