[mythtv-users] Anyone running a diskless frontend?

usenet at wingert.org usenet at wingert.org
Thu Feb 13 20:13:37 UTC 2003


One more thing.

There are X procotol compressors available (in ssh for example).  
However, these usually do gzip/bzip type compression as opposed to the DCT
type compression (yielding worse results).


> 
> Personally, I would not run X over ethernet.  I would export the root of a
> filesystem and run X locally on the diskless machine (much less bandwith 
> given the raw bulk of video).  Although I export mythtv sessions all 
> the time from one of PVRs for testing purposes, performance is fine.
> 
> If you are exporting the streams as opposed to X, the following should 
> yield your performance.
> 
> I haven't had much experience with the codec that MythTV uses (I am using TiVos for recording devices).  If I remember correctly 1 hour is around 2 GBs.  
> This is about 582 kB/s.
> 
> A good 100BT connection can sustain about 90 Mb/s (11 MB/s), in an optimal 
> environment.
> 
> Given this performance 100BT should be able to sustain approximately 19
> streams.  This does not include the disk bottleneck though.
> 
> Since X exports images in a more raw format, you essentially lose your
> codec compression rate.  So you could divide the number of streams by
> your compression rate to achive the number of X streams.
> 
> BTW - 100BT has a lot of bandwidth.
> 
> HTH
> 
> > 
> > Further to this discussion, I have been thinking about this.  <Disclaimer>  
> > this is a question, not a suggestion.  I haven't tried it and doubt it will 
> > be very efficient.</Disclaimer>
> > 
> > How about running the backend *and* frontend somewhere in a storage room or 
> > whereever you can't hear it.  Then next to your TV you have a Pentium 200 or 
> > some such just running X -query mythserver?  Vanilla pentiums used to be 
> > quiter than a mouse.  Double that with a nfs-root and you have a dead silent 
> > "frontend" that only has a network card and a TV-out PCI card.  The video 
> > card of course must have xv support.  You have to take care of audio.  How 
> > about nas?
> > 
> > Would the traffic choke a 100MB switch?  Is this even feasable to attempt?
> > 
> > Thanks,
> > IvanK.
> > 
> > On Thursday 13 February 2003 04:09 am, Bruce Markey wrote:
> > > Aaron Stewart wrote:
> > > > I dunno.. It seems like network transfer of data is adding another level
> > > > of complexity that could be avoided, but if sound dampening is
> > > > necessary, then it's a necessary evil :).
> > > >
> > > > My understanding was that an uncompressed mpeg2 stream ran at
> > > > 18mbits/sec, which translates to:
> > > >
> > > > send->18mbit
> > > > recv<-18mbit
> > > > buffer->18mbit (for delayed playback)
> > 
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> > 
> > 
> 
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