[mythtv-users] Mythtv playback quality poll

Garry garry at sneakyninja.net
Thu Jun 17 12:52:44 EDT 2004

resoli at tiscali.it wrote:

>Hi all,
>After a lot of trial and errors I finally have a working mythtv 0.15.1 
>splitted frontend-backend setup.
>Nevertheless, I am quite disappointed about the quality of what i see on
>old 25" Sony Trinitron: standard tv looks a lot better, firstly in terms
>of image crispness
>and then of motion fluidity (ther is no evidence of frame dropping, anyway).
>My frontend is an EPIA-M 10K (hw decoding enabled), backend is a Celeron
>1GHz with 
>PVR-250 tuner-encoder. 100MB full-duplex ethernet in between. Im using the
>EPIA s-video tv out.
>I am running epia-sources-2.4.25-r2 kernel and xfree-unichrome-4.4.0-r16
>from epia.kalf.org
>and libddmpeg-1.6.
>I capture  720x576 mpeg2 @ 4500/6000 (I tried also at higher bitrates).
>At this resolution
>and bitrate mythtv software playback cannot keep up on my EPIA (thanks Jelle
>for pointing
>this out), so I am forced to use hw-decoding.
>Here some thoughts about this:
>1) I was initially suspecting the quality of EPIA tv out, but DVD playback
>via xine looks good,
>and using a standard pc monitor does not change quality substantially (xine
>dvd playback
>is spectacular on a standard pc montor).
>2) Is a hw decoding lacks of quality problem?
>3) Using hw decoding, playback is mirrored on standard console (making it
>unusable), is it normal
>behaviour or something wrong in my setup?  
>Is someoune  achieving a mythtv playback substantially not distinguishable
>from standard 
>tv broadcast with hardware similar to mine? 
I run a pvr-250 with the same settings as yours, although on a Pundit 
running both back and frontend. I am having the same issues, with live 
TV not being  as fluid as 'normal' TV.

One thing I did notice was the motion was smoother when I used my 
desktop machine as a frontend, but as that's only got a monitor 
connected, I can't really do a like-for-like comparison.

However, I've ruled out the incomming TV signal, the pvr-250 card, TV 
out and my setting as a potential cause, as watching recorded programs 
is fine. Not quite normal TV quality, but close, and certainly 
'smoother' than live TV. (recording profile settings are the same as 
liveTV profile)

I suspect my issue is caused by some performance bottleneck on the Pundit.

Do your recordings have a better quality? If so, this rules out a lot of 
potential causes....


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