[mythtv-users] 1080i to 1080p Deinterlacing on Backend was Raspberry Pi now ships with 512MB RAM

Scott Knight scott at scottknight.com
Wed Oct 17 14:35:55 UTC 2012


on 10/17/2012 10:23 AM Michael T. Dean carved the following into a 
picnic table:
> On 10/16/2012 11:34 PM, Scott Knight wrote:
> > on 10/16/2012 11:00 PM Michael T. Dean carved the following into a
> > picnic table:
> >> And, yes, a system that's transcoding everything to H.264 (versus
> >> storing it in its native recording format) does make for an extremely
> >> power hungry system.
> >>
> > You have just touched on something I have looked at a few times and
> > never successfully figured out.  I already have a powerful backend
> > (Xeon E3) with power to spare because it does other things like
> > hosting VMs for building MythTV, cloud testing, etc.  It can commflag
> > at 1200+ fps on 1080i content.  What I have noticed is that 1080i
> > content looks pretty crappy no matter which deinterlacer I use on the
> > frontends (mixture of ION, ION2, 9400, GT430 all running VDPAU).  720p
> > content looks better and Blu-Ray looks stunning without even making
> > the frontends break a sweat.
> >
> > Is there a way to take my 1080i recordings and just deinterlace them
> > on the backend?  I don't care about transcoding out the commercials,
> > don't care what format they end up in, don't care about disk space, as
> > long as I can use whatever deinterlace algorithm looks best to my eyes
> > when it's played.  Maybe I don't understand the limitations of 1080i
> > deinterlacing, but it seems that with a good enough transcode, the end
> > result should be somewhere between 720p and Blu-Ray.
>
> This would only be better than deinterlacing on playback if it allowed
> you to use a better-quality deinterlacer while transcoding.  However,
> you're unlikely to find a deinterlacer better than the ones VDPAU
> provides.  So, it's likely that there's some other problem (perhaps even
> that your system isn't using the deinterlacer you think).
It is entirely possible (and seemingly more likely as we discuss it) 
that I don't understand what I am doing with the DVPAU settings. Your 
argument does make sense.  I was working on the assumption that given 
sufficient computing power, ffmpeg could do a 2-pass deinterlace that 
was better than what realtime VDPAU is capable of on a 9400.  If that 
assumption is flawed, then, no problem: I will just go back to trying to 
get a setting that looks good on the frontend.

Thanks, Scott


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