[mythtv-users] Frame by frame playback - 3 good, 2 "ghosty"

Dale Quigg dalequigg at gmail.com
Thu Jan 3 16:02:40 UTC 2008


On Wed, Jan 02, 2008 at 05:41:45PM -0500, Michael Heironimus wrote:
>  On Wed, Jan 02, 2008 at 03:31:45PM -0500, Jay R. Ashworth wrote:
> > On Wed, Jan 02, 2008 at 12:23:06PM -0800, Dale Quigg wrote:
> > > I thought I saw my question in the forum archives, but I couldn't find
> > > it again. I've noticed that when going "frame by frame" in a show,
> > > that there seems to be a repeated pattern of 3 "good" frames" and 2
> > > "ghosty" frames (especially if there is horizontal movement). This
> > > happens whether I use "Default" or "Highest" recording quality. I've
> > > also tried various settings for deinterlacing, but I've not seen any
> > > change in the output.
> >
> > Yup, it's interlace you're seeing. 3:2 pulldown from 24fps source
> > interlace, to be specific. For comparison, record a local news
> > broadcast (preferably one that has *not* gone hi-def yet), and frame
> > through that.
> >
> > Deinterlacing *can* help, though I don't know precisely which mode will
> > work best for you...
>
> The 3:2 pulldown is also commonly called "telecine", which might help if
> you searching the web for information. Deinterlacing is unlikely to help
> because the process creates one extra frame per each four in the
> original source, though it may help with other playback problems.
>
> The real question is this: do you notice it when you play it at normal
> speed? If not, the answer is "play it at normal speed". If you're
> watching ordinary NTSC TV the majority of the content you see has
> probably gone through this process. For that matter, DVD players do it
> on the fly most of the time.
>
> If you're looking to archive the material you can often (mostly) undo
> the process with an inverse telecine ("IVTC") or pullup filter.


Jay and Michael,

Thank you for your responses.

Michael - Thanks for the pointer.  Wikipedia explains telecine well.

> The real question is this: do you notice it when you play it at normal
> speed?
No, I don't really notice the blurred images.  I was just wondering if the
picture would/could look better if this were "fixed".

Thanks again!
Dale


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