[MEncoder-users] Best way to performance an inverse telecine

[Grozdan]

On Sat, Jun 26, 2010 at 3:35 PM, Eric Wescott <wescotte at gmail.com> wrote:
> I have quite a bit of HDV footage I recorded with an Canon HV30 camera using
> it's 24P setting. Canon offers optional 24p support on their HDV consumer
> camcorders: this mode officially is called “PF24″. Unfortunately, PF24
> doesn’t record on the tape a “pure” 24 frame progressive stream but instead
> it records 18 progressive frames and 12 interlaced ones — inside a 60i
> stream. Even worse, Canon does not include “flags” in that video stream to
> guide applications as to how to extract the 24 progressive frames out of
> this 60i stream.
>
> So, I need to perform an inverse telecine in order to get 24 progressive
> frames. I've followed the guide at
> http://eugenia.gnomefiles.org/2007/07/13/canon-hv20-24p-pulldown/
> for the -vf pullup, softskip and huffyuv codec which I eventually transcode
> to ProRes 422.
>
> However, I noticed there are several inverse telecine filters in mplayer.
> I've found the following methods at
> http://forum.doom9.org/archive/index.php/t-149298.html
>
> 1. -vf decimate=2:1000:1600:.001 -ofps 24000/1001
> 2. -vf framestep=2,filmdint=dint_thres=256,harddup -ofps 24000/1001
> 3. -vf pullup,softskip
> 4. -vf filmdint
>
> I don't quite understand all the additional arguments for the filters and
> which ones I should use..
>
> My question is this. Is one method better than another in terms of the final
> output quality? I don't care about how the filters degrade encoding speed I
> just want the best possible quality.

That really depends on the content you're dealing with. Best is to try
out all filters and see how they deal with your specific content. For
IVTC I prefer the filmdint filter as sometimes pullup doesn't seem to
behave properly. Note that some people report seeing a green line at
the top or bottom when using filmdint but I have yet to encounter such
thing

In the above filmdint example, what it actually does is slow down the
frame rate to half (with framestep=2) and then use filmdint (with
deinterlace disable which is the dint_thres=256 option) to bring it
down to 23.976fps... I suspect in that example one is dealing with
60fps content (actually 59.940fps) which is brought down to 29.970fps
(with framestep=2) and then filmdint brings it further down to
23.976fps (aka 24p)

>
> Thanks
> Eric Wescott
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