[MPlayer-users] new version of detc filter! (inverse telecine)

D Richard Felker III dalias at aerifal.cx
Sun Mar 9 19:07:12 CET 2003

I just committed it. Please send any comments to the list here.


On Fri, Mar 07, 2003 at 09:51:06PM -0500, D Richard Felker III wrote:
> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> In the next couple days I'll be committing a greatly improved version
> of the de-telecine (detc) filter. Some of the big advantages of the
> new design include:
> 1. Much better handling of irregular telecine patterns. The old code
>    tried to find a telecine frame and then stick to a fixed pattern of
>    2 telecine/3 progressive as long as possible. Thus, it absolutely
>    choked on weird telecine patterns, where video was spliced after
>    telecine was applied -- or even worse, where frames were dropped or
>    duplicated post-telecine to adjust the speed. The new code is much
>    more adaptive, constantly trying to catch and resync to telecine
>    frames and only using the 2/3 pattern when there's too little
>    motion to identify which frames are the bad ones.
> 2. Nonreliance on absolute thresholds. The old code had a lot of hard
>    coded threshold numbers used to detect whether a frame is
>    interlaced/telecine, and while these numbers worked fairly well for
>    my test material (SE Lain), they might not have worked well at all
>    for other stuff, especially live realworld footage. The new code
>    only uses a few threshold parameters for special situations, and
>    those can probably eventually be removed.
> 3. Better metrics for determining presence of interlacing. The old
>    ones could severely underestimate interlacing in areas with
>    significant horizontal noise.
> Overall, this code seems to be working much better on my test
> material (still SE Lain). At this point I'm mostly happy with it, but
> I'm still planning to work on a 2pass version soon, based on the new
> algorithms. The benefits of 2pass telecine removal will include
> avoiding false positives by examining future material (prevents
> excessive frame dropping), realtime telecine removal in mplayer for
> use with DVDs and SVCDs (so you don't have to reencode first), and
> resilience to mencoder's bad behavior (nonsense frame skipping and
> duplication that makes detecting telecine harder).
> I'll post again in a few days once I put some finishing touches on the
> code and commit it. After that, I'd appreciate it if some users with
> telecined files/discs could test and see if it's fully working! Also
> I'd appreciate some before-and-after testing to make sure there are no
> cases where the old (current) version works better than the new code
> I'm about to commit!

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