[MPlayer-dev-eng]

Arpi arpi at thot.banki.hu
Sun Feb 16 13:41:27 CET 2003


Hi,

> after using mencoder for awhile I came across movies with (real)
> 29.97 fps which were created from a 24 fps source by inserting a
> duplicate frame after every 4th frame. When (re)encoding these movies it
> would be clever to drop these duplicated frames to save bandwidth and to
> eliminate the jerky motion artefacts.
> 
> But to only use the option '-ofps 23.976' is not satisfactory because
> mencoder bluntly drops every 5th frame regardless of being duplicates
> or not; or missed I something?

isn't -vop dint the same? afair it was written for the same purpose.

> Some implementation details; how I see this problem; things I would like
> to discuss:
> - To detect the duplicated frames it is necessary to buffer at least 6
>   frames (you cannot display/encode the frames and decide afterwards
>   'Oh, I wanted to skip that frame'). But buffering (at least of this
>   amount) is not supported by the vf-API (am I right?). So I had to
>   expand it by introducing a new image-type MP_IMGTYPE_BUF.

ehh
why do you need 6 frames for detecting duplicated frame?
keep only the previous one (IMGTYPE_IP) and comtare teh current one with
the previous, if the same, drop it.

> - All in all it seems that the libMPcodecs API does not like buffering
>   and skipping frames that much, it is not designed to provide such
>   things, is it?
yes


A'rpi / Astral & ESP-team

--
Developer of MPlayer, the Movie Player for Linux - http://www.MPlayerHQ.hu
    "However, many people beg for its inclusion in Debian. Why?" - Gabucino
  "Because having new software in Debian is good." - Josselin Mouette
"Because having good software in Debian is new." - Gabucino


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