[MPlayer-users] regressions & requests

Oswald Buddenhagen ossi at kde.org
Sat Dec 4 14:44:48 CET 2004


i'm recording from tv with mencoder. mpeg4+mp3, both vbr. as mencoder
uses a quite uncommon way of ensuring a-v sync, it is also about the
only tool capable of re-muxing (cutting, merging) the files without
making a mess of the a-v sync. however, there are a few problems, some
of which are regressions:
- merging became totally impossible. even the ugly "cat & remux" hack
  doesn't work any more, as the rest of the stream is ignored after the
  first part.
  and my request for mencoder accepting multiple input files went
  without _any_ reaction ...
- when re-muxing a file that has no index (or -noidx is specified), the
  index of the new avi points to non-i-frames. this leads to very
  "interesting" effects.
- -ss & -endpos need the option to specify an exact frame. specifying a
  frame with a timestamp is both cumbersome and imprecise (no floats,
- feature request: when the encoder detects black (or, more generically,
  uniformly colored and possibly dark) frames, automatically make the
  first frame in such a series an i-frame. this would help cutting
  commercials on stations that do soft-blends.

now some blueSkyDreams stuff:
- auto-crop while encoding.
  the usefullness of this for tv recording should be obvious.
  i suppose it is not possible to create avis with changing dimensions,
  so a prerequisite for this would be an auto-chunking feature (another
  old request of mine that went without _any_ reaction ...).
- auto-enable-deinterlacer while encoding.
  conditionally enable a preselected deinterlacer depending on whether
  the input is detected to be interlaced.
both the auto-crop and auto-enable-deinterlacer should operate on a
per-show basis, but obviously this is practically impossible to
detect. consequently the detections should be done at key frames. the
encoding needs to be held up a few frames until the detection is done.
the cost of doing casual detections should be by far smaller than
deinterlacing and encoding full-size all the time.
- mencoder could support suspend & resume triggered from the outside,
  prolly via some signals (USR1 and USR2 maybe). that would ease the
  integration with tools like the german commercial cutting service

btw, TomsMoComp (the amazing deinterlacer, you know ;) is now even in
transcode. for an experienced mplayer hacker it should be a matter of
minutes to integrate it ...

Chaos, panic, and disorder - my work here is done.

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