Deinterlacing

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MythTV Deinterlacing

Deinterlacing is the process of converting traditional Interlaced Video into a Progressive Picture that can be displayed on modern non interlaced display devices such as LCD or Plasma screens.

There is a lot of general information on deinterlacing at Wikipedia in these two articles:

MythTV has several options for Deinterlacing. The configuration options for deinterlacing can be found under Mythfrontend->Utilities Setup->Setup->TV Settings->Playback. On Playback Profiles (3/9) edit each entry, The Primary and Fallback deinterlacer may be set on the 2nd sub-page.

GeneralPlayback.jpg

  • Linear Blend
  • Kernel (Less Motion Blur)
This requires SSE support compiled into your Kernel
  • One Field
  • yadif, something apparently Michael Niedermayer wrote for mplayer/ffmpeg that's fast but more CPU intensive than above
  • Greedyh

MythTV has a number of 2x deinterlacers which attempt to turn 30 Hz (or 25 Hz) interlaced video into 60 Hz (or 50 Hz) progressive video. The aim is to improve on non-2x deinterlacers which look fine for static scenes but appear jumpy when the scene contains motion.

  • Bob 2X Framerate
Shows first one field then the other scaled to the entire height of the picture. For low- or no-motion scenes Bob 2X discards half the vertical resolution of the picture.
This requires Xv or XvMC video acceleration
This is also called Line Doubling and more information can be seen here (under line doubling): http://en.wikipedia.org/wiki/Deinterlacing#Deinterlacing_methods
  • Yadif 2X and GreedyH 2X
Attempt to recover additional spatial information by looking forward and/or back in the video stream. GreedyH looks only at the prior field, while Yadif looks both forwards and backwards.


Important.png Note: If using a Nvidia TV output (composite/svideo) & watching PAL/NTSC signals there should be no need to deinterlace video because the TV output's flicker filter's default setting (of 127) makes interlaced material look perfectly natural - exhibited on FX5200 svideo output - YMMV.