[Gllug] reading DVD is slow

[Peter Grandi]

>>> On Sat, 15 Oct 2005 00:06:29 +0100, Pooly <pooly7 at gmail.com>
>>> said:

pooly7> [ ... ] But still when I read DVD, it's damn slow ! 20%
pooly7> of the CPU is used by mplayer,

So it most likely is not DMA being disabled on the DVD drive.

pooly7> the other 80% by Xorg (the same when it was Xfree
pooly7> without dri/drm). [ ... ]

DRI/DRM is for OpenGL (3D graphics and games) acceleration, not
for DVDs.

For DVD ''acceleration'' there are three different ways:

* CPU which supports DVD-decoding-friendly extensions like MMX
  and others. This reduces the time used by the player to decode
  the DVD, not by X to display it.

* Various types of DVD acceleration in the graphics chipset,
  either to zoom the image or to perform various stages of the
  conversion to a displayable image. These help with the speed
  of the decoding and also with the speed of the displaying the
  decoded image.

* Video overlays, these accelerate the display of the decoded
  image.

Even without video overlays and DVD acceleration in the graphics
chipset most recent systems should be able to decoded DVDs. What
you can do is:

* Depending on your CPU type make sure that MPlayer is using the
  right type of CPU dependent optimization.

* Switch to a somewhat faster decoder; I find that for DVDs VLC
  is a bit or significantly more efficient than MPlayer or Xine.

* Make sure that whatever DVD-helping acceleration of the
  chipset is enabled (if supported) in the VIA graphics chip
  driver (e.g. the XvMC or VIDIX is enabled).

* Make sure that if the VIA graphics chip driver supports
  overlays the decoder/player does user them.

By looking at the 'man mplayer' page looking for the suitable
keywords you can fidn the appropriate stuff. For example it
looks like there is a 'unichrome_vid' drivers in MPlayer for
'vidix', so that looks like a promising starting point.

Check also if the XvMC ('XVideo-MotionCompensation') extension
is enabled in the X server or if you can use the 'xvmc', 'vidix'
or at least 'xv' output modules of MPlayer.

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