[mythtv-users] Recommendations needed for new FE box

Gary Buhrmaster gary.buhrmaster at gmail.com
Fri Jul 27 18:34:22 UTC 2018


On Fri, Jul 27, 2018 at 5:48 PM Ashu Desai <ashu.desai at gmail.com> wrote:

> I thought VDPAU was the "better" one here,

For those of discerning tastes (i.e. the quality addicts),
in the de-interlacing world, what you want is MCDI(*)
(motion compensated de-interlacing).  MADI (motion
adaptive de-interlacing) is a lower complexity
implementation which some find adequate.  With
the exception of extremely powerful systems, those
require hardware assistance(**).  There are also various
software de-interlacers, at varying levels of quality
(and software demands).

While today all the major vendors have hardware
support of MCDI, that was not always true.  Nvidia
was, for years, considered the gold standard in the
HTPC world for video quality.  MythTV's implementation
of VDPAU included the MCDI support.

Early gen Intel VPUs did not support advanced hardware
de-interlacing, and the original VAAPI also did not.  Later
Intel hardware added (first) MADI, and eventually MCDI.
A later version of VAAPI now supports those, but it uses
a different architectural approach that MythTV was never
updated to use (a couple of people have reportedly
looked at it, but it was determined to require enough
work (i.e. time) that it was simply not done).

Over the years FFMpeg has add support for advanced
hardware accelerated decode and de-interlacing,
including for Intel based MCDI (they also have a lot more
devs dedicated to the video pipelines they support).
However, as David Engel points out, MythTV did not
utilize FFMpeg in ways that took advantage of some
of those new/improved capabilities, and that the work
by Peter Bennett may(***) be able to be leveraged to
support in the future.





(*) There are subtle differences between hardware
implementations of MCDI, but while it is possible to
observe differences in synthetics, it is the rare
individual that will be able to see the difference in
common scenarios in move vendors latest hardware.
On the other hand, many can see the difference
between MCDI and blend (a simple software
de-interlacer).

(**) And hardware assistance to run in any reasonable
power budget.

(***) "May" as in someone still has to do the work.
Typically that happens when someone with the
appropriate skills has the itch to do the work.


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