[MEncoder-users] Tuning hqdn3d

[Phil Ehrens]

Andrew Berg wrote:
> When I use hqdn3d, it does a pretty good job of reducing noise, but it
> makes the video "blurry" and I lose some wanted detail. I don't know
> what the parameters really do, so what should settings should I try in
> order to make it work the way I want it to?

This is highly subjective, and reasonable people will say I am
on crack, but this is what I do:

I avoid using hqdn3d on live material, and use nr instead.
Something I might do with moderately bad source is nr=120 and
unsharp=l3x3:0.1 to compensate a bit. When all I want to do is
to hide some slight mosquito noise, nr=60 works very nicely.

With animated material, start with 3:2:3:3 and increase the value
of each component by "1", (for example, the next higher setting
would be 4:3:4:4) until it becomes too blurry, then back off.
With really awful multi-generation VHS stuff I have gone as high
as 12:11:12:12. Pretty scary.

Related observations that are veering off-topic:

Something that's a bit irritating is that when you use mplayer
to feed ffmpeg via a FIFO, the nr is applied late, and
it would be nicer to be able to apply it before the mplayer
filters. But it may also be good, because it's probably the
reason why my combination of nr and unsharp looks so good.

Note that the result of applying hqdn3d with Transcode is much
better looking than with mencoder. I have no idea why this should
be. The obvious difference is that with Transcode there are no
"snail trails" even with very high values.