[Ffmpeg-cvslog] CVS: ffmpeg/libavcodec motion_est.c,1.115,1.116

Corey Hickey bugfood-ml
Sat Jan 21 22:38:39 CET 2006


Michael Niedermayer wrote:
>>As you can see, the PSNR hits a plateau at around sc_threshold=-3000, so
>>I don't think testing lower values would yield any better PSNR. As far
> 
> maybe try -20000, -40000 and -80000 too just to be sure

Ok, I'm doing so now.

>>as visual quality goes, I didn't see any of the same gains as with my
>>sc_factor patch. I found a few new I-frames at higher values of
>>sc_threshold, but they weren't placed in locations that improved
>>bad-looking high-motion scenes as much as with sc_factor=6 (which,
>>incidentally, yields 42.97 PSNR with current CVS).
> 
> iam curious how vqcomp=0.7 or larger and various vi_qfactors (both negative
> and positive) would affect these relations :)

Well, I'm sure they would.... Now that I think about it, higher values
of vqcomp might work best with higher sc_factor values.

>>+{"sc_factor", NULL, OFFSET(scenechange_factor), FF_OPT_TYPE_INT, 6, 1, 16, V|E},
> 
> why 16? larger values should be ok too

That was the range you suggested I test, originally. I suppose I might
as well make it INT_MAX and note in the man page that 1-16 is a sane range.

> except these the patch is ok and can be applied

Does this pair of patches look ok? I want to be sure I'm not about to
break something on my first ffmpeg commit. :) Differences:

* sc_factor=1 is default
* INT_MAX is the maximum value
* all sc_factor lines are at the bottom, below other parameters
* mplayer man page description is a bit more detailed

-Corey
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