"solarization" problem with Xmpeg ?

[bumblebe]

I've alternating between Vidomi and Xmpeg and using the XVID codec. I like Vidomi but the problem there is it's poor sound processing. On the other hand, Xmpeg has one big problem on my test movie, it "solarizes" white colors, i.e. whites are completely washed out so as to become almost fluorescent. In other words, highlights are "blown".
I'm thinking this could be due to the resizing filter being used. Althought I'm unsure whyit even needs a resizing filter since I'm not resizing !
I've switched from the default "Bressenhaum" or something like that to SSE Bicubic, but it's MUCH slower. I'll report back when my encode is finished. Too bad you can't seem to select a start point for the encode too in Xmpeg !

[Selur]

strange,.. normaly I use pseudo bicubic or brssenham und I never saw this 'solarized white colors' could it be that you contrast on yout monitor or the playback filter are kind of miss set ?

Cu Selur

[bumblebe]

Don't think so, because I'm palying the vidomi and xmpeg encodes on the same computer/monitor !
It may have nothing to do with the filter, but since all other settings are similar, I thought I'd try that !
Do you know of a way to deactivate the filter, it shouldn't be needed when no resizing is being done, right ?

[bumblebe]

Well here's the lowdown my friends and it's not very favorable to Xmpeg...
Comparison in Picture (http://www.pbase.com/divx/xmpeg_vs_vidomi)
The Bressenham has this nasty solarization in the sky on the second series of pics.
While SSE_BiCubic is decent, it's not quite as sharp as Vidomi's resize, not to mention half the speed !
No resizing took place here so I'm not event sure why a filter is needed...oh well !


PS - The aspect ratios are different and I think Vidomi get it right, too bad the sound coming out of Vidomi is so crappy !

[sarahjh69]

you don't tell us what version of xmpeg ur using!

I find 4.2b works perfectly

where 4.5 has aspect ratio problems.....

[bumblebe]

sorry, I'm using 4.5 the latest version. Is that older version still available, I'd be curious to see if that "solarization" problem existed at the time.
Was the speed equivalent to 4.5 ?

[bumblebe]

well I couldn't find 42b so I used 42a and I get exactly the same solarization problems...

[Selur]

"Do you know of a way to deactivate the filter, it shouldn't be needed when no resizing is being done, right ?"
U can't activate it, and normally resizing is done because videodata on DVDs is saved with 720*480 (NTSC) or 720/576(PAL) (often anamorphic).

Strange is that I can't see this effect on my Xmpeg encodes,..
What Color Space/Format are u using in Xmpeg? (personally I go for Yv12)
And what iDCT?

Cu Selur

[bumblebe]

makes sense for the resizing, thanks.
I'm in YUV12 too and iDCT is optimized MMX.
I'm concerned it's the resizing thoughm, because as you can see in BiCubic it's much better.
Maybe it's just a movis that xmpeg chokes on but that's not a very good sign :-(

[Sestrata]

I had the same "solarization" with bresenham filter. It's easy to solve that: DON'T USE "keep aspect ratio" in global options and "prevew aspect ratio..." in outpad.
- first write resolution you want (for exs. 640 x 352)
- then crop to remove black borders (for exs. 640 x 272)with dragging border lines in the crop window.
You can see prevew and will notice that there's no solarization any more.

Sestrata

[bumblebe]

yep it's gone but now my aspect ration is all messed up, what the fix for that ? A dedicated player that can change aspect ratios possibly ?

[Sestrata]

If you have PAL 720x576 (1:1.85) then resize first to 640x352 (or another suitable you have calculated for 1:1.85). If the movie is 1:2.35 crop after to 640x272. That is nearest to the exact aspect ratio, so you can play in all players. This method is "first resize - then crop" and works fine with bresenham filter.

Sestrata

[sarahjh69]

v4.2 does not have the aspect ratio problem
zoomplayer from www.inmatrix.com allows lots of aspect ratio
options.