small trouble with mpeg2dec3 here

[Teegedeck]

I just hope I haven't overlooked anything obvious - I really think I haven't. Well, trying to get to the point: with Avisynth 2.5 and mpeg2dec3 v.1.00 I've experienced some strange white dots on areas with sharp contrasts. See the attached picture (captured frame from avs loaded into Vdub). I've broken it down to the following: the problem does occur in combination with every resizer except bilinear, no matter whether I crop or not. No trouble with mpeg2dec for Avisynth 2.5. Upgrading to Avisynth alpha from 21st of January doesn't help.

Also, I get an unhandled exception in VDub when I switch on mpeg2dec3's deringing and load the resulting avs into Vdub. This is what it throws at me when I scan through it:
cpu5 --> illegal instruction at 0x0743f576
cpu6 --> 0x09c0f576
cpu2="xxxxxo" --> 0x0d4bf576
cpu2="xxxxxx"--> 0x03bbf576
cpu2="xxxxox --> 0x070cf576

The interesting part: for a couple of weeks I could borrow someone else's Athlon XP PC (this is the machine I first installed Avisynth 2.5 on) and didn't notice any such thing. But now on my poor Celeron here...:scared:

[sillKotscha]

Hi Teegedeck,

on some scripts I've noticed these dots, too. I wasn't aware that it could be related to mpeg2dec3. But as you said, you can only see them in VDub [preview]. After encoding (and comparing frame by frame _ avs vs. encode) these dots are gone with the wind...

about the unhandled exception... I *think* it has something to do with avisynth's cache handling - but for sure, I don't have any clue. Sorry.


regards Sill

[Teegedeck]

Well, it would be strange if the dots were gone in the final encoding. They aren't in mine, I'm afraid.

[Teegedeck]

I seem to have forgotten the attachment. Here we go.

[vlad59]

IIRC the dering code was optimized by TrBarry and is only useable on an iSSE capable CPU. So if your Celeron is below 600 or 500MHz (I don't remember well) you won't be able to use it.

[Teegedeck]

Thanks, that explains the deringing problem. :o
Sad that also the deblocking code gives me problems. [Errr; forget that. I meant, the problem with those dots does always appear when I use mpeg2dec3 and a resizer different from bilinear; no postprocessing involved here.]Time for an upgrade, I guess.

[mfluder]

Hi Teegedeck. You are not the only one with this problem. I also have a problem of those white dots appearing when I use AviSynth 2.5 and every resizer except bilinear. Take a look at this (http://forum.doom9.org/showthread.php?threadid=37756&perpage=20&pagenumber=4) thread and search for my post where I attached a zip file with images showing the problem. I even sent a clip to sh0dan but he couldn't reproduce it. It looks like it has something to do with my Celeron because I tried this clip on my friends computer (Celeron II) and everything looks fine. Needless to say, I don't have this problem with AviSynth 2.0x and regular mpeg2dec. As you said, it's time for an upgrade but until then I could really use this 25% of speedup ;) So sh0dan can you please take a look again at this problem (if you have time) as it looks like it's not specificaly related to my system but more generally to those old Celeron processors (which btw only have MMX instructions) which Teegedeck also happens to have (are we the only one?).

mfluder

[sh0dan]

Oh - so you only have MMX - that could explain something. I'll have a look at the MMX resize code to see if the problem lies in that part!

(It's on my list now, but I'm pretty busy right now, but I promise to take a look at it as soon as possible.)

[vlad59]

I read the post processing code of mpeg2dec3 and if it's really the same code as the one used to buil mpeg2dec3.dll. It should work with MMX only, there is some prefetch (available only with iSSE) instructions but they are disabled.

I'll try to recompile this version and test on my K6II400.

[kxy]

I am also having white dots, I am using AMD Athlon XP 1700.