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21_already
13th March 2004, 23:56
Hey, i joined this forum basically to report what i think is an unreported bug in Xvid. I hope it's in time 'cause i had to wait 5 days for membership to clear.
I'm using Koepi's build of release copy 3 version 29022004, but i found the same problem in release copy 2 pretty much a day before RC3 came out.
Here goes:
I think it may be some kinda MS bug but when i code first pass files things mess up.
Here's the problem specifically.
I'm trying to do a two pass encode, but i did the first pass on its own with the intention of doing a second when i had time

I'm using AS level 5 with GMC, adaptive quantization, Qpel, 2 bframes with closed GOV and packed bitstream
On programs that try to create AVI files even though i tell Xvid to Discard the first pass (full quality first pass unchecked) an AVI file containing basically nothing is created anyway.
Trying to open this file of course ends up in the player crashing type stuff.
More importantly on Windows XP (SP1) Explorer crashes pretty horribly when it tries to render an image for thumbnail previews, and even for the thumbnail on the folder containing the file itself.
This means whenever i even OBSERVE the folder containing one of these files in thumbnail view i get a crash with error report saying a bunch of stuff (too much error report stuff to reprint)
I tried it with two different encoders (Rad Video Tools Bink & Smacker and DVDx 2.2) and with two different Sources (a high def. quicktime file and a DVD) and get the same problem. The 2nd pass files made from these work fine
I decided to find what function it was that could be causing it so i tried again using level 0 simple profile and the problem disappeared.
I went back to Advanced simple profile and knocked out features one by one to see which was the culprit:
it was B-VOPs swithced on (regardless of amount, packed bitstream or closed GOV)

Hmm, anything else i need to include? uh, using a laptop, 1.4GHz Pentium M??? i don't think the rest is important.

As i said, i know it's a micro$oft problem, but i've made similarly empty Divx AVI files the same way with no problem, Windows simply renders a black screen as a preview.
It's not really a problem that affects quality, coding or playback, but it's annoying nonetheless and not something you'd expect (partly because explorer doesn't crash for about 20-30 seconds after the error message appears).
I gotta say, if it is due to Xvid itself then i think it's a pretty important problem to fix, i can see a lot of new users getting into Xvid and being put off by something like this.

On another note, gotta compliment you guys on the quality. Thanks.

Edit:
i just did a search and found someone named soujir0u made almost the same report in April 2003 on Xvid 05042003-1 but he didn't get a reply (but did get 231 views)

I hope i'm not reporting something already reported, but like i said, it was there in RC2 and still there in RC3

LigH
14th March 2004, 00:02
Usually, to save disk space, no video frames are written during a 1st-pass (per default, the option "Discard on first pass" is enabled). There are no video frames in the resulting AVI (just "drop frames"), so you can't expect any preview...

P.S.: Welcome to the doom9 forum!

21_already
14th March 2004, 01:36
Thanks for the welcome LigH

It's just that i was kinda concerned because it causes problems accessing all the other files in the same folder and i kinda like having thumbnails turned on.

P.S. have i posted in the right area? I wasn't sure, and was trying not to annoy too many ppl with my first post here

sysKin
14th March 2004, 02:42
Originally posted by 21_already
P.S. have i posted in the right area? I wasn't sure, and was trying not to annoy too many ppl with my first post here LOL, don't worry, your post is perfect :D

Welcome to the forum.

It's a weird thing that b-frames have any effect on this - the empty AVI should be identical, regardless of encoder settings. It should just have all frames dropped. It's obviously windows' fault if it crashes seeing an avi with all frames dropped....

Or maybe AVI requires first frame to be a keyframe? If standard requires it, then windows is not bo blame (too much. imho overy program that crashes when given invalid data is lame. xvid is also lame in this sense, unfortunately).

Anyway. The solution will be not to drop the first frame. Unfortunately I can't tell if it's going to help, bacause I don't have windows XP.

@21_already: if I made a modified xvidvfw.dll which does not drop the first frame, would you be so kind to check if 1st pass does not crash anymore? :)

Radek

21_already
14th March 2004, 06:14
uh, sure i'll try it and report back

pardon my stupidity though, you'll have t tell me where to put the .dll ... in system32 folder right? do i need to register it? (i'm not really sure how to do that on its own)

Anyway, thanks for taking the time!

mikeX
14th March 2004, 10:10
i have to say i can't verify any of this on a p4 running xp sp1a.
i don't get any thumbnail preview for that specific avi file the 1st pass leaves behind.
could it be in any way related to file associations??(i have avi's registered with mpc)
also the player does not crash either Media Player Classic, nor Window$ Media Player 9.
maybe a decoder issue?(some other decoder being used?)

i believe the issue is similar to one reported in one of the 'xvid crashes WMP9' threads but i think it was on win2k system...

@21_already
given that you have already installed xvid you will merely have to replace the new file with the one already in system32, no registering etc...:)



ok, found that thread i was reffering to:
http://forum.doom9.org/showthread.php?s=&threadid=67042&highlight=wmp%2A9

the decoder crashes explorer in win2k when previewing an xvid enoded avi file.

as you can see it is reffering to normal xvid files, but it could still be the same bug, right?

there is also some thumbnail talk in this old ffdhow thread:
http://forum.doom9.org/showthread.php?s=&postid=260597&highlight=thumbnail%2A#post260597

21_already
14th March 2004, 21:35
hmm, the second thread sounds familiar.
i never considered that WMP9 might be doing it but i guess microsoft must call its preffered method of rendering the file.
i too use MPC (the best!!!) and have avi's and everything else associated with it, though come to think of it NERO stole all my associations so all my icons are now NERO icons (i don't know how to change this - i think there was a thread on hydrogen-audio that was talking about it being unchangable at the moment for some reason or other, but files definitely do play back with MPC when i double click them). Could Nero possibly be the culprit?

It's definitelly with only 1st pass 'AVI's' if you can call them that: no problems with

hmm, if i could figure out how to attatch stuff on the forum then i could send one of these files if that would help?

edit - Forum Rules: "You may not post attachments" - duh
is there anyway i could get one of these files to the relevent person to look at? or would it not reveal very much?

hmm, i tried opening them again and they didn't crash MPC this time (very weird), but they still crash explorer consistently. I store them in a double layer of folders so they don't mess other things up.
Thanks for the tip about .dll replacement - i should have figured.

PhrostByte
15th March 2004, 09:06
RC stands for Release Candidate, not Release Copy ;)