Troubleshooting: AviSynth/Virtualdub just hangs...?

[pbristow]

I don't know if this is a problem with AviSynth, with VirtualDub, or just a quirk of my hardware, but here's a problem I run into occasionally, *only* in the context of using AviSynth with Virtualdub, and I wonder if anyone else has seen it and can shed some light on it.

I'll be working on a project - tweaking scripts, running tests via VirtualDub, checking the output files using KMPlayer - and everything will be working smoothly... And then suddenly, often in the middle of a run, some situation occurs where AviSynth/Virtualdub just stops processing anything, or just runs very, very slowly. CPU usage drops to almost zero; The Virtualdub "Status" window keeps updating "Time Elapsed", but the "Current Video Frame" either stops updating compleletly or else drops to only incrementing a frame per second or so, and "Total time(estimated)" starts growing from, say, an hour to more like 10 hours.

Anyone else encountered this before? Any tips on where to look for the problem? Is it some glitch in the Windows file system that stops/slows the delivery of new frames to AVIsource, maybe?

A reboot fixes the problem, until next time...

Everything else about the machine seems to work fine.
I'm on Windows XP, SP3, fully up to date with patches. The CPU is an Athlon II, running on an Asus M2N68-AM Plus mobo. This problem has been recurring over the last 6 months, approx.

Any insights very welcome, 'cos it's a pain in the bum! :mad:

[pbristow]

I guess it's just me, then... =:o\

[Floatingshed]

It has happened to me too but I found no cause or solution. Reboot and away we go...

[IanB]

What Source filter(s) are you using when you experience the problem?

What output compression codec are you using when you experience the problem?

What is the typical script you are using when you experience the problem?

Does the VDub "Run video analysis pass" option experience the slowdown?

How much virtual memory is the VDub process using in task manager when you experience the problem?

[pbristow]

Ian B: Alas, answering those questions would require me to have a log of all the occasions it's happened... Which I guess I'll have to start doing. =:o\

I can tell you that the output codec is usually, perhaps always, DivX, since that's the codec I use by far the most often. (For mezzanine files I'll sometimes use either Lagarith or M-JPEG (as supplied by Pinaccle with an editing package I bought years ago and never actually use, except for the codec! =:o} But because I'm always fighting lack of disk space, a lot of my mezzanine files are just max-bitrate DivX.) depending on the space/quality requirements - but I can't recall if this probelm has actually occured when producing anything other than DivX.

The one thing that strikes me as most likely to point to the problem is that this only happens since upgrading to a multi-core processor (the machine used to have a Sempron single core), so maybe somethings going wrong in the communication between cores... Although I'm pretty sure the problem has occured even when I wasn't using MT() or SetMTMode, which again suggests a problem with either the hardware or Windows rather than Avisynth's MT processing; on the other hand I did switch to an MT version of Avisynth at the same time I got the new processor (naturally enough), so it could be an obscure bug introduced in the version I'm using.

Version numbers:
AviSynth 2.57 tsp MT version 5, build:Mar 1 2007 [21:27:12]
VirtualDub 1.9.7, build 32661
DivX Community Codec v6.8.5
Windows XP SP3, fully patched.

Virtual memory can be anything from 1GB up to 2.5GB - I have been checking that whenever it happens, and there doesn't seem to be any pattern.
(I have 2GB real memory and a 4GB swap file).

Also, I've never used the "run video analysis pass" option. Given the rare and unpredicatble nature of the problem, I don't think it's feasible to spend a few weeks just running video anaysis passes to see if the problem eventually gets triggered. =:o\

[pbristow]

Floatingshed, what CPU do you have? Is it an AMD multicore?

[IanB]

Given you said a Reboot is needed to fix the problem, when it happens, things like "run video analysis pass" may help isolate which part is actually running slow.

The "run video analysis pass" just reads the source as fast as it can without doing any output encoding.

Also when it happens replacing your *Source() with *Source(...).BlankClip().ShowFrameNumber() and retry may eliminate the source filter as the problem.

Also installing a standard version of Avisynth when the problem occurs may eliminate the MT as the problem.

And of course check the CPU temperatures when the problem occurs. Is one core much hotter than the other.