Avisynth access violations, time to clear this

DJ Bobo · 14th March 2003, 03:31

Well, obviously, even if the syntax is right, with some DVDs (happened to me on 3 DVDs so far), you get access violations when you come to a given point.

A solution would be to encode the DVD in 2 parts, the first part till the frame where the violation happens and the second part what comes after.

Anyway, I think the problem is somehow related to mpeg2dec itself (and its other incarnations)

I mean even GKnot tells me that there is an access violation when I come to the problematic point -> quite obvious that mpeg2dec is involved

May be someone can do something about this ... MarcFD may be?

TNM · 14th March 2003, 09:15

Yeah, mgeg2dec usually gave me weird color interpolation so I just used mpeg2dec3

.

I got a lot of "access violation" with avs2.5 so I downgraded and sticked with avs2.08

DJ Bobo · 14th March 2003, 18:51

This problem is not related to a specific avisynth or mpeg2dec version. This problem happened before with avisynth 1.x and the normal mpeg2dec, and happens now with avs 2.5 and mpeg2dec3.

In all cases, I can clearly see some misscolored macroblocks at the point where the access violation happens (the macroblocks are not related to avs/mpeg2dec in *any* way, I can also see them in PowerDVD).

As of mpeg2dec3, may be MarcFD can implement some code to ignore the errors in the MPEG-2 video and process anyway...

Marc FD · 16th March 2003, 20:34

AFAIK, mpeg2dec is based on the standart implementation, and is very error-resistant (error-prone ? dunno how to say it in english ^^)

so, it's gonna be hard to avoid these error.

BUT

if there happen to very localised places, you can very easily get rid of them. just trim out the wrong gop (the entire gop, because mpeg2dec may decode the entire gop :/)

gotaserena · 18th March 2003, 02:51

I posted a similar issue to this one in the newbies forum. It seems that the problem is deeper than I thought, that is to say, avisynth (mpeg2dec3 and mpegdecoder) is (are) not prepared to deal with errors in MPEG-2 streams...

It is strange that I'm getting VirtualDubMPEG2 to parse the MPEG-2 file recorded from my capture card without any problems... AFAIK this mod used the same parsing filter as DVD2AVI, which in turn should be similar to mpeg2dec3. I'm baffled, and would greatly appreciate if somebody would tell me if there is a workaround to this problem in avisynth.

TIA

cweb · 12th June 2003, 13:04

I had the problem with a dvb mpeg2 recording which was very buggy
so it gave access violation errors in avisynth with Marc's mpeg2dec3,
but I did find a workaround: I used Nic's Mpegdecoder which allowed me to encode the file just the same but without problems.

Hope this might help all those with a similar problems.

face · 13th June 2003, 03:40

I was just encoding the LOTR HD version into WM9 and came into the same problem of access violation...so you guys say by taking out that one frame where this happen will fix the problem..??

sh0dan · 13th June 2003, 07:46

If you don't supply us with a part of the VOB/MPEG2 file that crashes there is no way to help you.

14th March 2003, 03:31	#1 \| Link
DJ Bobo Encoding Dinosaur! Join Date: Oct 2001 Location: Europe Posts: 1,750	Avisynth access violations, time to clear this Well, obviously, even if the syntax is right, with some DVDs (happened to me on 3 DVDs so far), you get access violations when you come to a given point. A solution would be to encode the DVD in 2 parts, the first part till the frame where the violation happens and the second part what comes after. Anyway, I think the problem is somehow related to mpeg2dec itself (and its other incarnations) I mean even GKnot tells me that there is an access violation when I come to the problematic point -> quite obvious that mpeg2dec is involved May be someone can do something about this ... MarcFD may be?

14th March 2003, 09:15	#2 \| Link
TNM CG Movies Freak Join Date: Oct 2002 Location: SG//VN Posts: 51	Yeah, mgeg2dec usually gave me weird color interpolation so I just used mpeg2dec3 . I got a lot of "access violation" with avs2.5 so I downgraded and sticked with avs2.08 Last edited by TNM; 14th March 2003 at 09:20.

14th March 2003, 18:51	#3 \| Link
DJ Bobo Encoding Dinosaur! Join Date: Oct 2001 Location: Europe Posts: 1,750	This problem is not related to a specific avisynth or mpeg2dec version. This problem happened before with avisynth 1.x and the normal mpeg2dec, and happens now with avs 2.5 and mpeg2dec3. In all cases, I can clearly see some misscolored macroblocks at the point where the access violation happens (the macroblocks are not related to avs/mpeg2dec in any way, I can also see them in PowerDVD). As of mpeg2dec3, may be MarcFD can implement some code to ignore the errors in the MPEG-2 video and process anyway... Last edited by DJ Bobo; 15th March 2003 at 16:23.

13th June 2003, 03:40	#7 \| Link
face Registered User Join Date: Apr 2003 Location: Texas Posts: 4	Same Problem I was just encoding the LOTR HD version into WM9 and came into the same problem of access violation...so you guys say by taking out that one frame where this happen will fix the problem..??

13th June 2003, 07:46	#8 \| Link
sh0dan Retired AviSynth Dev ;) Join Date: Nov 2001 Location: Dark Side of the Moon Posts: 3,480	If you don't supply us with a part of the VOB/MPEG2 file that crashes there is no way to help you. __________________ Regards, sh0dan // VoxPod

16th March 2003, 20:34	#4 \| Link
Marc FD XviD fan Join Date: Jun 2002 Location: France Posts: 907	AFAIK, mpeg2dec is based on the standart implementation, and is very error-resistant (error-prone ? dunno how to say it in english ^^) so, it's gonna be hard to avoid these error. BUT if there happen to very localised places, you can very easily get rid of them. just trim out the wrong gop (the entire gop, because mpeg2dec may decode the entire gop :/)

18th March 2003, 02:51	#5 \| Link
gotaserena String Theorist Join Date: Mar 2003 Location: Na terra dos 10000 lagos. Posts: 218	I posted a similar issue to this one in the newbies forum. It seems that the problem is deeper than I thought, that is to say, avisynth (mpeg2dec3 and mpegdecoder) is (are) not prepared to deal with errors in MPEG-2 streams... It is strange that I'm getting VirtualDubMPEG2 to parse the MPEG-2 file recorded from my capture card without any problems... AFAIK this mod used the same parsing filter as DVD2AVI, which in turn should be similar to mpeg2dec3. I'm baffled, and would greatly appreciate if somebody would tell me if there is a workaround to this problem in avisynth. TIA

12th June 2003, 13:04	#6 \| Link
cweb Registered User Join Date: Oct 2002 Location: The Pandorica Posts: 528	I had the problem with a dvb mpeg2 recording which was very buggy so it gave access violation errors in avisynth with Marc's mpeg2dec3, but I did find a workaround: I used Nic's Mpegdecoder which allowed me to encode the file just the same but without problems. Hope this might help all those with a similar problems.