DVD to AVI file Jerky Jumpy

[Dolfin the Mammal]

I use DVD Dycrypter, DGIndex, AC3Delay, VFAPI, and Virtual Dub Mod to create an avi file. Now and then I get a jerk in a scene. It does not happen often within the whole movie. I don't think I see it in all the avi files I create. If I had to guess, I would guess that the jump was to properly snyc the sound file and the video file. I say this because the audio does not seem to jump with the video. The audio seems smooth through the jump in the video. I am also guessing that the jump happens in different places when I start the movie over again. My last comment is that I have not kept a record of if the jumps come in an avi file when AC3Delay was used. That is possible. I will start to record when I use AC3Delay, presently.
I have read the posts having the keywords jumpy, jerky, avi, and Virtual Dub, but did not find anything that seemed to fit my situation.
Has anyone found a solution to this imperfection.

[jagabo]

If the jerks don't happen at the same place every time you have a playback problem, not an encoding problem.

Pentium 2? Get a faster computer. Or encode with smaller frames. MP3 may be eaiser to decode. Actually, I find it hard to believe you could have a Pentium 2 with a GB of DRAM.

[Dolfin the Mammal]

Thank you for your reply.

You are right, jagabo. I have changed my profile to reflect the proper Pentium4 entry.

I went back to a file where I had been keeping track of where the jumps were and reran it. The jump was definitely in a new place.

If I have a play back problem, what would be some procedures to identify and fix this category of problem?

Thanks for your help.

Dolfin

[jagabo]

OK, a Pentium 4 should be able to play standard definition video pretty smoothly.

Some things I've seen that can cause problems:

1) Some background task occasionally hogs up the CPU causing the player to fall behind. Typically, the audio will be OK but the video will jerk. If the problem is very severe the audio will break up too. Bring up Task Manager (Alt+Ctrl+Del) and see if some other task is eating up CPU cycles. Try killing off processes you don't need -- at least as an experiment to see what process might be causing the problem.

2) Video overly has been disabled. The graphics card's video overlay feature usually accepts YUY2 or YV12 video data for display. If overlay is disabled the decompressed video has to be converted to RGB (for display on the desktop) by the CPU. This extra work can cause jerky playback.

3) I've seen poor AC3 decoders cause problems with video playback. Does your jerkiness only occur with AC3 audio?

4) You didn't mention what video codec you were using in your AVI files. Uncompressed RGB or YUY2 video will often play with jerks because the amount of data that needs to moved from the hard drive to the display is too large. h.264 decoding can be very taxing on the CPU, if you're using that. Divx and Xvid shouldn't be a problem.

5) If you're playing off a DVD bad multiplexing can cause problems. If the player has to seek back and forth through the file to get the matching audio and video data you will have problems with CD or DVD media which seeks very slowly.

[Dolfin the Mammal]

jagabo,

my gut says that your number 3 is the answer. I use AC3Delay. Is there a better free program out there that you think would do a better job? Is there any way to check if my AC3Delay is the culprit? I looked for a log of Virtual Dub Mod or AC3Delay to see if they would tell me which jobs used a delay fix on the audio. I had no luck there. Do you know of any way to find out if the audio part of the finished file was fixed for a delay?

I think I can rule out the other possible bugs because:

I have experienced your #1 when my Spybot scheduled scan kicks in so I know how that acts and it is different than the problem I am trying to solve, I think. Please keep in mind that the jumps do not come often during the whole film and are very intermittent. Maybe the are three or four jumps in the whole film, at most.

If the problem was your #2, would not the jumps be all the way through the film on a regular basis? I have a GeForce2 MX/MX400. I believe the video overlay is turned on by default from what I could understand from looking at the Geforce Utility for changing settings.

For #4&5, I am using Xvid as a compression codec and I play off my computer monitor.

Appreciatively,
Dolfin

[jagabo]

I don't know anything about AC3Delay. You might try using AC3 Filter instead.

Some players are better than others. You might try a different media player like VLC, MPC, KMPlayer, etc.

[Dolfin the Mammal]

jagabo

I'll play around with the possibilities you gave me. Thank you for all your ideas and help.

Take care.

Dolfin

[jagabo]

One note about VLC and KMPlayer -- they both have their own AC3 filters (along with most other audio and video codecs) built in. That eliminates a lot of the problems you can get with conflicting Directshow filters.

[Dolfin the Mammal]

jagabo,

Thank you for continuing this thread, above and beyond... I consistently use VLC player, but knowledge about how to properly use codecs has always alluded me. I end up loading everything on top of each other, as a new file calls for a different codec. I am aware that one should try to separate directshow filters from non-directshow codecs, that is, adjust non-MS filters so they do not play directshow based files. I am talking in the dark here and am not sure if this knowledge is correct or even if I have applied this concept correctly. ??

As you have said, VLC is a good player. Could my problem be an improper use of my library of codecs? What is the proper way to administer codecs within one's operating system?

I still need to down load and play with the AC3 program you suggested to see if my AC3Delay program was the problem. I will do that shortly.

Thanks Jagabo,

Dolfin