Still Jerking!!

[wuzzbert]

Can anyone help, I posted a thread on this forum recently explaining that when I convert avi files to Mpeg-2 files using TMPGEnc I noticed that the picture looked jerky. This was very noiceable especially when the camera panned around. I was advised to check what resolution the file was in (NTSC or PAL) and to keep this the same for the output file. I did this but the problem is still there. I use the wizzard to set everything up however all I do is ensure the resoultion is the same and reduce the file disc percentage used to 99%, everything else I leave as it is!

What can or should I do to elimate the jerkyness???

[Ripper2860]

The file should be interlaced. If so, try changing the FIELD ORDER.

[wuzzbert]

What do I do if it is not interlaced?

Also, What should I change the field order to?

[Ripper2860]

Sorry -- I mis-understood the post. When I read "camera panned around", I thought it was an AVI created by a camcorder or dv vidcam you have. These are typcally Interlaced.

I assume the AVI file looks fine when you play it?

After you select the AVI file in the wizard, you should be presented with a BOX showing what TMPGEnc has been able to determine of the source file. It will show whether the file is INTERLACED or NON-INTERLACED. If the source is INTERLACED, then you will also have an entry for the FIELD ORDER. Just change the FIELD ORDER. If iTMPGEnc detects the Source as BOTTOM FIELD FIRST, change it to TOP FIELD FIRST and vis-a-versa. Encode a small portion of the AVI and test to see if it makes a difference. Incorrect field order typically manifests itself as "jerkiness" and most specfically in horizontal panning shots.

Not sure if this is your problem, but worth a shot.

BTW -- It might be helpful if you used AVICodec or GSpot and posted up the particualrs of the source AVI file. Also use AVICodec on your resulting MPEG2 files. It may reveal addtional needed info. and provide better assistance.

[wuzzbert]

Yes the avi files are ok when I watch them before conversion, and these clips are not from a camcorder. Thanks for your help and I will give the field order option a try.

It's just so fustrating because I think to myself 'right I've found a way of converting perfectly and then on the next file it's a load of ****'

I'm not bothered about time as long as I can get good results, because I can set it going and just go to bed and leave it. I know that a lot depends on the quality of the source files but I keep finding when I do convert sometimes the quality significantly deteriorates, and I'm not looking for perfection, I just want to watch a half decent result.

Any more tips would be great, Thanks!

[fmctm1sw]

Is this a movie? And what resolution are you converting at?

[wuzzbert]

It is a movie in two parts which I have joined, but I'm not sure of the resolution as I am away from my home pc. What resolution should I be looking for to give good results?

[fmctm1sw]

I know I sound like a broken record but I had the same problem with movies. Left to right movement (or left to right too I guess), seemed jerky and maybe even looked like it flickered. But, if they look fine to you before converting... well... I'd double check the AVI file for this left to right movement. I had this exact probelm and I resolved it by doing an IVTC.

[wuzzbert]

What is one of them??

[fmctm1sw]

Well, I was going to link you to lukesvideo.com but it's down for some reason... Basically, after you make sure you have you field order right, you step through the avi file frame by frame and look for interlaced frames and progressive ones. Interlaced frames will looked combed or a little blurry. If you can count 3 progressive frames followed by 2 interlaced ones (on a consistent basis), a telecine has been perfomed on your material. I'll stop there before I get into IVTC (Inverse telecine).

[wuzzbert]

Would you like to expand on exactly how to do this or is it too complicated for a novice like myself

[fmctm1sw]

Nope, not at all.... How to check for it? You can use virtualdub to step through the frames. Before I get all into IVTC, I'd like to make sure your material has been telecined though... I'll try to find a link...

[SteveLF]

I used to get the same problem on my dvd player (Yamada 2100). Although it will play NTSC, I get the jerky Vid problem.

I switched to using Canopus procoder(1.5) to convert my aviS to PAL, it does a fantastic job of this, although it is a little slow.

I also convert the sound files to a constant bit-rate codec in virtual dub (usually one of the ADPCM ones) before converting to eliminate sound sync problems.

Steve