encoding lines

[mreuter]

After encoding our home video we notice on playback that there are lines running vertically evenly accross the screen. They appear lighter in color and are particularly noticable against solid color background. We have tried various filters during this process and have been unable to remove these lines. We believe the lines are caused by the encoding process, since they are not there in the avi file and are still present even when we remove all filters. We are using the lastest version TMPGEnc. We are making mpeg 2 for DVD. Any help in this area would be appreicated.
Thanks.

[gadgetguy]

I had a problem similar to what you've described but I discovered after closer examination that the original AVI also had the vertical lines, but they were much less noticable. The encoding process enhanced the lines. What process/program are you using to create the AVI?
What are you using to determine that the vertical lines are not in the AVI?
If they truly are not in the AVI, what are the specs for the source, and what template/settings are you using to encode?
If you can, would you show us a screen shot of before and after? Preferably of the same frame?

[mreuter]

Thanks for the reply. After a closer look at my collection of test AVI and MPEG files, you may be on to something. The source went through several steps on the way to the encoder, and you may be able to spot my problem if you know the steps... Originally taped on a Sony Hi8 handycam early one Christmas morning (low light made for grainy video). Hi8 tape played back on a Sony Digital8 (TRV350), and captured(transferred) on PC as DV via firewire. Free sample app from MS used to transfer and store as DV Type2. Then VirtualDub is used to edit undesired sections, and to "clean up" the video using filters. The edited data is stored as an AVI using the Panasonic DV codec. Finally, TMPGEnc is used to encode the file to mpeg. In an effort to find the source of the problem, I used VDub to create a 3 min long AVI file which I could save with various filter combinations. After reading your reply I looked closely at the original AVI file, and the 3 minute version, and it appears the lines are showing up (or at least getting worse) by just editing the DV AVI file with VDub and saving it. No filters were enabled in VDub, but does the Panasonic Codec cause the data to be "reencoded" on every save? I thought I was into the digital realm, where I could make perfect copies, but maybe I am wrong. Thanks again for any help you can provide.

[mreuter]

A little further testing confirmed the problem. If I load the AVI file into VDub, save it using the Panasonic DV codec to a new filename, and then load the new file, and save it.... After about 6 generations, the lines make it look like my kids are spending Christmas in jail. I guess the answer is to load the original AVI into VDub, do any editing and filtering, and then use the frameserver to send it uncompressed to TMPGEnc. Any other suggestions?

[junkmalle]

Use Video -> Direct Stream Copy in VirtualDub. That way it won't reencode the DV.

[jimmalenko]

I guess the answer is to load the original AVI into VDub, do any editing and filtering, and then use the frameserver to send it uncompressed to TMPGEnc. Any other suggestions?

I use this guide for my "caps" to DV via a canopus ADVC-100. You use AVISynth scripts to co-ordinate opening your file in virtualdubmod, you can automatically insert Trim commands to put your edits into effect, and add any filters supported by AVISynth (I *think* there is a way to use vdub filters too). That particular guide makes use of a noise reduction filter called convolution3D, but with a little tweaking of the script you can use any filters you like. The final stage is opening the script in your encoder, with all edits and filters being applied "automatically" on your original DV-AVI.

Might be worth checking out

[MrMoody]

I've seen VDubMod occasionally do this on the display but never the output. I haven't figured out why. It seems to be related to scaling/aspect ratio. I suspect either a driver or codec issue. Anyway, jim and junk are right, don't re-compress the file. Either way they're suggesting will work.

[gadgetguy]

Use Video -> Direct Stream Copy in VirtualDub. That way it won't reencode the DV.

While that's true, you also can't apply any Vdub filters.

Applying all filters at once and frameserving will give better results than saving repeatedly to successive files. Also try Jimmalenko's suggestions. I haven't read through the suggested guide, but AviSynth is a very powerful tool. It is well worth your while to get to know it. And you can use it in combination with Vdub while you are learning how to script.

[dipstick]

Author your project onto an RW and view it on a TV before you pass judgment. It may very well be simple interlaced scan lines you're seeing.

To minimize quality loss during multiple editing and filter adding, it's best to save to a lossless compression like Huffyuv or lagarith codecs. The file size will be much bigger, but the quality will be maintained.

I'm pretty sure VirtualDub has a built-in FrameServer, but I haven't used it in years.

[lordsmurf]

After about 6 generations

There is no reason to go 6 generations.