Can DVD -> AVI -> DVD improve quality?

[JoeBolden]

Can a DVD (from a VHS transfer) be converted to avi to clean up then back to DVD and improve the quality? The Transfer was done by another party so that part couldn't be changed

This movie was originally a VHS to DVD transfer
(This is about a public domain no copy restriction movie)
The following information was in the details for a movie by the uploader

"But when I started to play it I could see that it was just a VHS to DVD transfer. It had all the same sound flucuations and picture artifacts around the edges from the VHS transfer. So, I had all day available and ripped/demuxed with AutoGK in DIVX. Then I pulled out my copy of SONY DVD Architect 4.0. Ran the audio and video tracks thru and was able to crop out all the ragged edges from the VHS and clean/brighten the picture up a little. I was also able to clean up the audio track and get rid of most of that recurring wave sound the original VHS copy always had in it. Then I burned it into a new and improved DVD. I could have just uploaded the Divx but then it would still have had the crappy picture and sound."

Question 1 Can this statement "improved DVD" be true?

Question 2 Is there a way to cleanup a VHS to DVD transfer without converting to avi if all you have is the DVD (after the transfer)? not what was done above

Question 3. Since the original DVD was transfered from VHS. Is it true there was no improvement in quality that would be lost by converting to avi to clean up and then convert back to DVD?

Question 4. If you convert convert a DVD to avi without any compression highest quality (keeping large file sizes) to do cleanup or other adjustments and reconvert back to DVD will there be any loss in quality?

When I say avi I refer to Dvix or Xvid.

Any answers, comments, suggestion or other ideas are gratefully welcomed.

Thank you,

Joey

[manono]

Question 1.

Could be, but since that clown didn't know how to go about it right, I kind of doubt just how much he improved it. It sounds like all he did was crop, resize, and maybe adjust the levels, hardly a major improvement. And any "improvements" were probably more than negated by the conversion to XviD/DivX first.

Question 2.

Of course there is. And you sure as heck don't want to convert it to AVI first. How do you do it? By encoding from the DVD source via an Avisynth script file frameserved to the encoder. Any cropping, resizing, and other filtering for cleanup is taken care of in the script. I do this sort of thing all the time. You can also do the same thing frameserving and filtering with VDub, but that's much slower and produces somewhat inferior results.

Question 3.

Like I said, he probably wiped out any possible improvements by doing the conversion to AVI first.

Question 4.

DivX and XviD by definition are very lossy, so you can't use them together with without any compression. Lossless (not uncompressed) means something like Lagarith or HuffYUV, not XviD or DivX. So, yes, there will be a huge loss of quality converting to an XviD AVI first. Especially so using AutoGK for the job, even at target quality 100%.

[Richard_G]

Bottom line is that you can never improve the quality of a video. If it has been compressed to Xvid or DivX the detail has been thrown away and you can never get it back because it simply isn't there. All you can do is to soften it and blur parts to make it appear better quality when in actual fact you've made it worse.

[mats.hogberg]

@ JoeBoldenon't hijack threads please. Start a new thread for a new question.

Do not hijack topics.
Please try to stick to the author's first post in each topic, if you want to discuss something else, create a new topic.

I've split this out for you, as a separate thread.

/Mats

[guns1inger]

If you need to convert to avi - and some programs simply do work better with avi than with mpeg - then use a lossless format such as Lagarith or Huffyuv. Never use end-user codecs like Divx or Xvid.

[JoeBolden]

-Thought I would get answers similar to these but wanted to be sure before explaining these to the seeder.

Thank you very much manono, Richard_G and guns1inger for your informable clear and concise replies.

Thank you mats.hogberg for correcting my error of not starting a new thread.

I see newbies and even sophomores uploading these with or without knowing. If there is a way to make a concise mention of this in the newbie FAQ's and in a couple of other pertinent guides or FAQ's Stickies etc. to point this out please do so.

It is never recommended to convert a DVD to avi and then convert it back to DVD. There will be a huge loss of quality converting to an XviD AVI first. Whether using AutoGK or other Divx or Xvid conversion programs for the job, even at target quality 100%.

This applies even for cleaning up the video (links to that

You should never upload a DVD that was converted from DVD to avi and then back again. This isn't fair to the downloaders as they have to use much more of their bandwidth to do so. Even worst is to upload the reconverted DVD and not mention this fact in bold noticeable text. It is at least a deception. I would go so far to say dishonest if you knew that but still did it.

Thank you,

Joey

[manono]

You have to be careful how you word it. AVI can be all kinds of things. XviD is lossy AVI. Lagarith is lossless AVI. When I have some heavy filtering to do, as that kind of source often requires, I'll create a Lagarith AVI before then sending that to CCE, also using an Avisynth script file to frameserve.

[moviebuff2]

Hello everyone:

I downloaded Lagarith. How do I add it to VirtualDubMod? I copied the .dll to VirtualDubMod but Lagarith does not show in the codec compression list.

Thanks

[manono]

Right-click the inf file and Install. It's explained in the included ReadMe.txt:

Normal installation (Non-Windows 64):
Right-click on lagarith.inf and select install to install the codec. If you
do not see an install option, make sure you extracted the files, and are using
the extracted lagarith.inf file.

[moviebuff2]

Thanks, manono. I got it.

[SatStorm]

I do this with other peoples projects frequently, but a bit different.

I rip the DVD to my PC then I load the parts to Virtualdub mpeg2 direct. Then, I add some filters like rmPAL (if the source is PAL), msu smart deblocking, neat video, video denoise, etc....

Then I frameserve and re-encode to mpeg2. There is visual improvement sometimes, but as you know filtering also takes off some part of the picture. It may be visually better, but technically is not.
I always keep the original too.