Rip to Recode, or Shrink to Recode?

[CobraPilot]

I make two backups of my DVDs:

o Via DVD Shrink to a DVDR-SL
o Via Nero Recode to a CDR (Nero MP4) from the DVD Shrink files

Question about using Nero Recode for the CD backup:

Which would produce the better MP4: Recoding from the already-compressed DVD Shrink files or from non-compressed DVD files via DVD Decrypter (or Fab Decrypter)?

The end result is one large .mp4 file that fits on a CD-R either way, but I'm wondering if there is a definitive answer as to which does/should produce the better .mp4.

Anyone have any experience in comparing the two methods?

[ricardouk]

I make two backups of my DVDs:

Which would produce the better MP4: Recoding from the already-compressed DVD Shrink files or from non-compressed DVD files via DVD Decrypter (or Fab Decrypter)?

you would get better results from a non compressed dvd.

if you use a compressed source you're compressing a file that has already been compressed so there will be a a bigger loss of quality

[zworg2]

As above..

Use teh original source material for both processes.

It *might* take longer, i dont know, but quality wise much better.

[jimmalenko]

The DVDShrink bit would seem like a redundant step to me. Going straight from the source DVD to mp4 in one hit should result in the better quality file. Whether it's actually noticably better is possibly another story ....

[CobraPilot]

As noted in my original post, the use of DVD Shrink is for purposes of the backup to DVDR-SL. I then also do a backup to CDR, sort of a "I really want to see the movie again and neither of the DVDs will play" safeguard.

So, to get the movie to fit on a CDR, lots of compression is necessary, obviously.

While it may seem logical that using Recode from a non-compressed rip might be a better quality MP4 than using Recode from a DVD Shrink compression, I was just wondering if anyone had actually made objective or subjective comparisons between the two methods, or is relying on a "logical" assumption. You still have to compress big DVD files to smaller MP4.

If there's no apparent visual difference (a BIG "if"), then using DVD Decrypter or DVDFabDecrypter is probably an unnecessary third step in the process, DVD Decrypter=>DVD Shrink, DVD Decrypter=>Recode vs. DVDShrink=>Recode.

It may be time to run an experiment. Hope my eyesight is sufficient to make an accurate evaluation between the two methods!

[CobraPilot]

I finally got around to making a "scientific"/non-scientific comparison between these two methods . . .

The Nero Recode bitrate to compress a DVD to a 700mb CD is the same whether you start from a DVD Decrypter-compressed file (DL to SL) or a DVDFabDecrypter uncompressed file. This is the "scientific" comparison.

The non-scientific: My semi-calibrated eyeballs can't tell the difference between the two Nero Recode versions.

Soooo, it can be a two-step vs. three-step process: No need for DVDFabDecrypter unless DVDShrink fails.

[guns1inger]

Of course the bitrate will be the same regardless. Bitrate is only related to the end size, not the starting size or quality. So this on it's own has no scientific merit.

Comparison of only one disc is also meaningless. Depending on the quality of the original, and how much you had to shrink it by, there may well be very little difference in quality. But the next disc may well be a very different story. It is quite possible to Shrink Disc A by 20% and get very little visual difference, then shrink Disc B by only 5% and get artifacts a'plenty.

So to date, all you have actually proven is that

a. Nero Recode 2 is consistent when calculating the bitrate for a given target size

b. Some disc you encoded twice looks the same both times, even though one was run through DVD Shrink first, and one wasn't. A test that has no validity for any other disc you might try.

I'm convinced.

[zworg2]

wow any more bitchy on a year old thread and i'd think you were female!

[guns1inger]

Just trying to clear up some recent disinformation that had been added. I don't go grave robbing.

[CobraPilot]

Ahhh, the classic tact of the Aussies . . . . .