How can quality be lost?

[Sgt_Strider]

Let's say I take a DVD-9 disk and I only want to keep the main movie file and the ac3 5.1 audio and use DVD2ONE to make it, how can quality be lost? Wouldn't the bitrate and filesize be the same as it would be on the original disc? I can understand that by keeping everything in the DVD-9 disc and compress it to fit it on a DVD-5, of course there will be a quality loss to fit it into a smaller disc. What if I just want to take the "main" movie file and just keep it and dump all the extras. Will quality be lost? I keep on hearing that it'll be transcoded and etc.

[Doom9]

well.. it depends how large your main movie is. If it's below 4.7mio bytes on the original DVD then you can strip away the extras and not loose any quality. But on many occasions the main movie is larger than a DVD-5 in which case you'll have to transcode to fit it on a DVD±R (which is capacity wise the same as a DVD-5).

[69Mws]

Well, it's not said that on all DVDs the main-movie only is small enough to fit on a DVD-R.

I saw DVDs where the main-movie had a playtime of just 90 mins. and it also contained only 192 kbps audiotracks, but its Titleset had a quite enormous size of ~8 GB :p

Greetz
69Mws

[69Mws]

ups, Doom9 was faster ;)

[Sgt_Strider]

Originally posted by Doom9
well.. it depends how large your main movie is. If it's below 4.7mio bytes on the original DVD then you can strip away the extras and not loose any quality. But on many occasions the main movie is larger than a DVD-5 in which case you'll have to transcode to fit it on a DVD±R (which is capacity wise the same as a DVD-5).

I'm actually a little confuse by your DVD Decrypter guide when using it to strip away the things that I need to burn on to a DVD. On the "main" ripping guide, you stated for file mode, just insert the DVD and then DVD decrypter will automatically chooses the vob and the necessary files as your default to rip to a directory. Should you need more files, you can also do that. However one of the steps in making the DVD with DVD2ONe, the guide mention that when the DVD is inserted and the files are automatically chosen, you press ctr+a to select "all" the files in the DVD to rip to your drive. Now I'm confuse, which one is the right one? Is there a different purpose for both approaches?

[69Mws]

It depends on what you wanna do. If you wanna backup the whole dvd, then choose file-mode and by pressing "ctrl-a" all files will be selected for ripping.

If you wanna movie-only, then you may choose IFO-Mode. In that case DVDDec automatically selects the largest Titleset and rips the VTS_xx.VOBs and its VTS_xx.IFO to a folder you specify.

For processing movie-only with dvd2one that's enough, you don't need to rip the whole dvd for that.

Greetz
69Mws

[Sgt_Strider]

When using DVD2One or CloneDVD and decide to rip the movie out along with one audio track, how do I know for sure that either of those software won't transcode the video to fit the DVD? Let's assume that the whole package comes to 4.0GB. How do I know that during the removal process that neither of the software transcoded or reencoded the movie, even though its not needed to fit the DVD-5 disc? thx

[luphy]

You can tell by comparing the size of the titleset
with the original.

Shrink actually says 'copying' instead of 'encoding'
when it is processing a disc that does not require
any compression.