When to reencode a DVD in mpeg-2 vs mpeg-4?

[catinhat2000]

I'm not sure if i'll use the right terms here, and I understand there are no hard fast rules, but I was hoping to get some opinions.

When backing up a largish movie (i.e., the stripped down movie is about like 6 - 7 GB) to a single layer DVD, is there a rough cutoff where I'm better off switching to an XVID or X264 opposed to reencoding in CCE?

My understanding is that if the compression is smallish, sticking with mpeg2 is generally better, right?

Is it more of a bitrate thing then a size thing?

Thanks!

[CWR03]

A lot depends on your future intended use of the backup. A DVD5 copy has the advantage of being playable in most standalone players, while an MPEG-4 copy needs either a specialized device or a PC.

As far as determining when to use which on a quality basis, my determining factor is always to make an .ISO image output and see how it looks - if I'm dissatisfied with the quality I either try to find something to remove from the backup which I likely won't use or switch to MPEG-4. Since every disk has a different level of compression due to motion or colorspace, there's really no guideline to follow at all. Even two disks with the same amount of data can come out completely different in quality.

[Whiskeyfather]

Mpeg4 codecs have better motion estimation engines so they'll start to block on much lower bitrate than mpeg1/2 will......
(if you were to try to encode same source on 700kbit/s target bitrate,mpeg4 will ALWAYS win.....)
so i don't waste my bitrate on mpeg2....

[BigDid]

Hi,

Another factor could be keeping chapters or not. It is possible but not easy in mpeg4, and easy/usual in mpeg2 :)

Did