DivX to MPEG2 conversion - ideal data rate

[danniballoon]

I wondered what the ideal data rate is when converting DivX to MPG2?

If for instance the DivX file has a video data rate of 936Kbps, what would the ideal data rate be for the MPG2 file, to maintain qualty and yet not have an unnecessarily large file ?

I've been making the MPG2's twice the size of the DivX file, which seems to work reasonably well, but wondered if this was the ideal. I convert a lot of DivX stuff to MPG2 so that it can be authored to a DVD that will play in any machine.

[guns1inger]

The best method is to not convert them at all, but to get a Divx capable player. But if you must convert, the general rule is 3 - 4 times the bitrate of the source is required. You have to remember that you are usually also increasing the resolution, so you have to compensate for the higher number of pixels, as well as for the fact that mpeg2 does not compress as much as mpeg4.

Personally, I treat the source as any other, and look at the running time. I then use a bitrate calculator to work out the correct bitrate. The source bitrate is immaterial.

[jagabo]

I usually use an MPEG2 encoder that supports constant quality encoding (TMPGEnc Plus, CCE). I select the quality I want and the encoder uses whatever bitrate is necessary to deliver that quality (at each frame, constrained to DVD legal bitrates of course) regardless of the source.

This works especially well with 22 or 45 minute TV episodes. Convert all the episodes then put as many as will fit on a DVD.

[theewizard]

yep what they said, i primarily use CCE then author with GFD, I used to use convertX a lot and still do sometimes, I have tempgenc but only use it if I want ot edit / join mpeg files