golden rule' bitrate conversion from one video format to another !

[greendesert]

1) Is there any 'golden rule' for video and audio bitrate conversion to retain the same quality.

avi @1500 video kbps and audio 128 kbps= mpeg1 video@???? and audio ????? kbps
wmv @1500 video kbps and audio 128 kbps = mpeg1 video@???? and audio ????? kbps

2) any approx idea of the ratio of file size increase ?
3) would increasing the bitrate for burning video to play on dvd player would lead to increase in quality.
4) What could I do to decrease the bright flickering which happens after conversion, when run on the dvd player ?? though it looks fine on monitor ?

These are the queries from a novice user

[guns1inger]

1. No. The closest to a 'rule' for video would be to expect a 3 - 4 fold increase for your normal mpeg4 material when converting to mpeg2. That said, there are a lot of variables, including just how high the original bitrate was. AVI is a container format whose contents are defined, in part, by the codec used. This can also therefore influence greatly the expect file size for conversion.

2. File size is directly related to bitrate.

3. Once the data is lost, you can't get it back. If the original was over compressed to begin with, re-encoding at a higher bitrate will have no effect at all on the quality. However re-encoding at an inadequate bitrate will do further damage.

4. I have never experienced the flickering that you are talking about, however pulsing and shimmering are usually signs of over-compression. You might be able to filter some of it out using avisynth and something like the bolckbuster plugin, however this usually comes at a cost of detail.

[jagabo]

Use a constant quality encoder and you'll always get exactly the right bitrate for the quality you ask for.