DVD2SVCD and VBR bitrate settings?

[vcddude]

Hello,

When making VBR SVCD backups of my DVDs with DVD2SVCD I use the following encoder settings:

Max Avg Bitrate: 2400
Min Avg Bitrate: 1600

Max Bitrate: 2520
Min Bitrate: ????

My question has to do with the best Min Bitrate to use. Should I use 0, 300, 500, or 1200? (all of which I have seen recommendations for in this forum).

Seems to me that using something low like 500kbps will produce poor results as video encoded that low would look crappy. If I set it to 500kbps, would the encoder actually encode video at that very low quality rate? How does the encoder figure out what bitrate to use in the first place?

Any info on the ramifications this setting has on overall video quality?

Thanks,
vcddude

[Vejita-sama]

Multipass VBR encoding works as follows. The first pass is normally a CBR pass, where the same bitrate is used for all scences. The VBR is then applied to each additional pass.

The program will determine where high motion and low motion scencs occur. The program will raise the bitrate in the high motion scences (but not above the max entered) and lower the bitrate in the low motion scences (but not below the min entered). But do so such that the ave equals what you entered. This way you can still predict the final size of the encoded MPEG. The more passes the better the bitrate will be spread out.

Most people recommend:

Max - DVD players max supported bitrate. This allows the program to really work it's magic on those few high motion video scences.

Ave - from bitrate calculator to determine the final final size of your MPEG (normally to fill your media)

Min - 300. It's unlikely that the bitrate will actually get that low, however, setting the min as low as possible allows the program to raise the bitrate to the max in high motion scences, whiling maintain the average.

For example, if you used, 2000,2100, 2500. Then the VBR encode will not be very good. During fast scences you can't really raise the bitrate all that much as there's not much 'wiggle room.' Verses, 300, 2000, 2500. Now the program can raise the bitrate to 2500kbit/s for long periods of time (if need be) because it has the 'wiggle room' to play with the bitrate.

[macleod]

to ensure maximum compatibility with all dvd players (provided they will play the chosen format), use a min of 300. Some (few) dvd players cannot handle bit rates that fall below the 300 mark.

[vcddude]

Great, thanks for the clarifications!

vcddude