Bitrate for Black and White?

[ln108]

I hope this is an easy question to answer: Would I be right in assuming that if one is encoding a black and white film to MPEG-2, one can get away with a lower bitrate, and still maintain comparable quality, than if one were encoding color?

In other words, would a higher bitrate be needed for a similar film in color than for one in black and white, to produce equal quality (presumably because, in the black and white film, less information is being processed)?

Thanks for any input!

[Mug Funky]

a lot of the time the bitrate is the same...

in theory (bitrate setting problems aside) the output should be greater than 2/3 the size, but that is only for DCT components.

basically the colour planes are still being encoded, but as blank grey blocks. and the motion vectors would still take up the same space, which means the size difference would be quite small.

usually a black and white film will compress significantly better simply because an old film (well restored) is likely to be slightly blurrier.