VBR -vs- CBR

[dab1968]

Does anyone know which is better, Variable Bit Rate or Constant Bit Rate, and why?

[THoff]

It depends on the situation.

CBR is easier and faster to encode, and causes fewer problems when fast forwarding or reversing. If you aren't running out of disk space or have to lower your CBR bitrate below about 6000Mbps to make it fit, then stick with CBR.

VBR is useful to fit longer videos onto a disk, or to encode highly variable video where one scene is really simple (static backgrounds, little movement) and the next is highly complex (explosions, special effects, fast panning). In that case VBR encoding can be used to use a specific average bitrate, and the encoder is allowed to shift data around to compensate for the more or less demanding video frames. VBR doesn't really become effective unless you use multi-pass encoding, and unless the minimum and maximum bitrates aren't close to the average bitrate.

[GeorgeW]

CBR is easier and faster to encode, and causes fewer problems when fast forwarding or reversing. If you aren't running out of disk space or have to lower your CBR bitrate below about 6000Mbps to make it fit, then stick with CBR.

probably a typo, but I think you meant 6000kbps

[THoff]

CBR is easier and faster to encode, and causes fewer problems when fast forwarding or reversing. If you aren't running out of disk space or have to lower your CBR bitrate below about 6000Mbps to make it fit, then stick with CBR.

probably a typo, but I think you meant 6000kbps

You're absolutely correct. Mea culpa.

[Trevor Andrew]

Have a read at this page, it contains a bit rate calculator with quite a good explanation.

http://dvd-hq.info/Calculator.html