Bidirectional

While many of the settings available under the Advanced Codec tab will simply affect picture quality, the Bidirectional setting can affect compatibility so this is an important one to consider.

Without going into too much detail about how video compression works, you should understand that the output file is basically a mixture of partial images with a few complete pictures sprinkled around (keyframes). DivX will start with a complete picture then progressively apply changes to make the picture move. Every once in a while, a new, complete picture is displayed and the process starts over again.

Turning the Bidirectional setting off, reduces the number of complete pictures that a DivX player has to track while displaying your video. Changing the setting to Adaptive Single Consecutive, makes DivX players remember more pictures at one time.

The catch is, not all players are capable enough to handle Adaptive Single Consecutive encoded videos. Particularly, small devices like phones may have trouble playing those videos. However, any devices that are DivX certified for the Portable profile or better, will be able to handle those videos with no problem.

You certainly want to use Adaptive Single Consecutive if your DivX player can handle it. Most can and it will provide significantly better picture quality in almost every case.