A .vaf file is a Video Information File. You would find these files often in a DVD2SVCD output folder when using the Cinema Craft Encoder (CCE) to encode MPEG-2 video with a Variable Bitrate (VBR).
The Cinema Craft Encoder is often regarded as the highest quality MPEG-2 encoder available. For new users, it can be used with DVD2SVCD to easily convert, DVD to DVD, DVD to SVCD, AVI to SVCD and AVI to DVD. You can also use it with DVDRebuilder to make DVD backups. The resulting quality is usually very high (depending on the input)