In the DVD+RW Video format, video can be encoded with a variable bit-rate (VBR). Because the writing process takes place at a constant bit rate, the writing process needs to be suspended and continued frequently. Normally, this would result in a linking loss, making the disc incompatible with read-only devices like DVD Video players and DVD-ROM drives. With DVD+RW it is possible to perform lossless linking, i.e. to suspend and continue the writing process without linking loss. This feature makes the format very efficient and suitable for random write in data as well as video applications.
http://www.licensing.philips.com/information/dvdrw/documents161.html