This article was previously published under Q295579
When you try to play a DVD, you may be unable to do so, and you may receive an error message that relates to your third-party DVD decoder program or your hardware Motion Pictures Expert Group (MPEG) decoder.
This issue can occur if the DVD you want to play contains a .vob file that is too large. As of June 26, 2001, the most common file types that are used by DVD manufacturers have a .vob or .dat file extension, and the DVD-Video standard only allows single extent files. An extent descriptor under the Universal Disk Format (UDF) standard can only describe 1 gigabyte (GB), and larger files need more descriptors.
UDF uses a 32-bit integer as the size of an extent, the top two bits of which are reserved, so there is a maximum extent size of 2^30 - 1. MPEG2 data is normally written a block at a time, and this means that the block size is 2^30 (or 1GB-2KB). Because of this, if the .vob file size is greater than or equal to 1,073,741,824 bytes (the block size), the .vob file is not playable.
You can use Windows Explorer to view the size of a .vob file.