 The IH-BD (Intra-Hybrid Blu-ray) format includes a 25 GB rewritable layer (BD-RE) and a 25 GB write-once layer (BD-ROM), designed to work with existing Blu-ray Discs.Blu-ray Disc specifies the use of Universal Disk Format (UDF) 2.50 as a convergent-friendly format for both PC and consumer electronics environments.It is used in the latest specifications of BD-ROM, BD-RE, and BD-R.