The purpose of this specification is to define the storage file format for SMPTE Layered Video Extension (VC- 4) video streams which extends a file format that is compliant with the ISO Base Media File Format. The VC- 4 video streams can be dependent on any base layer video streams such as SMPTE ST 421 (SMPTE VC-1), ITU-T H.262 (MPEG-2), ISO/IEC 14496-2 (MPEG-4 Part 2) or ITU-T H.264 (MPEG-4 AVC), etc. The storage format for VC-4 shall be extended from a particular file format which encapsulates a base layer video stream on which the VC-4 shall be depedent. The following file formats derived from ISO Base Media File format shall be extensible from this specification but are not limited to these:

• MP4 file format (ISO/IEC 14496-14)

• AVC file format (ISO/IEC 14496-15) S

• MPTE VC-1 file format (SMPTE RP 2025)

The file format for storage of VC-4 content uses the existing capability of the ISO base media file format. In addition, the following new extensions to support new features of VC-4 codec are specified:

• VC-4 Sample: a newly defined sample including a subset of enhancement layers or all enhancement layers of a picture.

• VC-4 Extractor: a structure to enable efficient extraction of bitstream segment units from samples in other tracks instead of containing duplicate media data.