(registered 2022-07-13, last updated 2022-07-13)

Media type name: image

Media subtype name: dpx

Required parameters: N/A

Optional parameters: standard – If specified, the parameter indicates 
   the version of the SMPTE standard with which the file complies. At 
   the time of IANA registration, the possible values are st268-1 
   (for SMPTE ST 268-1) and st268-2 (for SMPTE ST 268-2).

   If the standard parameter is absent, the file can comply with any 
   version of the SMPTE standard.

Encoding considerations: binary

Security considerations: DPX files only encode images with      
   corresponding metadata and do not employ executable content.
   The header defines a "user-defined information" section that can 
   contain arbitrary binary data. As such, a maliciously coded file 
   could contain a binary blob comprising executable content. 
   Therefore, the user-defined header must not contain executable 
   content, and implementations that receive, display, or otherwise 
   process images must preclude the execution of any executable 
   content that might be received.

   Some files also contain a “standards-based metadata” section that 
   can include arbitrary XML. Such XML could include potentially 
   harmful or malicious links to other resources.

   Implementations will need to ensure that a received file can be 
   handled within the available memory. DPX allows run-length 
   encoding, so decoders will need suitable bounds checks to ensure 
   that memory locations outside the allocated decoded image buffer 
   cannot be altered.

   DPX files do not have integral encryption or authentication. A 
   32-bit “encryption key” field is defined in SMPTE ST 268-1, but 
   the standard does not specify an encryption algorithm; therefore, 
   utilizing the field for encrypting picture data will generally not 
   be interoperable. Any file protection, privacy, or integrity 
   requirements must be handled using an external mechanism.

Interoperability considerations: SMPTE ST 268-1 has been very widely 
   used since it was standardized (initially as SMPTE 268M:1994) but 
   has experienced some interoperability issues in practice. These 
   issues have occurred primarily due to conflicting interpretations 
   relating specifically to how the pixel data is ordered, packed, 
   and padded. SMPTE ST 268-2 has improved interoperability due to 
   the inclusion of metadata that resolves ambiguities that are 
   present in ST 268-1. However, ST 268-2 is a more recent standard, 
   whereas ST 268-1 has been widely used for many years prior and is 
   employed in voluminous archives.

   Both ST 268-1 and ST 268-2 define core fields and values. Files 
   must include all core fields, and reader or receiver 
   implementations must interpret all core fields and values.

Published specification: SMPTE ST 268-1; SMPTE ST 268-2 (which 
   incorporates ST 268-1 by reference)

Applications which use this media: DPX is derived from Kodak's Cineon 
   format and is used primarily as a file format for digitization of 
   camera-captured frames and as a digital intermediate file format.

Fragment identifier considerations: N/A

Restrictions on usage: N/A

Additional information:

   1. Deprecated alias names for this type: N/A
   2. Magic number(s): hex 53 44 50 58 (most-significant byte first
      file) or 58 50
   3. File extension(s): dpx
   4. Macintosh file type code: N/A
   5. Object Identifiers: N/A

Person to contact for further information:

   1. Name: Director of Standards Development
   2. Email: standards-support&smpte.org

Intended usage: COMMON

Author/Change controller: Society of Motion Picture and Television 
   Engineers ("SMPTE")