Dolby Vision is digital rights management (DRM) agnostic if the encryption follows ISO/IEC 23001-7.
To facilitate stream reformatting before decryption, it is required that at least the Network Abstraction Layer (NAL) length field and the nal_unit_type field (the first byte after the length field) of each NAL unit is left unencrypted, and it is recommended that the entire slice NAL headers remain unencrypted.

In addition, it should be noted that:

• For other NAL structured video sample description stream formats (for example, avc3, hvc1, and hev1), only video slice data should be encrypted. The size and type headers of a video NAL slice should be unencrypted. For the other NAL types, no encryption is needed.
• There are multiple NAL units per sample, requiring multiple pieces of clear and encrypted data per sample.
• NAL units that do not contain video slice data need not be encrypted, and should not be encrypted if they contain information that must be accessed prior to decryption, such as caption information contained in SEI NAL units.
• Although some of the statements about encryption are recommendations in ISO/IEC 23001-7, some DRM systems will define the following items as requirements moving forward:
  • NAL units that do not contain any audio or video data must remain entirely unencrypted. This means that the Dolby Vision reference picture unit must remain entirely unencrypted.
  • NAL units that contain audio/video data must have the slice header unencrypted.
  • In the MP4 box structure, the four-character-code (4CC) of the sample description (for example, dvh1 for profile 5) must be replaced with encv, and the 4CC of the unencrypted samples must be specified in the Original Format Box (frma).