Constraints on Dolby Digital Plus bitstreams in online containers

A Dolby Digital Plus bitstream must meet certain conditions to be delivered in any of the supported online containers.

If your product encodes Dolby Digital Plus bitstreams, ensure that your product uses the proper settings to meet these requirements. To prevent subsequent decoding problems, we recommend that a multiplexer reject a bitstream that is not compliant.

A Dolby Digital Plus bitstream must:

• Have a maximum data rate of 3,024 kbps.
• Have a sample rate of 48 kHz for all substreams present in the bitstream. (The value of the fscod parameter must be set to 0.)
• Have a constant number of blocks per frame for all substreams in the bitstream. (The value of the numblkscod parameter must be the same for all substreams.)
• Have a constant number of independent substreams.
• Within each independent substream, these bitstream parameters remain constant:
  • bsid
  • bsmod
  • acmod
  • lfeon
  • fscod
• Have a constant number of dependent substreams.
• Within each dependent substream, these bitstream parameters remain constant:
  • bsid
  • acmod
  • lfeon
  • fscod
  • chanmap
• Have a strmtyp value of 0 or 1. strmtyp values of 2 (transcoded) or 3 (reserved) are not supported.
• Have an acmod value of 1 or more. An acmod value of 0 (1+1) is not allowed.
• Be encoded in big-endian format.