MPEG-2 Transport Streams


The new Dolby AC-4 features are supported by a new bitstream format. Some of the changes impact multiplexing Dolby AC-4 in an MPEG-2 transport stream, so multiplexers must be able to support the new format. Multiplexing Dolby AC-4 into an MPEG-2 transport stream differs from most other codecs (for example, Dolby Digital Plus and Dolby Digital), because although Dolby AC-4 is frame based, it does not have a fixed frame rate or a constant frame size. With Dolby Digital Plus or Dolby Digital, the multiplexer can use a byte stream buffer and operate on chunks of constant sizes with known durations, whereas for Dolby AC-4, the multiplexer needs to take different frame sizes and frame durations into account.


For more information, contact Dolby to obtain access to the Dolby AC-4 Content Creation Development Kit.


HLS or MPEG-DASH


Full details on HLS and MPEG-DASH multiplexing and packaging can be found in the Dolby Online Delivery AC-4 System Development Kit. This can be downloaded through the Dolby interoperability Support Center Portal. Access is provided after a free registration process. If you are not a Dolby licensee then please sign on using the "Dolby Labs Consumer Products Partners" option.