Dolby® Digital Professional and Dolby® Digital Plus Professional
Engine supports media files containing Dolby Digital Pro and Dolby Digital Plus Pro encoded audio. WAV, MXF, MP4, QT MOV and MPEG TS files that contain common formats of Dolby Digital Pro and Dolby Digital Plus Pro can be processed in Engine for Loudness Compliance. Profiles for the loudness settings can be created for Dolby Digital Pro and Dolby Digital Plus Pro in the same way as for PCM audio, and with the same flexibility.
Engine supports Loudness Compliance for audio encoded in Dolby Digital Pro and Dolby Digital Plus Pro formats. Engine also supports the encoding of PCM audio into these formats. Files containing encoded audio are also compatible with many of the available modules within an Engine system.
Dolby Digital Pro and Dolby Digital Plus Pro are carried in a pair of channels in the media file. This means that the equivalent of a stereo pair in the file is used to hold the Dolby encoded audio. Dolby Digital Pro and Dolby Digital Plus Pro are most commonly used to carry a 5.1 track. Additional audio channels that are associated with the 5.1 can also be carried. Note that ‘associated’ in this case has a special meaning. It requires that the extra channels are related audio, so you could have a stereo version of the same audio also included in the Dolby Digital Pro or Dolby Digital Plus Pro. However you could not carry a completely independent stereo along with the 5.1 and this is due to the way the associated channel is added.
If you need to carry an unrelated stereo along with the 5.1, then this would have to be carried separately. Engine would require that the stereo and the unrelated 5.1 were each independently encoded, and so this scenario would need four PCM channels to contain the encoded audio.
When carrying out loudness compliance on a pair of tracks containing Dolby Digital Pro or Dolby Digital Pro encoded audio, you merely connect our Loudness module to that stereo pair. Engine automatically works out the number of channels and whether it is 5.1 or stereo etc, then applies the correct loudness algorithms. There is no need to have advance knowledge of the program layout of the encoded audio.
Dolby is a registered trademark of Dolby Laboratories.