Specifications

5.1-Channel Production Guidelines Preparing the Source Delivery Master
6-4
6.4 Time Code
Time code plays two important roles in preparing mixes for Dolby Digital encoding.
First, it is common to use some form of SMPTE or MIDI time code for synchronizing
recording machines (DA88, ADAT) and digital editors (Pro Tools or MIDI
sequencing program) while recording and mixing material. It is important to be aware
at the beginning of a project what the final time code delivery format will be.
Working in that format will save time later and prevent possible errors in frame rate
and synchronization. This is especially true when working with video. Even with the
introduction of high-definition video formats worldwide, varying frame rates and
time code modes (including drop-frame) will be around for some time to come.
Second, if the material is going to be encoded using Dolby Digital for either DVD or
Digital Television, it might be necessary to add a time code stamp to the Dolby
Digital bitstream at the time of encoding. This is done by sending the time code from
the source material into the Dolby Digital encoder Time Code input and selecting
Enable Time Stamp from the setup section of the Dolby Digital encoder. Dolby
Digital has the ability to add a time code stamp to the associated Dolby Digital frame.
This stamp can be used to align the Dolby Digital audio file with a compressed video
file containing a corresponding time code stamp. This process can be done with either
a DVD-authoring station or DTV encoder.
Having the correct time code that matches the picture is essential to proper audio and
video synchronization. In addition, it is also very important that the time code source