DVD Demystified

Essentials of DVD Production
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the home environment. Establish consistent audio levels and equalization
throughout all audio on the disc, including menus and supplements. This is
especially important with multiple audio tracks from various sources, since
the viewer will be able to jump at will between them, and will be bothered
by inconsistencies in level or harmonic content. Resist the temptation of
locking out the audio key on the remote control, which will only annoy your
viewers. Instead, get all sources in PCM format so they can be matched and
harmonized before being encoded.
Tips and Tricks The following tips will assist you in preparing the audio
assets:
■ Make sure timecode is included with the audio so that it can be
synchronized with the video.
■ It’s almost always a good idea to mute the audio for a second or so at
the beginning of each segment. This ensures that the player (or
receiver) doesn’t clip the audio as it begins the decoding process.
■ If you are doing 5.1-channel Dolby Digital encoding, or using
multichannel DVD-Audio PCM tracks, test the downmix.
■ If you do your own encoding, request the Dolby Digital Professional
Encoding Manual from Dolby Labs.
The Zen of Subwoofers If you understand the proper use of the LFE
channel, you belong to an elite minority. As Dolby Labs has pointed out over
and over, apparently with little success, LFE does not equal subwoofer. All
5 channels of Dolby Digital are full range which means they are just as
capable of carrying bass as the LFE channel. Most theaters have full-range
speakers. They don’t need separate subwoofers since most of the speakers
have a built in subwoofer. In the home, it’s the responsibility of the receiver
or the subwoofer crossover to allocate bass frequencies to the subwoofer
speaker. This is not the responsibility of the DVD player (unless it has a
built-in 5.1-channel decoder) or of the engineer mixing the audio in the studio.
The LFE channel is heavily overused in most audio mixes. A case in
point is a certain famous movie released on laserdisc with Dolby Digital 5.1
tracks in which the booming bass footsteps of large dinosaurs were placed
exclusively in the LFE channel. When downmixed for two-channel audio
systems, the bass was discarded by the decoder, leaving mincing, tiptoeing
dinosaurs; this was not the fault of downmixing or the decoder. It could have
been fixed by a separate 2-channel mix, but it also could have been fixed