Dolby Laboratories DP570 Specifications download pdf (Page 15)

Standards and Practices for Authoring Dolby

Digital and Dolby E Bitstreams

PC running

Dolby Recorder application

DP569 Dolby Digital

Encoder

Dolby Digital

output

Mixed audio stems

to DP569

Dolby Digital

DP562 Dolby Digital

Decoder

Audio out to

amps/monitoring system

Timecode

Figure 2 DP569/DP562 with Dolby Recorder

This method, while effective, suffers from two main drawbacks.

1. The resulting audio from the decoder is out of sync with the picture. The coding

delay inherent in the encoder, coupled with the latency of the decoder, creates a

minimum overall sync error of about 219 ms. The coding delay within Dolby

Digital encoders is adjustable from a minimum of 187 ms up to a maximum of

450 ms, while Dolby Digital decoders, adhering to SMPTE 337M, add a latency

of 32 ms on the decode side. While the resulting audio gives the engineer an

accurate representation of the effects of the selected metadata parameters, the

delays involved create a less-than-ideal monitoring situation.

2. This configuration provides no method to use common console functions such as

Solo/PFL and Speaker Dim/Mute during mastering. As the monitoring system is

connected to the output of the DP562 in this configuration, any solo or dim/mute

functions existing on the console cannot be used.

These three issues notwithstanding, using an encoder and decoder back-to-back

provides an accurate method of selecting and previewing metadata parameters for the

creation of a Dolby Digital data stream, as well as creating the actual stream itself.

4.2 DP570/DP569 with Dolby Recorder

The preferred method of selecting, previewing, and authoring metadata for inclusion

within a Dolby Digital data stream is through the use of the DP570 Multichannel

Audio Tool paired with the DP569 Encoder. This configuration uses the DP570 for

both the monitoring and authoring functions of metadata, and frees the DP569 to

simply encode the audio and create the resulting Dolby Digital data stream with the

selected metadata parameters.

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Dolby Laboratories DP570 Specifications Page 15