Dolby Laboratories DP570 Specifications download pdf (Page 12)

Standards and Practices for Authoring Dolby

Digital and Dolby E Bitstreams

Because of the relationship between dialogue normalization and dynamic range

control, it is necessary to select the appropriate dialnorm value prior to previewing

dynamic range profiles. As the amount of dynamic range compression used is

ultimately selected by the consumer for their own specific listening needs, it is

important to preview the dynamic range control profiles through a variety of

compression settings before selecting one to include in the metadata stream.

3.6 Downmixing

Simply put, downmixing allows consumers to enjoy a 5.1-channel television

broadcast, DVD, or game console without requiring a complete home theater setup.

More technically, downmixing is a function of Dolby Digital that allows a

multichannel program to be fully reproduced over fewer speaker channels than for

which the program is optimally intended.

As with stereo mixing, where the mix is monitored in mono on occasion to maintain

compatibility, multichannel audio mixing requires the engineer to reference the mix

to fewer speaker channels to ensure compatibility for downmixing situations. In this

way, Dolby Digital, using the metadata parameters that control downmixing, is an

“Equal Opportunity Technology” in that every consumer who receives the Dolby

Digital data stream can enjoy the best audio reproduction possible, irrespective of the

number of channels in their playback system.

It is important to understand the output signals found on each piece of equipment that

can receive a Dolby Digital program in the home (see Table 1). Set-top boxes (STB),

such as those used for the reception of terrestrial, cable, or satellite digital television

typically offer an analog mono signal modulated on the RF/Antenna output, a line

level analog stereo signal, and an optical or coaxial digital output. DVD players offer

an analog stereo signal as well as a digital output, and possibly six-channel analog

outputs as well. Portable DVD players offer an analog stereo signal, headphone, and

digital outputs. DVD players found in computers and game consoles offer a digital

output and possibly six-channel analog outputs, as well as analog stereo and

headphone outputs. 5.1-channel amplifiers, decoders, and receivers have six-channel

analog outputs and possibly six speaker-level outputs.

In all cases, the analog stereo output is a downmixed version of the Dolby Digital

data stream while the digital output carries the Dolby Digital data stream to a

downstream decoder or integrated amplifier with Dolby Digital capability.

The analog stereo output of these units can be one of two different stereo downmixes.

One is a stereo-compatible Dolby Surround downmix of the multichannel source

program that is suitable for Dolby Surround Pro Logic decoding. This downmix is

called left-total/right-total or Lt/Rt. The other type of downmix is a simple stereo

representation (called left-only/right-only, or Lo/Ro) suitable for playback on a stereo

hi-fi or via headphones, and from which a mono signal is derived for use on the

RF/Antenna output from a set-top box. The difference between the two downmixes is

how the surround channels are handled. The Lt/Rt downmix sums the surround

1 ... 11 12 13 ... 26

Comments to this Manuals

No comments

Dolby Laboratories DP570 Specifications Page 12

Comments to this Manuals

Related products and manuals for Networking Dolby Laboratories DP570