Standards and Practices for Authoring Dolby Digital and Dolby E Bitstreams ® Issue 3 ,m.
Standards and Practices for Authoring Dolby® Digital and Dolby E Bitstreams Dolby Laboratories, Inc. Corporate Headquarters Dolby Laboratories, Inc. 100 Potrero Avenue San Francisco, CA 94103-4813 Telephone 415-558-0200 Fax 415-863-1373 www.dolby.com European Headquarters Dolby Laboratories Wootton Bassett Wiltshire SN4 8QJ, England Telephone (44) 1793-842100 Fax (44) 1793-842101 Dolby, Pro Logic, and the double-D symbol are registered trademarks of Dolby Laboratories.
Standards and Practices for Authoring Dolby® Digital and Dolby E Bitstreams Table of Contents 1 Scope and Purpose .............................................................................................. 1 2 Definitions ............................................................................................................. 1 2.1 Dolby Digital ............................................................................................... 1 2.2 Dolby E............................................
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Standards and Practices for Authoring Dolby® Digital and Dolby E Bitstreams 1 Scope and Purpose Dolby Laboratories has developed products and technologies that enable audio professionals to create their own Dolby Digital data streams, allowing greater control and precision. This document is intended to encourage the use of these tools by mixers, engineers, producers, and directors to master their own audio.
Standards and Practices for Authoring Dolby® Digital and Dolby E Bitstreams 2.3 Metadata Metadata is additional control information that is carried along with the encoded audio program and provides essential information about the audio to a Dolby Digital decoder.
Standards and Practices for Authoring Dolby® Digital and Dolby E Bitstreams 3 Perceptual Coding vs. Metadata It is generally not necessary to monitor the Dolby Digital coding process from encode to decode simply to preview the effects of the coding algorithm. However, it is very important to monitor the effects of metadata on the source audio either through the encode/decode process or through the use of a DP570 Multichannel Audio Tool.
Standards and Practices for Authoring Dolby® Digital and Dolby E Bitstreams the sound of the decoded program based upon a consumer’s listening conditions. It is therefore vitally important to monitor the effects of metadata while mastering a Dolby Digital data stream.
Standards and Practices for Authoring Dolby® Digital and Dolby E Bitstreams DBS, etc.). Setting the Dialogue Normalization parameter is crucial to the proper operation of home decoders and provides three main functions: 1. In multimedia postproduction, the level-matching of dialnorm allows different content (i.e., titles, short movies, game replays, etc.) to be interspersed, maintaining the same comfortable listening level in the home.
Standards and Practices for Authoring Dolby® Digital and Dolby E Bitstreams Dialogue Normalization in a Dolby Digital decoder cannot be defeated. Dialogue Normalization alone does not assert any compression or expansion on the program material but simply adjusts the audio to a standardized level (See ATSC A52 www.atsc.org/Standards/stan_rps.html).
Standards and Practices for Authoring Dolby® Digital and Dolby E Bitstreams Dialogue Level Setting Null Band Low Early Cut Range Cut Range Centered at the Dialogue Level Parameter Boost Range Low Ouput Level High listening. Additionally, when enjoying a television broadcast or DVD in an environment with a high level of ambient noise, quieter portions of the program are drowned out by the ambient noise.
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.
Standards and Practices for Authoring Dolby® Digital and Dolby E Bitstreams channels and adds them in phase to the left channel and out of phase to the right channel. This allows a Dolby Surround Pro Logic decoder to reconstruct the L/C/R/S channels for a Pro Logic home theater. The Lo/Ro downmix adds the left and right surround channels discretely to the left and right speaker channels. This preserves the stereo separation for stereo-only monitoring and provides a mono-compatible signal.
Standards and Practices for Authoring Dolby® Digital and Dolby E Bitstreams Table 1 Example of Consumer Products and Output Options 5.1-Channel Amplifier 5.1-Channel Decoder High-End DVD Player DVD Player Digital I/O 5.1-Channel Analog Outputs X X Two-Channel Analog Outputs RF Remodulated Output Notes The regular A/V amp X X X X X (X) X X X X X X Often HDTV X X X IDTV X X High-End TV X Usually SDTV TV set with an integrated digital TV tuner Large screen TV with 5.
Standards and Practices for Authoring Dolby® Digital and Dolby E Bitstreams DP569 Dolby Digital Encoder Mixed audio stems to DP569 Dolby Digital output PC running Dolby Recorder application Timecode Dolby Digital DP562 Dolby Digital Decoder Audio out to amps/monitoring system 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.
Standards and Practices for Authoring Dolby® Digital and Dolby E Bitstreams Emulator out to amps/monitors DP570 Multichannel Audio Tool Mixed audio stems to DP570 Console solo bus Audio router output Timecode Metadata DP569 Dolby Digital Encoder Dolby Digital output PC running Dolby Recorder application DP562 Dolby Digital Decoder For file confidence monitoring Figure 3 DP570/DP569 with Dolby Recorder This configuration provides several key features. 1.
Standards and Practices for Authoring Dolby® Digital and Dolby E Bitstreams EX-EU4 Dolby EX Surround Encoder 0101 Ls/Bs/Rs stems to SEU-4EX Lt/Rt output to Ls/Rs input through A/D DP570 Multichannel Audio Tool Emulator out to amps/monitors L/R, C/LFE stems to DP-570 Timecode Dolby Digital output Metadata Digital audio router output: L/R,C/LFE, Ls/Rs Console solo bus DP569 Dolby Digital Encoder PC running Dolby Recorder application DP562 Dolby Digital Decoder For file confidence monitoring Ls/Rs
Standards and Practices for Authoring Dolby® Digital and Dolby E Bitstreams To router In Video Sources B Venus2001 DVP Stream Select Video PHILIPS A Flag A B Flag MetaData Sw B Metadata Metadata Dolby Digital encoded audio CH 1&2 or stereo B Dolby E or stereo audio Dual DP572 Dolby E Decoders CH 3&4 6-channel (5.1) or stereo audio CH 5&6 DP569 Dolby Digital Encoder DAP DAP 6-channel (5.
Standards and Practices for Authoring Dolby® Digital and Dolby E Bitstreams Emulator out to amps/monitors DP570 Multichannel Audio Tool Mixed audio stems to DP570 Video Sync Dolby E Output Console solo bus Audio router output Metadata (one frame delay) 00:00:00:00 DP571 Dolby E Encoder Digital VTR Figure 3 DP570/DP571 for Digital Television Distribution The output of the DP571 is delayed one video frame from reference.
Standards and Practices for Authoring Dolby® Digital and Dolby E Bitstreams 6 Frequently Asked Questions Aren’t Dolby Digital and “5.1” the same thing? No. A stream encoded in Dolby Digital can carry any number of channels, from a minimum of one mono signal to a maximum of six channels in a 5.1-channel home theater configuration. In digital television broadcast, Dolby Digital is commonly used in a two-channel stereo configuration.
Standards and Practices for Authoring Dolby® Digital and Dolby E Bitstreams Additionally, it is important that each of the main channels be equidistant from the mixing position. If this is not possible, the DP570 Multichannel Audio Tool has builtin delays that can be added to each channel as needed. Please refer to the User’s Manual for more comprehensive information. I am recording and mixing a music-only program and I don’t want the consumer to assert any compression on the audio.
Standards and Practices for Authoring Dolby® Digital and Dolby E Bitstreams How can I set the DP562 decoder to emulate the most common dynamic range control settings on consumer decoders? The front panel of the DP562 has four buttons that deal with the dynamic range control settings: None, Custom, Line, and RF. None is a professional set-up mode that defeats both dynamic range control and dialnorm, and is only used for installation and signal tests.
Standards and Practices for Authoring Dolby® Digital and Dolby E Bitstreams The LFE channel in contrast, is specifically produced with low-frequency information exclusive to this channel. Content producers have specifically created this LFE channel to include extra sound-effects information for emphasis in effects, such as explosions, crashes, gunshots, and such.
Standards and Practices for Authoring Dolby® Digital and Dolby E Bitstreams How much space does an *.ac3 file consume on my hard drive? It is simple to calculate the needed disk space for a *.ac3 file. First, determine the number of seconds in the program. In this example, a 90-minute program and a Dolby Digital data rate of 448 kbps is used: 5,400 sec. × 448,000 bits per sec. [Dolby Digital data rate] = 2.4192 gigabits 2.4192 gigabits / 8 [for byte conversion] = 302.
Standards and Practices for Authoring Dolby® Digital and Dolby E Bitstreams 1. Record the Dolby E stream so audio and picture are in sync on tape. This requires advancing the source tracks one frame before encoding to compensate for the one frame of delay in the Dolby E encoding process. This method maintains audio/picture sync on the recording media to facilitate editing.
Standards and Practices for Authoring Dolby® Digital and Dolby E Bitstreams Can I buy a consumer version Dolby E decoder for my home theater? No. Dolby E is a professional technology and is not licensed for consumer use. How do I get from Dolby E to Dolby Digital? To create a Dolby Digital data stream from a Dolby E stream, it is necessary to decode the source Dolby E stream to baseband PCM digital audio and then encode the selected digital audio program using a Dolby Digital encoder.
