Dolby E Metadata and DP571 Setup

• The originating encoder in the Dolby chain must be set to “internal” metadata source or controlled by an external device (DP570, PC software etc).

• Metadata from an external source cannot be edited in a DP571 if incoming metadata is incorrect it must be rebuilt from scratch (this is only applicable to live programmes).
• A Dolby E stream uses 75ohm unbalanced connections – if the loop through connectors on a DP571are not feeding another device they should be terminated.

• The most important DP571 setup parameters to check are:
o Program Config (should be 5.1 + 2 for most programmes).
o The Frame Rate (The factory default is 29.97fps, UK default is 25fps).
o The Bit Depth (should be 20 bits) the Dolby E Metadata Source (internal or external)
o Dolby D metadata is enabled.

• The “Bit Depth” setting does not refer to the number of bits used by the audio signals but rather the number of bits available in the AES-3 channel used to transmit the Dolby E signal. Six channels of audio can be transmitted down a 16bit link while 8 channels can be transmitted down a 20 bit link.
• The gain of a Dolby E stream must not be changed as it will corrupt
• A Dolby E stream suffers one frame of delay on each encode and decode. The standard delivery requirement is to align the stream to be “sync encoded” at each point in the chain. (Live programmes only)
• For tape delivery the stream must be laid so that the encoded audio is in sync with the video and any stereo audio. The “Audio Advance” function or a video frame delay will be used to correct lip sync errors. The PCM stereo audio will also be delayed to compensate.
• For live or as live programmes the stream must be timed so that the encoded audio is in sync with the video and any stereo audio. It is the responsibility of the area receiving the stream to compensate for the decoding delay
• The DP571 has a “reversion mode” which tells the unit what Dolby E and Dolby Digital metadata parameters to use in the event of a metadata failure. This should be set to “last used”. This setting guards against temporary metadata failure disrupting Dolby Digital
encoding.
• In the “Metadata Params” menu there are eight programs for which metadata can be changed. The number of active programs depends on the “Program Config” setting. If Program Config is set to the default 5.1+2 value then Program 1 will contain the metadata
for the 5.1 stream. Program 2 will set the metadata for the additional stereo pair. If the Program Config is set to 8X1 then Program 1 will set the metadata for channel 1, Program 2 for channel 2, Program 3 for channel 3 etc. It is worth noting that all eight programs remain viewable even if the selected channel configuration does not make use of them. The DP571 gives some indication of error conditions the following table explains the meaning of the front panel error indication lights.

Light Indication               TC Green:                                 Yellow:                                                               Off:
Valid timecode signal    Frame rate does not match video reference     No TC signal detected

Fault Red:                                  Off:
Hardware-related fault condition    No fault condition

Remote Not used
PCM Dly                        Green:                                                     Yellow:                                        Off:
Valid PCM signal                                      non 48kHz signal                       no PCM signal
Error Red:                                                       Off:
Input not valid for current settings                 No error condition
V Ref Green:                                                                                    Yellow:                                                                         Flashing Red:
Lock with a valid analogue composite video signal   Video ref doesn’t match the selected frame rate in the DP571     The internal clock is not locked to the incoming reference

Factory Reset Changes
The two key parameters to be changed after factory reset are Dolby Srnd EX parameter and the Srnd 3dB Attn.
Lo/Ro stands for Left only / Right Only. This down mix is the best suited for reproduction form stereo speakers or headphones. It is created by mixing the Ls and Rs channels into the front L and R channels. The Centre is split between the L and R channels. The levels the other channels are mixed in at are set by the metadata. LFE is ignored. The Lo/Ro mix preserves left/right separation
and allows a mono compatible down mix

**Lt/Rt stands for Left total / Right Total. Ls, Rs and Centre are folded down into the left / right pair using parameters set by the metadata. LFE is ignored. In an Lt/Rt mix the surrounds are summed and added to the left channel they are also added to the right channel out of phase which allows a Pro Logic decoder to reconstruct the surrounds. This is a stereo compatible Dolby down mix and is
not the ideal down mix for stereo reproduction Reset unit prior to first use The Dolby E encoder model DP571 can be reset to factory defaults by power cycling it while holding down the enter key until “factory defaults” appears on the LCD. Press the setup key when
prompted to confirm.

Pressing the Shift, → and Esc keys simultaneously will perform a soft reset.
Dolby E DP571Settings
Programme Config 5.1 + 2
Frame Rate 25
Bit depth 20
Programme Description Preferred – programme title and episode no
Reversion Mode Last used (for live programmes)
Metadata Source 1st
Unit in chain Internal (for live programmes)
Metadata Source
subsequent units External (for live programmes)
Dolby D Metadata Enabled

Dialogue Level
(Dialnorm)
-22 to -27 permitted
-31 allowed for “total” music performance

Channel Mode 3/2 Indicates channels are in use
LFE Channel On Enables or disables the LFE
Bit-stream Mode Complete Main (CM)
Describes the audio service carried in the bit stream – information only

Line Mode Compression Film Standard Designates preset compression configuration for line mode decoding. Most high-end decoders allow the compression
to be defeated.
RF Mode Compression Film Standard
Designates preset compression
configuration for RF mode
decoding, cannot be defeated.
RF Over modulation
Protection Disabled
Protects against over
modulation by adding preemphasis
when a Dolby Digital
stream is RF modulated.
Centre Down mix Level 0.707 (-3.0dB) Recommended
The level of the centre channel
in the L and R if the listener has
no centre speaker.
Surround Down mix
Level 0.707 (-3.0dB) Recommended
The level of the surrounds in the L and R if the listener has no rear speakers.

If the surround  content is very important use a higher level. The surround content may interfere with the main mix

Dolby Surround Mode Disabled Indicates whether a two channel encoded bit stream contains a Dolby Surround Lt/Rt program and requires Pro Logic decoding
Audio Production Information No  Indicates whether the mixing level and room type parameters are set – not required.
Mix Level 80dB
Indicates the approx mixing
level in the control room –
information only.
Room type Small Indicates the control room type – information only.
Copyright Bit Yes Indicates the material is copyright protected – information only, not copy protection
Original Bit-stream On Indicates whether the encoded Dolby Digital stream is the master – information only
Preferred Stereo Down mix Lo/Ro    Designates preference for Lt/Rt
(pro logic – stereo compatible) or Lo/Ro (stereo) down mix
Lt/Rt Centre Down mix Level 0.707 (-3.0dB) Rec Level of centre channel in Lt/Rt down mix
Lt/Rt Surround Down mix Level 0.707 (-3.0dB) Rec Level of Surrounds in Lt/Rt down mix
Lo/Ro Centre Down mix Level 0.707 (-3.0dB) Rec Level of Centre channel in Lo/Ro down mix
Lo/Ro Surround Down mix Level 0.707 (-3.0dB) Rec Level of Surrounds in Lo/Ro down mix

Dolby Surround EX
Mode Not Surround EX Identifies the stream as being coded for 6.1 Dolby EX. N.B. the default is not indicated which must be changed.
A/D Converter Type Standard Information only DC Filter Enabled Applies a 3Hz DC blocking filter before encoding.

Low pass Filter Enabled Pre encoder anti-aliasing filter.

LFE Low pass Filter Enabled Applies a 120 Hz 8th order low pass filter to the LFE channel before encoding

Surround 3 dB
Attenuation User choice Used to preserve compatibility with older film formats

Surround Phase Shift:
Lo/Ro Disable

Unit settings will not be affected by a soft reset. It is suggested that a full reset is completed prior to setting up the encoder using this guide

ALWAYS CHECK WITH DELIVERY SPECS and CLIENT PRIOR TO ENCODING AND LAYBACKS

cheers

geo