
XT3 Series DISK RECORDER - Version 10.05 - Software Technical Reference Manual
10.05.D
EVS Broadcast Equipment SA – July 2011
1.4.5 DOLBY AUDIO MANAGEMENT
SOME DEFINITIONS
Dolby Digital or Dolby 5.1 or AC-3, is an audio coding system containing up to 6
discrete channels of sound, with 5 channels for normal-range speakers (20 Hz -
20,000 Hz) (Right front, Center, Left Front, Right Rear and Left Rear) and one
channel (20 Hz - 120 Hz) for the LFE, or subwoofer.
Dolby E is a professional coding system optimized for the distribution of
surround and multichannel audio through two-channel postproduction and
broadcasting infrastructures, or for recording surround audio on two audio tracks
of conventional digital video tapes, video servers, communication links, switchers,
and routers.
DOLBY CONFIGURATIONS IN XT3 SERVERS
Case 1: The 5.1 audio signal is carried on 6 discrete PCM audio channels
•
Available on an XT3 in all configurations
• The audio can be analogue, digital or embedded depending on the
configuration
• In AES audio, if the audio is correctly genlocked to the video, the sample rate
converter can be switched off.
Case 2: The 5.1 audio signal is coded in the two-channels Dolby E
standard
•
Dolby E over AES/EBU links
o Set the configuration of the pair of channels carrying the Dolby E signal to
“DY” in the AVCFG. This has two effects :
• It disables the sample rate converter on the input channels
• It forces all transitions to a hard cut.
If the sample rate converter is activated and the audio configuration is a mix
between PCM audio over AES and Dolby E over AES, the sample rate converter
will only be applied to the PCM over AES signal.
• Dolby E Embedded in the SDI/HD SDI stream
o Set the configuration of the pair of channels carrying the Dolby E signal to
“EY” in the AVCFG. This will force the transition to a hard cut.
o The sample rate converter parameter does not apply to embedded audio.
The Dolby E transitions will be correct as long as:
• the configuration is correct
• the AES stream containing Dolby E is correctly synchronized with the video
Dolby E transitions will not be correct (2 frames of mute at the transitions) if the
AVCFG is set to E instead of EY or D instead of DY.
Audio effects (scrub, slow motion) are not possible in Dolby E. If they are used
anyway, the audio will be muted.
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