Decoder Status
When the decoder is enabled, the decoder reports whether it is locked to a valid compressed audio (Dolby E) stream. A valid stream
is defined as follows:
• Compressed (Dolby E) audio frames are embedded in the AES3 data according to SMPTE 337M.
• The Dolby E frame must be correctly formatted with a valid CRC.
• For Dolby E, the video frame rate indicated in the Dolby E stream must match the current video frame rate used by the video
encoder. An alarm is generated if the frame rates do not match.
The decoder also reports if PCM bypass and/or switchout are active.
The Dolby E program configuration, video frame rate and bit depth are reported when the decoder is locked to a valid Dolby E
stream.
It is possible to view the Dolby metadata associated with each Dolby E program by navigating to Audio Module N -> Audio Decode M
-> Metadata Status -> Metadata Status (Program X) menu.
It should be noted that metadata status updates relatively infrequently (approximately every 10 seconds) and consequently may not
always match the current input metadata.
The following parameters configure an audio encode of the decoder output:
The parameters listed in the table below control downmixing at the input to the encoder, if it is required to match coding modes. By
default downmix is controlled by the Dolby metadata from each decoder output as each Dolby E program has its own associated
Dolby metadata. However it is possible to override the Dolby metadata parameters with user-specified (fixed settings) if desired.
When transcoding to Dolby Digital there are the following additional controls
Decoder Type
Can only be set to ‘Dolby E’ at present.
PCM Bypass
When set to ‘On’, the main input is passed through to program outputs 1-4 if compressed audio is not detected
at the input (see diagram below).
When set to ‘Off’, program outputs 1-4 are replaced with silence if compressed audio is not detected at the
input.
Program outputs 5-8 are always replaced with silence when compressed audio is not detected at the input.
Switchout
When set to ‘Auto’, uncompressed audio on the ‘switchout’ input is passed through to program output 1 if
compressed audio is not detected at the input (see diagram below).
When set to ‘Off’, the ‘switchout’ input is never used.
Parameter
Description
Input Source
Specifies the encoder input source.
For audio transcode, the input source should be set to ‘Decoder 1 (Audio Module N)’, where N is the audio
module number (1 on the EN8100, 1 or 2 on the EN8190).
Set to ‘Off’ to disable the encoder.
Dolby E Program
This is used to select the program output (1 to 8) from the Dolby E decoder. For example, for a 5.1+2 Dolby E
stream, then program 1 contains the 5.1 stream and program 2 contains the 2.0 stream.
It is possible to route the same Dolby E program to multiple encoders if desired.
If the specified Dolby E program output is not present in the Dolby E stream, then the encoder input is
replaced by silent audio and an alarm is generated.
Parameter
Description
Downmix metadata
override
Set to ‘On’ to always override the downmix parameters in the metadata with fixed (user-specified)
parameters.
Set to ‘Off’ to use the metadata values (if they exist).
Downmix metadata
reversion mode
Specifies the behaviour on loss of metadata from the decoder output.
Set to ‘Use fixed settings’ to use the user-specified parameters when metadata doesn’t existed.
Set to ‘If available, maintain last received metadata values, otherwise use fixed settings’.
Downmix type
Specifies the downmix type. This setting is always used (the preferred downmix type in the Dolby metadata is
ignored, even if metadata override is set to ‘Off’).
‘Lo/Ro’ is a downmix that is suitable for playback on a stereo hi-fi or headphones.
‘Lt/Rt’ is a downmix that is compatible with Dolby Pro Logic receivers.
Centre mix level
Sets the centre channel mixing levels when downmixing to L/R channels (-3.0 dB, -4.5 dB or -6.0 dB).
Surround mix level Sets the surround channel mixing levels when downmixing to L/R channels (-3.0 dB, -4.5 dB or zero gain).
Parameter
Description
Metadata controls
encoding mode
Override default coding mode with coding mode indicated in decoder program configuration or live metadata (if
present).
When set to ‘On’, the encoder will use the same coding mode indicated by the decoder metadata. Note it is not
possible to obtain a 5.1 encoder output unless this option is enabled.
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