GUIDE TO INSTALLATION AND OPERATION
IRD-3811 |
43
4 User Reference Guide
4.1 Decoding MPEG Transport Streams
The user can input DVB-ASI signals up to 80 Mbps on either ASI input connector. Alternatively, the Ethernet can be
configured to receive an IP stream (see section 3.4.15).
To select an input, go to the
Input Menu
and then
Input Selection
Once a valid transport stream signal enters the decoder, the first valid service found is decoded automatically (AUTO
selection mode only) if no selection was previously made. If the previously-selected service does not exist in the
stream, the IRD picks the first found in the PAT. The secondary audio will be set to NONE by default while the first-
found audio stream will be selected.
In order for a service to be decoded, the following conditions must be met:
a) The transport stream must be ISO 13818-1 compatible
b) The video stream must be MPEG2 in the 4:2:0 color profile
c) The audio stream can be MPEG1 layer 2, MPEG2, AC3 or AAC-LC
d) The video bit rate is not more than 26Mbps
e) The transport stream bit rate is below 80Mbps
To select a service within the transport stream, go to the
Input Menu
into
Service Select
. For iControl, please
refer to section 3.4.6. The name of the service will be displayed when available (the name is as per ATSC VCT
and is unavailable for non-ATSC streams). When the service name is not available, the card displays the
service number as per PAT.
Audio-only services can be decoded; the output display will be blacked.
4:2:2 video will not generate any errors but the display will be fuzzy
The IRD has a maximum parsing capability of 64 services per transport stream. An error is generated
if the stream has more services, and only the first 64 entries of the PAT will be selectable.
Whenever the stream cannot be decoded, the outputs are set to freeze or black according on user
selection.
Any change in PAT or PMT will trigger the service selection system. This makes it possible to use in
an ASI hot-switch context.
4.2 Decoding Audio
The IRD-3811 can decode 2 audio streams simultaneously.
If no audio PID was previously selected or if the selected PID does not exist, the IRD automatically selects the first
found audio in the corresponding PMT.
The following audio coding formats are currently supported:
•
AC3 audio up to 5.1 channels
