GUIDE TO INSTALLATION AND OPERATION
36
| IRD-3802
4 User Reference Guide
4.1 Decoding MPEG Transport Streams
The user can input DVB-ASI signals up to 80Mbps on either ASI input connector. Alternatively, the Ethernet
can be configured to receive an IP stream (see section 3.4.9).
To select an input, go to the
Input Menu
into
Input Selection
.
Once a valid transport stream signal enters the decoder, the first valid service found is decoded automatically
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 either MPEG4 or MPEG2 in the 4:2:0 color profile
c) The audio stream can be MPEG1 layer 2, MPEG2, or AC3
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 3.4.3. 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 input signal contains erratic data, the audio decoders are stopped until the
situation is resolved. This prevents invalid data from entering the decoder and corrupting the
audio. The audio is then muted for a period of about 6 seconds.
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-3801 can only decode 1 audio stream while the IRD-3802 can decode 2 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.