Chapter 9 - MPEG decoder
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The list of video channels always appears first.
MODE
->
AUDIO List
displays the list of audio
channels.
MODE
>
VIDEO
List
takes you back to the video list. All channels marked with (*) are
encrypted.
Use the
Up
/
Down
arrow keys to select the required channel from the list. The
or
buttons scroll
between the pages of the channel list.
Press
ENTER
to call up additional details about the selected channel. This includes the channel
name, provider and PIDs (packet identifiers) of the associated elementary streams.
Some channels are broadcast with second audio programming (e.g. several languages). You can
choose the required audio programme in the “programme properties” menu.
Pressing
ENTER
again switches to the channel. The screen now shows just the video channel. The
speaker sound can be checked at the same time.
Note:
For digital transmission, no conclusions can be drawn about the reception quality based on the
quality of the picture and sound. The picture and sound are always perfect to a certain transmission
quality, below which the signal cannot be reproduced. Only within a small threshold range can you
notice characteristic blocks in the picture (“brick wall effect”) and constant interruptions to the sound.
Broadcast quality can only be determined based on measurements (BER, MER).
Press
ESC
to return to the previous channel list, from which you can select another channel.
OSD/VID
takes you back to normal measuring mode.
9.4 Display
of
MPEG
video parameters
As soon as a live picture can be seen, the MPEG decoder displays the following parameters in a
window at the lower right edge of the screen.
Profile and level:
e.g. MP @ ML
Chroma format:
e.g. 4:2:0
Video resolution:
e.g. 720*576
Letter Box Format: 4:3 or 16:9
The parameter window can be displayed or hidden at any time using the
or
arrow keys.
9.5
Video bit rate measurement
The MPEG decoder measures the current bit rate of the video stream being broadcast while a live
picture is shown. It is shown in the unit [Mbit/s] in the window described in the section above. The
measuring period is 1 second.
9.6
Dynamic program switching
Some program providers divide their programming into regional content at specific times. This means
that, for example, 4 programs may appear in the MPEG program list which have the same content at
certain times and different content at other times. The program map table (PMT) in the data stream
therefore changes over time. In this way, the station can prompt the receiver to use different packet
identities (PIDs).
In the standard setting, the MPEG decoder of the instrument uses the PMT that was sent at the time
of the last program search. In other words a static PMT.
The dynamic PMT update function can be activated using
MODE
->
Settings
->
Dyn.program
switching
. If you start the program now, the decoder continually searches for a new PMT version. If
the device detects a change in the PMT, the current program is stopped, the message “Dyn. program
switching” appears and then the program is restarted with the updated PIDs. These settings are
saved in the non-volatile memory and remain active until they are deactivated in the above menu.
