Tieline Merlin PLUS User Manual page 278

278 Merlin PLUS User Manual v2.0
8. Select the remote codec FEC setting in the Remote FEC screen and press
Important Note: FEC can only be programmed for use with the Music and MusicPLUS
algorithms.
Configuring RFC 2733 FEC in the Codec (Sessionless Connections only)
1. Press the HOME
2. Use the navigation buttons on the front panel to select Connect and press the
3. Select IP and press the
4. Select Sessionless and press the
5. Select Peer-to-Peer and press the
6. Use the down
7. Navigate to FEC and press
8. Select Enable and press
9. Select the FEC Percentage and press
10. Select the FEC Delay used by the codec and press
Important Notes:
·
The FEC Delay configured should take into account the packet arrival (jitter buffer)
strategy at the remote codec. For example, if the maximum jitter buffer at the remote
codec is 1000 ms, the FEC Delay setting should be lower, to ensure there is enough
time for FEC packets to arrive and replace lost packets prior to audio playout.
·
By default, the codec will use the audio stream IP address as the remote FEC IP
address as well. This can be adjusted in the Program Manager panel in the HTML5
Toolbox web-GUI.
·
The default local and remote UDP audio FEC ports are 9002.
·
Any of the available algorithms can be selected when configuring RFC 2733 FEC in the
codec.
How does FEC work?
If you enter a FEC setting of 20% and you are losing one packet in every five sent, the lost packet
will be replaced by FEC to maintain the quality of the connection. If you are losing more packets
than this, say one in three, it will be necessary to increase the FEC setting to 33% to compensate.
Note: There is an inverse relationship between FEC settings and the jitter-buffer millisecond setting
that you use for IP connections.
So why not use 100% FEC every time? The answer is because you need twice the bit rate to
achieve full redundancy and depending on the link conditions, this could potentially cause more
dropouts because of network congestion than it fixes. Here is a simple rule to remember: Your
maximum uplink speed is the maximum bandwidth you have to play with. As a rule of thumb, try not
to exceed more than 80% of your maximum bandwidth. If your link is shared, be even more
conservative.
You should also consider the maximum upload speed at the remote end too. Is the connection
shared at either end? Your bit rates, FEC settings and buffer rates must be pre-configured at both
ends before you connect, so it's always better to set your connection speed and balance your FEC
according to the available uplink bandwidth at each end for best performance.
button to return to the Home screen.
button.
button.
button.
navigation button to select Setup and press the
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button.
button.
© Tieline Pty. Ltd. 2017