iCap Alta TS Usage Recommendations

The Alta TS Scaling Guide provides helpful guidance on resource scaling.

The server running the licensed software must be able to reach licensing.eegapis.com over HTTPS (TCP port 443). Computers with typical web browsing require no special licensing setup. However, if you are allowing this outbound connection through a special firewall exception, add licensing.eegapis.com to your allow list. If the allow list only supports fixed IP addresses or does not update DNS frequently enough for correct functionality, use proxy0.licensing.eegapis.com (23.21.205.168).

For installations where no internet access at all is available, alternative licensing schemes such as hardware dongles for desktop software, or custom site licenses for other products may be available instead.

With the firewall exception created, confirm the networking on the TS is configured correctly, and is enabled:

1. Test your connection by starting the Alta service and then using your iCap username to validate the license once you have opened an exception on your firewall.
2. If you are starting multiple virtual machines (ex. host and guest) on different IP addresses, but the same subnet in Bridged Adapter mode, be sure to randomize the virtual MAC addresses to avoid duplication.
3. If you are using using multi-cast, use source-specific multicast to prevent another device from plugging into the network and connecting to another multicast group.
   Note: Some network switches may not support this.

Always set the output transport rate 1 to 2 Mbps higher than the input rate to allow more bandwidth for Alta encoding processes. With no CBR (constant bit rate) set, the output bit rate will match the input rate.

The exception is with CC Stream Out Only enabled. In these cases, do not set the CBR because the system removes everything other than captions from the output.

When using a caption output format other than ATSC User Data, also use Low Latency mode (below).

In addition to setting the CBR Transport Rate 1 to 2 Mbps higher than the input rate, enable Low Latency Mode (LL) when using any Caption Output Format other than ATSC User Data. This avoids adding unnecessary bandwidth to the stream for video processing or multiplexing that does not need to occur in these formats.

The exception is when CC Stream Out Only mode is set to enabled. In these cases, to not enable Low Latency mode, regardless of the caption output format, and do not set a CBR. 

Requirements for Low Latency mode with a set CBR:
Do not transmit Program Clock References (PCRs) upstream every 200 ms. If the period between PCRs becomes longer than 200 ms, the system sends the entire buffer to the output without adding the correct padding. This is unlikely to present a problem a few times over a long run but we recommend not allowing the PCR period to consistently be over 200ms.

• 50 in low-latency mode
• Regular mode: 500 for a 1-second GOP stream, 1000 for 2-second GOPs, and 2000 for 3-second GOPs.
• 800 ms is the default.
• Increase the buffer size by 400 at a time (or double the prior value) if you experience a high rate of jitter errors or buffer overuns in the logs. Recommended to increase by 400 at a time until see better performance. 

Only runs properly with non-ATSC formats and when low-latency mode is off, so make sure this is the case in your configuration.
CC Stream Out Only mode for DVB Subtitles output TS rate is fixed and calculated as:

1.5 mbps + (n -1) * 1 mbps where n=number of subtitle services/PID's

Available log levels:

• 0:Trace (most verbose)
• 1: Debug
• 2: Information
• 3: Warning (default, same as if left blank)
  
• 4: Error
• 5: Fatal (least verbose)

Depending on your needs, set to 0 or 1 when troubleshooting. If you are not troubleshooting, set to 2 or 3 to reduce system load.

Ensure the configured value in this setting matches the Display Style setting in LEXI or other authoring software.

• pop-on
• rollup

With pop-on selected, there is one picture update per scroll cycle for each row of captions that appear (one row at a time). This bypasses both individual word and character updates and the scroll animation.

Note: There is approximately 3-4 seconds of extra latency in pop-on mode, compared to rollup mode in addition to rollup mode's typical latency.