Understanding broadcast telemetry

Using the Church Webcasting System, YouTube, etc. Including cameras and mixers.
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they007
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Posts: 13
Joined: Sun Jan 16, 2011 8:59 am

Understanding broadcast telemetry

#1

Post by they007 »

I'm going to be Webcasting our stake conference in a few weeks and I've been doing tests to try and ensure things go as smooth as possible. I'm curious if anyone here can share insight into the broadcast telemetry charts that are available. I've attached one from the test I did today for reference.

The left side of the chart has a health score of 1-100 but I'm not really sure how to interpret that. What line should I be looking at? None of the lines on my chart ever seem to be over 50% but everything seems to be working fine.
The building has 25mb (up and down) internet from Frontier FIOS. I've configured the Teradek to send 1280x720p video at about 2mbps. The attached chart was from 2.1, others I done were 2.5 or 1.75 I think.
The chart never seems to show me reaching the target bitrate, but the folks receiving the test say everything looks good. No pixilation or other display problems. I guess it OK that I seem to be sending less than 2mbps if the video is static, or should I change something to try and reach the target more often?

Any thoughts/experience you can share would be appreciated.

thanks,
Jon
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egibb
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Posts: 10
Joined: Wed Nov 05, 2014 8:41 am

Re: Understanding broadcast telemetry

#2

Post by egibb »

Great questions. I am no expert here but have asked Global Support enough questions and done enough testing that I have a good idea on what is happening. See my other forum post - viewtopic.php?f=27&t=35131

For the sending site, the Orange recieve rate is the rate at which the data you are sending to the servers. It will go up and down but should stay close to your target (blue dots). If you can't maintain that, perhaps you need higher bandwidth or set the Teradek to a lower max rate. We run 1080p cameras and could get away with 1700ish kbps without any noticable video quality decay.

For the receiving sites, that's a different story. We watch the Buffer Health indication (see attachment). When the blue fill drops off, you'll know they will soon freeze or auto adjust to a painfully low bitrate. If they aren't able to maintain buffer health, then have the receiving site increase their Max Buffer Limit (see other post) or manually adjust the Video Quality to something less that Auto. We are settling on a Buffer Limit of 120 seconds, which is better than the old 4 min default but gives us some breathing room above the current default of 30 seconds. The auto setting on Video Quality will default to match what bitrate you are webcasting at.
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Eldon Gibb - STS
Sherwood Park Alberta Stake
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