Technical Data on OTA Channels

[zippyfrog]

I was browsing the info on RabbitEars technical data for the Chicago market. When you dig down to the Technical Data, you can see the amount of video Mbps for each channel. I have a couple of questions:

1) What is the maximum Mbps that can be on a single frequency? Does it change per channel? For example, I see CBS is set at 15.9 Mbps and the sub channel is at 2.2. Does that mean the maximum is 18.1 Mbps? (Looking at the others, when you add them up they don't add up to 18.1, so I assume the maximum is based off of the frequency)

2) Is there a historical listing of the video data? I have been watching the NFL on FOX (WFLD) and I have noticed more pixelation this year, and the technical data the video is variable from 4.7-10Mbps. WPWR is and HD channel sharing the frequency now. I am curious what WFLD was designating last year as I feel like last year's NFL broadcasts were sharper.

 

[osu1991]

There are 19.2 Mbps available to use within each 6Mhz channel.

I don’t know how they split it up for channel sharing.

 

[comfortably_numb]

I don’t know how they split it up for channel sharing.

It can vary depending on how many subchannels they have, and/or the quality the network wishes to have on the main channel. If its not a "Big 4" network, then it can vary further

 

[Trip]

I was browsing the info on RabbitEars technical data for the Chicago market. When you dig down to the Technical Data, you can see the amount of video Mbps for each channel. I have a couple of questions:

1) What is the maximum Mbps that can be on a single frequency? Does it change per channel? For example, I see CBS is set at 15.9 Mbps and the sub channel is at 2.2. Does that mean the maximum is 18.1 Mbps? (Looking at the others, when you add them up they don't add up to 18.1, so I assume the maximum is based off of the frequency)

The maximum for all data is 19.39 Mbps. That's for all video, audio, guide data, etc. Practically, video bitrates will usually add up to about 18 Mbps.

2) Is there a historical listing of the video data? I have been watching the NFL on FOX (WFLD) and I have noticed more pixelation this year, and the technical data the video is variable from 4.7-10Mbps. WPWR is and HD channel sharing the frequency now. I am curious what WFLD was designating last year as I feel like last year's NFL broadcasts were sharper.

SI Parsing by TSReader 2.8.48a

That's a TSReader capture from before channel sharing began. The number shown in the chart at the bottom is the average over the run of the capture, not a minimum or maximum. Ignore the value given near the top of the page, as it appears to just be a string value included in the metadata and doesn't reflect the actual bitrate of the stream.

- Trip

 

[zippyfrog]

Thanks Trip - that is the data I was looking for. Didn't realize they dropped that much bandwidth dedicated to WFLD. But it is definitely noticeable in their NFL broadcasts, including the game on right now.