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Godfather
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Discussion Starter · #1 ·
How many regular video channels can be put on each transponder without causing compression problems? It seems to me that dish is loading up some of their transponders with a very large amount of local channels.:confused:
 

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Godfather
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Discussion Starter · #3 ·
boba said:
Are you a newbie or did you just wake up? It has been about 8 years since they had a good compression rate on their transponders.
Thats good information, but I still would like the number of channels on a transponder and at what number does it start causing compression problems?
 

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Hall Of Fame
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There is no absolute answer with statistical multiplexing compression ratio is in constant flux. The need of the data stream determines the compression. Sporting events with a lot of changing information need more bandwidth than a cartoon with constant information and little movement needing changes. The number of channels on a transponder are also changable, the data stream tells your receiver where to look for a transponder. Example Ch 110 could be on transponder 1 today but over night it could be moved to transponder 7, you just go to ch 110 so it is transparent to you, but your receiver knows where to find it.
 

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samhevener said:
Thats good information, but I still would like the number of channels on a transponder and at what number does it start causing compression problems?
Sam,

There is no HARD Answer. Dish and DirecTV both use Statistical Multiplexing. Meaning the bitrate of any one channel on a transponder can get more or less bandwidth depending on the amount of Movement on the screen at one time.

Both DBS providers try to balance their transponder loads. Both providers try to mix high bitrate with some Low Bitrate channels.

With that said some channels will look great and some will not, it depends on how high the bit rate needs to be to resolve a GREAT picture, with Statistical Multiplexing if a channel needs a higher bit rate and another channel is not using as much then that one channel may get more bandwidth.

At the moment both providers are cramming about 10-13 SD channels per transponder. If you wanted excellent picture for all channels then a channel load of 6-8 per transponder would likely be a channel load that almost all subs would be happy with.

These numbers are based on MPEG2. Over the next few years the DBS providers will need to migrate to MPEG4 to maximize their bandwidth. MPEG4 will likely allow about triple the number of SD channels per transponder with slightly better Picture Quality.

John
 

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Channel(s) could move overnight, but that is not a normal thing, A move from one transponder to another would show up in the Uplink Activiy Report.

Normal transponder loading for MPEG2 SD channels is now at 12. Much of the problem with locals may be the backhaul bandwidth allowed for each channel.

You will see some MPEG4 SD channels listed on 148w which exceed the 12 channels per transponder and this would be considered normal loading, since MPEG4 requires less bandwidth.
 

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Godfather
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Discussion Starter · #7 ·
The information from all of you really helped me learn more about the way the providers operate. I have reviewed several library books on the subject (most out of date) and am learning more all the time. Thanks to everyone for the good information.
 
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