Originally Posted by JoeKustra
Very interesting. I installed the program and the results:
NBC/CBS 18.5 Mbps average
ABC 9.96 Mbps for Castle
SyFy HD 12.10 Mbps for Continuum
No Fox shows but I'll record one tonight.
Thanks for the tip.
Originally Posted by Kelson
Sounds like you have higher bitrates than for Philly OTA.
ABC = 8 Mbps
NBC = 14.5 Mbps
CBS = 17.5 Mbps
FOX = 14-15 Mbps
Maybe your provider is not so bad after-all.
In the case of the different resolutions on the same physical channels that doesn't really matter as each channel is seperate from each other. A 6 MHz RF cable channel using QAM 256 can carry a payload of 38.8 million bits per second which is 2 6 MHz RF channels that are 19.4 million bits per second each. The cable tv industry uses a term WYSIWYG (what you see is what you get), which simply means they retransmit the same payload that the content owners provide them with. The reason you see some of the bit rates real low is because the provider of those channels are stat muxing additional channels on thier feeds. In the case of WPVI in philly they have Live Well HD and a 480i sub channel included with WPVI HD so this leaves about 10 million bits per second for ABC HD. Here in the wilkes barre DMA the CBS and NBC affiliates don't have any sub channels so you will see high bit rates with those channels. WVIA and Wolf have multiple sub channels so their main HD channel will have bit rates as low as 9 million bits per second on thier main HD channel. If your cable operator only has permission to carry ABC HD then they can stick this channel with two other HD channels as they will groom out Live Well HD and the 480i sub channel.
When you deal with the cable/sat channels these channels come from the source mostly compressed in MPEG 4 so the bit rates are quit low for the HD channels, 6 to 10 million bits per second. The cable company can not improve the picture quality of a over compressed channel from the source. When the channels are remodulated to send to the consumer, the average bit rate for these channels will be in the range of 10 to 14 million bits per second using MPEG 2 compression. This explains the 3 HD channels per RF channel. Once cable moves to MPEG 4, which is starting to happen with Cox, then they will be able to put 4 HD channels per RF channel.
Once the move to MPEG 4 takes place with cable any device that has a clear QAM tuner and older cable cards devices, including the DHG, will be rendered useless as these devices can only decode an MPEG 2 stream. The only cablecard device that can decode an MPEG 4 stream and also tune up to 1 GHz is the Tivo Premiers. I do not know if the older Tivos have this capability. This is the main reason why I always suggest to get a Tivo if you have cable. Those of you that are holding onto the DHG will be dealt the final death blow when MPEG 4 comes to your system.