Comcast HD Quality Reduction: Details, Screenshots - AVS Forum

[David Farber <dave () farber net>]

http://www.avsforum.com/avs-vb/showthread.php?t=1008271

Comcast HD Quality Reduction: Details, Screenshots
Last updated: March 24, 2008

Until recently, most Comcast systems passed all HD as is from the  
content provider, without any added compression or quality reduction.  
In response to competitive pressures from DirecTV and Verizon FiOS,  
Comcast recently decided to sacrifice some quality to improve  
quantity. By early April, most Comcast systems will recompress and  
degrade their HD, much like DirecTV and Dish Network do on their  
MPEG-2 channels. This creates room for new HD channels without the  
need to eliminate a significant number of analog channels.

Previously, Comcast allocated a maximum of two HD channels per  
38.8Mbps QAM, so each channel had the full 19.4Mbps available if  
needed. Now, with the addition of new channels, Comcast is squeezing  
three HD channels into each 38.8Mbps QAM. Furthermore, some existing  
QAMs with two HD channels are being recompressed in preparation for  
new channel additions.

But what does that mean? How much difference is there, really?

To find out, I decided to compare the quality of the same programs on  
Comcast and Verizon FiOS. I recorded the same program from the same  
channel, at the same time, on both Comcast and Verizon FiOS in N. VA.  
I compared the size and bitrate of each MPEG-2 recording, as well as  
the subjective quality with video.

Note when I tested channels late last year, there were no differences  
between the two providers on HD. Any differences are new.

picts etc follows djf 

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