For those of you who don't yet know, Comcast Sacramento added 6-9 new HD channels this week, though not all zip codes are receiving the new channels (I think we receive five of the nine in Elk Grove. When Comcast added five new channels last winter, we only received three in Elk Grove). During the past month or so, other markets around the U.S. also started receiving these new HD channels.
That's the end of the good news.
The bad news is this: Comcast (in Sacramento and around the nation) now is officially cramming three HD channels onto a single, 6MHz slice of spectrum. Previously, only two HD channels were broadcast on each 6MHz slice of bandwidth. This change is significant, and has resulted in a noticeable and dramatic drop in HD picture quality on the cable TV network once known for pristine HD picture quality. Obviously, Comcast has been forced to make compromises, and add compressed HD channels in response to all the new channels being added by DirecTV, Surewest, and soon, Dish.
Unfortunately, Comcast doesn't have the bandwidth or updated MNPEG4 hardware on their system to do this properly and maintain a high level of quality. Comcast SAcramento isn't reducing the HD quality on all HD channels, but this development does not bode well for future services.
Coincidentally, last week I also learned that Comcast (in Sacramento and around the nation) routinely crams 9-12 SD channels onto single, 6MHz slices of spectrum, whereas the industry standard to maintain high picture quality is supposed to be about six SD channels. Of course, knowledgeable customers can tell you that Comcast's SD picture quality varies wildly from hour-to-hour, day-to-day and channel-to-channel. Just last week, a field tech told me that this happens because engineers constantly reconfigure each channel's spectrum assignment as they work on the local network. If CNN looks great today, it may be on a slice of spectrum shared by just six other channels. Tune in tomorrow, and CNN may have been moved to bandwidth shared by eleven SD channels -- in which case the over-compressed picture will look terrible.
As for the latest HD resolution problems, reports indicate that Comcast is broadcasting select new HD channels by reducing the bit-rate per channel, though this is not yet being done on all HD channels. I am not sure whether Comcast is over-compressing the data or down-rezzing 1080i channels from 1920x1080i to 1440x1080i, which is what DirecTV used to do with their infamous (and fuzzy) "HD Lite" channels. Like Comcast is now doing, some of DirecTV's seven, original HD channels were down-rezzed to "HD-Lite" resolution, and then compressed using MPEG2 compression. DirecTV now uses the more modern MPEG4 compression for all their new HD channels and the picture quality is said to be very good, though I have not yet seen this for myself.
Meanwhile, angry Comcast customers are condemning this change and the degradation of service. The topic is being discussed on Broadband Reports online forums and on the AVS Comcast Sacramento forum as well. Comcast Sacramento is bandwidth-starved, and this problem is destined to dog the local franchise for the next couple of years.
For this reason, we finally are ready to dump Comcast ASAP, and we're reconsidering Surewest and DirecTV, though I'm still leaning toward DirecTV due to SureWest's lack of a polished DVR, DirecTV's lead in the number of HD channels, and the mediocre picture quality on Surewest's SD channels. We may switch to Surewest Internet though, and thus be in a position to consider adding their HDTV in the future.