Is Comcast Squeezing Your HD Picture?
My thanks to bfdtv over at AVSForum for his very interesting post on the compression that Comcast is using on some of their HD channels as compared to Verizon’s FiOS service. The link is here. http://www.avsforum.com/avs-vb/showthread.php?t=1008271.
Apparently, in order to free up more bandwidth to add more HD channels, Comcast is further compressing their HD feeds with the predictable disastrous effects on picture quality. In the past, cable operators like Comcast were putting two HD channels into one 38.8 Mbps QAM slot. This was enough for two full bit rate full resolution HD channels with no degradation in picture quality. Now, they are compressing 3 HD channels into that same QAM slot with a noticeable effect on picture quality as is evidenced in bfdtv’s screen captures.
Furthermore, you do not have to be a Comcast subscriber to note this diminished picture quality. This 3:1 compression is being performed at the Comcast Media Center’s Headend in the Sky(HITS) in Denver which feeds the cable channels to many other cable companies including Cox and Charter. The 3:1 compression does not effect all HD channels, at least not as of yet. Select channels without much in the way of motion are being grouped together in groups of three. The affected channels are as follows: Discovery HD, SciFi, USA, Food, National Geographic, Universal HD, A&E, HGTV, Starz, Cinemax, HBO, TLC, Animal Planet, Discovery HD Theater and History.
Despite the theory that compression artifacts won’t be visible or as visible on channels with static images, the screen captures show otherwise. The images from Comcast’s feed as compared to the same shows on FiOS show motion artifacts galore and a very noticeable drop in picture quality to the point of being unwatchable. I for one would be quite upset if the images on my screen were so degraded.
Frankly, this is shocking to see from Comcast who had been running ads crowing about the quality of their HD PQ as compared to DIRECTV's "HDLite." Now it appears that Comcast has jumped into the same boat as DIRECTV. In fact, Comcast’s picture quality may be even worse than DIRECTV's as DIRECTV uses a more efficient compression algorithm MPEG4 compared to Comcast’s MPEG2.
For those subscribers at Comcast and other cable companies who obtain their HD feeds from the HITS facility and who have noticed that their HD channels don’t look as good as they did a few months ago, you now know why. Those once beautiful full bit rate HD signals are being choked to death by Comcast, all for the sake of adding more HD channels. The better approach would be to spend the money necessary to upgrade their cable systems to add more bandwidth to add more HD channels. Saving a few bucks by degrading the channels you already have to add new ones is not the way to go and is a clear step backwards for all fans of high definition television.
I would suggest that those of you that care about the quality of their HD experience complain to Comcast or their own cable company about what they are doing. Otherwise, they will continue to do so and spread the practice to other channels as well. They will take your silence as a sign that you are not noticing what they are doing to the signal which will only encourage them to continue and even worse, expand the practice. Tell them you are as mad as hell and won’t take it anymore! Or, at least, that you will switch to another service if it continues. Loss of subscribers is the only thing that will get their attention! The ball is in your court, HD fans!
For more high-def news and views, please click: TVPredictions.com.
Apparently, in order to free up more bandwidth to add more HD channels, Comcast is further compressing their HD feeds with the predictable disastrous effects on picture quality. In the past, cable operators like Comcast were putting two HD channels into one 38.8 Mbps QAM slot. This was enough for two full bit rate full resolution HD channels with no degradation in picture quality. Now, they are compressing 3 HD channels into that same QAM slot with a noticeable effect on picture quality as is evidenced in bfdtv’s screen captures.
Furthermore, you do not have to be a Comcast subscriber to note this diminished picture quality. This 3:1 compression is being performed at the Comcast Media Center’s Headend in the Sky(HITS) in Denver which feeds the cable channels to many other cable companies including Cox and Charter. The 3:1 compression does not effect all HD channels, at least not as of yet. Select channels without much in the way of motion are being grouped together in groups of three. The affected channels are as follows: Discovery HD, SciFi, USA, Food, National Geographic, Universal HD, A&E, HGTV, Starz, Cinemax, HBO, TLC, Animal Planet, Discovery HD Theater and History.
Despite the theory that compression artifacts won’t be visible or as visible on channels with static images, the screen captures show otherwise. The images from Comcast’s feed as compared to the same shows on FiOS show motion artifacts galore and a very noticeable drop in picture quality to the point of being unwatchable. I for one would be quite upset if the images on my screen were so degraded.
Frankly, this is shocking to see from Comcast who had been running ads crowing about the quality of their HD PQ as compared to DIRECTV's "HDLite." Now it appears that Comcast has jumped into the same boat as DIRECTV. In fact, Comcast’s picture quality may be even worse than DIRECTV's as DIRECTV uses a more efficient compression algorithm MPEG4 compared to Comcast’s MPEG2.
For those subscribers at Comcast and other cable companies who obtain their HD feeds from the HITS facility and who have noticed that their HD channels don’t look as good as they did a few months ago, you now know why. Those once beautiful full bit rate HD signals are being choked to death by Comcast, all for the sake of adding more HD channels. The better approach would be to spend the money necessary to upgrade their cable systems to add more bandwidth to add more HD channels. Saving a few bucks by degrading the channels you already have to add new ones is not the way to go and is a clear step backwards for all fans of high definition television.
I would suggest that those of you that care about the quality of their HD experience complain to Comcast or their own cable company about what they are doing. Otherwise, they will continue to do so and spread the practice to other channels as well. They will take your silence as a sign that you are not noticing what they are doing to the signal which will only encourage them to continue and even worse, expand the practice. Tell them you are as mad as hell and won’t take it anymore! Or, at least, that you will switch to another service if it continues. Loss of subscribers is the only thing that will get their attention! The ball is in your court, HD fans!
For more high-def news and views, please click: TVPredictions.com.
posted by webmaster @ 7:22 AM
7 Comments
7 Comments:
Here in Anaheim, CA, Time Warner Cable manages to squeeze 12 SD signals or three HD signals into a signal channel. Some days the picture is unwatchable due to all the macroblocks and audio hesitations.
I live in Nashville, TN, and I've certainly noticed a difference. Just the other night, I was watching Law & Order: SVU, and the picture was stuttering so bad that it seemed like the framerate had dropped to about 20 frames/second. I thought something was wrong somewhere down the line, but I didn't think Comcast would be doing it on purpose..
COMCAST TNT,TBS A&E THEY ALL LOOK BAD
Really is a shame at how downhill the quality has gone and it wasn't pristine to begin with but still much nicer. I hate macro-blocking!
Slightly off topic but this really makes me appreciate HDM so much more, especially blu-ray. I can only hope Warner no longer will produce blu-ray titles reduced down to HD DVD's specs once they are finallly done with HD DVD releases.
Direct TV used HD-lite on their MPEG=2 channels but on their new national MPEG-4 channels, they do not appear to be using HD-lite.
web blogs like this one and the tvpredictions site have forced comcast to do this, so your are getting what you asked for
every few days there is a post about how comcast can't keep up with the HD channels sat is offering, so now they have to respond but stuffing in the channels, quality be damned.
it was much better getting a select group of channels in real HD quality, than a whole bunch more starved back to SD quality, with more artifacts than the SD feed; in some cases the SD feed is now more enjoyable to watch
I agree with one of the anonymouses. To categorize all of DIRECTV's HD as hd lite is not honest but a cheap shot. And yes I have DIRECTV. Espnews went HD on Wednesday for DIRECTV and Espn and Espn 2 do look worse than Espnews HD and again to the other post's point that not all DIRECTV HD is hd lite only the mpeg2. Mpeg4 signal looks great. Not perfect but a heck of a lot better than I could ever get though Comcast. Plus I have 60 HD channels with all I am subscribing to (Starz and the HD xtra pack are included also to get me to 60). Plus the fact I am not in a Fios area and Qwest is partnering with DIRECTV (I am in a Qwest service area) I am fine with everything I get from DIRECTV. I would like to see the whip be a little less biased and/or inaccurate.
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