Where are you?

I watch a lot of NBC HD content and see nothing wrong...

Markham, Ontario

I believe that Rogers has now started compressing their HD.

None of the HD shows that we record that are typically taking 8 GB per hour are getting much past 6 GB. The first episode of Carrier on PBS HD, which is 2 hours, is only 11.1 GB. That is only about 5.5 GB per hour.

This is rapidly approaching DVD video and not HDTV. I feel that we are now due a MAJOR refund or a discount on our HD subscription fees.

As for a timeframe, I first detected the drop in file sizes as of Apr 24th. I will be continuing to monitor the file sizes VERY closely all week.

It doesn't matter if they started compressing. If you can notice a lot of artifacts that ruins the experience then you could complain. It's perceptual coding, like lossy audio formats and noticing the quality difference in a blind test. If you can't notice any difference between the original master and the compressed file then you really shouldn't worry about the compression. But if you can hear a difference, then you can do something about it. I would talk to Rogers and try to get a deep discount from them if you notice adverse effects. Just call to cancel your service, telling them that Expressvu made you a better offer, and you'll be transferred to the customer retention department where, as they say, let the haggling begin.

I think that the quality of picture on most (if not all) HD channels is somewhat degraded in the last 2-3 days. I haven't noticed any pixelation, but it appears that the picture is typically softer, even a little grainy in some darker scenes in the movies (just not as crisp as it used to be). I've been watching a few of the sports events in the last few days (NBA, NHL) on different HD channels and it just doesn't seem to be as sharp as before. Don't want to jump the gun and say that it has started, but something has changed.

I was just thinking the same thing ... I've been watching House and Hockey tonight and unless its my mind playing tricks on me ... something's changing.

Interesting the people are again reporting compression on channels that are not scheduled to have compression (read the link in post 1 of this thread.)

I'm not necessarily saying its compression. Just that signals are different. There was a problem last week with BigBangTheory and HowIMetYourMother. While watching TV tonight the images appear a bit softer. Maybe my eyes are adjusting and have gotten used to HD now (I've had it for about 10 days now). But I'd really hope its the signal and not my TV or my eyes :)

Just checked and there don't appear to be 3 HD channels per QAM at my location.

Channel - QAM

545 - 519
541 - 801
540 - 519
537 - 789
536 - 465
535 - 759
534 - 759
533 - 819
532 - 531
531 - 783
530/525 - 849 (same channel)
529 - 789
528 - 807
527 - 807
526 - 705
524 - 801
523 - 543
522 - 543
519 - 783
517 - 549
515 - 537
514 - 765
513 - 537
512 - 825
509 - 855
508 - 855
507 - 849
506 - 825
505 - 549
503 - 115
502 - 507
501 - 795

Please excuse any typos that may have crept into the above.

Thanks for taking the time to do that 57. Good to have a baseline for any future changes.

A newbie question so please excuse me if it doesn't make sense.

Is it possible to have 2 HD channels PLUS one or more SD channels on a single QAM? If so ... is that something Rogers has done in the past or is planning on doing in the future? Wouldn't / Couldn't that impact signal quality?

Is it possible to have 2 HD channels PLUS one or more SD channels on a single QAM? If so ... is that something Rogers has done in the past or is planning on doing in the future? Wouldn't / Couldn't that impact signal quality?Very possible, and something I wondered myself earlier in this thread (http://www.digitalhome.ca/forum/showthread.php?p=734055#post734055).

As I said in that post, the only way I know to confirm it would be to check the QAM frequency on the SD digital channels. And yes, it could impact signal quality.

Sorry to have stirred things back up...

Late last night a few more shows recorded and they were all more normal as in 6.5 to 8 GB.

Who can say what was going on in the last few days but whatever it was, it seems to have been an anomoly.

Instead of us trying to police it, wouldn't it be nice if we could trust the distributors to be open and truthful about what compression they are adding to our HD, if any?

I asked Shaw and was told they don't give that kind of information to their customers. But then I know for a fact they have something to hide (they regularly squeeze 3 HDs per QAM), so I wasn't surprised by that answer.

I suspect Rogers would say something similar, but has anyone asked them?

Yes, it would be nice if we could trust them. I know I don't; too many times in the past I've been given wrong information by them, about all kinds of things.

As a matter of fact, just recently I had one of their technicians come to my place to check on a signal strength issue. I took an opportunity and mentioned how I've heard of Rogers' plans to further compress the HD signals. He told me that was the way how things were normally done (having multiple channels on a single QAM), and how he never heard of any adiitional plans of further compression. Talking to their customer service reps on the phone would probably lead to even lower level of information, at least based on my previous experience. They just either don't know or don't want to talk about anything technical.

I am afraid we are completely at their mercy, and they know that very well. Unless you want to change the service provider and go satellite instead of cable, there's not much you can do. And those other guys are a piece of work on their own, too. I'd really love to be eventually proven wrong.

Right now I think the only thing we can do is monitor the size of recordings and if we notice any significant differences...then, I have no idea what we can do.

not only the size of the recordings but more importantly that list that 57 posted (not everyone has a pvr). I mean 2 HD channels per QAM channel , simple to check on the Rogers STB's. thats what they need for a 1080i signal at full 19.38 Mb/s. for a 720p broadcast they dont need the full 19.38 Mb/s data stream. Inevitably they will have to do it at some point unless they get rid off the Analogue Channels. The technology will improve and consumers will not see the difference if Rogers Engineers do it properly. that is exactly the job of a broadcast engineer , to maximize the amount of info it broadcast at the lowest posible cost. otherwise no company will need engineers in their staff , just average joes that can read technical info and install whatever equipment is available in the market.

Us consumers could do something though, stop asking for more new HD channels to be transmited along the already crowded transmition channel , whatever it is , either a fiber-coaxial network as it is the case with Rogers or Satellite based network as in the case of BEV.

Now I have to go , let me enjoy the Blu-Ray version of The Golden Compass at full 1080p at 24 Hz with DTS-HD Master Audio 7.1 Sound (theoretically 100% identical to the Master Audio) but in this case my transmition line is an HDMI 6 ft cable that will be more than happy to carry the almost sometimes 36 Mb/s data stream. OH!!!, if only Rogers could bring a fiber optic cable to my house, I would be so happy!!!!!!! lol lol lol.

Late last night a few more shows recorded and they were all more normal as in 6.5 to 8 GB.
Recorded 10 hours of Discovery and got 8 GB/hour.

Regarding putting SD channels on the HD QAM, I don't think the stat muxing that Rogers is considering will allow for that. I recall discussing this issue with another technician a long time ago and no cable service provider mixes SD & HD. The SDs are already "rate shaped", probably in a slightly different way, and of course with 8-12 channels per QAM.

Regarding putting SD channels on the HD QAM, I don't think the stat muxing that Rogers is considering will allow for that.I can't speak to what Rogers is capable of because I don't know what equipment they are using.

But there certainly are stat muxes on the market that can combine HD and SD channels together. One example is the Scientific Atlanta Regulus stat mux (http://www.scientificatlanta.com/customers/Source/7001145.PDF) which claims: "Any combination of 1080i, 720p and normal standard definition may be statistically multiplexed together."

Just saying we should not assume they won't try it. It would be one way to squeeze the HD without it being as blatantly obvious as going 3 HD per QAM.

for a 720p broadcast they dont need the full 19.38 Mb/s data stream.The technology will improve and consumers will not see the difference if Rogers Engineers do it properly.

Where to start.. lol... Perhaps you could explain why a 720p broadcast does not need "the full 19.38 Mb/s"? In my experience, a 12Mbps 720p broadcast still has compression artifacts, so there is certainly room for improvement--it doesn't look anywhere near equivalent to the uncompressed 663Mbps stream (1280x720x12bppx60fps). I think most people would be able to tell the difference between a 12Mbps and 19Mbps 720p broadcast, given good quality equipment and a few fast-motion scenes.

"As the technology improves" then the compression used by the broadcaster will improve as well. And I think at this point the quality of MPEG-2 compression has about reached its limit. Rogers will find it very difficult to re-compress a well-compressed 19Mbps signal to a 12Mbps without losing any quality. Only if Rogers switches their network to MPEG-4, will it be possible for them to provide a lower-bitrate signal of consistently equivalent quality.

Now I have to go , let me enjoy the Blu-Ray version of The Golden Compass at full 1080p at 24 Hz with DTS-HD Master Audio 7.1 Sound (theoretically 100% identical to the Master Audio) but in this case my transmition line is an HDMI 6 ft cable that will be more than happy to carry the almost sometimes 36 Mb/s data stream. OH!!!, if only Rogers could bring a fiber optic cable to my house, I would be so happy!!!!!!! lol lol lol.

I think there's a problem with your HDMI cable if it's only carrying 36Mbps. HDMI always carries *uncompressed video* and, if you're listening to Master Audio, then uncompressed audio as well (since no Blu-Ray player can output a DTS-HD MA bitstream yet). Your cable is carrying 600Mbps+.

It will be a long, long time (if ever) before cable companies transmit uncompressed video to your home.

voyager 6868, as you said 720p acctually does benefit from having the full 19.38 at its disposition but depending on the type of programming (fast motion scenes) tv providers will be able to get away with reducing the bitrate for the 720p signal. a good example WNED PBS Buffalo affiliate more than a year ago was broadcasting 3 tv channels (1 HD) and the HD one was a 1080i format , OTA as we know using the ATSC standard. compression artifacts started to appear and their engineers decided to switch the HD feed to 720p as it is now. so now they have the same PBS HD feed they get at 1080i re-formatted to 720p plus the other 2 standard def 480i PBS channels. But no apparent compression artifacts , and I mean apparent because it all boils down to wether you want to watch the screen only 1 foot away or at least 3 times the height of the screen.

But your are right it will be better to have the full 19.38 Mbps even for a 720p signal.

And who knows maybe Rogers will start using MPEG4 in the far future, there are some other technologies as well like SVD for them to use before.

On the third and last topic you are also right unfortunaelly for me, lol lol. the HDMI 1.3a cable , not only carries uncompressed digital video and 8 channels uncompressed digital audio but also control signals as well. the TMDS technology that HDMI use (DVI uses the same by the way) together with the electrical caracteristics of the cable and conectors (defined by the HDMI standard) allows them to have 3 TMDS channels (0, 1 and 2) transmiting at a maximum 10.2 Gb/s total link. As you correctly pointed out more than enough for a 1080p at 24 Hz frame rate uncompressed data stream plus the 8 channels (7.1) uncompressed digital audio. I just mistaken the video codec Blu-Ray disc use , which is VC-1, typically at 35 - 40 Mbps the maximum depending on the scene with the fact that the HDMI cable is acctually carring the decoded video info by the player which is an uncompressed data stream. As one of my profesors Engineers back in Cuba used to say that is a concept mistake and it is unacceptable. Quite a few students failed the class and had to leave the university for concept mistakes like this. What ever the mistake was or for that matter the class. Hopefully no cuban engineer reads this forum so I do not have to surrender my profesional degree, lol lol lol.

Now back to finishing the movie because I could not finished it last night, lol lol lol.