|Topic Review (Newest First)|
|2006-01-06 10:20 PM|
I never assumed "digital" would be better than analogue just because it was digital, but these guys advertize in their panflets that the image is DVD quality. Well that may be true in the sense that it has the same number of pixels, if they are all compressed and bleeding into each other to create a fuzzy image it really urks me. I consider myself rather tech savy, and if they fooled me into getting it, I can only imagine what Joe Bloe is expecting. There is no way they should be able to sell this product as DVD quality PQ when my own tests with analogue are blatently obvious with regards to analogues superior PQ. Compared to my DVD player? It doesn't even come close. It really is BS.
I am really wondering if i would have a similar experience with a satalitte provider knowing what I have learned from the Kaphyr links. My initial impression is that it is pretty poor as well from what I have seen at other's homes but I cannot be sure unless the test environment was my own (same STB, cables, TV etc...)
Thanks to all on your input on this matter. It is greatly appreciated. I can only recommend to others, that if you take the HD plunnge, you should consider how much of HD you will be watching relative to SD knowing what we discussed above.
|2006-01-06 07:01 PM|
Originally Posted by CarlJF
I agree with you. While the quality of each SD channel may be different, whenever the quality of the same SD channel is better in analogue than in digital, then Videotron has a serious problem.
In another thread I proposed an explanation for this. I imagined that Videotron has many satelite servers located all over its territory, one in each neighbourhood. Each satelite server receives high quality digital SD and HD images that are uncompressed using many very high bandwidth optical fibers coming from a central hub. Theses satelite servers re-create analogue SD signals for re-transmission to our homes and since there is no shortage of data capacity on the optical fibers, the analogue quality can be very high. But because the final distribution to our homes must pass over a single coax cable with a much lower capacity and given that this same coax must also carry VOD, and internet and VOIP telephone between a cluster of homes and the local server, Videotron has chosen to lower the bitrate for each digital SD channel.
Videotron must respect the channel bandwidth and channel spacing rules for analogue transmission which were established over 60 years ago. This standard assures a minimum quality for each analogue channel. I believe that one of the reasons that Illico cable boxes have become so inexpensive recently is because Videotron would like to eliminate analogue SD transmissions. Doing so would allow Videotron to make more money by recycling the analogue channels for use as digital channels.
The solution would be to have our homes linked by optical fiber instead of 75 ohm cable. We see fiber optic transceivers used in many industrial and commercial data processing applications. Given that many Videotron subscribers spend between $500 and $1000 per year for single or bundled packages, I can't understand why there hasn't been a desire on the part of the cable TV industry to make the final connections from the servers to the homes using optical fibers.
You are correct in stating that had you known about the limitations of digital cable, you might have chosen another supplier of speciality channels. The problem is that with any alternative supplier of a digital signal, whether using satelite, copper telephone lines, or cell phone antennas, there will always be pressure to reduce quality and increase profit. Only when subscribers can pay a tarif based on the quantity of data being purchased will we be able to strike a reasonable balance between quality and cost.
|2006-01-06 05:07 PM|
Originally Posted by montreal
|2006-01-06 03:15 PM|
On the subject of picture quality, whether SD or HD, I asked a question earlier last year concerning the effect of bitrate on HD quality, and I was given the impression that if we are talking about a static SD or HD image, then all the pixels are in place, be it 1920 by 1080 pixels for HD or 640 by 480 pixels for SD. It is only when the static image changes, that the bitrate will influence the speed and number of pixels that can be modified in a given time delay. If this interpretation is correct, then when viewing a static image, say of an outdoor panarama, then we should find both the SD and HD single frame image living up to their potential.
If we are reading in this thread about SD picture quality not living up to the expectations of Videotron subscribers, can we agree that this disappointment only happens when there is a need to constantly change a large number of a frame's pixels (sports)?
PBS at times has a slow moving travelogue simultaneously in SD and HD. Are not both these frozen HD and SD images impressive?
How does Videotron acquire its local and distant SD signals? A 640 by 480i image needs a source analogue signal over 6 mhz. I doubt that Burlington Vermont puts more than 3.5 mhz in their OTA analog transmission. So no matter how faithfully Videotron digitizes this signal from Burlington for distribution over its cable network, the static image from Burlington will never approach the 640 by 480 pixels of DVD quality.
On the other hand, there are many speciality channels that Videotron can only receive via a satelite feed, and here the digital signal leaving the source studio may survive its voyage with all 640 by 480 pixels per static frame still intact.
|2006-01-06 01:26 PM|
For SD digital reception, most of us support your position that SD channels are not as good as DVD and in fact are not as good as analog. BTW, having the Telemax package and therefore having access to basic cable as well, I have a splitter upstream with one out to my SA8000HD and the other out to the TV and I view SD channels in analog format when not recording.
To support your view, if you click the following link, you will see the complete QAM arrangement for the Montreal network. SD channels with less than 4 Mbps video bitrate are fare but those below 3 Mbps give poor PQ. The Canadian HD channels have very good Video bitrate and the US channels are now acceptable (except the NBCHD for audio bitrate) but would be better if the feeds came from Detroit instead of Buffalo. ABCHD in Buffalo cannot provide DD 5.1 audio although they have the audio bitrate to do so.
Member Kaphyr is a programmer and Videotron engineers would do well to have him, at least, as a consultant.
There's another table available, this time with complete information and with valuable comments, but it's in French. If it can be useful the link follows:
|2006-01-06 12:19 PM|
I've got Illico last december and also found that the picture quality in SD was not very good and worse than when I used the analog cable.
After reading many post on this forum, I noticed that I'm not the only one with this problem.
Since Videotron annouce his Illico service has giving "crystal clear DVD quality pictures", which "crystal clearly" isn't true, I've contacted a consumer defense organisation to ask them if any measure, legal or not, be taken since Videotron is clearly doing false publicity and sells their Illico service and STB based to consumer, in part, on false pretense. Many consumer would have stayed with their analog cable if they would have know that their PQ will be worse with Illico.
Since many peoples already have contacted Videotron on this matter without any improvement, maybe some kind of group action may force them to give the quality they promised.
Anyway, I will tell you what the consumer organisation answers me.
|2005-12-29 12:10 PM|
When I have my stb connected with hdmi...I can not change that setting, it just says auto-hdmi.
If I connect with component then it does allow. But when I go back to hdmi cable its back to the old stuff.
I also tried have both hdmi and component cable at the same time and on the tv I would select the different feed. What that does is that component feed works but hdmi is gone.
|2005-12-29 10:03 AM|
I agree with the comments here but suspect (along with Videotron's control over the compression ratio) that is also the decoder box that is causing this problem (based on other forum posting I have read on this topic - see link below). I have read other discussions that the SA8300HD decoder (or its analog tuner) is the cause of poor SD video quality. I recently made the switch from the standard illico tuner (3200?) and even though I am not making a side-by-side comparision, I recall that the SD channels looked a bit better than they do now via the SA8300HD. Non-HD programming on the HD channels looks better than on the SD channel. I usually just set the display to zoom (I have a 4:3 HDTV) and it still looks better than the SD feed.
Check out the AVS forums for more on SA8300HD and other HD-related topics...
|2005-12-29 05:48 AM|
See the discussion on this topic and the resolution to the SD PQ problem:
|2005-12-28 09:34 PM|
Originally Posted by JLACH
|2005-12-28 02:22 PM|
You can check bitrates by recording a long programme to a DVR or HTPC, seeing how large the file is and then calculating the average bitrate over the period of the recording.
Remember though that cable companies do "rate shaping", therefore the bitrate is not constant for channels and the rate can vary depending on the programming - sports (action) may require more bitrate to be watchable...
Rogers has stated that they typically put 8-12 channels/QAM, which would indicate a bitrate of around 3-5 Mbps. I have confirmed this roughly with my SD recordings, which were typically 3-4 Mbps (the worst I ever saw was just under 3 and it was one of the "poorer" PQ channels).
Satellite companies do not "publish" their bitrates, so you'd need to find someone who's done the testing and has done the arithmetic correctly (some posts on this site have poor arithmetic)
|2005-12-28 02:09 PM|
Thanks for the feedback. I had taken a look at the FAQ and it helped me rule out a lot of potential causes. But i believe that it comes down to videotrons feed.
I too have the pace551HD. I was first wondering if it was the box but i went over to a buddy's who has the a HD-PVR from videotron and he had the same PQ. I could only conclude that it was the digital signal as on different TVs, different STB showed similar PQ in SD. In testing the analogue, it showed to be far superior to digital SD.
Here is an interesting link i found.
It's in french but it should give you an idea of the bitrates that videotron is using for image in each channel which is a factor in PQ. I would tend to agree that in general, the channels assigned a higher bandwidth for video had better PQ.
After searching these forums, it seems to me that the consensus is that satelitte has slightly better SD PQ. A question for the satelitte guys. Do most of your SD channels have >3 Mbits. Is there a way to check this?
Thanks in advance
|2005-12-28 01:24 PM|
I have the pace551 with HD and I might sound crazy...but when I try the base SA 2200 with svideo, CBC and SRC (and others) looked much better than now with the new pace. Even my direct videotron cable plugged into my toshiba 57hx84(alltime 1080i) looks better than with the pace.
Sure...On the hd version of CBC when there's a non HD show it looks better Like #606 versus #06....but the standard channel looks much crapier than with the old SA or direct analogue cable.
Its as if the resolution is downgraded on purpose for the std channel to make the HD channel look much better....(being paranoid again)....or maybe the base feed doesn't get nice processing over my dmi connect.
HD channel with HD show looks awsome (like World jnrs on TSNHD).
|2005-12-28 12:56 PM|
Originally Posted by Robot1501
On Rogers Ontario, where they have the bandwidth, many of the digital channels have excellent PQ (better than analogue), while some digitals are poor.
See also the Digital Home FAQ on "Poor SD PQ".
|2005-12-28 11:59 AM|
Yeah, Digital SD is very poor on Videotron, always has been. I watch mostly HD, so I can live with it.
If you want a better SD signal, StarChoice or ExpressVu are better options (I personally prefer StarChoice). It looks like the DSR530 has been finally fixed, so they're an option now. Bell is offering free PVR rentals for new 2 year contracts too.
One tip for Videotron tho: If your SD program is being shown on the HD channel, it offers a much improved picture. Try that out first.
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