SD resolutions dropping on 110W

[BuddyBoy]

How many transponders do you think Dish has?

Irrelevant. The point is, you were wrong when you wrote:

DVD video is almost 9Mb/Sec...You can't push that over satellite with current technology

I have a recent episode of "Hells Kitchen" sitting on my 622's external hard drive that is 5071MB for a one hour episode. That's over 11Mb/sec. So much for your claim that you can't push 9Mb/sec over satellite with current technology.

 

[buckchow]

And you'll lost FF/FB features for recording with the long GOP.

Well, the longer the GOP is the less precisely you'll be able to start at a given point in a recording. The current lengths max out around 2 seconds, which should be more than sufficient for any normal viewing. Nobody's losing FF/FB features, at least not yet.

 

[Smith P.]

Trick mode based on I-frames, so with long GOPs your fast motion, etc will be not just jumpy, but ...
brr, I don't want to see it !

 

[kstuart]

Mark this as a classic " I think I know something about digital video because I've read a couple of articles thread ".

 

[mike123abc]

buckchow, as I recall DVD books require 1 to 10 for I-frame - correct ?

DVD NTSC is 18 limit on GOP. PAL is 15.

The technology for much higher quality SD MPEG-2 video at the current bitrates definitely exists, so that's not the issue. I like your thinking that patents may somehow be involved with limiting the technology being used. If they decided to try to come up with their own filtering and/or encoding methods in order to avoid patented technology, or they decided to only use technology based on expired patents, that could explain a lot.

The key is that it has never been a limit of the MPEG-2, it has been a limit on the real time encoders with muxers. Any of the channels could be compressed better than what Dish does with non real time multi pass methods...

 

[TheKrell]

Any of the channels could be compressed better than what Dish does with non real time multi pass methods...

Which is precisely why the encoding to mpeg-4 should be happening at the content providers' facilities, and not at Dish uplink centers. Content providers might even adjust the timing, e.g. with shorter or longer commercials, so that they could stat mux their 10 channels optimally.

 

[buckchow]

It's very disappointing that some people following this thread really don't believe the SD PQ could be improved on Dish while it remains MPEG-2. It's still going to be a few days before I can get my samples and other data together for a final comparison that should put this issue to rest. Until then, please enjoy this little comparison of a close-up of part of a shirt covered with little designs. Zoomed to 3x, taken from frames rescaled to a 4:3 aspect ratio so that proportions are correct. Dish is on the left, Bell is on the right.

​

Note that for this comparison, Bell's bitrate is 15% higher than Dish's, however Dish is using a resolution 15% below 640x480 (544x480). Even though Bell is using a resolution of 704x480, I am generously assuming that the source material was only 640x480 so that Dish's resources are only equivalent to Bell's rather than exceeding them. If both providers were handling the video in similarly advanced and professional manners, then the only real visible difference should be that the Dish sample would have slightly less horizontal detail. This is obviously not the case since Dish has distorted their image in a number of ways including mangling shapes and bathing everything in the blurry glow of their heavy edge enhancement.

Also note that the channel on Dish was HBO East, so it should be reasonable to say that Dish had a high-quality source to start with.

 

[CowboyDren]

So much for your claim that you can't push 9Mb/sec over satellite with current technology.

Granted. I don't know what the technical limitation of a single transponder is. My core point was that the total bandwidth available, divided by the number of channels, makes the following utter nonsense:

There's nothing to stop them from committing an entire transponder to a single HD channel and sending down something in excess of 30Mbps, except the receiver's ability to decode such a high bitrate signal.

There's a LOT that stops them from doing just that.

 

[jlong27]

Here's what would fix it all. Dish should convert all SD channels to HD. SD shows on HD channels are great. A good example is Spike.

 

[CowboyDren]

I agree, except that it requires deploying THOUSANDS of MPEG4 receivers to replace the old units still in service that can't decode HD channels.

Time Warner advertises themselves as "Home of Free HD," and a satellite service could pick up a lot of business by announcing that there's no surcharge.

 

[HDRoberts]

I agree, except that it requires deploying THOUSANDS of MPEG4 receivers to replace the old units still in service that can't decode HD channels.

Time Warner advertises themselves as "Home of Free HD," and a satellite service could pick up a lot of business by announcing that there's no surcharge.

Thousands? Try more than 10 million.

 

[GaryPen]

As bad as that image above is, nothing looks worse than Dish Locals in SD. Absolute garbage. And, quite frankly, their HD locals, while fairly good, don't look as good as my local cableco's HD locals, let alone OTA HD.

 

[kstuart]

It's very disappointing that some people following this thread really don't believe the SD PQ could be improved on Dish while it remains MPEG-2.

http://www.freeimagehosting.net/​

As I mentioned before, the fallacy here is that there is a systematic way that it can be improved.
There is a strong likelihood that there are certain SD channels that need attention, and the engineers have their hands full adjusting the new Viacom and Local HD channels.
If you notice a problem with the PQ of a channel, feel free to send an email directly to the PQ engineers at:

dishquality _AT_ echostar _DOT_ com

 

[mike123abc]

As bad as that image above is, nothing looks worse than Dish Locals in SD. Absolute garbage. And, quite frankly, their HD locals, while fairly good, don't look as good as my local cableco's HD locals, let alone OTA HD.

The cable and OTA should be the same, the cable company should just be remodulating them to QAM, not changing them.

The OTA HD from Dish in my market looks really good, but then again we only have 4 channels, 3 on Dish at this time. Lots of room so the compression is light.

 

[buckchow]

There is a strong likelihood that there are certain SD channels that need attention, and the engineers have their hands full adjusting the new Viacom and Local HD channels.

The kind of damage shown in the image I posted last night is not isolated to just a few certain channels. The damage is caused by a combination of unnecessarily aggressive filtering and reduced horizontal resolution (704 -> 544). As I mentioned earlier in this thread, it is almost every channel on 119W and some of the channels on 110W that are affected by this. This isn't a recent problem, it has been that way for years. The new issue of the horizontal resolution being reduced even further (544 -> 480) that initiated this thread is not directly related to this ongoing issue, but it can definitely further complicate it as highly filtered channels such as Encore Westerns are also dropped to 480x480.

While some or all of their engineers may be preoccupied at the moment by the matters you mentioned, that doesn't help to address the fact that they don't appear to have made any serious effort in previous years to address complaints about SD PQ made both directly to Dish and about them on forums such as this one. It seems to me that it would be impossible for them to be unaware of what they are doing to their video and how it can hurt their business. If they really have the superb encoders you are so confident that they do, then delivering PQ comparable to Bell should not be difficult. Why then do they appear to be going out of their way to kill the picture quality instead of retain it as well as possible?

 

[buckchow]

For anyone wondering about Bell vs. Dish bitrates since Bell's PQ tends to be so much better than Dish's, I came up with the information below. This information was obtained on 2/21/2009. One "channel" is considered to be one video PID in a given transponder's mux. Channels with bitrates below 500kbps, which both providers had a few of, were not counted since those are just stationary graphics and would artificially lower the average bitrates for both providers. The orbital locations being examined are 91W (Bell) and 119W (Dish) since both only carry SD programming and both are primary locations for the providers. Dish's PQ tends to be worst on 119W, so that also makes this comparison interesting.


Bell TV @ 91W
- National Transponders = 32
- Number of Channels = 342
- Average Channels per Transponder = 10.7
- Display Resolution = 640x480
- Typical Encoded Resolution = 704x480
- Raw Average Bitrate Per Channel = 2.219Mbps
- Effective Bitrate Per Channel at Display Resolution = 2.018Mbps


Dish Network @ 119W
- National Transponders = 16
- Number of Channels = 169
- Average Channels per Transponder = 10.6
- Display Resolution = 640x480
- Typical Encoded Resolution = 544x480
- Raw Average Bitrate Per Channel = 2.096Mbps
- Effective Bitrate Per Channel at Display Resolution = 2.466Mbps


In comparing these two satellites, the raw average bitrate per channel on Dish is only 5.5% below that of Bell. Since Dish has reduced the encoded resolution on their SD channels to 544x480, they have an effective bitrate of (640/544)*2.096Mbps = 2.466Mbps for the display resolution of 640x480. This effective bitrate is 11.1% higher than Bell's raw bitrate for video at 704x480, and 22.2% higher than Bell's effective bitrate at the display resolution of 640x480.

What does this all mean? Basically, all aspects of Dish's current SD PQ should be equal or superior to Bell with the notable exception that Dish's picture will have about 15-23% less horizontal detail (15% relative to 640x480, 22.8% relative to 704x480). The loss of this detail can cause vertical lines and edges to merge together (as seen with the spots on the shirt in the last comparison image posted) or become slightly jagged, but should otherwise not noticeably damage the picture. The picture, however, is very noticeably damaged in a number of other ways, so...

 

[buckchow]

Resolutions are starting to drop to 480x480 on 119W now too. The heavy filtering remains present, which destroys the vertical resolution, so you can imagine that you're getting a picture comparable to something like 480x240. On 110W, most channels encoded at 480x480 are comparable in their retained detail to something like 480x360. This is utterly disgusting.

 

[Pepper]

Their new youtube encoders are doing a marvelous job!

 

[kstuart]

...the fact that they don't appear to have made any serious effort in previous years to address complaints about SD PQ made both directly to Dish...

So, you have emailed the engineers directly at

dishquality _AT_ echostar _DOT_ com

with your complaints ?

I've never failed to get some sort of reply from that address, and the email goes directly to the engineers, instead of going to Bangalore...

 

[buckchow]

Contacting dishquality has been in the back of my mind for a few days, but personally I would rather not contact them just yet. I want to give it another couple of weeks so I have a better idea of how widespread the latest changes are going to be before I waste my time and energy writing a very long e-mail to them.