How much "Bull" is there in HD-lite?

veryoldschool · 02-21-07, 11:43 AM

I don't know for one, how much bull there is in the many posting & "experts" about how the HD signal is distorted, compressed, bit starved, etc...
When I moved to HDTV, I started with a 1080i capable TV. 1080i is a 1920 x 1080 image.
Now I know that bandwidth = big dollars & everyone [providers] is trying to maximize their content & minimize their costs. This makes perfect sense. It is a business.
What I don't understand are "the reports" of how they're doing this.
Again my reference is a 1080i HDTV. I see that OTA channels look the best. For me, D* MPEG-4 look better than my cable's MPEG-2 [all the same channel for accurate comparison].
Now there are many posting that D* is reducing "something" with their MPEG-2 HD. Many have posted that they change the resolution from 1920 to either 1440 or 1280.
I can't believe that if they did this I couldn't see it. This isn't 10%, which I noticed with my first TV's [CRT RPTV] over scanning, but something more like 30%.
Now D* must be doing something to reduce bandwidth usage with MPEG-2 but it seems [to me] that reducing the resolution isn't what is happening.
So if the size isn't being reduced, then the color depth is about the only thing left.
In the PC world this would be: instead of 32 bit color reducing it to 24 bit.
Just one person trying to understand what is really going on & trying to weed through the bull.

keith_benedict · 02-21-07, 12:21 PM

Thinking in PC terms, it wouldn't really equate to using 32 bit color vs. 24 bit color. A better analogy would be using 96bps encoding when ripping CD's vs. 128bps encoding. You will notice a difference if you have decent speakers (and ears).

Or an even closer analogy would be changing the quality level from 12 (highest) for saving a JPEG, to 8 (medium quality). You will notice a difference, but it will be very slight. When you start showing those pictures in sequence (say 30 of them per second), the difference will be more noticeable. You will notice less smooth transitions from frame-to-frame because things are just slightly off in each frame.

**Tom Robertson** · 02-21-07, 12:21 PM

Quote:

Originally Posted by veryoldschool

I don't know for one, how much bull there is in the many posting & "experts" about how the HD signal is distorted, compressed, bit starved, etc...
When I moved to HDTV, I started with a 1080i capable TV. 1080i is a 1920 x 1080 image.
Now I know that bandwidth = big dollars & everyone [providers] is trying to maximize their content & minimize their costs. This makes perfect sense. It is a business.
What I don't understand are "the reports" of how they're doing this.
Again my reference is a 1080i HDTV. I see that OTA channels look the best. For me, D* MPEG-4 look better than my cable's MPEG-2 [all the same channel for accurate comparison].
Now there are many posting that D* is reducing "something" with their MPEG-2 HD. Many have posted that they change the resolution from 1920 to either 1440 or 1280.
I can't believe that if they did this I couldn't see it. This isn't 10%, which I noticed with my first TV's [CRT RPTV] over scanning, but something more like 30%.
Now D* must be doing something to reduce bandwidth usage with MPEG-2 but it seems [to me] that reducing the resolution isn't what is happening.
So if the size isn't being reduced, then the color depth is about the only thing left.
In the PC world this would be: instead of 32 bit color reducing it to 24 bit.
Just one person trying to understand what is really going on & trying to weed through the bull.

Your analogy is very apt. The resolution of the image remains the same. With the DIRECTV (and Dish Network too) MPEG2 channels comparison on the bitrate level is very simple. Smaller bitrate is gonna be worse picture quality.

With your average episodic TV series, you really can't see much difference. The studios aren't shooting with HD in mind. Where it becomes painfully obvious to me are fast moving pictures as in sports. I remember a NASCAR event last year where the sparkles as the cars passed the crowd looked worse than SD! And this year, our local NBC affiliate stopped broadcasting a subchannel because of complaints now that NBC was carrying NFL games again.

Where things get very tough to compare at a bitrate level is an MPEG2 to MPEG4 transcoding. MPEG4 is meant to be much more efficient and still lossless. So you can't say "fewer bits from the original, must be worse picture."

HTH,
Tom

Que · 02-21-07, 01:42 PM

Here is a bit I put in another post. Hope it helps.

http://www.cnet.com/4520-7874_1-5137915-1.html

Quote:
HD Lite is an informal term used to describe the broadcast of a particular HDTV channel with reduced picture quality. In most cases this means that the channel originates with a particular video encoding, resolution, and bit rate, but is re-encoded or rate shaped by the multichannel video programming distributor (i.e. cable television or DBS provider) to save bandwidth. Reduced video quality is characterized by reduced sharpness, reduced detail, excessive compression artifacts (mosquito noise and blocking), and in some cases, washed-out colors. The reduced video quality is most often caused by poorly done recompression, low bit rates (from recompression or rate-shaping equipment), or reduced resolution. When HD Lite uses reduced resolution, it is most commonly 1280 x 1080i or 1440 x 1080I, which is in contrast to the 1920 x 1080i and 1280 x 720p resolutions that most networks, over-the-air broadcasters, and cable/satellite HDTV channels provide.

Here a link that show each channels bit rate

http://www.widemovies.com/dfwbitrate.html

Here are some more HD-Lite links:

http://www.stophdlite.com/

http://www.urbandictionary.com/define.php?term=HD+Lite

http://en.wikipedia.org/wiki/Hd_lite

[Edit] You might even need to calibrate your TV http://www.smartcalibration.com/hdnetpatterns.html

veryoldschool · 02-21-07, 02:10 PM

My belief is that D* doesn't reduce the resolution to 1440 or 1280, or I could see it.
While links to information can be good, they can also add to the BULL surrounding this topic.
This was why I started this thread, to weed through the bull & not to spread more. FWIW

dgordo · 02-21-07, 02:12 PM

You are wrong. MPEG2 is 1280.

veryoldschool · 02-21-07, 02:22 PM

Quote:

Originally Posted by dgordo

You are wrong. MPEG2 is 1280.

And you know this because?

dgordo · 02-21-07, 02:24 PM

Because my HR10 with old software allows me to see the resoultion of all channels.

texmex · 02-21-07, 02:29 PM

Quote:

Originally Posted by veryoldschool

My belief is that D* doesn't reduce the resolution to 1440 or 1280, or I could see it.
While links to information can be good, they can also add to the BULL surrounding this topic.
This was why I started this thread, to weed through the bull & not to spread more. FWIW

You are aware that the HR10-250 can be hacked and the D* streams can be extracted to your PC? MPEG2 1080i streams from D* ARE REDUCED TO 1280 X1080 (it's actually 1280x1088; a quirk in the encoder adds the extra 8 pixels) - this is FACT, not bull. Just because you can't see the difference on your setup doesn't mean it isn't true. Bitrates are squashed down to the 9 - 13 mbps range, depending on the channel.

P Smith · 02-21-07, 02:30 PM

Not again !

BTW, I can see MPEG-2 headers in sat stream with the numbers; yes, it's REAL numbers, DTV doing 1280x1080.

[Boring pointless discussions, we have known the number for last years]

P Smith · 02-21-07, 02:36 PM

My grandma cannot read newspaper without glasses - is that mean no news there ?

veryoldschool · 02-21-07, 02:44 PM

Quote:

Originally Posted by P Smith

Not again ! I can see MPEG-2 header in sat stream with the number; yes, it's REAL numbers, DTV doing 1280x1080.
[Boring pointless discussions, we have known the number for last years]

Thank you. Not having the older boxes I didn't know.
This was why I asked.. to hear some real facts & not what someone read somewhere.
I can say that I've seen some "softness" with the LA feeds over the MPEG-4 for the same channel.
And then there are those posts say that the MPEG-4 is the same way, which doesn't make sense.
As I stated bandwidth usage is costly, How they utilize it is important.

veryoldschool · 02-21-07, 02:48 PM

Quote:

Originally Posted by P Smith

My grandma cannot read newspaper without glasses - is that mean no news there ?

Grandpa is using his glasses...

P Smith · 02-21-07, 02:55 PM

Don't insult me - I can read without glasses !

Xaa · 02-21-07, 03:02 PM

Quote:

Originally Posted by P Smith

Not again !

BTW, I can see MPEG-2 headers in sat stream with the numbers; yes, it's REAL numbers, DTV doing 1280x1080.

[Boring pointless discussions, we have known the number for last years]

Can you see it for the MPEG4 as well? I've been told that those are not reduced to 1280. Can anyone confirm that?

Xaa

**Stuart Sweet** · 02-21-07, 03:08 PM

Veryoldschool,

something you haven't said is whether your TV is truly capable of displaying 1080i resolution. A quick Google search seems to indicate that it does, so the following does not apply to you, but it is worth saying.

Just because a TV can receive signals in 1080i does not mean it can display them in 1080i. Only within the last year has 1080 resolution been affordable. Prior to that, almost all panels had a native resolution of 1366x768, and while you could take in 1080i it was downsampled when displayed. In a scenario like this, there is negligible difference between 1920x1080 and 1280x1080 since both are going to be normalized to 1366x768. Even current Sony CRT HDTVs which advertise themselves as 1080i capable are only showing a native resolution of roughly 800 lines.

In that case, the primary difference between a native 1080i signal and "HD-Lite" would be the compression artifacts from artificially lowering the bandwidth, not the actual resolution. In addition, there's research over at the AVS forums which seem to conclude that the perceivable difference between 720 and 1080 is really small when viewed on sets smaller than 42" at reasonable viewing distances.

Bottom line is, of course, are you satisfied with your picture or do you think it can or should be better. For me, the "nut" at the center of the HD-Lite controversy is not resolution per se but overcompression. I see a lot more block noise and posterization in high-saturation 3/4 tone areas with DirecTV's MPEG-4 channels than in over-the-air broadcasts of the same. Technically my TV can only show 1366x768 so it's not the resolution I'm reacting to, it's the compression level. Same with SD channels. Picture quality on some channels - Discovery-owned channels specifically - is really rotten but it's not because it's 480i, it's because it's painfully overcompressed. Even the black level seems artificially high. You can bet that it doesn't look like that at their studios.

dgordo · 02-21-07, 03:14 PM

Quote:

Originally Posted by Xaa

Can you see it for the MPEG4 as well? I've been told that those are not reduced to 1280. Can anyone confirm that?

Xaa

As far as I know, no one can see the MPEG4. D* fixed that in the HR20.

**Stuart Sweet** · 02-21-07, 03:19 PM

Quote:

Originally Posted by dgordo

As far as I know, no one can see the MPEG4. D* fixed that in the HR20.

Yeah, I've heard the same thing, that resolution is not reduced in MPEG-4 feeds, but there are still compression issues.

paulman182 · 02-21-07, 03:28 PM

Quote:

Originally Posted by veryoldschool

I I can't believe that if they did this I couldn't see it. This isn't 10%, which I noticed with my first TV's [CRT RPTV] over scanning, but something more like 30%.
Now D* must be doing something to reduce bandwidth usage with MPEG-2 but it seems [to me] that reducing the resolution isn't what is happening.
So if the size isn't being reduced, then the color depth is about the only thing left.

Sorry if I'm off base but I think you are misunderstanding. The resolution that is allegedly being reduced shows up in lack of picture detail, not size of the image...has nothing to do with overscanning. The picture will not be as sharp as it could/should be.

I can't comment on the decreased resolution, because I really have nothing to compare it with. But I do see "blocking" in fast-moving scenes with flashes such as explosions, etc., most recently while watching "Star Wars" on HBO HD.

dgordo · 02-21-07, 03:29 PM

I have not seen a MPEG4 feed so I cannot comment on the quality.

veryoldschool · 02-21-07, 03:30 PM

Quote:

Originally Posted by lamontcranston

Veryoldschool,
something you haven't said is whether your TV is truly capable of displaying 1080i resolution. A quick Google search seems to indicate that it does, so the following does not apply to you, but it is worth saying.
Just because a TV can receive signals in 1080i does not mean it can display them in 1080i. Only within the last year has 1080 resolution been affordable. Prior to that, almost all panels had a native resolution of 1366x768, and while you could take in 1080i it was downsampled when displayed. In a scenario like this, there is negligible difference between 1920x1080 and 1280x1080 since both are going to be normalized to 1366x768. Even current Sony CRT HDTVs which advertise themselves as 1080i capable are only showing a native resolution of roughly 800 lines.
In that case, the primary difference between a native 1080i signal and "HD-Lite" would be the compression artifacts from artificially lowering the bandwidth, not the actual resolution. In addition, there's research over at the AVS forums which seem to conclude that the perceivable difference between 720 and 1080 is really small when viewed on sets smaller than 42" at reasonable viewing distances.
Bottom line is, of course, are you satisfied with your picture or do you think it can or should be better. For me, the "nut" at the center of the HD-Lite controversy is not resolution per se but overcompression. I see a lot more block noise and posterization in high-saturation 3/4 tone areas with DirecTV's MPEG-4 channels than in over-the-air broadcasts of the same. Technically my TV can only show 1366x768 so it's not the resolution I'm reacting to, it's the compression level. Same with SD channels. Picture quality on some channels - Discovery-owned channels specifically - is really rotten but it's not because it's 480i, it's because it's painfully overcompressed. Even the black level seems artificially high. You can bet that it doesn't look like that at their studios.

I went for the big bucks [for me] & trashed my bank account along the way.
My first Sony HD RPTV could do 1080i [but with 10% over scan], My current LCD 1080P [is native 1920x1080 and "only" 46"] has a soooo much better PQ. The fine detail really knocks me out.
In "blonde speak" it's "the dots". The smaller & tighter the better looking [to me].
I learned a lesson when I installed a HDTV tuner card in a PC with a 1600x1200 monitor. Tight dots is the way to go. [dot/pitch]
As for the over compression: Yeah that still get to me. My MPEG-4 channels are sharp, but with a moving [panning] camera, "plain" backgrounds can look like crap until there is enough "bits" to sync the shades/details again. Too much compression....
Still MPEG-4 comes damn close to OTA MPEG-2. FWIW

harsh · 02-21-07, 03:31 PM

Quote:

Originally Posted by tibber

Your analogy is very apt. The resolution of the image remains the same.

I would argue that you need to be more specific about what "resolution" metric you're referring to. Video resolution and pixel resolution (matrix size) are two decidedly different measurements.

Quote:

With the DIRECTV (and Dish Network too) MPEG2 channels comparison on the bitrate level is very simple. Smaller bitrate is gonna be worse picture quality.

DirecTV and, to a lesser extent, Dish Network both participate in reducing the pixel matrix of some (E*) or all (D*) of their 1080i HD content. A reduction in pixel resolution will result in a reduction of video resolution. Bitrate is inversely proportional to compression. It isn't separate and apart from compression.

Quote:

Where things get very tough to compare at a bitrate level is an MPEG2 to MPEG4 transcoding. MPEG4 is meant to be much more efficient and still lossless.

MPEG4 is not any more or less lossless than MPEG2. Both are lossy algorithms. MPEG4 is more efficient (because it looks at compressing a much larger chunk of video), but the satcasters use this efficiency to decrease the bitrate, so it ends up being a wash on PQ.

What you see all comes down to how high they turn up the compression (lower the bitrate).

veryoldschool · 02-21-07, 03:35 PM

Quote:

Originally Posted by paulman182

Sorry if I'm off base but I think you are misunderstanding. The resolution that is allegedly being reduced shows up in lack of picture detail, not size of the image...has nothing to do with overscanning. The picture will not be as sharp as it could/should be.
I can't comment on the decreased resolution, because I really have nothing to compare it with. But I do see "blocking" in fast-moving scenes with flashes such as explosions, etc., most recently while watching "Star Wars" on HBO HD.

I think by now I do understand...
The [D*] MPEG-2 HD tends to look "softer" than the same program on OTA or MPEG-4, when I can compare them.

raott · 02-21-07, 03:56 PM

**Tom Robertson** · 02-21-07, 04:00 PM

Quote:

Originally Posted by raott

What amazes me is that you knew so little about the issue yet started a thread to "weed through the bull" and "not to spread more" implying that there was no such thing as HD-Lite. You must be a D* VP.

Come to my house and I'll show show you a football game recorded off ESPNHD that looks attrocious and then tell me that HD Lite is "bull".

He started a thread, got answers, bull has been weeded and unspread. So what was your point, again?

Cheers,
Tom