longhornsk57's profile

Mentor

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33 Messages

Friday, July 13th, 2012 1:39 AM

what's up with 1080i setting but no 1080p?

So I ordered HD upgrade. On the DVR settings I figured I'd see what settings there are, so I go the screen settings and the highest one is 1080i...

What's up with that? Am I really getting interlaced frames? Can this DVR not output 1080p?

What am I missing here?

I have to believe you guys are getting 1080p...

Tutor

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7 Messages

11 years ago


@SomeJoe7777 wrote:

Yes, you are correct on those scenarios, and as we've discussed, the answer would be the "native" output option to avoid all of these issues. A "1080p" output option would work also, but there are two problems with that setting:

1. Not all HD TVs can process a 1080p signal. Older HDTVs, specifically rear-projection CRTs would not operate with that setting.
2. 1080p (either 24 fps or 60fps) is not a legal signal over component cables. HDMI is required by spec (some devices and TVs violate this spec and send 1080p/24 over component anyway, but whether it works or not is manufacturer- and device-specific).

The U-Verse boxes use one of two scaler/deinterlacer processors:

1st generation boxes (Motorola VIP1200/1216/1225, Cisco IPN330/430/4320) use the Sigma Designs 8634.
2nd generation boxes (Motorola VIP2250, Cisco ISB7005/7500) use the Broadcom 7405C.

Both of these are not the top-end scaler/deinterlacers on the market, but they're decent. I've seen much worse in a lot of consumer TVs.


Obviously I was talking about a 1080p TV. If your TV is 720p or 1080i, then those output settings would be fine, although, again, native could still be better depending on the scaler/deinterlacer.

 

My box is a first gen unit and the deinterlacer is really bad. It looks like it mmight just be duplicating fields rather than interpolating, and there's absolutely no motion compensation or inverse telecine going on. Furthermore, the scaler doesn't take interlacing into account very well. 480i channels appear to separate fields and then scale, and then recombine fields, then deinterlace if necessary. This produces horrible results. The proper method should be deinterlace to 60p, scale, and then re-interlace if necessary. 

 

The deinterlacer and scaler are some of the worst I've see. Basic progressive-to-progressive scaling might not be bad, but combined with any combination of interlace and progressive, and there's going to be issues that almost any TV is going to do better. Again, this is just my experience with a first gen box. Haven't tried a second gen. I'm guessing they're better, but still not likely as good as most decently priced TVs and receivers.

 

Furthermore, 1080p over component is legal. It didn't use to be, but it is now. I know my PS3 will output 1080p over component, and my receiver and TV will both accept it as input.

Expert

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9.4K Messages

11 years ago

If 1080p over component is now allowed, that's great, but it doesn't mitigate the problem with many of the existing HDTVs that don't support it. Nevertheless, the box could conceivably support it as an additional setting in the menu, and run the normal 15-second test as it does with the other modes.

Both the Sigma Designs 8634 and Broadcom BCM7405 claim to be motion-adaptive deinterlacers:

http://www.sigmadesigns.com/products.php?id=59
http://www.broadcom.com/products/IPTV/IPTV-Solutions/BCM7405

Many times I see exactly what you're talking about with 480i content that has been upscaled, but I don't think this is occurring in the U-Verse box. As an example, when watching a 720p station (like FOX) and they run a commercial that is 480i, I believe the error is actually on their end when the 480i content is upscaled to 720p. It does indeed look like the fields were separated and separately resized, resulting in very noticable interlacing artifacts when the final 720p frame is transmitted.

Try watching a true 480i feed from one of the SD-only cable channels (don't use a local channel or a channel that has an HD equivalent, because most of those use a HD master feed and it's downscaled to 480i for the SD feed). Watch the 480i feed with the STB output set to 720p or 1080i, and I don't think you will see those interlacing artifacts.

Tutor

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7 Messages

11 years ago


@SomeJoe7777 wrote:
If 1080p over component is now allowed, that's great, but it doesn't mitigate the problem with many of the existing HDTVs that don't support it. Nevertheless, the box could conceivably support it as an additional setting in the menu, and run the normal 15-second test as it does with the other modes.

Both the Sigma Designs 8634 and Broadcom BCM7405 claim to be motion-adaptive deinterlacers:

http://www.sigmadesigns.com/products.php?id=59
http://www.broadcom.com/products/IPTV/IPTV-Solutions/BCM7405

Many times I see exactly what you're talking about with 480i content that has been upscaled, but I don't think this is occurring in the U-Verse box. As an example, when watching a 720p station (like FOX) and they run a commercial that is 480i, I believe the error is actually on their end when the 480i content is upscaled to 720p. It does indeed look like the fields were separated and separately resized, resulting in very noticable interlacing artifacts when the final 720p frame is transmitted.

Try watching a true 480i feed from one of the SD-only cable channels (don't use a local channel or a channel that has an HD equivalent, because most of those use a HD master feed and it's downscaled to 480i for the SD feed). Watch the 480i feed with the STB output set to 720p or 1080i, and I don't think you will see those interlacing artifacts.


I have changed my box to 720p mode, and displayed interlaced channels. The imge flickered, even on completely static images. It's clear it's not motion adaptive, at least on the first gen box. The deinterlacers may be capable of it, but the u-verse box must not be taking advantage of it if so.

 

Also, I was specifically referring to 480i content being displayed on 720p/1080i output on U-verse. I have also seen the same effects on network-upscaled content as well, which is just flat out shameful imo, but that's not what I was talking about. I know for a fact the content looks vastly better if I watch an SD channel with the U-verse box set to 480i, so my set can deinterlace and scale properly.

Mentor

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64 Messages

10 years ago

All I know is that since ditching uverse and switching to directv the pictire is much better.  Even at 1080i on my bravia 55 inches and even in my basement on my 2005 hd ready tv mitsubishi ws65315.  Almost looks new.

ACE - Professor

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2.5K Messages

10 years ago


@autismdefensedotcom wrote:

All I know is that since ditching uverse and switching to directv the pictire is much better.  Even at 1080i on my bravia 55 inches and even in my basement on my 2005 hd ready tv mitsubishi ws65315.  Almost looks new.


I am glad you are happy. However, I find that the picture that I get in high definition from U-Verse is excellent.

 


Owning a computer and not having the internet is like buying a refrigerator and not stocking it with food.

Scholar

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204 Messages

10 years ago

all of this nonsense would be moot if UVERSE offered a "NATIVE" option.

 

Id rather have my $3,000 TV scale the picture than some rented set tob box

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