Comcast Ch 791 (Xfinity 3D) looks BAD ! - AVS Forum

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umenon's Avatar umenon
12:56 PM Liked: 22
post #1 of 5
03-28-2012 | Posts: 1,157
Joined: Jan 2001
I am not sure if my local COMCAST office is to blame ... but here is my problem ...

My cable box is set to lock to native mode.

ESPN3D is broadcast in 720p TopBottom ... looks very good.

Xfinity3D (Ch. 791) is broadcast in 1080i SideBySide ... looks awful ! ... Why you ask? Because the source they use is 720p. So 720p 3D signal is being up-converted by Comcast to 1080i and sent in SBS format. It looks AWFUL !

The very same 3D content that they broadcast on Xfinity 3D is available in OnDemand. However those are all in 720p TopBottom. They look much better !

Also as a an FYI ... I have subscription to HBO 3D and STARZ 3D ONDEMAND. Both these are sent in 1080i SBS ... and they look very good.

I believe the problem with Xfinity 3D shows is that the source is originally in 720p. And mucking with it seems to destroy the 3D fidelity.

Any ideas?
Rudy1's Avatar Rudy1
06:43 AM Liked: 116
post #2 of 5
03-30-2012 | Posts: 3,212
Joined: Oct 2000
What city are you in? Here in downtown Fort Lauderdale, both ESPN 3D and Xfinity 3D look very good. I don't know about the actual resolution of the source material, but I've seen most of what they broadcast on both channels and didn't observe any artifacts or other problems with the signals. As for the OnDemand content, my display reports the signal types as 720p for ESPN 3D, and either 1080i or 1080p for all other programs. The movies from HBO and Starz are usually in 1080i, but in the Movies section I've watched "The Adventures of Tintin" and "Transformers" in 1080p. My set-top box is the RNG110.
umenon's Avatar umenon
08:44 AM Liked: 22
post #3 of 5
03-30-2012 | Posts: 1,157
Joined: Jan 2001
Quote:
Originally Posted by Rudy1 View Post

Here in downtown Fort Lauderdale, both ESPN 3D and Xfinity 3D look very good.

Rudy ... thanks for the response.

I have the Cisco RNG120 (?) box as well. Can you PLEASE do the following check for me ...

- Please verify that Channel 791 is broadcast for you in 1080i and Side By Side.
- Watch a few minutes of any show on Ch. 791.
- Now switch to Comcast OnDemand
- Go to free 3D Movies. Before you do ... please make sure that your Cisco Box is set for NATIVE (i.e. no upconversion).
- Confirm that the same show (on Ch. 791) is available under the Free 3D movies section. If not, use another source material for comparison.
- Confirm that the show is in Top Bottom and 720p. (As opposed to 1080i SBS on Ch. 791)
- Watch this ONDEMAND show in 720p TopBottom NATIVE mode.

How do the two compare in quality. According to my findings ... the ONDEMAND version will look much better.

Quote:
Originally Posted by Rudy1 View Post

The movies from HBO and Starz are usually in 1080i

I have NO COMPLAINTS about ESPN3D and HBO 3D / STARZ 3D ... they look fine. The problem with Xfinity 3D (Ch. 791) broadcast channel is that the source files are not meant to be broadcast in 1080i SBS ... since they are all 720p media. Which is why the same source looks better when viewed from the OnDemand menu.
Rudy1's Avatar Rudy1
06:03 PM Liked: 116
post #4 of 5
03-30-2012 | Posts: 3,212
Joined: Oct 2000
I just performed the tests you indicated, and here are my results:

- (Please verify that Channel 791 is broadcast for you in 1080i and Side By Side) Channel 791 is indeed broadcast here in Side By Side 1080i.
- (Watch a few minutes of any show on Ch. 791) Right now a Palladia show is on ("World Stage: Snoop"), and it looks good.
- (Now switch to Comcast OnDemand) I switched to the OnDemand menu and found this very same program in the 3D offerings under Music.
- (Confirm that the show is in Top Bottom and 720p) "World Stage: Snoop" is reported by my TV as a SBS 1080i signal. And it doesn't look any better or worse than the signal from channel 791.

I've verified that the cablebox is set to native output; according to the menu, the following output modes are selected: 480i, 480p, 720p, 1080i, and 1080p. The model number is RNG 110.
Analog2112's Avatar Analog2112
07:05 AM Liked: 10
post #5 of 5
06-09-2012 | Posts: 3
Joined: Sep 2008
I'm surprised you guys see what is on Xfinity and "on demand" differently, they are the same for me. I think all around the Comcast is terrible although I agree that espn3d, HBO and Stars are the best of everything offered but I was hoping it would be a lot closer to what I see with a BD.

I have the Motorola dx 3400, I have to use pass-through/native mode or else the option for top/bottom isn't available (although side to side works and it looks no better with the cable box set to 720p or even 1080i).

For me though, espn3d (334 for me) is always top/bottom but everything else is always left/right Xfinity 3D (333) and everything in "on demand" including stars and hbo.

If only the comcast looked as disk then I wouldn't feel guilty at all about buying a 3d projector smile.gif
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