Belle Nuit test

[stiltman]

OK, so this is related to the WDTV1 and version 2.
Jagabo made this post https://forum.videohelp.com/topic374280.html#2014773
It got me wandering, so I downloaded all the pictures. I did this to mainly test my WD Live TV via component.

I have a older HDTV (42" plasma) with only composite, component, and DVI inputs. It does 720p and 1080i.
If you look at the test pics, you will know what i'm talking about (hopefully).
If I load the testchart.tiff with my WDTV set to 1080i (YUV or RGB doesn't matter), the red boxed areas look like they are blinking on the TV


Now if I set the WDTV to 720p (YUV or RGB doesn't matter), the blinking has stopped. However, the red boxed area is very blury and smuged



So my question is why?
All the colors look right and the gray scale looks perfect too.
I haven't tested it via DVI, because I will never have the WDTV hooked up this way.

[jagabo]

When you feed the test image to your HDTV as 1080i it arrives at the TV as an interlaced image. The proper way to view an interlaced image is one field at a time. In the areas with thin horizontal lines you have one field that is black and one field that is white. When viewed on an interlaced display it would be flashing black and white! Your TV is doing the best it can to duplicate this. Here's a 4x nearest neighbor enlargement of what a "perfect" interlaced display would show you (slowed down to 2 fields per second rather than 60 fields per second):



I'm not sure how you produced those sample images. They are showing evidence of digital resizing and maybe chroma subsampling errors. Use the 720p Belle Nuit test pattern to test 720p output.

[stiltman]

My pics above are just print screens of the original. They are in no way representitive of what they actually look like on my TV. I just needed something to represent which fields I was refereing too.

Even though my TV will accept 720p, it native resolution is 1080i, so it scales everything to that. The 720p test pict didn't look as good.

I'm curious as to why fields 4 and 2 were not flickering, does it have to do with the size of the lines?

Also, if I take the original tiff files, tat are compressed, MAC color space and change them to uncompressed interlaced jpg, would it produce the same results? Not sure if bmp can be set as interlaced

Thanks for the reply

[poisondeathray]

Where can I read more info about the various test patterns, significance, interpretations and what they mean?

Any books or websites?

[jagabo]

I have a older HDTV (42" plasma)... Even though my TV will accept 720p, it native resolution is 1080i

I thought all plasma screens were progressive? What model is your HDTV? A quick Google search shows that there is an interlaced plasma technology called ALiS -- is your TV one of those?

I'm curious as to why fields 4 and 2 were not flickering, does it have to do with the size of the lines?

They should have been flickering a little bit (looked like they were bouncing up and down by one scan line). But yes, the reduced flickering has to do with the thickness of the horizontal lines.

Also, if I take the original tiff files, tat are compressed, MAC color space and change them to uncompressed interlaced jpg, would it produce the same results?

No. JPG usually uses 4:2:0 chroma subsampling. So the blue/red lines will get their colors messed up.

Not sure if bmp can be set as interlaced

Uncompressed RGB BMP (BMP does support compression but people refer to uncompressed RGB when using BMP). An image like that is interlaced if you say it's interlaced, progressive if you say it's progressive.

Another thing you should be aware of: I'm pretty sure component video sends the chroma channels at lower bandwidth than the luma channels. So even though the luma channels is nominally 1920x1080 (two 1920x540 fields) the chroma channels are 960x1080 or less. This will cause blurring of the vertical blue/red lines.

[jagabo]

Where can I read more info about the various test patterns, significance, interpretations and what they mean?

The Belle Nuit site explains a lot of it: http://www.belle-nuit.com/testchart.html

[stiltman]

My HDTV is a Magnavox (Philps seconds) 42MF230A/37 from 2005
http://www.m4c.magnavox.com/cgi-bin/dcbint/cpindex.pl?scy=US&slg=AEN&cat=FLAT_TV_CA&sc...nk_UserManuals

[jagabo]

My HDTV is a Magnavox (Philps seconds) 42MF230A/37 from 2005
http://www.m4c.magnavox.com/cgi-bin/dcbint/cpindex.pl?scy=US&slg=AEN&cat=FLAT_TV_CA&sc...nk_UserManuals

The manual doesn't indicate the native resolution of the panel. There weren't many plasmas back in 2005 that had 1920x1080 native resolution. A little Google searching indicates the native resolution of that set is 1024x768. And the plasma panel is progressive, not interlaced. If your TV has 1920x1080 resolution with pixel-for-pixel mapping you should be able to see each of the black and white lines in the "1" area. As mentioned earlier, when fed as an interlaced signal the horizontal lines may not resolve and will flicker because of the deinterlacing.

Here's an extreme close-up snapshot of my TV displaying the 1920x1080 Belle Nuit pattern:

That's the top of the "1". You can see the alternating black and white lines on the left, the alternating red and cyan lines on the right.

[stiltman]

I don't have any problems seeing them, except for the flickering. I'm pretty sure that 1024x768 is the vga port. The vga port will only output 4x3 which I just found out not to long ago...never hooked anything up to it.

However with this testing, and close up looking, I found that I'm starting to get more pronounce vertical lines on the right side. This is a logic board problem, as someone else had the same problem. It would also point to the problem I'm having hooking stuff up via HDMI-->DVI

I'll have to find my BB reciept and the advantage plan to see it it's still covered..I bought it B-friday 2005

[jagabo]

It's very common for widescreen plasma TVs to have 1024x768 (non square pixels) or 1366x768 (square pixels) native resolutions. It wasn't until a year or two ago that full 1920x1080 resolutions plasmas became common -- and only at the high end. They've worked their way down to the middle ground now.

[stiltman]

YEAH!!!!!

Just found all the info (every freaking reciept and rebate forms) from the day I purchased it back ALMOST 4 years ago.

Glad I got the pro plan for 4 years
I'm going to call BB...

This will start the extremely long process of getting it fixed or replace. I've been reading how bad BB is for extended warranties..not looking forward to it

$1799.99 with a $300 rebate. If they can't fix it, I'm going to demand another Plasma. Any current Plasma is better than this one

I wont take a low end LCD

[jagabo]

42" 720p plasmas are running about US$600 to $700 these days.

[stiltman]

Yeah, I'll just tell them it has to have a pc input like my current useless one

Least that way they wont be able to give me one of their crappy Insignia TVs. Then again, like I said before, most any current Plasma will be better than my 4 year old one.