[pete4]

Ok. Now I'm confused more than ever. I'm looking at the pictures of the charts in pst #37 and none of those pictures look anything like the chart itself. I displayed the chart on my monitor and zoomed in to see how this should look like at high magnification and there is vertical red line under each white line with blue lines in between. Every single picture shows some red lines missing and where are the blue/gray lines in between? What am I missing? I know my TV is not 444, because border between red and blue rectangle has one pixel wide red/blue line, so TV interpolated color from pixels on both sides to get color in the middle, but the portion of the chart with vertical red lines somehow I'm not getting.

Are those all failures?

 

[thepoohcontinuum]



Quote:
Originally Posted by pete4 /forum/post/21398000


Ok. Now I'm confused more than ever. I'm looking at the pictures of the charts in pst #37 and none of those pictures look anything like the chart itself. I displayed the chart on my monitor and zoomed in to see how this should look like at high magnification and there is vertical red line under each white line with blue lines in between. Every single picture shows some red lines missing and where are the blue/gray lines in between? What am I missing? I know my TV is not 444, because border between red and blue rectangle has one pixel wide red/blue line, so TV interpolated color from pixels on both sides to get color in the middle, but the portion of the chart with vertical red lines somehow I'm not getting.

Are those all failures?

It sounds like you're looking at the wrong place on the belle-nuit chart Because for the 444 test, there shouldn't be a "vertical red line under each white line with blue lines in between". See this link , it shows where you should be looking.

 

[pete4]

I'm sorry to bother you guys, but I must have wrong chart then. On the Belle-nuit chart I downloaded, squares 4,3,2 and 1 seem all the same, except for the thickness of vertical/horizontal lines, going from 4 pixels wide to one pixel wide. It's red line, blue line, no black spaces in between, all the way. If I zoom in on the area it shows the same pattern on the square 1 as on the square 4. My 1080p computer monitor, which should be RGB 444 shows full pattern with no black spaces in between, no missing red lines, unlike the picture you linked in your msg. Can you zoom in on your chart and tell me what you see in square 1? I see the same red/blue line pattern as in other squares and therefore can't understand why they have red lines missing, no blue lines and yes I'm looking exactly at the portion marked in your example. Can this chart be subpixel? It's size is 1920x1080, is my picture viewer not rendering this file properly?

I think it is basic to understand what the chart should look like, before we decide which TV actually has 4 4 4 and I think similar confusion was in previous input delay thread.

 

[thepoohcontinuum]



Quote:
Originally Posted by pete4 /forum/post/21403042


I'm sorry to bother you guys, but I must have wrong chart then. On the Belle-nuit chart I downloaded, squares 4,3,2 and 1 seem all the same, except for the thickness of vertical/horizontal lines, going from 4 pixels wide to one pixel wide. It's red line, blue line, no black spaces in between, all the way. If I zoom in on the area it shows the same pattern on the square 1 as on the square 4. My 1080p computer monitor, which should be RGB 444 shows full pattern with no black spaces in between, no missing red lines, unlike the picture you linked in your msg. Can you zoom in on your chart and tell me what you see in square 1? I see the same red/blue line pattern as in other squares and therefore can't understand why they have red lines missing, no blue lines and yes I'm looking exactly at the portion marked in your example. Can this chart be subpixel? It's size is 1920x1080, is my picture viewer not rendering this file properly?

I think it is basic to understand what the chart should look like, before we decide which TV actually has 4 4 4 and I think similar confusion was in previous input delay thread.

Yeah, I think you're looking at the wrong belle-nuit chart. If I recall correctly, the older belle-nuit charts did not have the 444 test portion in square 1, but the newer one does.


Did you read question T1 in the first post yet? If not, read that. It'll link you to the newer belle nuit test image, and provide example pics of what 444-PASS and 444-FAIL looks like.

 

[pete4]

Thank you very much, it was different chart and it was driving me insane. Does it make difference that chart is for 720p? 1080p chart would help to see if the overscan is messing things up. BTW if you google belle-nuit chart, it seems you get the old one, that's how I got mine.

 

[Neeley]

Hi fellas. Just signed up.


Over the last few days I've been looking for a 32" tv mainly computer use, if it wasn't for doing some intensive research and accidentally discovering the 4:4:4 subsampling stuff, without any doubt I would have bought the wrong TV.


Luckily I found the list and information in this thread which has been a lifesaver, and I want to give something back as my appreciation.


Yesterday I bought a SONY BRAVIA KDL-32EX723 and I can confirm it works perfectly well with pc use, clear text, nothing blurry whatsoever. I have it hooked up via HDMI to HDMI from my graphics card and spent a couple of hours fiddling with the settings.


Here's a pic of the screen I just took, sorry about my phone camera interference but you can see the text is perfect.


If anyone wants any info I'm more than happy to help if I can.


Thanks, Neil.

 

[thepoohcontinuum]



Quote:
Originally Posted by Neeley /forum/post/21407349


Yesterday I bought a SONY BRAVIA KDL-32EX723 and I can confirm it works perfectly well with pc use, clear text, nothing blurry whatsoever. I have it hooked up via HDMI to HDMI from my graphics card and spent a couple of hours fiddling with the settings.

Black text on white background isn't the best test for 444. To be absolutely sure, use the Red-Magenta test or Belle-Nuit test (see question T1 in the first post). Assuming it passes, glad you found the right TV

With your HDMI->HDMI connection, are you getting audio through your TV speakers, or did you disable hdmi audio? Cause if you are getting hdmi audio, the EX723 would be the first TV (that I know of) that allows HDMI audio without breaking 444 capability.

 

[Neeley]



Thanks.....


I haven't done any audio tests yet but will do later, it runs to an external dac at the moment so I've no idea.


Will it be worth buying a DV-I to HDMI cable to gain any extra improvement?

 

[Lessen]



Quote:
Originally Posted by thepoohcontinuum /forum/post/21386795

B4) Why do TV / Movie studios do chroma subsampling?


For the most part, it’s because of modern limitations in data storage capacity and transmission bandwidth.


For example, all blurays are subsampled down to 4:2:0 at the mastering studio (this is according to official bluray spec). As a result, most bluray titles have an average video bitrate of 25 Mbps. Assuming a 2 hour movie, you need a storage medium that can hold ~22.5 GBytes; which a bluray disc can do no problem. Now lets do 4:4:4 (no subsampling) on that same 2 hour movie. Going from 4:2:0 to 4:4:4 quadruples the amount of information required. So that 25 Mbps becomes 100 Mbps, and 22.5 GBytes becomes 90 GBytes; not even a dual-layer bluray disc can hold that much data.


If a bluray disc can’t hold it, don’t expect satellite/cable/fiber to transmit this kind of data either.


Note: the numbers used in this example are under review; will update when straightened out

Those numbers are rather wrong

Note: for all of this I assume 8 bit component depth.


4:4:4 RGB or YCbCr has 3 full-resolution components, so 8*3 = 24 bits per pixel total. So one frame is 1920*1080*3*8 bits = 49.8 Mbit. At 24 fps this results in a datarate of 49.8*24 = 1.2 Gbps.


Chroma subsampling only affects the two chroma planes, not luma. So luma is full resolution (1920*1080) while for 4:2:0 each of the chroma planes is half resolution in each dimension (1920/2 * 1080/2). So one frame of 4:2:0 is (1920*1080 + 1920/2 * 1080/2 + 1920/2 * 1080/2) * 8 bits = 24.9 Mbit, half of 4:4:4. At 24 fps this results in a datarate of 597 Mbps.


But comparing uncompressed bandwidth numbers is only meaningful for HDMI, not Blu-ray or HDTV transmission as those are always compressed. And over HDMI, only 4:2:2 and 4:4:4 are supported, not 4:2:0.


It's a little hard to compare how different subsamplings affect compression, but to start with chroma has much less information than luma no matter the subsampling and thus compresses extremely well, to the point that the great majority of the bandwidth goes to luma data. Anyway, with modern codecs (H.264), 4:4:4 does not take significantly more bandwidth than 4:2:0, and in some cases (upsampling a 4:2:0 to encode as 4:4:4) might actually take less bandwidth due to the larger prediction modes available to 4:4:4 and better interpolation filter (H.264 only.)


The main reason movies are all 4:2:0 is simply because that's the way things were done long before MPEG (it's the original lossy compression, by a factor of two.) The main reason I can think of for modern TVs to subsample is to reduce the required processing power for all the processing done. Or maybe for a PenTile matrix, but no TVs have them as far as I'm aware.

Quote:
Originally Posted by thepoohcontinuum /forum/post/21386795


When HDMI audio extensions are enabled, *something* causes 4:4:4 to fail. I have no idea if this is a TV issue, or a video card issue, or a HDMI issue, or an EDID specification issue, or a combination.

RGB support (4:4:4) is required for all HDMI devices. This is the native format of the framebuffer in computers, making YCbCr support completely optional. There is absolutely no reason for the video card to convert to YCbCr, let alone subsequently subsample to 4:2:2 before sending the data over HDMI. The only place the conversion and subsampling would logically take place is in the TV.


I'll have to try my TV later, I'm honestly quite surprised that getting 4:4:4 from TVs is hard.

 

[pete4]

I already pointed out the data rate difference is not as much as OP listed, but it's all academic at this point. The fact is very few 2011 TV's support full RGB and I would be first to say it's totally stupid, because at least this is what my TV does ( LG 47LW5300): Computer tells me it sends either YCBr 444 or RGB 444 (that's the only options I have in my video driver advance settings and YCBr is a default ), so TV receives full RGB signal. Somehow it's strips full RGB into 422, process the signal and then interpolates 422 back into 444 right before displaying it on the panel. No wonder TV has 130 ms input delay with design like this. I'm hoping against hope it's software issue fixable with firmware update, but most likely it's hardware limitation. Why PC signal doesn't go straight to the panel, bypassing all this meaningless processing is also mystery for me. Had I know all this before purchase, I probably would buy another panel, but it didn't come to my mind. My 5yr old HDTV has no problems like that.

Quote:
Originally Posted by Lessen /forum/post/21416864


Those numbers are rather wrong

Note: for all of this I assume 8 bit component depth.


4:4:4 RGB or YCbCr has 3 full-resolution components, so 8*3 = 24 bits per pixel total. So one frame is 1920*1080*3*8 bits = 49.8 Mbit. At 24 fps this results in a datarate of 49.8*24 = 1.2 Gbps.


Chroma subsampling only affects the two chroma planes, not luma. So luma is full resolution (1920*1080) while for 4:2:0 each of the chroma planes is half resolution in each dimension (1920/2 * 1080/2). So one frame of 4:2:0 is (1920*1080 + 1920/2 * 1080/2 + 1920/2 * 1080/2) * 8 bits = 24.9 Mbit, half of 4:4:4. At 24 fps this results in a datarate of 597 Mbps.


But comparing uncompressed bandwidth numbers is only meaningful for HDMI, not Blu-ray or HDTV transmission as those are always compressed. And over HDMI, only 4:2:2 and 4:4:4 are supported, not 4:2:0.


It's a little hard to compare how different subsamplings affect compression, but to start with chroma has much less information than luma no matter the subsampling and thus compresses extremely well, to the point that the great majority of the bandwidth goes to luma data. Anyway, with modern codecs (H.264), 4:4:4 does not take significantly more bandwidth than 4:2:0, and in some cases (upsampling a 4:2:0 to encode as 4:4:4) might actually take less bandwidth due to the larger prediction modes available to 4:4:4 and better interpolation filter (H.264 only.)


The main reason movies are all 4:2:0 is simply because that's the way things were done long before MPEG (it's the original lossy compression, by a factor of two.) The main reason I can think of for modern TVs to subsample is to reduce the required processing power for all the processing done. Or maybe for a PenTile matrix, but no TVs have them as far as I'm aware.




RGB support (4:4:4) is required for all HDMI devices. This is the native format of the framebuffer in computers, making YCbCr support completely optional. There is absolutely no reason for the video card to convert to YCbCr, let alone subsequently subsample to 4:2:2 before sending the data over HDMI. The only place the conversion and subsampling would logically take place is in the TV.


I'll have to try my TV later, I'm honestly quite surprised that getting 4:4:4 from TVs is hard.

 

[pete4]

I forgot to mention another thing: in theory at least since TV should be getting full luma, black text on white screen should be crisp, but on mine it isn't. Most small fonts are one pixel wide as they should be, but some are 2 pixel wide, like there was some extra processing done there. I was trying different menu options to fix it, but there is not much left in PC mode and I did double check for overscanning as originally for some strangest reason I can't comprehend both video card and TV defaulted to overscan (what's up with that prehistoric relic of analog TV? Why is it even here, on digital TV with no analog OTA channels and at least in my case no analog cable channels).

Can you tell overscan is my personal "pet peeve"?

 

[irkuck]



Quote:
Originally Posted by Lessen /forum/post/21416864


It's a little hard to compare how different subsamplings affect compression, but to start with chroma has much less information than luma no matter the subsampling and thus compresses extremely well, to the point that the great majority of the bandwidth goes to luma data.

....

The main reason movies are all 4:2:0 is simply because that's the way things were done long before MPEG (it's the original lossy compression, by a factor of two.) I'll have to try my TV later, I'm honestly quite surprised that getting 4:4:4 from TVs is hard.

I would say the main reason for 4:2:0 is that it is very reasonable thing to do. You mention correctly chroma has much less info and compresses extremely well. If not 4:2:0 the next would be 4:2:2 which provides so high quality that it is used as professional studio standard with multiple editing in mind. Thus, there is no reason to go beyond the 4:2:0 especially at the level of compression used in consumer products.

 

[thepoohcontinuum]



Quote:
Originally Posted by Lessen /forum/post/21416864


Those numbers are rather wrong

Note: for all of this I assume 8 bit component depth.

Thanks for that very informative post (and you too pete4). Question though... According to the post here , most bluray movies have a video bitrate of around 25 Mbps, how does that number relate to your theoretical calculations? Going from 4:4:4 1.2 Gbps to 4:2:0 25 Mbps is one heck of a compression ratio.


Is it because there's two-factor compression going on? One compression during chroma subsampling (at the recording source), and one during the encoding process?

Quote:
Originally Posted by Lessen /forum/post/21416864


Or maybe for a PenTile matrix, but no TVs have them as far as I'm aware.

I'm only aware of one TV that has a RGBW subpixel layout, and that is the Westinghouse LD-3280 ( pic ). Is this a true PenTile panel? Who knows. Someone on AVForums mentioned it was a CHIMEI LCS-MVA along with the spec sheet ( link ).

Quote:
Originally Posted by Lessen /forum/post/21416864


I'll have to try my TV later, I'm honestly quite surprised that getting 4:4:4 from TVs is hard.

Yup, the search for a 4:4:4 capable TV is a hard and arduous journey

As pete4 mentioned, you would think a TV would have enough "intelligence" to know its receiving a 4:4:4 signal and bypass all the TV/movie processing junk. But that's unfortunately not the case.


And please do check your TV for 4:4:4, the more test results we have the better.

 

[thepoohcontinuum]



Quote:
Originally Posted by pete4 /forum/post/21417888


I forgot to mention another thing: in theory at least since TV should be getting full luma, black text on white screen should be crisp, but on mine it isn't. Most small fonts are one pixel wide as they should be, but some are 2 pixel wide, like there was some extra processing done there.

There's probably some post-processing effect that's hard-coded and can't be disabled. I know with some 2010 LG's, they had an option called Edge Enhancer, which is basically a Sharpen function. Even though this was disabled in the menu, the TV was *still* sharpening things. This especially screwed up text since text pixels were being oversharpened and created a halo-effect around the letters.

 

[pete4]

I can tell you little bit about compression, but without going into real technical and mathematical side of things, way too complex for this thread.

Basically MPEG and other advanced video codecs will take first full video frame and compress it, by throwing out some detail (like above mentioned parts of chroma data) etc. similar way as jpeg pictures are compressed. The next 12 to 15 video frames are compared to the first full frame and only differences between the main frame and following 12-15 frames are recorded. Especially in stationary or slow panning video, there should be very little difference between frames, so they compress very well, something like 100:1 or more. At the same time the codec checks to never go above maximum bitrate. If it does, just like in jpeg compression, the compression level is increased, more data is thrown out etc. That's why, when you're using video tape and you have a dropout and loose part of the main frame, video can go blank for longer time, besides loosing one frame you're loosing subsequent 15 frames, which are coded from the main frame.

I hope this gives you at least some idea how it works.

Quote:
Originally Posted by thepoohcontinuum /forum/post/21418294


Thanks for that very informative post (and you too pete4). Question though... According to the post here , most bluray movies have a video bitrate of around 25 Mbps, how does that number relate to your theoretical calculations? Going from 4:4:4 1.2 Gbps to 4:2:0 25 Mbps is one heck of a compression ratio.


Is it because there's two-factor compression going on? One compression during chroma subsampling (at the recording source), and one during the encoding process?




I'm only aware of one TV that has a RGBW subpixel layout, and that is the Westinghouse LD-3280 ( pic ). Is this a true PenTile panel? Who knows. Someone on AVForums mentioned it was a CHIMEI LCS-MVA along with the spec sheet ( link ).




Yup, the search for a 4:4:4 capable TV is a hard and arduous journey

As pete4 mentioned, you would think a TV would have enough "intelligence" to know its receiving a 4:4:4 signal and bypass all the TV/movie processing junk. But that's unfortunately not the case.


And please do check your TV for 4:4:4, the more test results we have the better.

 

[iamstarfox]

Here's a photo I took of my 2011 Samsung UN32D6000 LED-LCD HDTV. I used a 15 year old digital camera(seriously!) ,so that may have an effect on the end image quality here. It doesn't have a raw format, so the pic was compressed when the camera saved it, and again when I cropped it down and resaved it in photoshop.


Anyway, I think this means it passes the 4:4:4 test. Or am I analyzing this wrong? I'm not sure. I know that text sure looks clear and sharp when I'm browsing the web while using the TV as a second monitor.


I should mention that I have to set the source name label to "PC" for things to look right. Also, I'm using an HDMI cable connected to my AMD 5870 graphic card. HDMI to HDMI, no DVI connector. In the great detailed intro post to this thread, I read about 4:4:4 not working with an HDMI cable that is also carrying audio... But, My PC to TV HDMI audio does work. I was even playing an MP3 over HDMI on the TV speakers when I took this pic. Does that mean this pic isn't an example of 4:4:4 after all?

 

[thepoohcontinuum]



Quote:
Originally Posted by pete4 /forum/post/21418752


I can tell you little bit about compression, but without going into real technical and mathematical side of things, way too complex for this thread.

Heh, thanks for sparing me the techno babble. Your explanation does indeed help. Guess I'll go find some technical documents online about this stuff, sounds like it'll make some awesome material during my bathroom breaks

Quote:
Originally Posted by iamstarfox /forum/post/21421042


Here's a photo I took of my 2011 Samsung UN32D6000 LED-LCD HDTV.

...

I should mention that I have to set the source name label to "PC" for things to look right. Also, I'm using an HDMI cable connected to my AMD 5870 graphic card. HDMI to HDMI, no DVI connector. In the great detailed intro post to this thread, I read about 4:4:4 not working with an HDMI cable that is also carrying audio... But, My PC to TV HDMI audio does work. I was even playing an MP3 over HDMI on the TV speakers when I took this pic. Does that mean this pic isn't an example of 4:4:4 after all?

Nice pic! Its definitely showing 4:4:4 capability, since the red lines are pixel perfect without any horizontal fringing. I'll add your TV model to the list of 444 TVs.


As for the HDMI->HDMI + Audio, that's definitely good news to hear. Since you have a 2011 model, I wonder if the manufacturer(s) have finally fixed the HDMI audio "bug" that prevented 4:4:4 with the older TVs.


Can you do me two things for me?


1) Provide an EDID report of your TV. To do this, run the Monitor Asset Manager (found here ), and then copy/paste the contents from the "Asset Information" window pane.


2) Open Catalyst / AMD Vision Center, and tell me what Pixel Format setting you're currently using. It should look something like this .

 

[Qaq]



Quote:
Originally Posted by thepoohcontinuum /forum/post/21418316


There's probably some post-processing effect that's hard-coded and can't be disabled. I know with some 2010 LG's, they had an option called Edge Enhancer, which is basically a Sharpen function. Even though this was disabled in the menu, the TV was *still* sharpening things. This especially screwed up text since text pixels were being oversharpened and created a halo-effect around the letters.

I can confirm this with my LG LCD. In PC mode (RGB) Desktop looks to sharp, photos look sharper and video affected a little bit too. Thats why I think its better for these TVs to use YCbCr transport in PVP mode over videocard's overlay (like Arcsoft TMT does). HDCP-encripted video streams seem not touched by video driver (directly at least).

 

[JoshZH]



Quote:
Originally Posted by Qaq /forum/post/21421601


I can confirm this with my LG LCD. In PC mode (RGB) Desktop looks to sharp, photos look sharper and video affected a little bit too. Thats why I think its better for these TVs to use YCbCr transport in PVP mode over videocard's overlay (like Arcsoft TMT does). HDCP-encripted video streams seem not touched by video driver (directly at least).

You have to calibrate sharpness, here :

http://www.lagom.nl/lcd-test/sharpness.php


My 42LK450 S-IPS looks perfect :

http://img683.imageshack.us/img683/2174/img3059g.jpg


P.S Dang, should've bought a new camera as well.


P.S.S Happy New Year!

 

[Lessen]



Quote:
Originally Posted by thepoohcontinuum /forum/post/21418294


Thanks for that very informative post (and you too pete4). Question though... According to the post here , most bluray movies have a video bitrate of around 25 Mbps, how does that number relate to your theoretical calculations? Going from 4:4:4 1.2 Gbps to 4:2:0 25 Mbps is one heck of a compression ratio.


Is it because there's two-factor compression going on? One compression during chroma subsampling (at the recording source), and one during the encoding process?

You could say that the chroma subsampling is a 2:1 compression ratio, then the video codec gives another 24:1 compression ratio, and that the latter is what really matters (24:1 for no visual degradation is actually fairly low for most content with a modern codec.) What compression ratios you can achieve are highly dependent on quite a few factors, including:


- Source image/video

- codec used

- what features of the codec are used

- encoder used

- how much quality loss is acceptable

- how seekable you want the encoded stream to be

- how variable you allow local bitrate to be


As a not-at-all comparable example, your test image tint-blue-rgb-1080p.png is 17.6 KB, but decompresses to a 6 MB raw 1920x1080 RGB image, for a compression ratio of 345:1.


Anyway, I tested my Sony KDL46HX800 for 4:4:4, and it supports it as long as you set the "Scene" to either "Game" or "Graphics". Otherwise it subsamples to 4:2:2. Which I guess isn't that surprising to me.


Note that my setup is probably different than everyone else's, so the two ways I tested:

- MacBook Pro with Mini DisplayPort to HDMI cable (with audio over HDMI)

- Copying the images to a memory stick and displaying them at 100% on my PS3


Photo:

​

EDID (since you asked iamstarfox): http://pastebin.com/DQTGRcp3