Media Room 2.1: Release Date, Features, Wish List?(now 2.1.2295)

[ruiner]

@LeafsFan:

There is no 'black level' flag as someone pointed out in MPEG compression. If that was the case Telus would just switch it on.

Could you please tell me where you got this information from? Because if you are stating facts like you know what you are talking about, make sure you can back it up. Otherwise you confuse people with misinformation.

http://iphome.hhi.de/suehring/tml/

From this link you can look at the documentation for the MPEG4 AVC reference software. Specifically you are looking for this link: http://iphome.hhi.de/suehring/tml/JM...JVT-AE010).pdf.

4.7.29.9 VUI_video_full_range_flag
Class: Numeric (Integer)
Description: This parameter indicates the black level and range of the luma and chroma signals. When not present, the value shall be inferred to be equal to 0 (default).

This is present in the bitstream at bit 87 and is set to 0 to specify 16-235 or 1 to specify 0-255; ie a "flag". Telus' encoders are incorrectly setting this bit to 1.

[LeafsFan91]

@Ruiner Everything I said applies to MPEG-2.

Just google ISO/IEC 13818 that's MPEG-2. You'll see there is no 'black level' flag in there. I thought Telus used Mpeg-2. I guess I should have been more clear and said mpeg-2.

If what Dr Dave (that telus uses Mpeg-4) is saying is true then you are right and there is a black level flag.

@Dr Dave ~ I read from PBS OTA broadcast that "it hasn’t been squeezed and squished to fit into a crowded cable or satellite stream."
I guess that was false advertising on their part. Maybe I shouldn't get facts on press releases anymore. LOL

[Dr.Dave]

Let's skip the personal attacks, please. I dealt with the offending posts.

[ruiner]

Yes, Telus is using MPEG4 AVC (H.264) which is what Bluray mostly uses. There is no way to provide a half decent looking MPEG2 high def stream with the kind of bandwidth they have available. Not with more than 1 stream and only to a small fraction of their subscribers anyhow.

And technically the ATSC spec for MPEG2 broadcast transmission allows colorimetry to be transmitted in the bitstream which could slightly screw up the colors and levels if set wrong.

Not noticing it on your TV between OTA and Optik is probably due to your TV doing some sort of dynamic contrast processing on the picture. Or its brightness/contrast being cranked up so high you can't notice it.

The first night after I moved here I watched HNIC on CBUT-DT and I immediately noticed the grey blacks as the installer was setting up my Optik the following day.

[warrenmr]

Originally Posted by ruiner

This is present in the bitstream at bit 87 and is set to 0 to specify 16-235 or 1 to specify 0-255; ie a "flag". Telus' encoders are incorrectly setting this bit to 1.

If this is as simple as changing a single bit in the encoding, why on earth hasn't Telus fixed this? Totally inexplicable.

[merve04]

Does Telus only use one uplink centre to distribute IPTV in all of their markets? As in there sat farm is located just off 113a st and 60th ave here in Edmonton. Should I just go and knock on the door and tell them to change it? lol

[LeafsFan91]

@Merve ~ DO IT. Come on we believe in you lol

@Ruiner I was playing around with my TV today and found a setting called HDMI black level (Almost all Samsung TVs have it). I did some research I found if you set it to low you are setting the colour scale to 16-235 and if it's normal it's 0-255. By default it was was low. So, my TV allows me to choose the color scale and that's different from dynamic contrast which dynamically dims the black light and does other stuff to get darker levels.

That's probably why I don't notice a thing. My TV isn't compensating. It chooses the colour scale on it's own. I believe ALL modern Samsung TVs have this setting. It's buried in the menu though so you may have to search for it. At least for me.

[Arthur Dent]

Originally Posted by LeafsFan91

@Ruiner I was playing around with my TV today and found a setting called HDMI black level (Almost all Samsung TVs have it). I did some research I found if you set it to low you are setting the colour scale to 16-235 and if it's normal it's 0-255. By default it was was low. So, my TV allows me to choose the color scale and that's different from dynamic contrast which dynamically dims the black light and does other stuff to get darker levels.

That's probably why I don't notice a thing. My TV isn't compensating. It chooses the colour scale on it's own. I believe ALL modern Samsung TVs have this setting. It's buried in the menu though so you may have to search for it. At least for me.

No TV, including yours, can compensate for the wrong Telus levels by setting the "HDMI Black Level" (as it is called on your TV's menu). If you use 16-235, you will get the results that everyone noticing the bug is getting. If you set it to 0-255, it will be much worse - blacks will be even more light grey.
The reason you might not be noticing the difference is because the brightness level on the input where your Telus STB is is set to 9-10 notches below the brightness level of the OTA tuner. Your TV, like almost every other TV, has different settings for brightness, contrast, HDMI levels etc. for every input. This is the only way the black level bug can be masked (not fully fixed) for now, and either you or the installer has adjusted the brightness levels differently on the two inputs.

[LeafsFan91]

@Arthur Let me make myself very clear. The settings on my OTA and HDMI are the SAME except for the HDMI black level and when I mean the same I mean exactly the same.

I would also like to see your reasoning on why a TV can't compensate for it. If what ruiner is saying is true (that 0-255) is being incorrectly set then my TV will be able to compensate. However if what you are saying about it being 25-220 then my TV probably can't. There's one problem with that though, how are they setting it to that when MPEG-4 encoders have only two options. 25-220 is used by no one so why would the encoder even have that option.

[ruiner]

I had forgotten about that bug in Samsung's firmware. When viewing YCbCr content (Optik TV, DVD, Bluray) the HDMI Black Level should be disabled and greyed out, but after viewing RGB content (PC, PS3, XBOX) it can become stuck and stay enabled for YCbCr sources.

With the HDMI Black Level set to low you are essentially working around the Optik black level bug. Set it to normal to see what everyone else is complaining about.

[Arthur Dent]

Originally Posted by LeafsFan91

I would also like to see your reasoning on why a TV can't compensate for it. If what ruiner is saying is true (that 0-255) is being incorrectly set then my TV will be able to compensate. However if what you are saying about it being 25-220 then my TV probably can't. There's one problem with that though, how are they setting it to that when MPEG-4 encoders have only two options. 25-220 is used by no one so why would the encoder even have that option.

LeafsFan, what happens to the blacks on your TV when you change from 16-235 to 0-255? Where are they lighter?

[Arthur Dent]

Originally Posted by LeafsFan91

@Arthur Let me make myself very clear. The settings on my OTA and HDMI are the SAME except for the HDMI black level and when I mean the same I mean exactly the same.

What are the HDMI black level settings for each? What is the brightness level set at for each?

[ruiner]

Arthur,

No TV, including yours, can compensate for the wrong Telus levels by setting the "HDMI Black Level" (as it is called on your TV's menu). If you use 16-235, you will get the results that everyone noticing the bug is getting. If you set it to 0-255, it will be much worse - blacks will be even more light grey.

HDMI allows transmitting the Gamut Boundary Description:

The HDMI source gamut is described either by a set of R/G/B range limits or by a set of vertices with or without indexed facets.
...
The minimal number of vertices is 4. In this case, and only this case, the vertices have the following meaning, in this order: black point, red primary, green primary and blue primary. This convention allows constructing the white point and the secondary colors (magenta, cyan and yellow) without transmission.

What the HDMI Black Level setting on Samsung TV's does is override these values with defaults. Normally when the Telus encoders send out 16-235 data packaged as 0-255, something that is black at 16 is suddenly grey when using a 0-255 gamut. But the HDMI Black Level setting corrects the gamut back to 16-235.

So the bug in Samsung's firmware (the setting isn't supposed to be active for YCbCr content) is probably helping to mask the issue since there are a lot of Samsung TV's out there.

[LeafsFan91]

Originally Posted by Arthur Dent

LeafsFan, what happens to the blacks on your TV when you change from 16-235 to 0-255? Where are they lighter?

When I turn HDMI black level on normal the blacks look greyer.

Originally Posted by Arthur Dent

What are the HDMI black level settings for each? What is the brightness level set at for each?

For OTA the HDMI black level isn't there. The option is gone. For my STB it's was on low by default. My brightness is 50 (out of 100) and my backlight is maxed out at 20 on both OTA and HDMI.

[Dr.Dave]

Several posts were deleted. Trolling, flaming and rude comments are not allowed. Please keep the tone friendly.