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Adjust the brightness

Discussion in 'NEO U9-H' started by vincenz0, Mar 13, 2017.

  1. WeK05

    WeK05 Audio Visual Master Specialist

    You are right. The screenshots basically give you an idea of the brightness issue before and after it is corrected (with one of the workarounds).
  2. Runge

    Runge Member

    In my experience the only way to make it "abnormal" is to reboot the device. Then it corrects itself after watching a 4K clip or similar as many have reported. The error doesn't just appear randomly.
  3. MINIX - Ken

    MINIX - Ken Former MINIX Team Member Administrator

    We tested with nougat and it doesn't display all blocks, in fact their native player shows more blocks than in Kodi.
  4. MINIX - Ken

    MINIX - Ken Former MINIX Team Member Administrator

    Thanks, we are working into this problem now.
  5. WeK05

    WeK05 Audio Visual Master Specialist

    That is bizarre. Shield has no issue with passing through blacker than black (1-15) or super-whites (236-254) in YCbCr or RGB Limted modes for both 1080p & 2160p. Are you sure that you were not using RGB Full color space? In that mode, you may not see the black bars at all and only a few of the lower white bars and that is what should be expected.

    Here is a clip that I recorded from the Shield. It shows 4-25 black bars and 230-251 white bars flashing (when the clip is viewed on a computer set to RGB Full mode). I am not sure whether this will show up in YouTube. You may have to download the clips and play it on U1/U9-H (MoviePlayer or after you have done the brightness issue workaround) or on PC using VLC media player.

    Shield 1080p grayscale
    Shield 2160p grayscale
    Last edited: Mar 27, 2017
  6. MINIX - Ken

    MINIX - Ken Former MINIX Team Member Administrator

    Your output seems to be 4:4:4 instead of 4:2:0
    I don't see anything above 235 flashing in your video... viewed from laptop and other boxes.
    Don't know why you are having different result using the same device... stuck.
    I tested on 4 different TVs. SONY HDR, SONY, LG, Samsung.
  7. WeK05

    WeK05 Audio Visual Master Specialist

    4K 24Hz and 1080p can only be 4:4:4 or 4:2:2. You can get 4:2:0 only with 4K 50/59.94/60Hz. I just didn't record that, but it is the same for all refresh rates.

    If you can't see +235 bars flashing on other boxes, then your TV is not calibrated correctly (which is again odd because TVs from the last decade or so hardly ever show white clipping). If you can't see it in VLC player on your laptop, then I don't know what to say. This is what I can positively say, there is no issue with Shield and the same applies to U1.
    Last edited: Mar 27, 2017
  8. MINIX - Ken

    MINIX - Ken Former MINIX Team Member Administrator

    I calibrated the way you instructed, adjust brightness until seeing 16 and above flashing.
    and now you are telling me I have to see 2-15 flashing?

    I'm really lost, man....
  9. MINIX - Ken

    MINIX - Ken Former MINIX Team Member Administrator

    We don't know how to proceed, the info is confusing...

    @WeK05 can we ignore all previous messages and start over again?

    1.) What's the problem?

    2.) How to check it?

    3.) What's wrong you think?

    Thank you very much.
  10. WeK05

    WeK05 Audio Visual Master Specialist

    If you have calibrated brightness to a level where you can barely see 16 and clearly see 17-25 flash, then it is correct. For contrast, you go up to a level where you cannot see 235 and higher flashing, but this is rarely achievable with modern LCD/LED TVs. You may see all the white bars even at maximum contrast. This is kind of OK.

    Calibrating to 16 doesn't mean that the lower levels are not present. They are still there, but you will not see them on your calibrated TV with YCbCr output. The clips that I have recorded are in full range YCbCr (0-255) with color range set to Limited in the VUI. The clips are to show that 1-15 and 236-254 values are passed through in YCbCr mode. When I said that you can see 4-25 flashing in the clips, I meant to say that you can see those when you watch the clips on a computer that is set to RGB Full mode. I have now clarified this in my original post. Shield was clamping the output to 16-235 in previous firmware. There are other players also that does clamping on YCbCr output. I think on X8/X8-H/X8-H Plus it is clamped. It may have been clamped on the U1 also in the beginning. I can't remember now.

    What is happening with the U9-H is, it is compressing/scaling 16-235 to 0-217. You will not be able to see 16-25 black bars or 235 and above white bars in the test pattern.

    1) The problem is: picture is dark on the U9-H in 8-bit 1080p mode and it is due to compressing and scaling of YCbCr output to 0-217. Normal output is 16-235 with passthrough of 1-15 and 236-254 when present in the video. This is how it is on the U1, Shield etc. Now, this kind of issue usually happens due to decoder color space transformation matrix error , but an overlay can also change the output.

    2) You can see it right on the Minix Metro launcher. It you look at the right/left sides of the launcher, you will notice that it is almost black with none of the graphic pattern visible.

    You can also verify this with the black and white steps pattern. You will see that the top half is uniform black and only 230-233 or so of the white bars are visible in the bottom half.

    3) Already explained in 1.
    Last edited: Mar 27, 2017
    KellyND1 and Runge like this.
  11. MINIX - Ken

    MINIX - Ken Former MINIX Team Member Administrator

    We have fixed the launcher (UI) brightness problem last week, but we are not sure does it mean this problem is fixed as well?? How to make sure? Any picture with patterns to verify?
  12. wrxtasy

    wrxtasy Well-Known Member

    A little birdy just told me - AML Android Nougat Firmware has the YCbCr output - bug fixed code in it for S905x and S912. ;-)

    HDR is better as well I'm told.
  13. Runge

    Runge Member

    I don't think so. The UI brightness problem is just a by product of the real problem already described by @WeK05
  14. WeK05

    WeK05 Audio Visual Master Specialist

    I can understand how the YCbCr output issue may have been fixed in Nougat SDK. The SoCs only pass HDR10 metadata in HDMI InfoFrame. They don't do anything more than that. The actual HDR10 processing takes place on the display. Since there wasn't a grayscale issue with 10-bit content I don't see how HDR can get better.
  15. WeK05

    WeK05 Audio Visual Master Specialist

    If you believe you have fixed the issue, you will be able to see at least some of the black bars (23-25 definitely) flashing in the black and white steps test pattern.

    Don't bother with the white bars, it looks like Amlogic Mediacodec clamps YCbCr output to 16-235. So, you will not see any white bars above 235 if you play the pattern in Kodi or another player that uses MediaCodec. I now see why you were saying that you were able to see only bars up to 235. Amcodec allows passthrough, so you will see 235+ bars in "MoviePlayer".
  16. MINIX - Ken

    MINIX - Ken Former MINIX Team Member Administrator

    Hello, a quick update to all you guys including @WeK05
    There are 2 issues here,
    1.) regarding the topic of this thread - brightness issue - it is confirmed to be fixed in the coming FW004 that we shall release shortly
    2.) for the grey scale issue - it's another problem related to amc-mediacodec's OSD layer, a fix is on its way and we don't want you guys to wait too long so we shall release FW004 first, then FW005 to address this issue.
    3.) both updates should come within April, at least our target is.
    Geoff Boardman, Runge and skynet like this.
  17. mis3

    mis3 Active Member

    Fast question.
    Is this a problem specific to Kodi-17? I cannot remember if Kodi-16 has this issue.
  18. Runge

    Runge Member

    No this is a problem related to the entire system, not just Kodi.
  19. Kris King

    Kris King New Member

    Any fix? Just bought the U9-H and everything I want to watch is dark and unwatchable.
  20. Villa

    Villa Administrator Administrator

    Have you updated the firmware?