Rock64: 4K SDR HEVC 10 bit washed out colors

Irda · July 3, 2020 at 10:35 PM

Hello,

I installed official LibreElec 9.2.3 on a Rock64 (LibreELEC-RK3328.arm-9.2.3-rock64.img.gz, so using kernel 4.4.154), and so far almost everything is working great OOB!

Thanks for the great job you guys are doing.

However, I noticed a small issue with playback on 4K HEVC 10 bits SDR files: the colors looks washed out (they are not that bright as they should be I guess, for example the Netflix logo looks almost orange instead of red). No issue when playing H.264 1080p files.

I turned off hardware acceleration, and the colors are now correct, but of course videos are playing super slowly because the CPU can't handle it.

I just wanted to know if that's a known issue, or if there is some kind of workaround.

Here are infos about the 4k media (I don't know if that's useful):

Code

Video
ID                                       : 1
Format                                   : HEVC
Format/Info                              : High Efficiency Video Coding
Format profile                           : Main [email protected]@High
Codec ID                                 : V_MPEGH/ISO/HEVC
Duration                                 : 1 h 1 min
Bit rate                                 : 14.8 Mb/s
Width                                    : 3 840 pixels
Height                                   : 1 920 pixels
Display aspect ratio                     : 2.000
Frame rate mode                          : Constant
Frame rate                               : 24.000 FPS
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 10 bits
Bits/(Pixel*Frame)                       : 0.084
Color range                              : Limited
Color primaries                          : BT.709
Transfer characteristics                 : BT.709
Matrix coefficients                      : BT.709

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If you need other informations, I'll be happy to give them, and do anything to help!

Thanks,

Irda

Irda · July 4, 2020 at 11:23 AM

A difference I noticed is when output is 4K, colorimetry is set to BT.2020 on hdmi (mediainfo tells the file is BT.709), while on 1080p it is set to ITU709. Both are limited range.

Here is the output on dmesg when playing 4K file:

Code

[138455.609058] dwhdmi-rockchip ff3c0000.hdmi: HDMI infoframe: Auxiliary Video Information (AVI), version 2, length 13
[138455.609067] dwhdmi-rockchip ff3c0000.hdmi:     colorspace: YCbCr 4:4:4
[138455.609076] dwhdmi-rockchip ff3c0000.hdmi:     scan mode: Underscan
[138455.609084] dwhdmi-rockchip ff3c0000.hdmi:     colorimetry: Extended
[138455.609091] dwhdmi-rockchip ff3c0000.hdmi:     picture aspect: No Data
[138455.609099] dwhdmi-rockchip ff3c0000.hdmi:     active aspect: Same as Picture
[138455.609106] dwhdmi-rockchip ff3c0000.hdmi:     itc: IT Content
[138455.609113] dwhdmi-rockchip ff3c0000.hdmi:     extended colorimetry: BT.2020
[138455.609121] dwhdmi-rockchip ff3c0000.hdmi:     quantization range: Limited
[138455.609129] dwhdmi-rockchip ff3c0000.hdmi:     nups: Unknown Non-uniform Scaling
[138455.609136] dwhdmi-rockchip ff3c0000.hdmi:     video code: 0
[138455.609143] dwhdmi-rockchip ff3c0000.hdmi:     ycc quantization range: Limited
[138455.609152] dwhdmi-rockchip ff3c0000.hdmi:     hdmi content type: Graphics
[138455.609159] dwhdmi-rockchip ff3c0000.hdmi:     pixel repeat: 0
[138455.609167] dwhdmi-rockchip ff3c0000.hdmi:     bar top 0, bottom 0, left 0, right 0
[138455.609191] dwhdmi-rockchip ff3c0000.hdmi: HDMI infoframe: Vendor, version 1, length 5
[138455.609201] dwhdmi-rockchip ff3c0000.hdmi:     HDMI VIC: 3
[139780.819976] dwhdmi-rockchip ff3c0000.hdmi: Rate 371250000 missing; compute N dynamically
[139787.485429] dwhdmi-rockchip ff3c0000.hdmi: Rate 371250000 missing; compute N dynamically
[139788.185497] dwhdmi-rockchip ff3c0000.hdmi: Rate 371250000 missing; compute N dynamically

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And here with a 1080p file:

Code

[139819.527386] dwhdmi-rockchip ff3c0000.hdmi: HDMI infoframe: Auxiliary Video Information (AVI), version 2, length 13
[139819.527411] dwhdmi-rockchip ff3c0000.hdmi:     colorspace: YCbCr 4:4:4
[139819.527420] dwhdmi-rockchip ff3c0000.hdmi:     scan mode: Underscan
[139819.527429] dwhdmi-rockchip ff3c0000.hdmi:     colorimetry: ITU709
[139819.527438] dwhdmi-rockchip ff3c0000.hdmi:     picture aspect: 16:9
[139819.527448] dwhdmi-rockchip ff3c0000.hdmi:     active aspect: Same as Picture
[139819.527456] dwhdmi-rockchip ff3c0000.hdmi:     itc: IT Content
[139819.527465] dwhdmi-rockchip ff3c0000.hdmi:     extended colorimetry: xvYCC 709
[139819.527474] dwhdmi-rockchip ff3c0000.hdmi:     quantization range: Limited
[139819.527483] dwhdmi-rockchip ff3c0000.hdmi:     nups: Unknown Non-uniform Scaling
[139819.527491] dwhdmi-rockchip ff3c0000.hdmi:     video code: 32
[139819.527501] dwhdmi-rockchip ff3c0000.hdmi:     ycc quantization range: Limited
[139819.527510] dwhdmi-rockchip ff3c0000.hdmi:     hdmi content type: Graphics
[139819.527518] dwhdmi-rockchip ff3c0000.hdmi:     pixel repeat: 0
[139819.527528] dwhdmi-rockchip ff3c0000.hdmi:     bar top 0, bottom 0, left 0, right 0

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