[Rockchip RK3399] HDR colorspace / banding issue

Kasty · July 20, 2024 at 8:04 PM

When playing HDR content on the Rock Pi 4 it triggers HDR on my Sony Bravia AG8 but there seems to be something wrong with the colorspace. The colors look washed out and there is visible banding. The TV seems to interpret the signal as BT.709 and limited range (auto setting). Manually changing the colorspace to BT.2020 on the tv doesn't fix the banding. Setting the range to full produces incorrect black levels.

I tried using a Raspberry Pi 4 with an identical setup, there the colors look correct with no banding. In this case the auto setting on the TV interprets the signal as BT.2020 and limited range.

Not sure if it matters, but when checking modetest on the Rock Pi there doesn't seem to be any colorspace property

Code

modetest -c

Connectors:
id	encoder	status		name		size (mm)	modes	encoders
64	63	connected	HDMI-A-1       	1440x810		41	63

props:
	1 EDID:
		flags: immutable blob
		blobs:

		value:
			00ffffffffffff004dd9048201010101
			011c0103809051780a0dc9a057479827
			12484c2108008180a9c0714fb3000101
			01010101010108e80030f2705a80b058
			8a009f295300001e023a801871382d40
			582c45009f295300001e000000fc0053
			4f4e5920545620202a30300a000000fd
			00173e0e883c000a20202020202001e6
			020365f05b61605d5e5f621f10140513
			0420223c3e1216030711150206016566
			2c0d7f071507503d07bc570600830f00
			006e030c002000b83c2f008001020304
			67d85dc401788001eb0146d000450380
			8660768fe200cbe305ff01e50f030000
			06e3060d01011d007251d01e206e2855
			009f295300001e0000000000000000b8
	2 DPMS:
		flags: enum
		enums: On=0 Standby=1 Suspend=2 Off=3
		value: 0
	5 link-status:
		flags: enum
		enums: Good=0 Bad=1
		value: 0
	6 non-desktop:
		flags: immutable range
		values: 0 1
		value: 0
	4 TILE:
		flags: immutable blob
		blobs:

		value:
	65 max bpc:
		flags: range
		values: 8 16
		value: 0
	66 content type:
		flags: enum
		enums: No Data=0 Graphics=1 Photo=2 Cinema=3 Game=4
		value: 0
	7 HDR_OUTPUT_METADATA:
		flags: blob
		blobs:

		value:

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compared to the Raspberry Pi

Code

modetest -c

Connectors:
id	encoder	status		name		size (mm)	modes	encoders
32	31	connected	HDMI-A-1       	1440x810		41	31


props:
	1 EDID:
		flags: immutable blob
		blobs:

		value:
			00ffffffffffff004dd9048201010101
			011c0103809051780a0dc9a057479827
			12484c2108008180a9c0714fb3000101
			01010101010108e80030f2705a80b058
			8a009f295300001e023a801871382d40
			582c45009f295300001e000000fc0053
			4f4e5920545620202a30300a000000fd
			00173e0e883c000a20202020202001e6
			020365f05b61605d5e5f621f10140513
			0420223c3e1216030711150206016566
			2c0d7f071507503d07bc570600830f00
			006e030c002000b83c2f008001020304
			67d85dc401788001eb0146d000450380
			8660768fe200cbe305ff01e50f030000
			06e3060d01011d007251d01e206e2855
			009f295300001e0000000000000000b8
	2 DPMS:
		flags: enum
		enums: On=0 Standby=1 Suspend=2 Off=3
		value: 0
	5 link-status:
		flags: enum
		enums: Good=0 Bad=1
		value: 0
	6 non-desktop:
		flags: immutable range
		values: 0 1
		value: 0
	4 TILE:
		flags: immutable blob
		blobs:

		value:
	37 Colorspace:
		flags: enum
		enums: Default=0 SMPTE_170M_YCC=1 BT709_YCC=2 XVYCC_601=3 XVYCC_709=4 SYCC_601=5 opYCC_601=6 opRGB=7 BT2020_CYCC=8 BT2020_RGB=9 BT2020_YCC=10 DCI-P3_RGB_D65=11 DCI-P3_RGB_Theater=12
		value: 0
	33 left margin:
		flags: range
		values: 0 100
		value: 0
	34 right margin:
		flags: range
		values: 0 100
		value: 0
	35 top margin:
		flags: range
		values: 0 100
		value: 0
	36 bottom margin:
		flags: range
		values: 0 100
		value: 0
	38 max bpc:
		flags: range
		values: 8 12
		value: 8
	7 HDR_OUTPUT_METADATA:
		flags: blob
		blobs:

		value:
	39 Broadcast RGB:
		flags: enum
		enums: Automatic=0 Full=1 Limited 16:235=2
		value: 0
41	0	disconnected	HDMI-A-2       	0x0		0	40
  props:
	1 EDID:
		flags: immutable blob
		blobs:

		value:
	2 DPMS:
		flags: enum
		enums: On=0 Standby=1 Suspend=2 Off=3
		value: 0
	5 link-status:
		flags: enum
		enums: Good=0 Bad=1
		value: 0
	6 non-desktop:
		flags: immutable range
		values: 0 1
		value: 0
	4 TILE:
		flags: immutable blob
		blobs:

		value:
	42 Colorspace:
		flags: enum
		enums: Default=0 SMPTE_170M_YCC=1 BT709_YCC=2 XVYCC_601=3 XVYCC_709=4 SYCC_601=5 opYCC_601=6 opRGB=7 BT2020_CYCC=8 BT2020_RGB=9 BT2020_YCC=10 DCI-P3_RGB_D65=11 DCI-P3_RGB_Theater=12
		value: 0
	33 left margin:
		flags: range
		values: 0 100
		value: 0
	34 right margin:
		flags: range
		values: 0 100
		value: 0
	35 top margin:
		flags: range
		values: 0 100
		value: 0
	36 bottom margin:
		flags: range
		values: 0 100
		value: 0
	43 max bpc:
		flags: range
		values: 8 12
		value: 8
	7 HDR_OUTPUT_METADATA:
		flags: blob
		blobs:

		value:
	44 Broadcast RGB:
		flags: enum
		enums: Automatic=0 Full=1 Limited 16:235=2
		value: 0

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Looking at the logs for the Raspberry Pi it seems to change colorspace and bpc before playing the video. I can't find anything like this in the Rock Pi logs.

Code

debug <general>: SetHDR: setting connector colorspace to BT2020_YCC
debug <general>: CVideoLayerBridgeDRMPRIME::Configure - setting max bpc to 12 (true)

Runnig kmsprint while playing the video on the Rock Pi it seems like it should be outputting BT.2020 (COLOR_ENCODING (46) = 2) though.

Code

kmsprint -p

Connector 0 (64) HDMI-A-1 (connected)
    EDID (1) = blob-id 68 len 256 (immutable)
    DPMS (2) = 0 (On) [On=0|Standby=1|Suspend=2|Off=3]
    TILE (4) = blob-id 0 (immutable)
    link-status (5) = 0 (Good) [Good=0|Bad=1]
    non-desktop (6) = 0 [0 - 1] (immutable)
    HDR_OUTPUT_METADATA (7) = blob-id 74 len 32
    CRTC_ID (20) = object id 62
    max bpc (65) = 0 [8 - 16]
    content type (66) = 0 (No Data) [No Data=0|Graphics=1|Photo=2|Cinema=3|Game=4]
  Encoder 0 (63) TMDS
    Crtc 1 (62) [email protected] 296.703 3840/1276/88/296/+ 2160/8/10/72/+ 24 (23.98) D 
        OUT_FENCE_PTR (19) = 0 [0 - 18446744073709551615]
        ACTIVE (22) = 1 [0 - 1]
        MODE_ID (23) = blob-id 76 len 68
        VRR_ENABLED (24) = 0 [0 - 1]
        GAMMA_LUT (28) = blob-id 0
        GAMMA_LUT_SIZE (29) = 1024 [0 - 4294967295] (immutable)
      Plane 2 (42) fb-id: 75 (crtcs: 1) 0,0 3840x1920 -> 0,120 3840x1920 (XR24 AR24 XB24 AB24 RG24 BG24 RG16 BG16 NV12 NV16 NV24 NV15 NV20 NV30)
          type (8) = 1 (Primary) [Overlay=0|Primary=1|Cursor=2] (immutable)
          SRC_X (9) = 0 [0 - 4294967295]
          SRC_Y (10) = 0 [0 - 4294967295]
          SRC_W (11) = 251658240 [0 - 4294967295]
          SRC_H (12) = 125829120 [0 - 4294967295]
          CRTC_X (13) = 0 [-2147483648 - 2147483647]
          CRTC_Y (14) = 120 [-2147483648 - 2147483647]
          CRTC_W (15) = 3840 [0 - 2147483647]
          CRTC_H (16) = 1920 [0 - 2147483647]
          FB_ID (17) = object id 75
          IN_FENCE_FD (18) = -1 [-1 - 2147483647]
          CRTC_ID (20) = object id 62
          IN_FORMATS (30) = blob-id 43 len 128 (immutable)
          rotation (44) = 0x1 (rotate-0) [rotate-0=0x1|reflect-x=0x10|reflect-y=0x20]
          zpos (45) = 0 [0 - 0] (immutable)
          COLOR_ENCODING (46) = 2 (ITU-R BT.2020 YCbCr) [ITU-R BT.601 YCbCr=0|ITU-R BT.709 YCbCr=1|ITU-R BT.2020 YCbCr=2]
          COLOR_RANGE (47) = 0 (YCbCr limited range) [YCbCr limited range=0|YCbCr full range=1]
        FB 75 3840x1920 NV15
      Plane 3 (48) fb-id: 71 (crtcs: 1) 0,0 3840x2160 -> 0,0 3840x2160 (XR24 AR24 XB24 AB24 RG24 BG24 RG16 BG16 NV12 NV16 NV24 NV15 NV20 NV30)
          type (8) = 0 (Overlay) [Overlay=0|Primary=1|Cursor=2] (immutable)
          SRC_X (9) = 0 [0 - 4294967295]
          SRC_Y (10) = 0 [0 - 4294967295]
          SRC_W (11) = 251658240 [0 - 4294967295]
          SRC_H (12) = 141557760 [0 - 4294967295]
          CRTC_X (13) = 0 [-2147483648 - 2147483647]
          CRTC_Y (14) = 0 [-2147483648 - 2147483647]
          CRTC_W (15) = 3840 [0 - 2147483647]
          CRTC_H (16) = 2160 [0 - 2147483647]
          FB_ID (17) = object id 71
          IN_FENCE_FD (18) = -1 [-1 - 2147483647]
          CRTC_ID (20) = object id 62
          IN_FORMATS (30) = blob-id 49 len 104 (immutable)
          rotation (50) = 0x1 (rotate-0) [rotate-0=0x1|reflect-x=0x10|reflect-y=0x20]
          zpos (51) = 1 [1 - 1] (immutable)
          COLOR_ENCODING (52) = 0 (ITU-R BT.601 YCbCr) [ITU-R BT.601 YCbCr=0|ITU-R BT.709 YCbCr=1|ITU-R BT.2020 YCbCr=2]
          COLOR_RANGE (53) = 0 (YCbCr limited range) [YCbCr limited range=0|YCbCr full range=1]
        FB 71 3840x2160 AR24

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Rock Pi logs: Link

Raspberry Pi logs: Link

Comparison Image:

Not sure what the cause is here, any ideas or suggestions?

**chewitt** · July 21, 2024 at 3:44 PM

I'm not sure RK3399 supports 10-bit output at the current time, so you'll have 8-bit output which results in banding.

There are improvements being submitted to the kernel, but these things take time.

Kasty · July 21, 2024 at 5:37 PM

Thanks for the quick reply! Alright, that's a bummer but understandable. Seeing the HDR triggering got me thinking it might be a user/setup problem. I'm quite impressed with how well LE works on it otherwise, having 10-bit HDR would make it perfect imo. I'll keep an eye out then and see if there is anything I can do to contribute. Thanks for the awesome work you guys are doing!