1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
|
From e842972404fa3a4a3571e64864be1e311a0ba4c9 Mon Sep 17 00:00:00 2001
From: triple-groove <triple-groove@users.noreply.github.com>
Date: Sun, 22 Feb 2026 16:07:56 -0800
Subject: [PATCH 3/5] fix(dsc): correct RC parameter tables to match VESA DSC
1.1 standard
The minqp444_8b, maxqp444_8b, and ofs_und8 tables in nvt_dsc_pps.c
contain non-standard values for the 8bpc / 8.0 bpp operating point
(column index 4). Ranges 9-14 have more constrained max_qp values
than the VESA DSC 1.1 specification (Table E-5), and range 11 has
an incorrect bpg_offset.
These deviations prevent the DSC encoder from quantizing aggressively
enough when the RC buffer approaches overflow on complex content,
causing visible block/tile "rainbow static" artifacts on sinks that
implement strict VESA-compliant DSC decompression.
Corrected values (all at column index 4 = 8.0 bpp):
minqp444_8b range 9: 4 -> 3
minqp444_8b range 13: 8 -> 7
minqp444_8b range 14: 12 -> 13
maxqp444_8b range 10: 10 -> 11
maxqp444_8b range 11: 11 -> 12
maxqp444_8b range 12: 11 -> 13
maxqp444_8b range 13: 12 -> 13
maxqp444_8b range 14: 13 -> 15
ofs_und8 range 11: -10 -> -12
Tested on RTX 5090 with Bigscreen Beyond VR headset (DSC 1.1, 8bpc,
8.0 bpp, RGB 4:4:4, 3840x1920@90Hz). Artifacts completely eliminated.
Signed-off-by: triple-groove <triple-groove@users.noreply.github.com>
---
src/common/modeset/timing/nvt_dsc_pps.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/src/common/modeset/timing/nvt_dsc_pps.c b/src/common/modeset/timing/nvt_dsc_pps.c
index ce6d6a795470..d100c57d9351 100644
--- a/src/common/modeset/timing/nvt_dsc_pps.c
+++ b/src/common/modeset/timing/nvt_dsc_pps.c
@@ -187,12 +187,12 @@ static const NvU8 minqp444_8b[15][37]={
,{ 5, 5, 4, 4, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0}
,{ 5, 5, 4, 4, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0}
,{ 5, 5, 4, 4, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 0, 0, 0}
- ,{ 6, 5, 5, 4, 4, 4, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 2, 2, 1, 1, 1, 1, 1, 1, 0, 0, 0}
+ ,{ 6, 5, 5, 4, 3, 4, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 2, 2, 1, 1, 1, 1, 1, 1, 0, 0, 0} // [9] col4: 4->3 (VESA DSC 1.1)
,{ 6, 6, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 3, 3, 3, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 0}
,{ 6, 6, 6, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 3, 2, 2, 2, 2, 1, 1, 1, 1, 0}
,{ 6, 6, 6, 6, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 4, 4, 4, 4, 3, 3, 2, 2, 2, 2, 1, 1, 1, 1, 0}
- ,{ 9, 9, 9, 9, 8, 8, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 6, 6, 5, 5, 5, 5, 4, 4, 3, 3, 3, 3, 2, 2, 1, 1, 1}
- ,{14,14,13,13,12,12,12,12,11,11,10,10,10,10, 9, 9, 9, 8, 8, 8, 7, 7, 7, 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 3, 3, 3, 3}
+ ,{ 9, 9, 9, 9, 7, 8, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 6, 6, 5, 5, 5, 5, 4, 4, 3, 3, 3, 3, 2, 2, 1, 1, 1} // [13] col4: 8->7 (VESA DSC 1.1)
+ ,{14,14,13,13,13,12,12,12,11,11,10,10,10,10, 9, 9, 9, 8, 8, 8, 7, 7, 7, 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 3, 3, 3, 3} // [14] col4: 12->13 (VESA DSC 1.1)
};
static const NvU8 maxqp444_8b[15][37]={
@@ -206,11 +206,11 @@ static const NvU8 maxqp444_8b[15][37]={
,{10,10, 9, 9, 8, 8, 8, 8, 8, 8, 8, 8, 8, 7, 7, 6, 5, 5, 4, 4, 4, 4, 3, 3, 3, 3, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1}
,{11,11,10,10, 9, 9, 9, 9, 9, 9, 8, 8, 8, 7, 7, 6, 6, 5, 5, 5, 5, 5, 4, 4, 4, 4, 3, 3, 2, 2, 2, 2, 2, 2, 1, 1, 1}
,{12,11,11,10,10,10, 9, 9, 9, 9, 9, 9, 9, 8, 8, 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 3, 3, 2, 2, 2, 2, 2, 2, 1, 1, 1}
- ,{12,12,11,11,10,10,10,10,10,10, 9, 9, 9, 8, 8, 7, 7, 6, 6, 6, 5, 5, 4, 4, 4, 4, 3, 3, 2, 2, 2, 2, 2, 2, 2, 2, 1}
- ,{12,12,12,11,11,11,10,10,10,10, 9, 9, 9, 9, 8, 8, 8, 7, 7, 7, 6, 6, 5, 5, 5, 5, 4, 4, 3, 3, 3, 3, 2, 2, 2, 2, 1}
- ,{12,12,12,12,11,11,11,11,11,10,10, 9, 9, 9, 8, 8, 8, 7, 7, 7, 6, 6, 5, 5, 5, 5, 4, 4, 3, 3, 3, 3, 2, 2, 2, 2, 1}
- ,{13,13,13,13,12,12,11,11,11,11,10,10,10,10, 9, 9, 8, 8, 8, 8, 7, 7, 6, 6, 6, 6, 5, 5, 4, 4, 4, 4, 3, 3, 2, 2, 2}
- ,{15,15,14,14,13,13,13,13,12,12,11,11,11,11,10,10,10, 9, 9, 9, 8, 8, 8, 8, 7, 7, 6, 6, 6, 6, 5, 5, 5, 4, 4, 4, 4}
+ ,{12,12,11,11,11,10,10,10,10,10, 9, 9, 9, 8, 8, 7, 7, 6, 6, 6, 5, 5, 4, 4, 4, 4, 3, 3, 2, 2, 2, 2, 2, 2, 2, 2, 1} // [10] col4: 10->11 (VESA DSC 1.1)
+ ,{12,12,12,11,12,11,10,10,10,10, 9, 9, 9, 9, 8, 8, 8, 7, 7, 7, 6, 6, 5, 5, 5, 5, 4, 4, 3, 3, 3, 3, 2, 2, 2, 2, 1} // [11] col4: 11->12 (VESA DSC 1.1)
+ ,{12,12,12,12,13,11,11,11,11,10,10, 9, 9, 9, 8, 8, 8, 7, 7, 7, 6, 6, 5, 5, 5, 5, 4, 4, 3, 3, 3, 3, 2, 2, 2, 2, 1} // [12] col4: 11->13 (VESA DSC 1.1)
+ ,{13,13,13,13,13,12,11,11,11,11,10,10,10,10, 9, 9, 8, 8, 8, 8, 7, 7, 6, 6, 6, 6, 5, 5, 4, 4, 4, 4, 3, 3, 2, 2, 2} // [13] col4: 12->13 (VESA DSC 1.1)
+ ,{15,15,14,14,15,13,13,13,12,12,11,11,11,11,10,10,10, 9, 9, 9, 8, 8, 8, 8, 7, 7, 6, 6, 6, 6, 5, 5, 5, 4, 4, 4, 4} // [14] col4: 13->15 (VESA DSC 1.1)
};
static const NvU8 minqp444_10b[15][49]={
@@ -934,7 +934,7 @@ DSC_PpsCalcRcParam
//else
{
const NvU32 ofs_und6[] = { 0, -2, -2, -4, -6, -6, -8, -8, -8, -10, -10, -12, -12, -12, -12 };
- const NvU32 ofs_und8[] = { 2, 0, 0, -2, -4, -6, -8, -8, -8, -10, -10, -10, -12, -12, -12 };
+ const NvU32 ofs_und8[] = { 2, 0, 0, -2, -4, -6, -8, -8, -8, -10, -10, -12, -12, -12, -12 }; // [11]: -10->-12 (VESA DSC 1.1)
const NvU32 ofs_und12[] = { 2, 0, 0, -2, -4, -6, -8, -8, -8, -10, -10, -10, -12, -12, -12 };
const NvU32 ofs_und15[] = { 10, 8, 6, 4, 2, 0, -2, -4, -6, -8, -10, -10, -12, -12, -12 };
--
2.53.0
|