Posting this as reference for anyone interested… Below is a lookup table for the export quality percent as it correlates to libx264 CRFs. I need to target specific CRFs when I export, so this table lets me find the quality percents that map to them. For instance, this table tells me that the default quality of 60% maps to CRF 20. Some installations default to 59% which is CRF 21. If I want to export at CRF 18, I can use 65% quality to get it.
Rename the attached .txt file to .csv to import it into a spreadsheet. Yes, this correlation can be expressed as a simple math formula, but sometimes it’s faster to just look stuff up. And yes, 100% quality packed a surprise that a math formula wouldn’t have predicted.
Shotcut Quality Percent to libx264 CRF Mappings.txt (708 Bytes)
Here is the contents if you don’t want to download it…
Quality,CRF
0,51
1,50
2,50
3,49
4,49
5,48
6,48
7,47
8,47
9,46
10,46
11,45
12,45
13,44
14,44
15,43
16,43
17,42
18,42
19,41
20,41
21,40
22,40
23,39
24,39
25,38
26,38
27,37
28,37
29,36
30,36
31,35
32,35
33,34
34,34
35,33
36,33
37,32
38,32
39,31
40,31
41,30
42,30
43,29
44,29
45,28
46,28
47,27
48,27
49,26
50,26
51,25
52,24
53,24
54,23
55,23
56,22
57,22
58,21
59,21
60,20
61,20
62,19
63,19
64,18
65,18
66,17
67,17
68,16
69,16
70,15
71,15
72,14
73,14
74,13
75,13
76,12
77,12
78,11
79,11
80,10
81,10
82,9
83,9
84,8
85,8
86,7
87,7
88,6
89,6
90,5
91,5
92,4
93,4
94,3
95,3
96,2
97,2
98,1
99,1
100,High 444 Lossless