树莓派4B配置两个HDMI不同分辨率

在树莓派4之前，都是一个HDMI接口，所以没有这个问题。而树莓派4B有2个HDMI接口，可以输出双4K。

在树莓派根目录下有一个文件config.txt,我们需要修改里面的参数。

下面的配置为HDMI0输出1080P 60Hz，HDMI1输出1024*768 60Hz。

[HDMI:0]
  hdmi_group=2
  hdmi_mode=82
[HDMI:1]
  hdmi_group=2
  hdmi_mode=16

hdmi_group=1代表CEA模式（电视规格分辨率，不包含音频，通常使用DVI接口）

hdmi_group=2则代表DMT模式（计算机显示器分辨率，包含音频，通常使用HDMI接口）

hdmi_mode参数表可以参考下面：

[tabs]
[tab name="hdmi_group=1 (CEA)"]

hdmi_mode	Resolution	Frequency	Screen Aspect	Notes
1	VGA (640x480)	60Hz	4:3
2	480p	60Hz	4:3
3	480p	60Hz	16:9
4	720p	60Hz	16:9
5	1080i	60Hz	16:9
6	480i	60Hz	4:3
7	480i	60Hz	16:9
8	240p	60Hz	4:3
9	240p	60Hz	16:9
10	480i	60Hz	4:3	pixel quadrupling
11	480i	60Hz	16:9	pixel quadrupling
12	240p	60Hz	4:3	pixel quadrupling
13	240p	60Hz	16:9	pixel quadrupling
14	480p	60Hz	4:3	pixel doubling
15	480p	60Hz	16:9	pixel doubling
16	1080p	60Hz	16:9
17	576p	50Hz	4:3
18	576p	50Hz	16:9
19	720p	50Hz	16:9
20	1080i	50Hz	16:9
21	576i	50Hz	4:3
22	576i	50Hz	16:9
23	288p	50Hz	4:3
24	288p	50Hz	16:9
25	576i	50Hz	4:3	pixel quadrupling
26	576i	50Hz	16:9	pixel quadrupling
27	288p	50Hz	4:3	pixel quadrupling
28	288p	50Hz	16:9	pixel quadrupling
29	576p	50Hz	4:3	pixel doubling
30	576p	50Hz	16:9	pixel doubling
31	1080p	50Hz	16:9
32	1080p	24Hz	16:9
33	1080p	25Hz	16:9
34	1080p	30Hz	16:9
35	480p	60Hz	4:3	pixel quadrupling
36	480p	60Hz	16:9	pixel quadrupling
37	576p	50Hz	4:3	pixel quadrupling
38	576p	50Hz	16:9	pixel quadrupling
39	1080i	50Hz	16:9	reduced blanking
40	1080i	100Hz	16:9
41	720p	100Hz	16:9
42	576p	100Hz	4:3
43	576p	100Hz	16:9
44	576i	100Hz	4:3
45	576i	100Hz	16:9
46	1080i	120Hz	16:9
47	720p	120Hz	16:9
48	480p	120Hz	4:3
49	480p	120Hz	16:9
50	480i	120Hz	4:3
51	480i	120Hz	16:9
52	576p	200Hz	4:3
53	576p	200Hz	16:9
54	576i	200Hz	4:3
55	576i	200Hz	16:9
56	480p	240Hz	4:3
57	480p	240Hz	16:9
58	480i	240Hz	4:3
59	480i	240Hz	16:9
60	720p	24Hz	16:9
61	720p	25Hz	16:9
62	720p	30Hz	16:9
63	1080p	120Hz	16:9
64	1080p	100Hz	16:9
65	Custom
66	720p	25Hz	64:27 Pi 4
67	720p	30Hz	64:27 Pi 4
68	720p	50Hz	64:27 Pi 4
69	720p	60Hz	64:27 Pi 4
70	720p	100Hz	64:27 Pi 4
71	720p	120Hz	64:27 Pi 4
72	1080p	24Hz	64:27 Pi 4
73	1080p	25Hz	64:27 Pi 4
74	1080p	30Hz	64:27 Pi 4
75	1080p	50Hz	64:27 Pi 4
76	1080p	60Hz	64:27 Pi 4
77	1080p	100Hz	64:27 Pi 4
78	1080p	120Hz	64:27 Pi 4
79	1680x720	24Hz	64:27 Pi 4
80	1680x720	25Hz	64:27 Pi 4
81	1680x720	30Hz	64:27	Pi 4
82	1680x720	50Hz	64:27	Pi 4
83	1680x720	60Hz	64:27	Pi 4
84	1680x720	100Hz	64:27	Pi 4
85	1680x720	120Hz	64:27	Pi 4
86	2560x720	24Hz	64:27	Pi 4
87	2560x720	25Hz	64:27	Pi 4
88	2560x720	30Hz	64:27	Pi 4
89	2560x720	50Hz	64:27	Pi 4
90	2560x720	60Hz	64:27	Pi 4
91	2560x720	100Hz	64:27	Pi 4
92	2560x720	120Hz	64:27	Pi 4
93	2160p	24Hz	16:9	Pi 4
94	2160p	25Hz	16:9	Pi 4
95	2160p	30Hz	16:9	Pi 4
96	2160p	50Hz	16:9	Pi 4
97	2160p	60Hz	16:9	Pi 4
98	4096x2160	24Hz	256:135	Pi 4
99	4096x2160	25Hz	256:135	Pi 4
100	4096x2160	30Hz	256:135	Pi 4
101	4096x2160	50Hz	256:135	Pi 4
102	4096x2160	60Hz	256:135	Pi 4
103	2160p	24Hz	64:27	Pi 4
104	2160p	25Hz	64:27	Pi 4
105	2160p	30Hz	64:27	Pi 4
106	2160p	50Hz	64:27	Pi 4
107	2160p	60Hz	64:27	Pi 4

[/tab]

[tab name="hdmi_group=2 (DMT)"]

hdmi_mode	Resolution	Frequency	Screen Aspect	Notes
1	640x350	85Hz
2	640x400	85Hz	16:10
3	720x400	85Hz
4	640x480	60Hz	4:3
5	640x480	72Hz	4:3
6	640x480	75Hz	4:3
7	640x480	85Hz	4:3
8	800x600	56Hz	4:3
9	800x600	60Hz	4:3
10	800x600	72Hz	4:3
11	800x600	75Hz	4:3
12	800x600	85Hz	4:3
13	800x600	120Hz	4:3
14	848x480	60Hz	16:9
15	1024x768	43Hz	4:3	incompatible with the Raspberry Pi
16	1024x768	60Hz	4:3
17	1024x768	70Hz	4:3
18	1024x768	75Hz	4:3
19	1024x768	85Hz	4:3
20	1024x768	120Hz	4:3
21	1152x864	75Hz	4:3
22	1280x768	60Hz	15:9	reduced blanking
23	1280x768	60Hz	15:9
24	1280x768	75Hz	15:9
25	1280x768	85Hz	15:9
26	1280x768	120Hz	15:9	reduced blanking
27	1280x800	60Hz	16:10	reduced blanking
28	1280x800	60Hz	16:10
29	1280x800	75Hz	16:10
30	1280x800	85Hz	16:10
31	1280x800	120Hz	16:10	reduced blanking
32	1280x960	60Hz	4:3
33	1280x960	85Hz	4:3
34	1280x960	120Hz	4:3	reduced blanking
35	1280x1024	60Hz	5:4
36	1280x1024	75Hz	5:4
37	1280x1024	85Hz	5:4
38	1280x1024	120Hz	5:4	reduced blanking
39	1360x768	60Hz	16:9
40	1360x768	120Hz	16:9	reduced blanking
41	1400x1050	60Hz	4:3	reduced blanking
42	1400x1050	60Hz	4:3
43	1400x1050	75Hz	4:3
44	1400x1050	85Hz	4:3
45	1400x1050	120Hz	4:3	reduced blanking
46	1440x900	60Hz	16:10	reduced blanking
47	1440x900	60Hz	16:10
48	1440x900	75Hz	16:10
49	1440x900	85Hz	16:10
50	1440x900	120Hz	16:10	reduced blanking
51	1600x1200	60Hz	4:3
52	1600x1200	65Hz	4:3
53	1600x1200	70Hz	4:3
54	1600x1200	75Hz	4:3
55	1600x1200	85Hz	4:3
56	1600x1200	120Hz	4:3	reduced blanking
57	1680x1050	60Hz	16:10	reduced blanking
58	1680x1050	60Hz	16:10
59	1680x1050	75Hz	16:10
60	1680x1050	85Hz	16:10
61	1680x1050	120Hz	16:10	reduced blanking
62	1792x1344	60Hz	4:3
63	1792x1344	75Hz	4:3
64	1792x1344	120Hz	4:3	reduced blanking
65	1856x1392	60Hz	4:3
66	1856x1392	75Hz	4:3
67	1856x1392	120Hz	4:3	reduced blanking
68	1920x1200	60Hz	16:10	reduced blanking
69	1920x1200	60Hz	16:10
70	1920x1200	75Hz	16:10
71	1920x1200	85Hz	16:10
72	1920x1200	120Hz	16:10	reduced blanking
73	1920x1440	60Hz	4:3
74	1920x1440	75Hz	4:3
75	1920x1440	120Hz	4:3	reduced blanking
76	2560x1600	60Hz	16:10	reduced blanking
77	2560x1600	60Hz	16:10
78	2560x1600	75Hz	16:10
79	2560x1600	85Hz	16:10
80	2560x1600	120Hz	16:10 reduced blanking
81	1366x768	60Hz	16:9
82	1920x1080	60Hz	16:9	1080p
83	1600x900	60Hz	16:9	reduced blanking
84	2048x1152	60Hz	16:9	reduced blanking
85	1280x720	60Hz	16:9	720p
86	1366x768	60Hz	16:9	reduced blanking
[/tab]
[/tabs]

参考链接：
https://www.raspberrypi.org/documentation/configuration/config-txt/video.md
https://www.raspberrypi.org/documentation/configuration/config-txt/conditional.md