4

My display is a TV with resolution of 1366x768 @60 Hz. It has HDMI input option as well as PC input option. I prefer HDMI input but I'm not getting the appropriate image of RPI 4B with 4GB with HDMI. I borrowed a monitor and found that display is excellent without me doing any configuration from the RPI 4B. I'm a noob and could not set it correctly on my tv with built in screen configuration tool of RPI 4B. When I set 1366X768 resolution my TV first shows a message 'unsupported' but after about a minute the display comes on the screen which is not the best. I ran tvservice and got the following best score by GREP: HDMI:EDID Best score mode is now DMT (81) 1366x768p @60Hz with pixel clock 85 Mhz (score 5188835). I'm confused about DMT and CEA as I read somewhere that DMT is intended for monitors while mine is a TV. Even if DMT is the right option I need step by step guidance on how to set my TV display to DMT 81. Please help. (I've very little knowledge of linux commands but I'll be able to follow a detailed guidance).

1
  • add hdmi_group=2 and hdmi_mode=81 in your /boot/config.txt file - you can do this in the computer you used to burn the sd card - simply edit the config.txt file on the sd card (once inserted into your computer of course) - no knowledge of linux required May 3, 2020 at 0:32

3 Answers 3

2

You could try 720p mode as you have a Pi 4:

Full config details are here on the RPF site.

Add the following lines into /boot/config.txt

hdmi_group=1
hdmi_mode=69

and restart the computer.

Edit: To use dmt add:

hdmi_group=2
hdmi_mode=81

and restart the computer

2
  • 1
    why not use DMT 81 as reported May 3, 2020 at 0:30
  • 1
    No real reason - added to answer.
    – user115418
    May 3, 2020 at 2:11
0

I did a little research and ran the following commands (without quotes of course) in Terminal.

"/opt/vc/bin/tvservice -m CEA"

"/opt/vc/bin/tvservice -m DMT"

I also ran the following commands:

"/opt/vc/bin/tvservice -s"

"/opt/vc/bin/tvservice -d edid.dat"

"/opt/vc/bin/edidparser edid.dat"

As I wanted sound through HDMI, I preferred Group CEA and Mode 16 which appears as native. Next I took out the micro sd card and with a text editor uncommented and edited (in my android phone as my Windows PC is out of order) the relevant entry to change it to hdmi_group 1 and hdmi_mode 16 in the config.txt file. The following is the entry I uncommented and edited.

uncomment to force a specific HDMI mode (this will force VGA)

hdmi_group=1 hdmi_mode=4

My TV still shows a unsupported message at first but switches to 1920x1080 display after about a minute. I'll welcome further suggestions in this regard!

Here are the outputs I got from Terminal from the first two commands:

pi@raspberrypi:~ $ /opt/vc/bin/tvservice -m CEA

Group CEA has 16 modes:

       mode 1: 640x480 @ 60Hz 4:3, clock:25MHz progressive

       mode 2: 720x480 @ 60Hz 4:3, clock:27MHz progressive

       mode 3: 720x480 @ 60Hz 16:9, clock:27MHz progressive

       mode 4: 1280x720 @ 60Hz 16:9, clock:74MHz progressive

       mode 5: 1920x1080 @ 60Hz 16:9, clock:74MHz interlaced

       mode 6: 720x480 @ 60Hz 4:3, clock:27MHz x2 interlaced

       mode 7: 720x480 @ 60Hz 16:9, clock:27MHz x2 interlaced

(native) mode 16: 1920x1080 @ 60Hz 16:9, clock:148MHz progressive

       mode 17: 720x576 @ 50Hz 4:3, clock:27MHz progressive

       mode 18: 720x576 @ 50Hz 16:9, clock:27MHz progressive

       mode 19: 1280x720 @ 50Hz 16:9, clock:74MHz progressive

       mode 20: 1920x1080 @ 50Hz 16:9, clock:74MHz interlaced

       mode 21: 720x576 @ 50Hz 4:3, clock:27MHz x2 interlaced

       mode 22: 720x576 @ 50Hz 16:9, clock:27MHz x2 interlaced

       mode 31: 1920x1080 @ 50Hz 16:9, clock:148MHz progressive

       mode 32: 1920x1080 @ 24Hz 16:9, clock:74MHz progressive

pi@raspberrypi:~ $ /opt/vc/bin/tvservice -m DMT

Group DMT has 7 modes:

(prefer) mode 4: 640x480 @ 60Hz 4:3, clock:25MHz progressive

       mode 8: 800x600 @ 56Hz 4:3, clock:36MHz progressive

       mode 9: 800x600 @ 60Hz 4:3, clock:40MHz progressive

       mode 16: 1024x768 @ 60Hz 4:3, clock:65MHz progressive

       mode 22: 1280x768 @ 60Hz 15:9, clock:68MHz progressive

       mode 81: 1366x768 @ 60Hz 16:9, clock:85MHz progressive

       mode 85: 1280x720 @ 60Hz 16:9, clock:74MHz progressive 
0

Kind of late, but perhaps could help others looking for solution to the same problem as it did help me.

Short answer, put these commands into config.txt:

hdmi_drive=2
hdmi_group=2
hdmi_mode=87 
hdmi_cvt=1360 768 60

The hdmi_drive=2 is to run audio through HDMI. You also may need to add these and possibly other commands, check config.txt documentation link below.

hdmi_force_mode=1
hdmi_force_hotplug=1
hdmi_ignore_edid=0xa5000080

Long answer, Pi 4B doesn't support 1366x768@60 mode, but it supports 1360x768@60 which may work for you. But you need to set it manually. From https://www.raspberrypi.com/documentation/computers/config_txt.html: "The Raspberry Pi 4 can not support a timing where any of the horizontal timings are not divisible by 2. The firmware and Linux kernel will filter out any mode that does not fulfill this criteria. There is only one mode in the CEA and DMT standards that falls into this category - DMT mode 81, which is 1366x768 @ 60Hz

4
  • "Kind of late" and also WRONG - this won't work for Bullseye.
    – Milliways
    Apr 25, 2022 at 23:40
  • I suggest you to check comments before posting. I am running v11 Bullseye 2022.04.04 on a 1366x768 LCD panel and a Pi 4B at 1360x768@60 right now.
    – ptkatch
    Apr 27, 2022 at 16:21
  • What Comments? I prefer to follow the Raspberry Pi Ltd documentation. raspberrypi.com/documentation/computers/…
    – Milliways
    Apr 28, 2022 at 6:54
  • Your comments. You are misleading the users. The solution I posted has been tested on actual hardware. Which I wish you'd do too before posting a false claim. BTW, there's nothing in your link saying it won't work for Bullseye either.
    – ptkatch
    Apr 29, 2022 at 3:01

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.