What's pixel frequency for 720p 60hz

[modology]

Hi, I'm trying to set up RasphBerry Pi 3 so that it can display in 720p mode on my Sony BVM D20F1U.

It involes editing config.txt and users need to declare the HDMI Timing values

I'm not sure exactly how all of those related V sync, Hsync, etc... values are calculated... but the syntax is like this below:

Code: Select all

hdmi_timings=<h_active_pixels> <h_sync_polarity> <h_front_porch> <h_sync_pulse> <h_back_porch> <v_active_lines> <v_sync_polarity> <v_front_porch> <v_sync_pulse> <v_back_porch> <v_sync_offset_a> <v_sync_offset_b> <pixel_rep> <frame_rate> <interlaced> <pixel_freq> <aspect_ratio>

<h_active_pixels> = horizontal pixels (width)
<h_sync_polarity> = invert hsync polarity
<h_front_porch>   = horizontal forward padding from DE acitve edge
<h_sync_pulse>    = hsync pulse width in pixel clocks
<h_back_porch>    = vertical back padding from DE active edge
<v_active_lines>  = vertical pixels height (lines)
<v_sync_polarity> = invert vsync polarity
<v_front_porch>   = vertical forward padding from DE active edge
<v_sync_pulse>    = vsync pulse width in pixel clocks
<v_back_porch>    = vertical back padding from DE active edge
<v_sync_offset_a> = leave at zero
<v_sync_offset_b> = leave at zero
<pixel_rep>       = leave at zero
<frame_rate>      = screen refresh rate in Hz
<interlaced>      = leave at zero
<pixel_freq>      = clock frequency (width*height*framerate)
<aspect_ratio>    = *

* The aspect ratio can be set to one of 8 values (choose closest for your screen):

HDMI_ASPECT_4_3 = 1
HDMI_ASPECT_14_9 = 2
HDMI_ASPECT_16_9 = 3
HDMI_ASPECT_5_4 = 4
HDMI_ASPECT_16_10 = 5
HDMI_ASPECT_15_9 = 6
HDMI_ASPECT_21_9 = 7
HDMI_ASPECT_64_27 = 8

Can someone here point me to some website or show me which values for each parameter to setup a proper 720p 60hz mode ?
Thank you very much

[orange808]

Google "720p timings".

[Fudoh]

You don't need custom timings on the Pi. 720p60 is available as a standard timing and be forced by setting hdmi_group=1 and hdmi_mode=4 in the config.txt.

You also need to set your frontend to 720p. It's possible that the frontend/OS follows your config.txt already, but better set it twice than having to deal with additional resolution switches.

I'm not sure though why would want to run 720p on your BVM instead of using a native 240p output from the Pi.

[modology]

i'm using RGB-Pi 4.1 Alpha3.1 RPi3 (which is basically a custom version of RecalBox for users who uses RGB-Pi cable)
RGB-Pi cable is basicaly a Scart cable that connect directly to GPIO header and allow RPI to output RGB signal via GPIO

The reason i want to use 720p for the front end (emulatotstation) is because with 720p, you can see more details. text wont be so blurry and screenshots of each games are much clearer. It;s like taking advantage of 720p HD capability of my SONY BVM monitor. The great thing about it is that when you load ROM, for example SNES, resolution will be switched back to 240p for SNES games.

The config.txt of RGB-Pi 4.1 Alpha3.1 RPi3 is little bit different.
According to https://www.raspberrypi.org/documentati ... /README.md
hdmi_timings has to be specfified manually.
I've tried hdmi_group=1 and hdmi_mode=4 in the config.txt but it did not work, just black screen.

This is orginal config.txt of the RGB-Pi 4.1 Alpha 3.1

Code: Select all

hdmi_timings=450 1 50 30 90 270 1 1 1 30 0 0 0 50 0 9600000 1

display_rotate=0

audio_pwm_mode=2
disable_audio_dither=1

disable_overscan=1

hdmi_drive=2

config_hdmi_boost=0

hdmi_force_hotplug=1

boot_delay=3

disable_splash=1

# Overclock
gpu_mem_256=128
gpu_mem_512=256
gpu_mem_1024=512

avoid_safe_mode=1

dtoverlay=pi3-disable-bt-overlay

dtparam=audio=on
dtoverlay=pwm-2chan,pin=18,func=2,pin2=19,func2=2

dtoverlay=rgb-pi
enable_dpi_lcd=1
display_default_lcd=1
dpi_output_format=6
dpi_group=2
dpi_mode=87

kernel=zImage
overscan_scale=0

I believe that hdmi_timings parameter need to be specfied manually for 720p to works

[Fudoh]

As long as you exclusively want 720p from the Pi3, why just use a non-modified build of Recalbox ?

Or do you want 720p for the frontend while your Emus are still running at 240p ? I think the RGB-Pi image has been modified throughout, so I don't think you can easily switch the frontend back to HD.

[modology]

That's correct. I want my front end to run in 720p. On Recalbox, each emulator will have their own resolution settings, so different will have different native resolution switch settings.

I've emailed the RGB-Pi folk, he confirmed that /boot/config.txt ---> hdmi_timings value need to be changed to get 720p to works....

Well i'm pretty much clueless now... no idea what value to put in

[Fudoh]

the config.txt uses the modeline format, right ? Just look here https://www.mythtv.org/wiki/Modeline_Database