How to set hdmi_timing to display 720p 60hz 16:9 mode for Sony BVM 20F1U

[Huey Le]

Hi, i have SONY BVM 20F1U which can display 720p 60hz 16:9 aspect ratio.

My setup involves hooking RGB-Pi cable --> Scart to BNC cables --> hooked up to SONY BVM

After doing some research, it looks like i need to edit /boot/config.txt to change hdmi_timing parameter so that it will display as 720p 16:9

According to the syntax

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

I really have no idea how these value are calculated like clock frequency, Vsync polarity, etc...

Can someone please let me know which values that i need to put in hdmi_timing?

Thank you very much

[Substring]

@huey-le hi

Why would you want a HD resolution using the RGB-Pi ? it's mostly made to display lower resolutions ...

Now regarding the timing, it's something really complicated that can't be just done like that.

[Huey Le]

@substring

My SONY BVM monitor is capable of displaying 16:9 HD 720p and even 1080i.

The reason that i want to use 720p for the front end emulatorstation is that I can see more details, texts will be clearer and so are all the games screenshots as well. Basically it takes the best of both world, front end with 720p mode and when you load each game, they will switch to their according native resolution (e.g. SNES switch to 240p, etc....)

As you mentioned, it seems to be quite complicated with the timing. Would be nice if someone can help out. Thanks

[Substring]

@huey-le here is a tip : https://www.mythtv.org/wiki/Modeline_Database
look at the 1280x720 modeline and convert it to hdmi timing. I can't do it for you right now sadly. A modeline sums the values : visible, visible + front porch, visible + front porch + back porch, visible . ..... + sync whereas a HDMI timing just need the raw value of each : visible, both porches and the sync, for vertical and horizontal

[Huey Le]

@substring said in How to set hdmi_timing to display 720p 60hz 16:9 mode for Sony BVM 20F1U:

https://www.mythtv.org/wiki/Modeline_Database

Thanks. I will try to muck around to see if I get it to work.
I'd be deeply appreciated if you can spend some time to provide hdmi_timings if possible.
Thank you very much

[Substring]

@huey-le you could eventually give a try to :

hdmi_cvt=1280 720 60 3 0 0 0
hdmi_mode=2
hdmi_group=87

reference : https://www.raspberrypi.org/forums/viewtopic.php?f=29&t=24679&sid=4c0e33c3e707fccba5494107fe8260a2#p227301