MiSTer on a laser projector: 720p not working

[limi]

Trying to get MiSTer to work with a portable laser projector, Sony MP-CL1A.

It’s a very interesting projector with zero motion blur (similar to CRT), no image retention, always perfect focus (LASERS!), and comes in a portable package that can run off a 5V USB and also has a built-in battery — making it a potentially great travel companion for the MiSTer.

This one has me (and quite a few members of the Classic Gaming MiSTer Discord server) stumped.

The basics:

• The projector's specifications say it's a 1920×720 resolution projector.

• My goal, then, is to configure it to work with MiSTer at 1280×720, which is its “native” resolution.

• When I connect it to a Windows or Mac laptop, it defaults to 1280×720.
  (It's also possible to run it at 1920×1080, but I suspect it's doing (vertical) scaling at that point.)

• When I connect it to the MiSTer, it does not work using 1280×720 (video_mode=0), displaying "No Signal"

• When I try a 480p resolution, it works, and the colors are correct.

• However, if I configure it for 1920×1080, it displays, but swaps red and blue — see the following screenshot (ignore the fact that I'm projecting on to an uneven wall here):

image0.jpg (970.79 KiB) Viewed 4177 times

• As mentioned, when connected to a PC/Mac, both 720p and 1080p have correct colors. Here's the output from MonitorInfoView:

MonitorInfoView.png (58.3 KiB) Viewed 4177 times

I'd like to run it at its "native" 720p resolution (ignoring that it's capable of 1920 horizontal pixels).

I ran through all the pre-defined resolutions, and here are the ones that work:

Code: Select all

; 0 - 1280x720@60 — No
; 1 - 1024x768@60 — No
; 2 - 720x480@60 — Yes
; 3 - 720x576@50 — Yes
; 4 - 1280x1024@60 — No
; 5 - 800x600@60 — No
; 6 - 640x480@60 — Yes
; 7 - 1280x720@50 — No
; 8 - 1920x1080@60 — Yes, but colors reversed(!)
; 9 - 1920x1080@50 — Yes, but colors reversed(!)
;10 - 1366x768@60 — No
;11 - 1024x600@60 — No
;12 - 1920x1440@60 — No
;13 - 2048x1536@60 — No

I have also tried a bunch of custom video_modes that correspond to 1920×720, as well as standard 1280×720 definitions. A list of the ones I've tried:

Code: Select all

video_mode=1920,96,192,288,720,3,10,15,112020
video_mode=1920,96,192,288,720,3,10,15,134424 (50hz)
video_mode=1920,96,192,288,720,3,10,15,117621 (63hz)
video_mode=1280,64,128,192,720,3,5,20,73250
video_mode=1920,88,44,148,1080,4,5,36,148500

Other things I have tried are hdmi_limited=1 & 2, dvi_mode=1, none of which made a difference.

Here's the complete mister.ini that I'm using (comments removed) in case something else here might be interfering:

Code: Select all

[MiSTer]
key_menu_as_rgui=0
forced_scandoubler=0
ypbpr=0                
composite_sync=0 
vga_scaler=0          
hdmi_audio_96k=0 
keyrah_mode=0x18d80002
volumectl=0           
vscale_mode=0.5   
vscale_border=0 
bootscreen=0     
rbf_hide_datecode=1 
menu_pal=0           
hdmi_limited=0      
direct_video=0
fb_size=0        
fb_terminal=1 
osd_timeout=3600
browse_expand=0
recents=0
font=fonts/Amiga1.pf
reset_combo=1
dvi_mode=0      
video_mode=8
video_info=0
vsync_adjust=2

When running the 240p test suite in e.g. 1920×1080, the scrolling is smooth in vsync_adjust=2, so vsync does not appear to be the issue. I did try vsync_adjust=0 when I started out to ensure maximum compatibility, but it does not seem to make a difference in any of the resolutions listed above.

What else can I attempt to get this working at 720p with MiSTer? Again, it works fine in all the usual common resolutions (480p, 720p & 1080p) when plugged into a laptop. But I can't seem to find the correct settings for the MISTer.

[limi]

According to Elexor, the color issue might be an HDMI colorspace issue — MiSTer is outputting RGB, and the projector seems to be displaying it as YCbCr.

There are unfortunately no settings in the OSD on the projector itself, but computers seem to negotiate this setting correctly without me having to do anything.

Is there a way to change this for HDMI? I know there is a "ypbpr" ini file setting, but that only affects VGA output.

Will post the raw EDID dump from the device in a bit, in case that helps identify the 720p issues.

[limi]

Here's the EDID binary dump from the projector.

[limi]

Elextor tipped me off to a tool that Grabulosaure had made to dump the EDID info. Here's the output of what the Sony MP-CL1A supports:

Code: Select all

EDID version: 1.3
Manufacturer: SNY Model 5804 Serial Number 1
Digital display
Maximum image size: 160 cm x 90 cm
Gamma: 2.20
RGB color display
First detailed timing is preferred timing
Display x,y Chromaticity:
  Red:   0.6250, 0.3398
  Green: 0.2802, 0.5947
  Blue:  0.1552, 0.0703
  White: 0.2832, 0.2978
Established timings supported:
  640x480@60Hz 4:3 HorFreq: 31469 Hz Clock: 25.175 MHz
Standard timings supported:
  1920x1080@60Hz 16:9
  1280x720@60Hz 16:9
  640x480@60Hz 4:3 HorFreq: 31469 Hz Clock: 25.175 MHz
Detailed mode: Clock 74.250 MHz, 1600 mm x 900 mm
               1280 1390 1430 1650 hborder 0
                720  725  730  750 vborder 0
               +hsync +vsync 
               VertFreq: 60 Hz, HorFreq: 45000 Hz
Monitor name: MP-CL1A
Monitor ranges (GTF): 24-85Hz V, 14-70kHz H, max dotclock 160MHz
Manufacturer-specified data, tag 0
Has 1 extension blocks
Checksum: 0x5b (valid)

----------------

CTA Extension Block
Extension version: 3
Basic audio support
Supports YCbCr 4:4:4
Supports YCbCr 4:2:2
1 native detailed modes

27 bytes of CTA data
  Video Data Block
    VIC   1 640x480@60Hz 4:3  HorFreq: 31469 Hz Clock: 25.175 MHz
    VIC   3 720x480@60Hz 16:9  HorFreq: 31469 Hz Clock: 27.000 MHz
    VIC   4 1280x720@60Hz 16:9 (native) HorFreq: 45000 Hz Clock: 74.250 MHz
    VIC   5 1920x1080i@60Hz 16:9  HorFreq: 33750 Hz Clock: 74.250 MHz
    VIC  16 1920x1080@60Hz 16:9  HorFreq: 67500 Hz Clock: 148.500 MHz
    VIC  18 720x576@50Hz 16:9  HorFreq: 31250 Hz Clock: 27.000 MHz
    VIC  19 1280x720@50Hz 16:9  HorFreq: 37500 Hz Clock: 74.250 MHz
    VIC  20 1920x1080i@50Hz 16:9  HorFreq: 28125 Hz Clock: 74.250 MHz
    VIC  31 1920x1080@50Hz 16:9  HorFreq: 56250 Hz Clock: 148.500 MHz
    VIC  34 1920x1080@30Hz 16:9  HorFreq: 33750 Hz Clock: 74.250 MHz
  Audio Data Block
    Linear PCM, max channels 2
      Supported sample rates (kHz): 48 44.1 32
      Supported sample sizes (bits): 24 20 16
  Speaker Allocation Data Block
    Speaker map:
      FL/FR - Front Left/Right
  Vendor-Specific Data Block, OUI 000c03 (HDMI)
    Source physical address 1.0.0.0
    Supports_AI
    Maximum TMDS clock: 150MHz

Detailed mode: Clock 148.500 MHz, 1600 mm x 900 mm
               1920 2008 2052 2200 hborder 0
               1080 1084 1089 1125 vborder 0
               +hsync +vsync 
               VertFreq: 60 Hz, HorFreq: 67500 Hz
Detailed mode: Clock 74.250 MHz, 1600 mm x 900 mm
               1920 2008 2052 2200 hborder 0
                540  542  547  562 vborder 0
               +hsync +vsync interlaced 
               VertFreq: 60 Hz, HorFreq: 33750 Hz
Detailed mode: Clock 74.250 MHz, 1600 mm x 900 mm
               1920 2448 2492 2640 hborder 0
                540  542  547  562 vborder 0
               +hsync +vsync interlaced 
               VertFreq: 50 Hz, HorFreq: 28125 Hz
Detailed mode: Clock 74.250 MHz, 1600 mm x 900 mm
               1280 1390 1430 1650 hborder 0
                720  725  730  750 vborder 0
               +hsync +vsync 
               VertFreq: 60 Hz, HorFreq: 45000 Hz
Detailed mode: Clock 27.000 MHz, 1600 mm x 900 mm
                720  736  798  858 hborder 0
                480  489  495  525 vborder 0
               -hsync -vsync 
               VertFreq: 59 Hz, HorFreq: 31468 Hz
Checksum: 0x2 (valid)

[Slipard]

What's the input lag?

[limi]

Infinite, since it doesn’t show an image?

[Newsdee]

I've been trying to understand how these custom video settings are created, and found a detailed post from Grabulosaure which may help: https://www.atari-forum.com/viewtopic.p ... 16#p365316

So based on your EDID info:

Code: Select all

Detailed mode: Clock 74.250 MHz, 1600 mm x 900 mm
               1280 1390 1430 1650 hborder 0
                720  725  730  750 vborder 0
               +hsync +vsync 
               VertFreq: 60 Hz, HorFreq: 45000 Hz

If am not mistaken, that would translate to this:

Code: Select all

video_mode=1280,110,40,220,720,5,5,20,74250

[limi]

Thanks! Unfortunately that didn’t work either.

Based on CL1A EDID probing, I have tried the following variations, none of which worked:

Code: Select all

video_mode=1280,56,136,178,720,1,3,26,74250
video_mode=1280,56,136,192,720,1,3,276,99840
video_mode=1280,110,40,220,720,5,5,20,74250

[limi]

And here's what it shows in Windows when connecting the projector, it defaults to 1280x720, uses 8-bit RGB at 59hz or 60hz. It works in both modes, as well as 1920×1080 if I force that. So weird that it won’t show anything from the MiSTer.

Windows Screen Mode.png (37.43 KiB) Viewed 4011 times