I have used Pis quite successfully in the past for running a looping video on screens in a retail environment. Some by direct connection to a screen via HDMI, and others via PiView HDMI to VGA adpator, thence the VGA input on a LCD TV. Normally it works just fine.
However, had one the other day where the attached Sony 20" TVs (pair of them driven via an active VGA splitter) were not syncing to the Pi on startup - simply displaying a "out of range" message. So I tweaked the config.txt file in the boot partition to specify one of the screen modes they claimed to support, and got a boot screen up. Sorted, or so I thought. (The video loop is simply an AVI file played by omxplayer, and that is driven from a "while true" loop in the .profile for the user).
After some time playing the video (tens of minutes to hours typically) the screens seem to be losing sync, and need powering off and back on again to recover. I figured this might be screen mode related and attempted to investigate, but was getting confusing information.
My config entry is:
hdmi_group=2 hdmi_mode=26
Which according to
should be DMT, and 1280x768 120Hz reduced blanking
However, when the TV starts playing the Video, it briefly displays an overlay with "640 x 480 60Hz"
Also doing a:
sudo tvservice -s
gives:
state 0x12001a [HDMI DMT (4) RGB full 4:3], 640x480 @ 60Hz, progressive
Which suggests that omxplayer is changing the screen mode when the video runs (which would explain why the TV captions the mode on screen briefly), and possibly explains why the TVS eventually get fed up, if the mode is forever changing (the video loop repeats every 60 secs or so)
Can anyone shed any light on what is happening with omxplayer and the screen mode switching?