[beejay]

I have done that. The way I always have it. Still, it switched refreshrates where it shouldn't.

I don't believe refresh rate can change apart from at start/stop when set to "start/stop".
You'll need to provide a debug log which will show this.

If you can provide a sample file that triggers the refresh change (when you think it shouldn't) I can investigate.

EDIT:
are you sure it is a refresh rate change, and not just "no signal" or some other failure?
Is this definitely new to the most recent build?
Adding "refresh_change = 2" to config.txt will disable the code for detecting refresh rate changes on firmware.

I can independently confirm everything Gregoire reports.

I have a file which plays normally on Mac OS with codec info reporting a steady 25fps, when I play it on miappa's latest 0413 RPi build it goes crazy constantly switching back and forth between 24Hz and 60Hz about once per second. (Codec info fps also fluctuates between 23 and 25fps)

The OSD of the TV itself is definitely reporting a refresh rate switch as it flashes up the resolution and refresh rate each time it switches. I can also confirm that setting "Adjust display refresh rate to match video" to "On start/stop" does NOT stop it from constantly switching back and forth.

Furthermore even if I switch it to "Off" although the refresh rate doesn't change the picture blanks about once a second at the time when it otherwise would have been switching refresh rates, so it seems like the HDMI connection may still be re-initialising but back to the same refresh rate.

Setting refresh_rate=2 in config.txt does indeed prevent the problem from happening so I'll leave that in for the moment. With this set codec info reports 25fps.

There is a slight pause once per second like a dropped frame so it could well be a 24fps file whose container lies that it is 25fps, but that doesn't explain why it keeps switching to 60 Hz... (my default resolution is 1920x1080 at 50Hz, not 60Hz)

I'll see if I can send you a link to a sample file later tonight so you can hopefully reproduce it first hand.

I have this problem also. It was both with latest nightly gotham and official rpi frodo-build. My problem is its switching framerate between 24 and 60 during library browsing, file browsing etc. Inside the skin, not when watching movies though.