Playback timing issue IF auto refresh rate enabled

[StrangeNoises]

It looks like a timing glitch: Approximately twice a second, a skipped or jumped frame, on 23.976 and 24 fps material. Also affects 59.94Hz material (ie: 1080i@60) but apparently not 50Hz (1080i@50, 1080p@25). It looks less pronounced on the 1080i@60 material, but I believe it's the same problem, just modified by different timings. For the 23.976 and 24 fps material, it's very obvious when it happens, it's unwatchable, and not subtle. :-)

This only occurs if auto refresh-rate switching is turned on, and it has to switch to the correct mode for that refresh rate. And it does switch to the correct mode, confirmed with xbmc-xrandr. If I turn auto refresh-rate switching off, and manually select (in the XBMC GUI) the same correct mode for each example before playback, everything plays perfectly. So it would seem to be some playback timing state that's possibly set before the switch is complete, or even begun? NB: I have a configured playback delay of 3 seconds after refresh-rate change. Raising it to 5 seconds (enough to get a clear look at the time display in the top-right after the swtch before playback starts) makes no difference; playback is still broken.

The state of the "Sync playback to display" setting makes no difference. I had it off to begin with, turning it on didn't make it perceptibly better or worse.

This appeared in xbmc-xvba-testing builds in the last few days. I watch 1080i@50 tv content far more than anything else so I can't be sure when it first arose, but the August 4 build I made (commit 2c9e109) to confirm the fix for the previous issue #158 was definitely NOT exhibiting this issue (tested with that build again just now before replacing it with an up to date one), so it's arisen since then.

NB: Tested with multiple content examples. Movie raw blu ray rips:

23.976fps:
Alice in Wonderland
Alien
Aliens
Avatar

24fps
The Fifth Element
Coriolanus

Also tested,
South Pacific episode 1 (1080i@60)
2012 olympic opening ceremony, Planet Earth Special Edition episode 1 (1080i@50)

Interestingly Avatar played just fine, but it was the only exception. I have no idea why that should be different (mediainfo reports exactly the same framerates for that and the ones that failed); I can upload a minute or so of that and one of the others if required, but it takes a while so I'll do it on request only.

Debug log where most of these tests were made, on the current build: http://paste.ubuntu.com/5971440/

[FernetMenta]

i can see it, investigating ...

[FernetMenta]

should be fixed now

[StrangeNoises]

confirmed; looks fixed to me.