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Cannot leave mythfrontend screen when playing live dvb radio #469

Open Jpilk opened 2 years ago

Jpilk commented 2 years ago

What steps will reproduce the bug?

How often does it reproduce? Is there a required condition?

What is the expected behaviour?

What do you see instead?

Additional information

Jpilk commented 2 years ago

Sorry about the blank opening page.

This looks like a continuation of Trac #13156 and was mentioned in Issue #429.

https://code.mythtv.org/trac/ticket/13156

I rarely use myth in this way but ran into it while checking after a big UK Freeview channel reshuffle and retune today, on boxes running current master and master from 2021 July; but the Trac ticket is 4 years old.

FWIW My unresponsive screens were bordered windows in kde Plasma desktops, started from a konsole tab. CtrlC there seemed the simplest way to quit.

peper03 commented 2 years ago

For what it's worth, I looked at this a long time ago but finding a fix that didn't break other scenarios was beyond me.

Lots of stuff has been worked on since then but at the time the problem was related to having to have a certain amount of data buffered to get audio and video in sync. It only affected Live TV because it's, well, live. Recordings already have all the data available to fill the buffer but with Live TV it's coming in in real time.

Obviously an audio-only channel has no video but the code doesn't know that. It would wait for a fairly large amount of data (in the order of megabytes, I believe) to come in, which is done fairly quickly with video but audio-only at comparatively low bit-rates will take a long time.

When you try to exit, it's still waiting for the data and then it gets stuck in an endless loop.

Reducing the size of the buffer was not possible as there are apparently some devices that deliver audio and video chunks quite far apart from each other and A/V sync was then not possible.

Pausing playback (even briefly) and then resuming before trying to exit always seemed to work. I don't remember why, I'm afraid.

Jpilk commented 2 years ago

No key seems to have any effect while focus is inside the window border, and the mouse disappears there. Skipping doesn't happen. Right clicking on the window border and selecting 'close' yields a 'not responding' popup and will quit. CtrlC in the command screen quits too. I have the impression that if nothing is being painted within Myth's window Myth gets no input.