window-maximized observe property not reliable

[stax76]

Important Information

Provide following Information:

• mpv version: 0.32
• Windows Version: w10 1909
• Source of the mpv binary: shinchiro libmpv x64

Reproduction steps

In mpv.net I use an own window, occasionally people ask to implement mpv window properties, so I wanted to implement window-maximized, so I observe window-maximized. I get an initial change notification. When the property was set from CLI I set it via API. After that I expect to get overall 2 notifications but I get 3. It's easy for me to workaround, I don't know what's wrong but doesn't matter.

The issue is when I use cycle window-maximized in input.conf, then I don't get reliable results, it works maybe 8-9 times out 10, sometimes it's not sending the notification or other times 2 notifications together. My event handling code don't do anything special, the code that changes the form needs run asynchronously, it's likely that there is an issue in the client API. I remember a post from wm4 that related code is often rewritten which got me worried a lit bit but I really have nothing to complain, some things are complex by nature and everything is typically very stable and I always find a way to make things work, this is one of the rare occasions where I can't find a solution and it's not a real issue because users should rather not use window-maximized in input.conf but rather use the native Windows shortcuts win+up and win+down. I don't expect anything, it's all good, I just thought I post it anyway. I tried to reproduce it with mpv and lua but it only happens in mpv.net. I know a bit C and hope that in the future I can investigate such issues myself.

Log file: https://pastebin.com/MFn83epf

Thank you

[stax76]

With border=no the osc shows a top bar with min, max and close buttons, I wanted to support this bar in my frontend and I also wanted generally full window-minimized and window-maximized support because there are scripts that rely on it like pause-when-minimize.lua. All this was working but again only 8 out of 10 times, so I spent some time debugging. In client.h the documentation says properties can be observed with MPV_FORMAT_NONE, so I tried that and now it's 100 % reliable. 👍

[ghost]

So you're saying observing with any other format doesn't work always?

[stax76]

It works for other properties but not with window-maximized and window-minimized where MPV_FORMAT_FLAG is only 80% reliable while playback, without playback it's also 100% reliable.

[ghost]

Sounds like a legitimate bug then.