Merge pull request #25419 from vrabaud:ffmpeg

vrabaud · web-flow · commit c317a3ee89e7 · 2024-04-17T16:58:10.000+03:00
Fix race condition in InternalFFMpegRegister initialization. #25419 initLogger_ does not check if the logger has been initizalized before and it might initialize it several times from different threads, racing with other threads that are logging. ### Pull Request Readiness Checklist See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request - [x] I agree to contribute to the project under Apache 2 License. - [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV - [x] The PR is proposed to the proper branch - [x] There is a reference to the original bug report and related work
diff --git a/modules/videoio/src/cap_ffmpeg_impl.hpp b/modules/videoio/src/cap_ffmpeg_impl.hpp
@@ -927,7 +927,6 @@ class InternalFFMpegRegister
         if(!threadSafe)
             lock.lock();
         static InternalFFMpegRegister instance;
-        initLogger_();  // update logger setup unconditionally (GStreamer's libav plugin may override these settings)
     }
     static void initLogger_()
     {
@@ -965,6 +964,7 @@ class InternalFFMpegRegister
         /* register a callback function for synchronization */
         av_lockmgr_register(&LockCallBack);
 #endif
+        initLogger_();
     }
     ~InternalFFMpegRegister()
     {

Original file line number	Diff line number	Diff line change
`@@ -927,7 +927,6 @@ class InternalFFMpegRegister`
`927`	`927`	`if(!threadSafe)`
`928`	`928`	`lock.lock();`
`929`	`929`	`static InternalFFMpegRegister instance;`
`930`		`- initLogger_(); // update logger setup unconditionally (GStreamer's libav plugin may override these settings)`
`931`	`930`	`}`
`932`	`931`	`static void initLogger_()`
`933`	`932`	`{`
`@@ -965,6 +964,7 @@ class InternalFFMpegRegister`
`965`	`964`	`/* register a callback function for synchronization */`
`966`	`965`	`av_lockmgr_register(&LockCallBack);`
`967`	`966`	`#endif`
	`967`	`+ initLogger_();`
`968`	`968`	`}`
`969`	`969`	`~InternalFFMpegRegister()`
`970`	`970`	`{`