ofVideoPlayer setFrame issue with one video of many

Hey All

I am having trouble with setting frame of a particular video file due to it hanging the program.

I am using MacOs Mojave 10.14 and I believe AVFoundation ofVideoPlayer.

I have encoded the video from H.264 to Prores422. The clips range from 40 seconds to 1.45 minutes and also have varied sizes but I have resized most of then to 1280 x 720. including the file in question…

The interaction is that when pressing a button I am the setting the frame on the video in question.
There has been no issues with any of the other video files when setting frame apart from a very short delay time in setting to the particular frame which is ok. But on this particular file there is a longer hangup on the application and when i press again i get the loading symbol.

any ideas what it could be and how I might mediate it?

  case 49:
            mPrevVideoID = mVideoID;
            if(mPrevVideoID != mVideoID) mMovies[mPrevVideoID]->stop();
            mVideoID = 0;
            mMovies[mVideoID]->setFrame((int)ofRandom(1, mMovies[mVideoID]->getTotalNumFrames()-1));
            if (!mMovies[videoID]->isPlaying()) mMovies[videoID]->play();

I have now tested this on windows and the video setFrame seems fine with no application hang.