Hide Seconds count in Video

Is there a way to hide the number of seconds during video playback?

You can do it when you create the video (not for a video that is already rendered). There are a few hidden parameters that you can pass to the filmstrip comparison page that can be used to change the video rendering settings: https://github.com/WPO-Foundation/webpagetest/blob/master/www/video/compare.php#L365

Specifically, if you add &timeHeight=0 to the compare.php url then create the video, the time will not be displayed (passing &labelHeight=0 will also get rid of the label above the video).

If you have a private instance and want to change it for all videos there are several settings that can be modified in an ini file: https://github.com/WPO-Foundation/webpagetest/blob/master/www/video/render.php#L56