We support burning timecodes into the preview versions. This can either be done per video, by navigating to the "File > Recreate" menu and selecting the "Timecode" option, or this can be enabled for all uploaded videos through "General Settings > Video". Please be aware that by enabling timecode support, even videos that would normally not be transcoded (see this article for details), will now be transcoded to embed the timecode.
We will automatically attempt to detect the correct starting timecode and frame rate from the uploaded video. We check both the tags in the container and the video stream to see if it contains a valid timecode.