Anyone knows what part of registry is related to this film frame? I installed and uninstalled mp4box, avidemux, YAMB try to set default aspect ratios but failed, and now I have a new problem.

Anyone knows what part of registry is related to this film frame? I installed and uninstalled mp4box, avidemux, YAMB try to set default aspect ratios but failed, and now I have a new problem.

If you are asking about getting the sprocket perforations on the thumbnail, I would suggest using Icaros. It lets you specify file types to generate thumbnails for (including various video formats for which thumbnails are not generated by default). If you add .mp4 to its list, then it may change how the thumbnail is generated (i.e., use WMP to generate it like is done for .wmv files).
You can also customize the appearance of video thumbnails with Thumbnailer Lite:
