users upload videos with video preview, but because video has requirements for video encoding
Ogg = with Theora video encoding + Vorbis audio coding
MPEG4 = with H.264 video encoding + AAC audio coding
WebM = videos uploaded with VP8 video encoding + Vorbis audio coding
users must use format factory transcoding whether there is a way to transcode this with js or is it necessary for js to achieve this transcoding The code still directly prompts the user to go to the format factory to transcode