Ffmpeg Buddy
I say this with the best of intentions:  I wish this went a little farther.  A lot of the complexity comes from transcoding options, filters/transformations applied to the video/audio streams, and control of how the file gets put back together.(And sometimes there are oddities about how they interact, or there is one option that seems very deprecated.  It's like Eclipse, it's an engineer's tool, it's extremely powerful but god had no hand in the creation of the UX whatsoever, it is the unholy amalgamation of hundreds of modules that usually work, usually, mostly.)Give me checkboxes for "resize this video", "convert framerate", "decomb filter", "burn hardsubs filter", a reasonable set of x264 or x265 transcoding options, audio transcoding and downmux, and options for controlling how it all gets reassembled.It might help to list out some simple use-cases and then look at the ffmpeg features that would be required to get there, and then support those.  But again, it's sort of hard to capture everyone's use-cases, ffmpeg is such a swiss-army knife.Personally I use it for:* to direct-stream cut (no re-encoding) slices of videos for memes* to handle game replay captures (sometimes with re-encoding, sometimes not) and combine separate audio tracks into a file for youtube* to handle game replay captures (always with re-encoding) but with separate audio tracks preserved* to cut out audio tracks/subs that I don't want from a given movie/show when it becomes annoying* to transcode a movie/show for archival at the minimum size/maximum qualityetcIn particular I'm not sure how to really tell ffmpeg to handle multiple audio/sub streams without programmatic interaction - you kinda need to know there are 2 audio streams and 4 sub streams, because you need to tell it what to do with each stream you want included in the output file, even if you do the exact same thing to every stream.  If you have one show that's a little weird, fine, but without some kind of front-end it gets difficult to handle arbitrary content that is similar but not quite.