Browser playback is a stuttery mess

[Brumes]

I'd still give my ffmpeg command a try.  Swap mkv with mp4.  Or maybe convert to mkv?  The only thing that makes sense is that there is something off about your files since transcoding fixes it.

The command didn't work with the error: 

Code:

Invalid stream specifier: c. Last message repeated 3 times Stream map '0:c' matches no streams.

until I removed the " map '0:c' " after that it ran.
Converting to MP4 did not change anything.
Converting to MKV did cause it to transcode and playback normally.

Also i would like to add that the file plays back fine in VLC or JMP, its only when playing them in chrome or the mobile apps that the issue occurs.