Getting a black bar on gopro footage when viewing on vlc player on the left hand side, only happens when the gopro is mounted to chesty mount, that is gopro upside down but weirdly all other players play it fine.
Please open Tools -> Messages (set Verbosity to 2)
before you start the playback, and then paste the
full resulting log here or on Pastebin.com if it's too long.
Also upload a
short sample of your
original problematic file to Zippyshare.com or to WeTransfer.com and then post the link to the file here.
https://www.zippyshare.com
https://wetransfer.com
If needed cut it with DGsplit and read here about how to do it:
https://forum.videolan.org/viewtopic.ph ... 35#p193335
200 MB max should be enough.