Demuxing streamcopy tool?

[Honeyko]

Normally I use the venerable (and still updated) Avidemux utility to quickly yank short clips out of material I download (this being handy for posting to social media), but have run into a problem with a source file (mkv container) containing HEVC video and Opus audio.

Avidemux clipped and saves the sample, and can load and play its saved file (but only in, oddly enough, AVI containers), but nothing else I have can work with it (e.g., none of Facebook's or Youtube's built-in converters, MKVToolNix GUI, VLC Media Player, or VidCoder (based off Handbrake) can either play or manipulate the contents even if able to see them.

Sooo.... Need a better stream-copy clipper. -- Recommendations?

[sneaker_ger]

Youtube does not accept HEVC video, period. Try re-encoding using x264 encoder. If AviDemux messes up report it to the developers or try e.g. HandBrake.

http://superuser.com/questions/999022/how-do-i-trim-a-video-using-handbrake

[Midzuki]

My goodness --- HEVC-in-AVI was (somewhat) acceptable 3.5 years ago, when there were no other choices besides the infamous HEVC-in-FLV from Strongene.
Avidemux still sucks very-much, sadly.