Test experimental support of MKV/WebM container mixing in-development video format VP9 and audio format Opus. As of today this is the best video-audio combo with royalty-free web formats with better quality/weight ratio than “classical” VP8-Vorbis.
Major browsers and players support both VP9 and Opus, but separately: Standalone Opus audio (MIME audio/opus) is well supported. WebM container is implying VP8+Vorbis or VP9-Vorbis, putting another audio format (WAV, FLAC, Speex, Opus) is unexpected. video/mkv isn't a recognized MIME by browsers.
I hope for a consensus about extending WebM format specs to VP9+Opus and push support for browsers, making it an efficient H.264+AAC killer before fighting the emerging H.265+HE-AAC.
source: Quantum Ripples (AMV by Nostromo)
ffmpeg -i "Nostromo_-_Quantum_Ripples_720p@60_10b.mp4" -c:v libvpx-vp9 -c:a libopus -deadline best -crf 24 -b:v 300k -b:a 40k -threads 4 -y -ss 00:01:55.000 -t 13 "out.mkv"
~~ BEGIN HTML5 PLAYER ~~
~~ EOF ~~