WebM is a new age media file first developed and released in 2010. WebM is the container for VP8, VP9 & AV1(video) and Vorbis and Opus (audio). Perhaps unsurprisingly Google has been pushing its development with this very format being used for the higher quality video options on YouTube.
WebM vs MP4
WebM behaves very similar to the common MP4 (MPEG-4) in that it can be played in modern browsers and video players however still to this day you cannot play a WebM file on an iPhone. WebM is open source and is more efficient at video encoding, smaller file sizes whilst keeping a better overall quality than the aged MPEG.
However this encoding comes at a cost of a slower speed than x264 and x265, you could find reason with today’s storage availability why would a casual person bother with WebM over MP4 if it is slower and saves a bit of space.
WebM has a use
Understandably YouTube is having to store a ginormous amount of videos every minute therefor space matters, as does keeping quality when compressing the videos down significantly. Processing power also isn’t a worry for a tech giant like Google/YouTube.
This is where WebM is a winner, The modern video container that was made for web viewing can be utilized to be an efficient encoder if you have the power and need to save space.
Looking to the future with WebM being open sourced and the “several years” newer format it is an appealing option to use and be accustomed to. MP4 is common and simple but for how much longer can it be the norm and average performer before WebM truly catches on?
Getting WebM compatible and playing on IOS would be a great start but very likely this is Apple playing hard ball and wanting to utilize their own video (M4V) instead.