i tested the video today on my linux laptop.  it was extremely slow, and messenger was noticably slower.  messenger ran before flawlessly, but now is slow and strange.    we tried a conference with three people.  
"the audio is extremely choppy, it sounds like you're under water or something, or like there are ten of you."
"your video works though,"
"this is strange, lets try again tomorrow." (after half hour of trying for it to work.)
me: hmm. also, the window dragging around noticably screwed up the entire messenger chat. it almost felt like the window did not want to re-draw itself fast enough to be dragged around. as if it was "heavy" it didnt want to move around much.
also sending text from the chat into messenger was impossibly slow (7-8 seconds) for load of chat in jitsi, and 4-5 seconds for message to appear in jitsi, and then another 3-4 seconds for it to copy into messenger history, while trying to drag window around to see if it went in added another 12-24 seconds give or take.
it may be my laptops age, 2017, it may be something else. just wanted to inform. :)

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also, video message into group chat did not work after the fact when i tried to apologize to my friends, but in messenger 11.0.1 these messages of video worked fine.  (there was no audio attached to the mime type, brief error flashed.)

linux mint 18- kernel 4.4.x