Guys, i think i was not clear enough in my explanation so i should to clarify:
1. As my second browser i use Firefox 52 ESR with Adobe Primetime since 2018 and it show video\audio in twitter correctly. With "Good Twitter" extension that i mention earlier it even switch now to old layout in 52ESR and still show video\audio in twitter correctly.
2. New Moon with User Agent Mode "Firefox compatible" show twitter NOW in 2020 year with new layout with video\audio correctly.
3. New Moon with User Agent Mode "Native" show twitter with old layout BUT video\audio incorrectly.
As i can see New Moon is superior in speed to any browser in XP. Firefox52ESR is much slower, also Adobe Primetime CDM is bad decoder - very CPU hungry and constantly dropping video-frames, freezing on several seconds. I prefer New Moon 99% of my time, so to me it's or watch twitter without video and audio, or use "Firefox compatible" mode, login in new layout and see this crappy interface just to watch twitter videos in my favorite browser in XP.
So i just want to ask a question - is in future plans to change\modify built in AAC decoder in New Moon or it is not possible?
And i also have second question - was anybody ever crack mystery of video freeze after 23 min in Firefox\New Moon? I was thinking about that, was it always in code of Firefox since version 4? Or it pop-out in some later versions? Can somebody point me to long (like 25 min or longer) vp8 videos online to check was version Firefox 4 already with that bag? I mean what if that was not from the begging - than it can be tracked, right? It just my silly guessing.