Mine works fine.
Probably is not an integrated budget one. GMAs and Express Chipsets make problems.
@luucasalves, first check if hardware acceleration has been enabled in settings, because the screenshot says it has been disabled. You may need to unlock the advanced settings first if you haven't already done it. Then check everything that may be disabled in opera:flags. Secondly, don't test Opera's MP4 support with this Twitter video only. Check this:
If Opera plays all three videos correctly (video and audio), then it's fine. For the H.264/MP4 Opera relies on the system for decoding. For WebM and Ogg/Theora Opera has native support. I haven't come across any other videos with the black screen issue on the web, except those on Twitter posted here. They are MP4. I already shared my suspicions what the cause may be - the msmpeg2vdec.dll. It's just a guess, though. The audio is working, because another DLL is used for decoding the audio streams (usually AAC) within the MP4 - msmpeg2adec.dll and it is related to the GPU process if not the GPU itself.
SwiftShader has nothing to do with video playing. Opera can't use it properly. It's for the WebGL, which I'm still unable to use with my GPU (and probably you won't be).
@babogredac, try the same solution. Same error, although it's an AMD GPU.