We are trying to play 4K stereo videos via the UE’s media framework, but are encountering performance issues. 4K mono (in h.264) is running just fine, but when trying to go for 4K stereo (in HEVC), it plays at best at around 0.5x speed and occasionally is just a slideshow.
I have not yet done much testing with it, but would like to ask already now whether I should even expect this to work? What I already know is this:
4K mono video, 4096x2048, mp4, h.264, 80mbit/s, 30fps:
2K stereo video, 2048x2048 (top-bottom stereo), mp4, HEVC, 30fps, profile=main, level=6.1, tier=main:
smooth at any bitrate (tested up to 100mbit/s)
4K stereo video, 4096x4096 (top-bottom stereo), mp4, HEVC, 30fps, profile=main, level=6.1, tier=main:
0.5x playback speed at best (at any bitrate, from 0.2mbit/s to 100mbit/s!)
Interestingly, the video bitrate seems to not affect the playback performance at all in that last case. Could it be that it is bottlenecked not by decoding performance but by memory bandwidth when transferring around the decoded frames?
Gmpreussner, I think I read you say in some older post that the implementation is (was?) not very efficient, in that it makes some technically unnecessary copying of the decoded frames, do I remember correctly? Could that be related to this?
Test computer specs:
Intel i7-6700 @ 3.40 GHz (16 GB RAM)
GeForce GTX 980 (4 GB VRAM)
All videos are encoded using Adobe Media Encoder CC 2017.
There is nothing else happening in the game (film) while a video is playing.