It took me a while to find a video on YouTube that won't play, but this one will not...
www.youtube.com/watch?v=6dP4WAXqBtc
Cheers
Hugh
I restored AppleGVA from 10.14.3 and played this video in Safari without any problems. 1080p The specifications of this video are suitable for decoding. Nothing special.
![f1.png f1.png](https://forums.macrumors.com/data/attachments/742/742555-4c3265fe8c77b336f5e28fe23b474e86.jpg)
9400m has a Pure Video VP3 Decoder with full hardware decoding capability for MPEG-1, MPEG-2, VC-1/WMV9 and h264
The problem with video playback may be related to sound problems. But as I said, on my MacBook6.1 I do not see any problems with playback in Safari. I also downloaded this file and played it locally - and while playing the video locally, I watched the friezes of the picture during the preview. You can also check that this video is playing locally. As well as locally, but in a player with hardware acceleration turned off in the settings, for example, in VLC.
Replacing AppleGVA from High Sierra in Mojave only affects hardware decoding, because in High Sierra it works natively on the macbook6,1. It makes playing a movie like it is in the High Sierra. And after the patch again, I was able to play this video locally without friezes.
it is therefore difficult to say whether this patch will affect your problem whose nature is not clear.