Quite often, when playing back H.264 files on QuickTime Player on macOS 10.13.6, the CPU on my MacBook Pro 2017 will basically max out at > 200% for 10 or 20s, and then stay at 100% (regardless of whether I play back any content or just leave QT player paused in the background). Looks like a bug in QT player to me, but maybe this is normal or I'm just missing out something essential?
MacBook Pro (13-inch, 2017, 4 TBT3), macOS High Sierra (10.13.6)
If it's on a MBP with a TouchBar, it likely because TB interface for Quicktime renders out preview frames for scrubbing when each file is opened. Turning off App Controls for the TB doesn't fix it either. Still renders in the background. I have a maxed out 15" 2018 MBP, same for 2016 and 2017, and they all did the same thing. It's made what used to be a reliable computer for presenting video content on to something I try to avoid. The original retina MBP 15" was the last good one for video playback. It's still a good system for editing with FCP and Resolve, but for standard playback it's terrible. Quicktime took a definite dive since v7 Pro.
Good news is that the CPU usage remains low when playing the same files through Keynote. This should be confirmation that something is going on with the Quicktime player itself. The CPU load doesn’t ramp up on any other Mac without a TouchBar, so it seems like that’s the culprit.
I've submitted a bug report. I encourage you to do the same. This is unacceptable behavior for a core system application and use case. The Touch Bar is bad enough when it's just being unhelpful; it's unacceptable when its very presence impacts core system functionality.
same thing happens on my 2018 MBP 15
High CPU usage on QuickTime Player?
