Hi,
I have a dash cam that saves files in H264 or H265. When I take these files to my M1 Max MacBook Pro, they play very choppy in Quicklook, not at all in Quicktime Play and very very badly in iMovie.
The identical files on my 2015 MacBook Pro play perfectly...
It won't play or transcode on my M1 Ultra using FCPX 10.6.3 or Resolve Studio 17.4.6. It also won't play on my 2017 iMac 27 using FCPX 10.5.2, so the issue is not unique to Apple Silicon. On the M1 Ultra it also will not transcode using EditReady 22.2.1, but it can be transcoded using Handbrake 1.5.1 using either x264 or the x265 software encoder.
The file is HEVC using the Main 5.1 profile, 8-bit 4:2:0, 6.775 mbps, nominal frame rate 29.97 fps but frame rate mode is variable.
It was apparently encoded using a Chinese chipset from Hisilicon. My guess is it does not adhere to the proper encoding spec so it's simply "luck of the draw" about what software will and won't work. There is no "codec police" to enforce this, so any software or chipset can encode whatever they want with virtually no testing. Broadcasters and streaming providers typically validate content with utilities like Zond 265:
https://www.solveigmm.com/en/products/zond/
I don't have that utility (it's expensive) but seems plausible that clip would fail validation. This situation is typical with various security cams, dash cams, etc. The solution is not to put special workaround cases for each manufacturer into all software but the hardware manufacturer must test their encoding and validate it on common video software.