Hello guys, I recently bought a go pro and recorded some video in 4k but I can edit it as my MacBook pro drops frames like crazy during playback let alone trying to edit it in either Quik or Final Cut X. I guess I'm missing something and would like some help.
It is difficult to edit 4k H264 smoothly on almost any hardware or software. It is common that it will lag or drop frames -- whether Premiere or FCPX, even on a 12-core Mac Pro, most recent iMacs, including the iMac Pro.
FCPX is faster than Premiere at this because Premiere does not yet use Quick Sync hardware-assisted decoding on Macs. However even FCPX is not perfectly smooth.
The top-spec 2017 iMac 27 is probably the fastest current machine for this and can usually edit one stream of 4k H264 in FCPX fairly well, though not with perfect smoothness. The 2015 and earlier iMacs are slower/laggier, likewise the 12-core Mac Pro, and the 2015 or 2016 top-spec MacBook Pro. The 10-core Vega 64 iMP is about equal to the 2017 iMac in editing smoothness on 4k H264 8-bit 4:2:0 material.
If you set the FCPX viewer to "best performance" that helps a little. If you edit the 4k content in a 1080p project (aka timeline) that also helps some.
However the only thing that makes it really fast is creating proxy files or optimized media. Of those two proxy files generate a lot faster and take a fraction of the space. You edit with viewer in proxy mode, then before final export set the viewer to optimized/original and export. Otherwise your exported video will be at proxy resolution.
