Hello,  
I just came across your topic that is very close to the problem I'm having, maybe you can help me ?  

Equipment used :
- Phantom 4 Pro V2.0
- Mavic 2 Pro
- iMac 2013 under macOS High Sierra 10.13.3
- MacBook Pro 13 '' Touch Bar 2017 under macOS High Sierra 10.13.3
- Videos edited in 4K @ 30fps  

Preamble:
Using the Dlog profile on my drones, I am now forced to choose the H.265 format to enjoy the Dlog profile on the Mavic 2 Pro.  

Encountered problem :
First, you can not read M2P output H265 files on the Macbook Pro without lagging. But no problem on the iMac with Quick Time. Secondly, I am surprised that the H265 format file is the same size as the H264 format (135 MB for 10 sec in 4K @ 30fps). I thought that the H265 was lighter?  

Solutions:
I did the test to read files H265 edit with the P4P on the MacBook Pro and there it works! I tried with different drives, but still the same problem.  

Do you know why I am experiencing this problem and do you have a solution?  

I join you by link of download my video in H.265 of the M2P: https://transfernow.net/970ga1o4d953  
Thank you in advance for your answers

All I can tell you is, that your H.265 test video runs smoothly on my mid-2015 MacBook Pro (2.8 Ghz i7 with 16 GB RAM & AMD Radeon R9 2048 MB).

I always stick with H.264, sorry.

I’ve also been having issues with the MP2’s H265 files on a 2016 Macbook Pro (13 Inch). I don’t own the drone, by have been trying out straight from camera files offered by several youtubers.  
I’ve come to the conclusion that it’s the combination of 10bit footage and H265 footage that seems to choke the system. Any Dlog or HLG footage  (10bit) will not play without skipping frames in both Quciktime and FCX. The normal picture profile (8 bit) plays smoothly (even in H265).
The system I’m using has a 6th gen CPU (skylake), which also does not help things, I believe Kaby Lake and newer will perform better.
H265 footage from an iPhone X or GoPro also plays no problem.

Dlog and HLG can only be recorded in 10bit H265, so I guess the only solution if you’re looking to use these profiles is to create proxies or convert to Prores, both of these have resulted in smooth playback and scrubbing for me.

Thank you for your answers, that's what I thought.
Still amazing that the DJI Crystalsky screen reads without problems the videos and not the MacBook Pro !
I hope DJI will release H264 for DLog !

My MBP 15" 2017 reads OK, seems like human error on your side....

fansba9ba94c Posted at 2018-8-31 05:48
Thank you for your answers, that's what I thought.
Still amazing that the DJI Crystalsky screen reads without problems the videos and not the MacBook Pro !
I hope DJI will release H264 for DLog !

Crystalsky is likely playing the downlink video, not the full-res.

I can read it on the screen Crystalsky dji by inserting the MicroSD card directly and the quality is at the highest.

I have a Macbook Pro 13 "touch bar 2017, maybe the 13" is not powerful enough?

fansba9ba94c Posted at 2018-8-31 10:03
I can read it on the screen Crystalsky dji by inserting the MicroSD card directly and the quality is at the highest.

I have a Macbook Pro 13 "touch bar 2017, maybe the 13" is not powerful enough?

Does your MBP have a dedicated video card?  Memory installed?

MacBook Pro (13 pouces, 2016, quatre ports Thunderbolt 3)
Processor : 2,9 GHz Intel Core i5
Memory : 16 Go 2133 MHz LPDDR3
Video card : Intel Iris Graphics 550 1536 Mo

fansba9ba94c Posted at 2018-8-31 10:26
MacBook Pro (13 pouces, 2016, quatre ports Thunderbolt 3)
Processor : 2,9 GHz Intel Core i5
Memory : 16 Go 2133 MHz LPDDR3

So, you don't have a dedicated graphics card.  Your CPU is your GPU. 16GB memory is. . . Eh.  It will be slow..  Plus, it's an i5.  Those are why you are having these issues (slowness).

Okay, thank you for enlightening me. Hoping that DJI gives the choice in a future update to be able to record in Dlog in format H264.

Sorry to be the bearer of bad news. .  I hope DJI will provide that option as well.

Just use your iMac for post. My 27” iMac performs well (dedicated graphics card, latest i7 with 32GB memory.) I am in the process of upgrading memory to 64GB.

Thank you it's nice to have helped me.
Good continuation.
Looking forward

fansba9ba94c Posted at 2018-8-31 10:55
Okay, thank you for enlightening me. Hoping that DJI gives the choice in a future update to be able to record in Dlog in format H264.

You're not going to get 10 bit data in H264 at 100mbps bandwidth.

Yes but it's still a machine for the general public, it's not like an Inspire, Matrix see a Phantom. DJI could have left the choice of the 8 bit in H.264.
Finally what surprises me is to be able to read the videos on my Crystalsky screen and not on a MacBook Pro 2017 for almost $ 3000 !

my iphone x plays smoothly h265 10bit. My macbook (i5 - 2,9GHz, 8GBRAM) choking 10bit H.265 movie from 2 Mavic Pro.

I just stumbled upon this thread, so apologies for dredging up a month old problem  I tried out my new MP2 today and I am so happy with it, but the H.265 files will not play smoothly on my 2017 MacBook Pro! I am truly astonished that a Mac from only last year cannot play these files. My 27" IMAC from three year years ago plays them so smoothly.
It is pretty damned poor that Apple have manufactured and sold us these very new machines but they are incapable of playing H.265 files. Let's face it, MacBooks are hardly the cheapest!
Anyone solved this issue? Or indeed, can it be solved without having to buy yet another MacBook?

dawidm Posted at 2018-9-15 03:38
my iphone x plays smoothly h265 10bit. My macbook (i5 - 2,9GHz, 8GBRAM) choking 10bit H.265 movie from 2 Mavic Pro.

It's all about dedicated hardware. The iPhone X is build around HEIF and HEVC (H.265) image processing in the A9 chip. Desktop processors are still catching up to the new format.

Mac hardware is always 2-3 years out of date.
Later generation intel chips support h265 acceleration but older generations dont.

An i5 is really not great and a 2017 mac could easily have a 2015 processor.  Might be a 6th or 7th generation only.

fansa3119acc Posted at 8-18 09:45
It's all about dedicated hardware. The iPhone X is build around HEIF and HEVC (H.265) image processing in the A9 chip. Desktop processors are still catching up to the new format.

iPhone X uses A11 Bionic not the A9 (and yes huge differance, A11 has neural networking ASIC and huge step up on GPU and CPU and lower power usage).   

in terms of hardware decoding, H.265 is supported on fairly outdated hardware.    the issue is more down to intel and nvidia who like to make these seem like premium things.   everyone else even apple has at least put in HEVC/H.265 decoders in hardware for quite a long time now i mean iPhone 5S with its A7 chip in 2013 can do HEVC decoding..    hell i had an old radeon card from 2012 that can do HEVC/H.265 decoding in hardware.   

encoding, that's another story only in the last 3 or so years has it been mainstream accessible with hardware acceleration without needing specialized hardware or to chew up a ton of CPU for a hybrid solution..

I have a 2017 13" Macbook pro base 128gb model 16gb DRAM with the Intel Iris Plus Graphics 640 1536 MB graphics card. I have absolutely no issues playing back H.265 4k 30fps files. I've recently also upgraded from High Sierra to Mojave - still no issues.