With the recent kerfuffle about Quicktime on Windows, I'll pile on here with this post.
First, what I mean by DSLR, phones etc in MOV. Specifically I am referencing a MOV file which contains AVC (H.264) video and PCM or AAC audio.
The Quicktime AVC decoder seems to be fubar with respect to performance relative to the native AVC decoder built into Hitfilm. Now Quicktime forces apps like Hitfilm to jump through hoops just to be able to use it and that incurs an additional overhead but DNxHD done via Quicktime MOV and seems to be fine so that extra overhead appears to not be critical. So I fall back to the Qt AVC decoder being subpar.
On my machine I can take some Panasonic GH4 UHD MOV files and Hitfilm fails miserably trying to play those back. If I rename the files to MP4 to get Hitfilm to use its native AVC decoder the files playback fine. All else is equal. I can reproduce this with a Canon 7D2 1080p60 MOV file. My machine is pretty stout and most AVC plays fine but 60p in HD or 4K pushes it over the edge and thus my two referenced examples.
Even if your AVC file plays fine the rename will save you some CPU cycles which may help in system performance.
For those who wonder how the rename can work. MP4 files are 99.9% the same structure as Quicktime MOV files.
Back in the Hitfilm 3 days I suggested to FxHome that they bypass Quicktime for AVC+PCM/AAC type MOV files and decode those natively since they already have those decoders. This is not a unique idea. Sony Vegas does this and maybe/likely others as well. First, you can import common files without the need for Quicktime and all of its baggage. Second, apparently the Qt AVC decoder sucks performance wise.
Here is a Windows batch you can use to easily rename files since the Windows file explorer makes this process a bit tedious. You can save this in a file named "rename MOV to MP4.cmd". It has two modes of operation. You can select a number of files and drag and drop them onto the icon for this script and they will be renamed. Or you can drag and drop a single folder onto the script icon and all MOV files in the folder will be renamed.
EDIT: Here is a link to a ZIP file which contains two windows scripts. One to rename MOV to MP4 and the other to rename MP4 to MOV.
EDIT: Added M4V to MP4 and MP4 to M4V rename scripts.
Here is the text of a script to rename from MOV to MP4.
if exist %1\ goto folder
ren "%~dpn1.mov" "%~n1.mp4"
IF errorlevel 1 goto errorF
if NOT %1$==$ goto top
REM switch to passed directory
for %%I in (*.mov) do (
ren "%%I" "%%~nI.mp4"
IF errorlevel 1 goto errorD
echo !!! file rename error !!!
echo !!! folder rename error !!!