Alternatives to Handbrake?

I once tried as you suggest but found VLC failed on a few of my files - not sure why, may be they were just too old or legacy Window versions (suppose coding has changed a lot over the years) so always had to come back to Handbrake. Saying that Robert might have better luck.

It's worth noting Handbrake has now moved on and is at v1.0.3 so that might also be worth a retry - be aware if upgrading from v.0.10.* varieties they recommend not to do it through the app but instead direct from the site (I deleted the old first before dragging new into place just to be sure).

This might also be worth a read http://www.makeuseof.com/answers/limit-handbrakes-cpu-usage/ (it is for Win XP and therefore old!) because it discusses using the RF slider and/or adding code into the Advanced tab (once enabled) to limit processor use/reduce number of cores (assume the ":threads=1" command could be changed to 2 if using quad core machines to halve the cpu usage). Saying that they do also think dust might still be the problem (as per Limnos), you could "attacked" the back of the machine around the vents with a vacuum/soft brush - be gentle though 😁

What version of HandBrake are you using? Get the most recent version from HandBrake: https://handbrake.fr/downloads.php

I'm using Handbrake on my 21" iMac 2013 with no issues, certainly no sudden shut downs - I did however install after updating to Sierra.

Before you jump ship have you tried deleting App an reinstalling - if you download afresh from developers web site you will also ensure you have latest version (v0.10.5) which is shown as compatible with 10.6 to 10.12.

Worth a try if you haven't done so already.

(Opps, Bob got there before me).

Do you monitor your computer's temperatures? It could be the intense CPU activity is causing the computer to overheat and it is shutting down to prevent damage. When I use Handbrake it saturates the computer's CPUs and my computer temperatures are at standard maximum. Normally a computer should be able to handle this but if your computer is dusty or the fans have stuff on the blades it could be overheating. Even though my computer can handle it I also run a utility that clamps down on Handbrake's CPU usage (of course it takes longer to process) so my computer also runs a bit cooler.

I think Limnos may have the answer. That sudden shutdown could be caused by excessive heat.

CPUthrottle. You have to run it in a Terminal window. It takes a bit of understanding and configuration of the .sh script file. I have it set to only allow Handbrake to run at about 50% of my total CPU capacity ("100%" for my dual core machine) which leaves the rest for CPU greedy Firefox and a bit left over for other tasks. Of course that essentially doubles the processing time for videos. It also means my computer runs a bit cooler but if yours is really shutting down because of overheating you should look into that because it shouldn't normally, even at full CPUs.

It could also be you are seeing this because you upgraded to Sierra. I don't know if there's any basis for claims but with any OS upgrade there's always claims of computers running hotter, so if on top of this you are also running a CPU intensive application... You could see what the crash logs say, or maybe Etrecheck might pick up on something.

http://www.etresoft.com/etrecheck

Using Etrecheck - https://discussions.apple.com/docs/DOC-6174

If you saved your OS installers, you could install an OS that worked better with Handbrake on another hard drive and test to see whether the problem persists.