Purpose:
Hardware Decoding can provide better decoding performance and lower CPU usage when playing the HD videos during live view or playback.
You can switch the icon 
of Hard-Decoding Preferred to 
to enable decoding by hardware for live view and playback.
Notes:
- The Hardware Decoding requires iOS 8.0 or higher version; otherwise this option will not be shown.
- For hardware decoding, it supports resolutions of 704*576, 704*480, 640*480, 1024*768, 1280*720, 1280*960, 1920*1080, 2048*1536, and 2560*1920. For other resolutions, it will switch to software decoding.
- For H.265 video compression, the hardware decoding is not supported.
- The hardware decoding function should be supported by the device. If not, it will adopt software decoding by default.