I started using side by side video analysis for ski teaching over 15 years ago. It's great. I have not used a small form (tablet/phone) screen for skiing because the larger screen makes it a lot easier for the untrained to see the details I'm trying to point out. I also use the highest optical zoom I can so that I can get decent length clips while still getting the skier to be 1/2 to 2/3 of the frame even from the start. I haven't seen tablets or phones that can do that yet. That said, the ability to give more immediate feedback on snow vs having to go inside and see stuff on a PC screen is a plus for a phone/tablet. For me, the ability to control the slow motion speed over exactly the specific frames I want is the biggest plus over "regular video". You need to have a steady shot with the skier taking up most of the frame for the student for this approach to work well.
My secret for cold weather operations was to keep the camera in a case and limit the exposure time when filming. With video cameras filming a group of 5-10 people for 3 clips each and then going inside I never had a problem. For a smartphone, I'd consider using a charcoal heat pack to help recharge the camera warmth in between takes. But you do have to be careful with the potential for wild temp changes to introduce condensation inside the device.
A GoPro with playback on 12" tablet/notebook screen might be the perfect solution.
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I'm going to move this to our video forum, but leave a 30 day redirect here.
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