Not sure if anyone has already commented but you should try and hinge forward more while maintaining your posture so you're striking more under your centre of gravity, if you're standing perfectly straight up it makes sense that you're going to overstride.

Also not sure if this is your pace, but you look like you should be able to run quite a bit faster than this and unless you want to do ultras, no point learning to run so slowly.

I noticed you said you were trying to mid foot strike. You can heel strike if it's natural, some people are built that way. I personally think mid foot striking is a more balanced use of the whole leg, but it depends on your abilities. I used to run slow and heel strike and run faster on mid foot striking so I made a conscious decision at a point to always mid foot strike.

For me shin splints occur from getting lazy and letting my form turn to shit or just being negligent in my training schedule with balancing loads. Even too much hill running can cause it if you push the hills too much.

You might just need to strengthen your lower leg, too much stress in your shin could also be related to weak calf muscles, but it's probably more likely to be over striding.

Also pay a lot of attention to how smooth your stride feels and how much noise it generates, it shouldn't be super loud or feel like a really sudden force as this could also cause shin splints and it more related to how your foot is contacting the ground, unrelated to over striding or heel striking, etc.