No, you have evidence, not proof. The judge decides who is more believable.
What do you want to achieve by showing the video's? Two lines of thought about the wrist slashing is why you didn't help rather than stand and film, why didn't you remove the kids from the situation. Better to have a transcript rather than video.
re: Family violence - it can be important - but only if relevant, and you will need to demonstrate why your kids will be at risk.
It is hard work, and it should be hard work to cut out one parent. You just have to play it smart and not do silly things like show videos that have the potential to show you in just as much bad light as the mother.
We have explained why videos can backfire but we haven't seen the videos and can't give an informed answer. You are the one that needs to decide keeping in mind both the content and risks.