If it were me, I could put up with this if my brother sat us all down and said "look, these are her issues, I know it makes things difficult sometimes, but these are the things that set her off and I appreciate your help and patience managing it."
She's not a misbehaving spaniel, she's the woman he has just married! 
OP, your SIL sounds rather like my SIL (DH's brother's wife). In the case of my SIL/ILs, I see both sides.
SIL is a retiring middle-class introvert from another country, who has married into a large, extrovert, talkative, party-minded working-class clan. Both parties mean very well, but continually misunderstand one another.
My ILs are deeply involved in one another's lives, live close to one another, talk about 'private' things, see one another all the time, and like nothing better than getting together for a massive takeaway and cards session at which everyone teases one another mercilessly.
SIL if she's visiting (she and BIL live in another country, as so DH and I) is exhausted after half an hour of this, the decibel level freaks her out, she finds some of the accents difficult to understand, is upset by the banter (though not directed at her -- she once got very upset when her DH was being teased by his brother about his hair receding), and can't understand why PILs idea of hospitality is to turn the radiators up, shout questions, and offer her vast amounts of food every ten minutes.
My ILs, on the other hand, can't understand why she visibly hates every second, picks at her food, answers in monosyllables, and goes to bed at the earliest possible moment, why she and BIL didn't have any guests at their wedding, why they don't visit more often, and find her snobbish, stand-offish and no fun (and also blame her for the fact that BIL, a former wild child, is now a bit of a dullard.)
I'm very fond of my ILs, but it certainly took me a while to get used to their massive levels of interaction, the sheer noise of their gatherings, and the fact that they are not very good at imagining other ways of being. No one is at fault, exactly.
OP, is it possible something similar is the case with your SIL? I agree with pps that the mot obvious explanation for the wedding video thing is that she hated how she looked, or wasn't happy with how the day went, and doesn't want reminders in circulation. I don't think that's wildly unusual, tbh.