Better might be to use an HTML parser (or something like HTML::LinkExtor) and simplify what you have to look at.

(?:(?<!video).)+ is wrong.

for my $re (
   qr/"(?:(?!video).)+"/,
   qr/"(?:(?<!video).)+"/,
   qr/"(?:.(?<!video))+"/,
) {
   print("$re\n");

   for (
      '"...video..."',
      '"...video"',
      '"video..."',
      '"video"',
   ) {
      print("$_: ", /$re/?1:0, "\n");
   }
}
[download]

(?-xism:"(?:(?!video).)+")
"...video...": 0
"...video": 0
"video...": 0
"video": 0
(?-xism:"(?:(?<!video).)+")
"...video...": 0
"...video": 1        <----- XXX
"video...": 0
"video": 1           <----- XXX
(?-xism:"(?:.(?<!video))+")
"...video...": 0
"...video": 0
"video...": 0
"video": 0
[download]

(?:(?!video).)+ and (?:.(?<!video))+ should be equivalent. You can do benchmarks to be sure.