One aircraft is taking off and another is quick to land after it. Are they within safe limits?
They're not too close
They (almost certainly) are not closer to each other than is allowed.
It would be quite extraordinary if a pair of airliners at an airport were allowed by air-traffic control to approach each other in violation of limits, which not only include the distances of time and space demanded by safety, by additional margins as well.
If there had been a violation of those limits, it would have recorded as a matter of course and investigated.
On that basis I think it's safe to say that it's extremely unlikely that approach limits were violated.
The camera doesn't lie, but YouTube doesn't tell the truth either
A second point is that it is extremely hard for human beings to judge distances, positions and speed in three-dimensional space.
Frankly, it's a wonder that we're ever able to play table-tennis, but the fact is that when you're looking at a pair of aircraft you have little chance of accurately judging what they are doing in relation to each other.
That's especially so when the aircraft are on YouTube. I bet even a champion wouldn't be able to play table-tennis on YouTube...