it depends on the data. considering the kind of data your working with is one of the least mature media in the analytics industry (video), it might be both significantly more cost effective and likely to produce a high-quality result if you buy the dataset. That said, if you were thinking of spinning up an in-house data annotation resource, this might be a good opportunity to go that route, and I'm sure the ML team wouldn't have any complaints if you gave them a persistent data generating resource like that.