Impossible Software is a video advertising solutions provider. Their products enable advertisers and content producers to customize videos on demand, in real time, tens of thousands of times per hour. With web-based tools, clients can create video templates, including motion tracking and formatting, and then push them onto production delivery infrastructure. Impossible Software offers three levels of API: the real-time rendering API, a RESTful media management API, and a JSON-formatted video scripting language.
ffmpeg - it's free, but a lot of developers discover that it's neither as functional nor as scalable as they need. The care, feeding, and development burden thus draws significant resources away from their core application and UX.
A feature set that's grown through experience with real projects.
A team to watch the infrastructure to ensure delivery.