Purging, prefetching and setting a Cache Expiry Time of videos
Please note that the CDN caching of CDN Video, CDN Video Push and CDN Live services is fully under our control and you can't modify its settings. In particular you can't purge and prefetch your videos.
The Cache Expiry Time is set dynamically based on a popularity of your videos. Videos which are frequently played are cached for longer time than less popular videos. Every video file is cached for at least 24 hours and if it is not played for more than 24 hours then it expires from the CDN cache.
Please refer here for a streaming which allows to control the CDN cache.