Yes, they are, but keep in mind that external playlists are static, therefore you cannot not work with protected links.
Dynamic inline playlists
Alternatively, S3Media Stream 6.6 has a dynamic inline playlist feature which enables you to create private streaming playlists up to 20 media within your articles, making sure each expiring link is created on the fly. It has the option to set HTML5 fallback videos for mobiles.
However, in version 7, this no longer works because JW Player 7 doesn't allow more then one RTMP streaming link in the embedding code. We will repurpose this feature in later releases, but for now it is disabled.