You sure? The old native app could do this.
Actually, I think the Jasmine app can do background streaming
It seems like any app can play music in the background. I have pasted some info from developer.apple.com for reference.
Yup, audio can be played - that's not a problem. But audio directly from videos (effectively leaving the video playing in the background) wont work. Basically they would need to split the tracks, and provide audio as a separate feed. Whilst this can be done, it would be a bit of a pain in the ass to implement, and always has the odd quirk every now and then, the most common issue is keeping the audio and video in sync when you switch to and from the video feed.