Don't lag behind in background tab (chrome63+)

[ferreus]

Since Chrome63 automatically pauses html video only media elements, that creates a lag from real time stream when the user returns to the tab.

I wanted to always show the current video data for real time streams.

This seems to work pretty good, but i'm not sure if that's the right approach.

[mburger81]

Hello, are here any news about this problem?

[zhongqc]

For this issue, I inserted a repeated empty audio data.
But only passed in a few hours of testing.