Unfortunately, the soundtrack on this video is quite bad, so there is not much that could be translated. As it seems, these two migrants had been arrested for some kind of illegal activity, and the police officers were waiting for something – probably a prisoner transport.
Unfortunately also is that there is apparently no official police report on this incident, but from the original source and the comments it seems that the video was taken in June 2016 at Gelsenkirchen main train station.
The police officers in dark blue uniforms are federal police that are responsible for security at main train stations and airports. The officers in light blue uniforms are state police.
Over the course of the video, the arrest draws more and more attention from the public, but especially from other migrants who then threaten the officers.
The mob can be seen at minute 5+