1. B4A doesn't support rtsp protocol yet. Will it be possible later?
2. How to "jump" to middle of playing file? Ex: playing at 1:23, how to jump to 2:45?
1. MediaPlayerStream is a thin wrapper over the native MediaPlayer object.
Which means that Basic4android supports the exact same protocols that Android supports.
2. The native support for seeking doesn't work properly on most devices. If you like you can use the Reflection library and call seekTo method.
VLC media player probably doesn't use the native MediaPlayer support. As I wrote in a different thread there is no list of supported streaming protocols in Android documentation. Try searching for MediaPlayer and rtsp. You will find many similar questions with some possible helpful advices.