Playback Speed - 2x or 3x or 4x

Almost at all times, I find myself sliding the playback control to speed up the video playback to get a sense of what happened -- it might be nice to have an option to playback 2x or 3x or 4x -- so, when I review the video -- it's automatically 'fast' and I can see what happened in 30 seconds versus 1.5 minutes -- also, maybe these 'fast playback videos' could be automatically downloaded to my phone so it's faster to watch what happened-- maybe these fast videos could be smaller in size? Also, maybe an option to download these fast playback videos (which might be smaller in size) over wifi -- so If I'm at a friends with wifi.. and I want to quickly see what is going on at home... the videos are already on my phone due to wifi.