Microsoft Mobile has brought a new video editing app for Windows Phone 8.1 devices. The app known as video tuner lets you trim, crop, rotate, flip, mirror, and speed change of the videos using basic tools. In more advanced features, you can add music to your video and adjust the volume to suit particular scenes. You can adjust the exposure, contrast, and saturation levels. do that, too. There are some handy effect filters as well it seems.
Check the video tuner in action in below video and click on the installation link to get it on your device,