Most serious DSLR or MSC video shooters use either Adobe Premiere Pro CC or Apple's Final Cut Pro X to edit their footage; however, Avid's Media Composer has long been the editing suite of choice for TV and movie professionals. Now, the company has made a slightly scaled-down version of its pro tool, called Media Composer First, available to download and use for free.
The free version works in most respects pretty much the same way as its pro cousin, and only comes with a few limitations in terms of image resolution and available editing tracks.
There are four video and eight audio tracks, and exports are limited to Quicktime H.264 or DNxHD file formats at 1080p resolution and a frame rate of 59.94 fps. So if you're looking to output 4K video Media Composer First is not for you, but you can input 4K files if some of your raw footage was recorded at high resolution.