Using InstaChooser, you will be able to import videos from your device’s Camera Roll right into Instagram. This allows you to mix and match video created outside of Instagram along with the service’s own video authoring tools.
After installation, you’ll notice a new button on the video authoring page for importing video from the Camera Roll. The design of the tweak leaves much to be desired, as it sticks out like a sore thumb next to Instagram’s slick UI. Importing video is fairly seamless, even if you do have to deal with ridiculous prompts each time you wish to insert an outside clip (see our video above to see what I mean).
InstaChooser does feature a preference panel, but it contains nothing more than a simple kill switch, and that kill switch requires that you close out of Instagram each time you use it. Again, it’s not the most elegant experience, but this is pretty much the only option for those that wish to insert outside video.