If you are using After Effects or Adobe Premiere, there is a free plugin that you can use to automatically reformat footage into any aspect ratio. Atomic Stretch offers optimally bounded real-time stretching that can convert to and from any aspect ratio.
Atomic Stretch enables real-time video-retargetting in After Effects and Premiere, converting from and to any aspect ratio
The plugin does much more than scale the image to fit the new format. Re-projects the footage to fit the target aspect ratio. The results are really nice, too. There are options for having a tracking protected center, and to dim and desaturate the edges of the footage. The plugin might be great for reformatting vertical video, or older footage too.
The plugin is absolutely free and works on both MacOS and Windows systems, with After Effects and Adobe Premiere versions CS6 and higher.
Visit Atomic Image Labs to download the free Atomic Stretch plugin. [Via Mylenium]
