Motion Capture at 4K and Beyond
High resolution capture is beneficial even when the output resolution is reduced. Advantages include better image quality, but also extend to less familiar areas including creative flexibility, post-production, prints and future-proofing. This article summarizes how each of these aspects is influenced.
Better resolution has been a primary goal of technological advances in consumer video and cinema over the past several decades – from VHS to DVD to Blu-ray. With the recent push toward even higher resolution displays, such as Apple’s Retina devices, this trend is expected to continue. In those situations, higher resolution is clearly beneficial for detail and realism.
On the other hand, resolution also has other lesser known benefits – many of which apply even when the output resolution is reduced. A common workflow with television has been to capture at 4K or higher, but to downsize this for 1080P display. One’s initial reaction might be to think that all the original resolution has been wasted, and that one could achieve an equivalent result by just capturing at 1080P in the first place. However, as the applications below will demonstrate, that initial reaction would be a mistake.
First and foremost, downsized or “supersampled” images simply look better. They typically appear cleaner and with fewer artifacts, and have a more three-dimensional quality due to better micro-contrast and MTF. A 2X downsize often reduces image noise similar to a 1-stop reduction in ISO speed with traditional film, for example. Other defects, such as lens imperfections and image processing artifacts, are also made less apparent. The net result is that video codecs have a better input image, which improves bandwidth efficiency and quality – even when sharing at a small size online.
Note: Above comparison was made using a high ISO setting on a noisy digital video camera. Noise will be much lower with RED®, although the quality improvement from downsizing will be just as pronounced.
A higher resolution master expands the post-production possibilities. For example, one can crop to create an altogether different composition, or a tighter telephoto framing. Alternatively, one can intentionally pad the frame around a moving subject to decrease the chance they’ll accidentally fall out of frame. The end result is that re-shoots are less likely – reducing costs and production time.
Still frames from 4K+ video are well-suited for professional quality prints at a wide variety of sizes. This is particularly helpful when a fashion video will also be used as a stills photo shoot, or when movie frames need to be pulled for full-page magazine advertising. Such cameras effectively merge the roles of photographer and videographer. See shooting video for stills for techniques to improve results.
VFX & STABILIZATION
A higher resolution master gives VFX artists more to work with. Zooms, pans and other camera movements can be simulated in post-production without having to physically move the camera. Even pronounced vibrations or other unintentional camera movements can be minimized without sacrificing output resolution, for example. Similarly, corrections for lens distortion and perspective are less detrimental to image sharpness. Keying at a higher resolution is also more accurate, and can be critical with hair or other highly detailed green screen foregrounds.
When parallel cameras are used to capture stereoscopic footage, non-overlapping portions of each frame have to be cropped out. Having higher resolution frames minimizes this resolution loss – especially for subjects that need to extend further in front of the screen.
High resolution capture enables future re-releases on newer formats – improving the monetization potential of existing footage. We’ve already seen this happen with DVD and Blu-ray editions of past movies – often creating a substantial stream of additional revenue. With a future that will likely include internet delivery to high resolution displays and projectors, having higher resolution files will become more important than ever.