2017 BroadcastAsia Submission
by Tom McDonald, Technical Marketing Quantum
Virtual reality (VR) 360° video is creating new film, television and gaming experiences that enable audiences to control where their attention is focused. This is arguably the most significant change in the audience viewing experience since the advent of film.
Changing a 100-year-old paradigm is not without technical challenges. Answering the call first were visual effects
(VFX) artists. With a strong skill set in compositing, an understanding of 2D and 3D space, and a flare for the dynamic, VFX artists were the first to tackle VR post-production. The challenges of camera stitching, rig removal and panoramic image manipulation require many of the same skills.
Because VR 360° is a new medium, production budgets often are limited. VFX artists often are called upon to create compelling visuals to fill the void. Skilled artists can create a posse of 20 cowboys in a scene when a budget might support only three. A realistic ocean backdrop can be added to ship-board scene without requiring a drop of water.
Addressing the Demands of VFX and VR 360° Video
To create images that surround the audience, images from multiple cameras must be stitched together into a large panoramic image – the equivalent of 6K or 8K resolution image. For content targeting high-end head-mounted displays and 3D stereoscopic, finishing resolutions can be even higher. The challenge lies not only in having fast enough storage to support these large images, but also in meeting the storage requirements of editing and color grading VR 360°, which often differ from the demands of VFX and animation.
Editing and grading require storage arrays that provide unblinking sequential playback of ordered frames on disk. Visual effects and animation can require both sequential and random performance.
Fibre Channel storage area networks (SANs) are favored for sequential playback of large frames and files because SANs deliver deterministic, guaranteed bandwidth to each connected workstation. For animation work, file reads and writes are smaller, but occur randomly, and from a greater number of connected workstations. Random storage performance is most economical using an IP-based network attached storage (NAS) system. The “best effort” nature of IP protocols matches well with the iterative nature of animation, which does not typically require sequential playback of large files.
A Unified Approach
In practice, though, maintaining two different storage systems can be expensive and lead to costly duplication of large files. This is why some post facilities are turning to unified storage, a combination of SAN and NAS. By supporting both IP and Fibre Channel connections to the same shared storage infrastructure, this approach allows post facilities to avoid the time-consuming network-based transfer of files between workflow stages. It both minimizes down time and gives artists more time to create.
The random performance required for animation work can be further enhanced by solid state drives (SSDs), which use flash memory instead of spinning disk. Elimination of the time needed for drive heads to find file bits means that SSDs can deliver anywhere from 10 to 100 times more random performance than hard disk drives (HDDs).
All-flash arrays offer exceptional performance, but they can be expensive. A more affordable option is a hybrid array: a combination of SSDs and HDDs. Intelligence in the array controllers monitor the most readily used files and keep them in the flash storage portion of the array. If files are not used in a given time period, they are demoted to the more economical HDDs in the array.
Bridging the Editorial Divide
The efficiency gains from unified storage can be a big boost to VR 360° post. Artists are happier and more productive because creative software responds faster. They can create engaging content on time and on budget. Facilities that take advantage of this creative approach can start with a small unified storage configuration and then increase performance and capacity as needed. With such a flexible, powerful storage solution, content production companies can fulfill their viewers’ wildest visual dreams today and be prepared for the next big technology to take them even further in the future.
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