With roughly four times the pixels of standard HD footage (8.3 million versus 2 million), 4K footage offers remarkable sharpness, a great sense of depth and a much subtler color range. As 4K is quickly becoming commonplace in the footage business, we thought we'd ask a group of experts, including Carol Martin of FootageBank, Sterling Zunbrunn of Nature Footage and Peter Carstens of Framepool, to weigh in on the ins and outs of working with this exciting format.
Footage.net: What are the two or three most critical things a client needs to know about obtaining and using 4K stock footage?
Carol Martin: Size, size and size. The large file sizes have an impact on storage space needed, delivery options and viewability. Assuming a high-end codec is being used to preserve as much data as possible, the files will be cumbersome in many ways. Whatever editing system is being used, a lightning fast processor will be needed to view the clips, storage space will burn up at roughly three to four times the rate of HD, and files are generally too large to transfer over the internet.
Sterling Zumbrunn: 4K has to be seen to be believed. Once you move past screens that are 70 inches or larger, the differences are unmistakable. The additional resolution is a massive leap forward over HD. That said, 4K takes serious computing horsepower to work with. Even just viewing 4K footage at full resolution requires a computer with a fast processor and strong graphics card.
Peter Carstens: The client should consider if a 4K format is needed indeed, or is it just a trend or something he has heard of. The 4K shots can also be delivered in 1920x1080. The client also needs to consider higher production/editing costs, longer download times for master footage, and huge file sizes which are not easy to handle or to view.
FN: Given the dauntingly large file sizes, how do you deliver 4K footage to clients?
Carol Martin: Hard drive transfers are preferred. One to two small files can also fit on a Data DVD.
Sterling Zumbrunn: We deliver 4K+ files to our clients via our FTP server, but the files are so large that the speeds available are not adequate for transferring media in a reasonable timeframe. For this reason, we have invested in Aspera technology, which allows for peer-to-peer transfers using nearly 100% of available bandwidth. This is going to make it easier for our contributors to submit their 4K+ files, and it will deliver a better experience to our clients accessing their purchased clips.
Peter Carstens: Most shots are delivered via FTP like all other footage. Growing Internet speeds (and possible compression formats) make this possible. So far, we're able to provide 4K to the remote places of the world. In specific cases, and if the amount of shots exceed somebody's download possibilities and patience (since it would have to be done overnight, or even longer), 4K footage is delivered on hard drives.
FN: Is all 4K footage the same or are some versions of 4K better than others?
CM: As with any video format, codec is key to quality. A 4K file in the H.264 codec, for example, may have the aspect ratio of 4K but not an acceptable resolution for some end users. The cameras that capture with the least compression create the largest but highest resolution files.
Sterling Zumbrunn: There is a big difference among various 4K cameras. Consumer cameras such as the GoPro or the new Panasonic GH4 capture footage in a highly compressed format that is not optimal for many of our clients' needs. Further, the GoPro only captures at 15 frames per second, so the clips must be sped up. It's not a serious solution for 4K capture. The industry has gravitated toward the RED workflow, and nearly all of our clients request RED R3D RAW files when they are available. The advantages of starting with a raw file are numerous, as it offers colorists incredible flexibility for matching the look of their production while maintaining maximum quality. The RED DRAGON promises to deliver the best quality yet at 6K resolution, which is an astonishing 19 Megapixels per frame. Clients working on IMAX features and other large format film projects are excited about the additional resolution.
Peter Carstens: While people talk in common about 4K, the 4K standard image sizes for cinema and consumer TV (UHDTV) vary. Various clients have been asking for 4K in different sizes, but sometimes it was just a mistake since people still have to adjust to the new high-end format. The final 4K format to be delivered depends on the production type or depends on what the producer wants to achieve. Important is not only the size, but the technical recording parameters and technology.
FN: Is demand increasing for 4K?
Carol Martin: The demand for 4K is steadily increasing. Just like television was protecting for future HD delivery fifteen to twenty years ago by preferring access to film elements, many productions are currently protecting for future 2K and 4K delivery by accessing those formats when possible, even if the end product is not currently being delivered in 4K.
Sterling Zumbrunn: Demand is quickly increasing for 4K+, among all sorts of clients. We are in the process of re-acquiring all of our subjects in 4K. It's a great opportunity for cinematographers to re-shoot existing content.
Peter Carstens: Yes, with 4K TV prices falling, the consumers constantly wanting to have better picture quality, and channels now creating 4K VOD outlets, the demand for 4K is growing quickly. In order not to miss out in the future distribution of their productions, producers adapt to high end formats if costs are feasible.
FN: What kinds of clients are asking for 4K?
Carol Martin: Primarily feature films are asking for 4K. Secondarily, venues such as museums have embraced the format for its ability to stun the viewer in an educational setting. Some aesthetically higher-end television shows are currently being produced in 4K and some television shows which have proved hugely popular are using 4K for archiving reasons, even though neither are being broadcast in 4K yet.
Sterling Zumbrunn: All kinds of clients are asking for 4K. Theatrical clients always want 4K to deliver maximum on-screen quality. But even broadcast clients want to future-proof their productions in the event that they have the opportunity to repurpose it. We are also seeing growing demand from businesses and consumers that want to feature 4K displays for video decor.
Peter Carstens: Movie productions (cinema) and shots for CGI/VFX work, but also often TV movies, and high end corporate productions, as well some commercials.