TV-BAY Magazine
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Metadata rules When it comes to re-purposing and monetizing archive footage, digitization is essential. But for all its obvious benefits, long-term preservation in this new file-based world is not without its quandaries, as Will Strauss reports….. R egular readers of this column will know that I am frequently tasked with covering the sexiest of broadcast industry subjects. Indeed, just two months ago I got to discuss test and measurement (T&M). Well, if you thought that was intense, just wait for this month’s topic. Not only is it potentially even less glamorous than T&M, it has the potential to be an instant cure for insomnia. Unfortunately, it’s also a hugely important subject if you’re talking about storage and archive (as this issue of TV-Bay is). What am I talking about? Is it a gizmo? Is it a widget? Nope, it’s metadata. Hold on to your hats. This is going to be wild. Now, before I wade into the metadata stuff, let’s give this article some context. Whether owned by a broadcaster, a producer or a library, a content archive isn’t just a historical record of its acquisition efforts and its televisual or filmic output. In many cases it is its biggest asset. The exploitation of archive content is a big thing. Rich media content is in demand and, if you can make it available quickly and easily, archive footage and programmes can be re-licensed for a myriad of uses from historical documentaries and primetime clip shows to one-off mobile downloads. To make this happen, more and more archives are being digitized, turning film, tape and digital tape into files. This allows for instant retrieval and exploitation, micro payments, process automation and more. Yet, while digitization is a must, I see two major inconveniences when it comes to long-term preservation of file-based media: the choice of format that the footage should be archived in; and the amount of metadata required for it to be at its most useful. Currently, television is produced by anything from a smartphone to a 4k camcorder, in any format from mp4 to AVC-Intra. The commonly held belief is that you archive in the highest quality possible. Which would be AVC-Intra. But in several years time another format will be in vogue. So, 46 | TV-BAY MAGAZINE if we archive in AVC-Intra now, in order to re-use that content in the future, we would need to match it up with the ‘new’ format. To this you would have to transcode the AVC-Intra. And when the next format comes round after that, you would have to transcode it again. Is that a problem? Well, um, yes, because as each transcode takes place the content gradually gains coding impairments. And if you’re compressing or re-compressing it, you get even more impairments. This is far from ideal. What may be required (please don’t shoot me) is ANOTHER format. An agreed format that we stick to for archiving purposes. It must be one that is high quality, lossless, open, widely adopted and easy for future computer systems to recompile. The suggested format should be either lightly compressed (in order to keep storage requirements realistic), lossless compressed or completely uncompressed and it should be wrapped up in something like MXF. John Zubrzycki, the Section Leader for Archives Research at BBC R&D has done a lot of good work on this subject. He urges archive owners to “work together to present common requirements to industry” and argues for what he calls a “light compression standard” that can be used for SD and HDTV archiving. This would avoid the need to recode footage every time production moves forward. Which makes a lot of sense. So, that’s a potential solution to the format problem. What about this here metadata stuff then? In the new file-based world that TV now inhabits, metadata rules (pun intended) and the efficient implementation of metadata is key to content management and file-based workflows. Technical metadata is used, for example, to drive entire MAM systems or playout operations and, without it, some files simply won’t work properly in certain devices. While descriptive metadata (shot length, content, music type etc) is what interests humans and is the information required for indexing and archiving, monetizing and more.