Low-complexity compression enables 4K and even 8K upgrades without heavy investment in new infrastructure explains Jean-Marie Cloquet, manager of Barco Silex video division
High quality video formats offer a better viewing experience, so they will take a growing share of the market. But they also threaten to make part of the current infrastructure obsolete and force you to invest in more bandwidth in your IP network or more expensive SDI cabling in the studios. Unless you can make clever use of video compression.
Take the production infrastructure, for example. There is a trend towards transporting video over IP networks, and IP is gaining ground in the SDI-dominated contribution channels. The Joint Task Force on Networked Media (JT-NM) also aims to build future production environments based on Ethernet/IP networks.
But Ultra HD video at 60Hz requires up to 12 Gbit/s – too much even for the widely supported 10 Gbit/s Ethernet. So should you consider deploying even higher bandwidth network infrastructure such as 40Gbit/s? Or postpone your Ultra HD plans?
Not necessarily. Adding a lightweight, low-cost compression to your equipment can save the day. With a 4:1 compression, it would even become possible to transport up to three channels of 4k60 video in parallel over a 10 Gbps link. Likewise, a mezzanine compression can also upgrade legacy SDI infrastructure. It would allow, eg. to transport 4k60 video over 3G-SDI, or 1080p60 video over a common HD-SDI.
At Barco Silex, we have been comparing compression codecs, looking for the one that is best suited to upgrade the installed video hardware. A clear champion is SMPTE 2042, also known as VC-2, and more precisely to the High Quality Low Delay profile.
VC-2 LD was originally conceived at the research labs of the BBC. As a line-based intra-frame codec, it achieves latencies down to a few image lines. And it uses the same mathematical wizardry – wavelets – also used in JPEG2000, ensuring the highest quality compression available.
But as VC-2 targets low compression rates, it avoids the complexity associated with JPEG2000. The codec also allows setting a wide number of parameters to find the best trade-off between compression efficiency and complexity for any given application.
A key distinguishing feature of VC-2 is that it is a standardised and open technology, designed to avoid patent infringements. So it can be easily included in video production equipment as a hardware or software solution, without the potential costs, legal uncertainties, and practical difficulties of including other comparable codecs. Also the transport of VC-2 is under standardisation and will ease interoperability of the broadcast equipment.
So for those in the AV industry that are confronted with the choice between an expensive bandwidth upgrade or postponing to offer Ultra HD, there is a middle way: a light upgrade of your equipment to add low-complexity compression. VC-2 LD has all that it takes for a smooth transition to 4K, whether on IP networks or over SDI links.