GE AR . CAMERA CODECS
“The most uncompromising approach is to record
uncompressed images, as was
RAW CODECS It’s a reasonably safe assumption that much of the data-reduction mathematics in the more recent ProRes Raw is similar to non-Raw options, so electronic devices can more easily implement both in the same chips. Atomos has made an art out of very full-featured recorder-monitors capable of recording ProRes Raw; a feat common in early stages of digital cinematography”
requiring not only appropriate recorder engineering, but also detailed technical liaison with camera manufacturers. The Ninja Cast has it both ways, providing recording in ProRes Raw and streaming to more conventional, AVC-based distribution. Compressed Raw codecs, despite their recent popularity, actually go all the way back to Cineform Raw in 2002. Now open source, Cineform is used by Kinefinity, among others. The underlying approach is broadly similar to JPEG and ProRes, although built around wavelets – more complex wave shapes than sine waves, allowing for better compression, again, at the cost of computer workload.
Coming to an amicable resolution Separating brightness and colour mimics the behaviour of the human eye, which sees brightness more sharply than colour. In analogue broadcasts, colour was always a hitch-hiker on the black-and-white signal – and the same has persisted into digital. The resolution relationship between the two is often given as ratio: 4:2:2 indicates that, for every four brightness pixels, there are two pairs of colour difference pixels. While 4:4:4 implies there is no subsampling at all. This is colour subsampling. Such a fundamental part of modern image handling, it’s often considered separately from compression codecs. Red’s Redcode uses similar techniques. With the company’s stalwart dedication to sheer resolution, it has been challenging for some users to meet the high computing power demands. Red has shipped plug-in boards specifically intended to accelerate the process. Modern GPU-based workstations have made the extra hardware unnecessary. But the success of Red’s cameras, as well as the company’s contribution to the
HEAVY HITTERS Arri Alexa 65 (above) and Blackmagic Ursa Mini Pro 12K (below)
50. DEFINITIONMAGAZINE.COM
Powered by FlippingBook