The Future of Encoding is Almost Here: HEVC (H.265) is Coming to 1 Billion Devices
The advancements in lossy video encoding have been both consistent and amazing. H.264 (or AVC), that much maligned DSLR de-facto codec, sought to yield improved quality over its predecessors such as MPEG-2, all the while using half the bitrate, or lower, than such earlier codecs. Now, High Efficiency Video Coding or HEVC — likely to earn the alternate title H.265 — seeks to do the same compared to H.264, once more halving the bit rates necessary for equivalent, or even higher, quality. As it turns out, the tech world is already saturated with devices set to support HEVC playback.
The general model of functionality that makes this sort of thing possible is basically ‘smarter’ compression, which produces media with a smaller storage footprint at a higher quality — though this methodology means comparatively heavier processing intensiveness to decode in real time. Basically you sacrifice ‘weight’ in bits for harder ‘thinking’ in order to translate the more complex compression techniques. Everybody from the ISO/IEC‘s MPEG to the ITU-T‘s VCEG, among others, are poised to declare HEVC a jointly and universally accepted standard.
For what this palpably — and visually — means for the future of delivery encoding is demonstrated in the video below. Some may find a little irony in the fact that the clip’s 1080p version is very likely encoded in H.264 (but the differences are still pretty clear).
In terms of efficiency, HEVC Main Profile (or MP, one of the codec’s sub-specs) shows over 35% improved efficiency over H.264 High Profile (the sub spec favored for broadcast and Blu-ray) in terms of peak signal to noise ratio. To accomplish this, HEVC uses a number of compression ‘tools,’ some of which are advancements over H.264 principles, others of which are new — the major example of the latter is HEVC’s optimization for parallel processing, which basically means you can decode multiple parts of the media at the same time. Additionally, one of the mainstays of this type of codec, the macroblock, has expanded from H.264′s maximum of 16×16 pixels to a potential 64×64 — other key facets such as prediction (spatially and temporally, in all kinds of directions) is also present.
One of the wildest features of this codec is something called internal bit depth increase. Here’s an excerpt from Wikipedia, with the source citations left inline in case you case want to read the various documentation floating around:
Internal bit depth increase (IBDI) allows for pictures to be internally processed at a bit depth that is higher than the bit depth they are encoded at. IBDI can be done at up to 14-bits and is processed at that bit depth up until the point where the pictures are fed into the loop filters.
It’s tough to say right now whether upcoming DSLR models will be switching to HEVC for video encoding. If they do, that may not actually be a good thing for DSLR filmmakers, because even though it means you save storage space while improving quality, more complex compression tactics mean potentially longer transcode times, or perhaps a messier situation for pushing the grade. That said, it’s always nice to raise the quality ceiling of web video, where this codec will likely be seeing most of its action.
HEVC should also play a role in broadcast as well. While much of the TV world has switched to MPEG-4 encoding, they will surely be looking forward to a new standard that decreases bandwidth requirements, especially since this means they can add more channels and increase overall quality as they lower bitrates. HEVC will factor in to the adoption of 4K broadcasts and streaming as well. Much of the talk has been about the massive increase in bitrate for 4K, but the new H.265 standard will likely halve this requirement, and make broadcasting Ultra High Definition far more feasible within current limitations.
Either way, we’re going to see plenty of devices that already support the codec when it finally hits primetime. According to Videonet, “iPads are among the 1 billion CE devices shipped in 2012 capable of decoding HEVC.” We’ll have to wait for all those tongue-twistingly-titled standards organizations to settle things next year before the codec starts to roll out.