Saturday, February 9, 2013

H.265


The H.265/HEVC Standard is Probably Coming Sooner than Later


hevc-h265-logo



High Efficiency Video Coding (HEVC) or H.265 is a new video compression standard that is being developed by a Joint Collaborative Team of ISO/IEC MPEG and ITU-T VCEG (JCT-VC) for a while already as the successor of the currently very widely adopted H.264 (AVC) standard.

The H.265/HEVC has now entered in its final standardization stage and is probably going to be fully approved as a standard very soon, though it will take a while before it becomes widely available in all kinds of devices as the H.264 already is. The final Draft 10 has been presented a few days ago and had received first stage approval (consent) in the ITU-T Alternative Approval Process, so it can be just a month away from getting approved, and a the same time MPEG also announced that HEVC is entering their Final Draft International Standard (FDIS) status which can take two months to have it approved as an International Standard. And if you are wondering why it is important to have the successor of the H.264 standard approved and getting implemented in both software and hardware sooner than later, then you need to think about things such as 4K HDTVs (the standard supports up to 8K), HFR 3D (HEVC will support higher framerates) and other new technologies and products that are going to have more demands in terms of video resolution and storage/bandwidth requirements.

The original idea behind the HEVC is to improve the compression efficiency by a factor of at least two compared to the H.264/AVC compression standard for the same content retaining the same quality and though that goal might not be achieved in all conditions, the results demonstrated from the not yet fully finalized new HEVC compression standard are very promising. Of course the reduction of the bitrate requirements while retaining the same level of quality can only be achieved by increasing the complexity of the algorithms used for the compression and decompression of the video. This means slight increase in the time needed to compress HEVC/H.265 video as compared to H.264, but the decoding process is what will be more performance demanding, especially when going for higher resolutions than 1080p. Of course we are probably going to be getting hardware acceleration for encoding/decoding as well as dedicated hardware made to handle the extra load in devices such as HDTVs.

Now, you may be wondering how is H.265/HEVC going to be important for you in regards to stereoscopic 3D video support. Unfortunately the current Draft 10 does not cover stereoscopic 3D support, though such is going to be available via extensions of HEVC in order for it so also fully support stereoscopic 3D as well as multiview video and other more advanced features such as 12-bit video as well as 4:2:2 and 4:4:4 chroma formats, but we may have to wait until January next year for these extensions to become available. That should not worry you as you are not going to see H.265 available everywhere overnight, it is a process that will take a few years and meanwhile H.264 will most likely remain as the standard, the speed of adoption depends a lot on the industry and how soon H.264 will start hitting its limits a lot, so that the adoption of the successor may be speeded up. But for now we are still at least a month or two before the H.265/HEVC gets its final approval.

Now you can find a lot of similarities here between the H.264 and the upcoming H.265 standard and that is normal as the new one builds on top of the old one and further improves on some features as well as adds new ones. And similar to how the Multiview Video Coding (MVC) extension of the H.264/AVC standard was added as a means to ensure high-quality and resolution 3D video over a medium such as Blu-ray 3D, the upcoming H.265/HEVC will have a similar extension using the Multiview Video plus Depth (MVD) format. The new MVD format is going to be addressing one of the drawbacks that MVC has and that is to be able to provide multiview data for display on autostereoscopic 3D displays in a standardized way without having to increase that much the bit rate required for encoding the additional views. The 3D HEVC extension has been proposed to MPEG and VCEG and was chosen as the starting point for the development of an HEVC-based 3D video coding standard, but as already mentioned this will take some more time. The idea behind the H.265/HEVC and the 3D HEVC extensions relying on MVD is to ensure that the new video compression standard will be future-proof, so it will not only provide features that we are starting to get the need for at the moment, but also support for features that might be required in a few years from now.

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