Since the first 4K content appeared, there has been one common problem – 4K weighs too much. The future of 8K Ultra HD is better left unmentioned. We need huge disk arrays for storing raw material and unreasonably large ones for storing the final product and its promotion on optical media or on the Internet. Therefore, two years ago, work on the development of a new coding standard was accelerated, and the result was H.265, also known as High Efficiency Video Coding (HEVC).
The fields of application of this new standard are primarily broadcast television, multimedia and video surveillance. The new codec is an important key to the transition to higher image quality and will help reduce the load on networks. At half the bitrate, H.265 delivers the same visual quality as current H.264 / MPEG-4 Part 10 Advanced Video Coding (AVC), which currently compresses most video on the Internet. For example, online movie theaters now use a bitrate of about 4-6 megabits per second for 1080p/30 compressed H.264 video streams, while equivalent quality H.265 compressed images will sort of drop to 2-3 megabits per second. In fact, the figure of 50% primarily refers to relatively uncomplicated scenes where there are no sharp contrast drops and there is no intense movement of objects and backgrounds. The real numbers on arbitrary video are probably close to the 30% mark, but even this improvement is pleasing.
The HEVC standard will kickstart a new phase of innovation, from mobile devices to Ultra HD television. The changes will also affect video content collections in online movie theaters, VOD, OTT systems, and the like. And in addition H.265 will be the basis for encoding video on the already announced 4K Blu-ray discs.
We would like to focus on the main innovations of H.265 in order to cast aside all doubts about the origin of the standard and the version that it is just another marketing gimmick. There is no such a technological leap as between MPEG-2 and H.264, and old-school H.264 still has some powder in its powders.
The main improvements are as follows:
- Support for resolutions up to so-called 8K Ultra HD (8192 x 4320 = 35 megapixels).
- Maximum block size. In the H.264 standard it is 256 pixels (16 x 16), while in the H.265 standard the maximum size is 16 times larger (4096 = 64 x 64). In H.265 the block size is selected by the algorithm itself during the encoding process depending on the content of the encoded image.
- Parallel decoding capability. Unlike H.264, H.265 decoders allow separate and simultaneous processing of different parts of the same frame, which fully utilizes the advantages of multi-core processors and significantly speeds up playback.
- Clean Random Access (Clean Random Access). A randomly selected frame of the video sequence is decoded without the need to decode any images that precede it in the stream. H.265 does not require inserting intermediate reference frames (I-frames), which also significantly increase the bitrate of the video.
- 10-bit color coding and high color quality provided by the “upper” Main 10 profile. All existing standards offer only 8 bits. HEVC technology can also be used for photography (instead of 8-bit JPEG you can save the picture with a much smaller size and raise the sampling rate to 10 bits, which will give the picture a smooth gradation of brightness and colors).
- H.265 provides for automatic detection of the scan type, but is initially focused on progressive video processing (up to 120 frames). However, no problems arise in working with interlaced scanning.
And in conclusion, a few words about the timing of this mini-revolution. How long does it take for H.265 to become popular and affordable? In my opinion we are talking about 2-3 years. Chips for H.265, due to its sophisticated mathematical base, need better performance and more power than in the case of H.264. But as of the fall of 2014, the first smartphones with 4K video capture with HEVC encoding are already appearing, in the near future all consumer DSLR cameras will be equipped with the new chip, and then mid-priced TVs and media players will follow. By 2017, H.265 will become the standard for streaming movies and clips on online services like Netflix and YouTube, and then there will be no need to worry about the fate of the codec.