Advanced Protocols – H264 vs H265

2019-12-05T11:51:03+01:00December 4th, 2019|

In recent years the real revolution within the web landscape is the amount of multimedia content that is exchanged. In fact, today most of the internet traffic concerns the use of videos and therefore of streaming. Statistics for 2018 state that 58% of world traffic regards the downstream of video content. One of the elements that contributed to this evolution was undoubtedly the spread of higher bandwidth internet connections, with the ever increasing availability of fiber connections or fast adsl, and mobile connections , that are moving developments with the 5g future.

It is not just a question of infrastructure, but also of new protocols: in fact, the search to find the best compromise between bandwidth and video quality is continuing. To date, the most promising protocol to become the new standard for encoding multimedia content is called HEVC/H.265, surpassing today’s de facto standard H.264.

HEVC/H.265 allows a 50% reduction in the space needed to store the video as it uses efficient coding to encode it, maintaining a high level of image quality.

TechnologyRequested Band for 4K Broadcasting
H.26432 mbs
H.26515 mbs

 

To know more, go to this link.

The HEVC/H.265 standard has already been described and finalized, but is not yet widespread. The new video codec in fact has two limitations that to date do not yet allow its massive diffusion: the first is legal as it is under patent of various companies and therefore requires a high licensing fee, the other regards the computational cost, in fact encoding using HEVC/H.265 takes about ten times the computational cost of the H.264 codec.

It is probable that the same process has been taking place previously with the H.264 codec, which launched in 2003 only became widespread years later, when all the various hardware manufacturers began to insert specific decoders for this format. There are software that allow the decoding of HEVC/H.265 software, but this solution makes the decoding in terms of computational time and battery consumption in the case of mobile devices very expensive.

Both video compression codecs work by comparing the differences between consecutive frames, identifying those constant common areas. These image areas are then replaced with information describing the original pixels. The big difference between HEVC/H.265 is the ability to expand these areas (called CTU coding tree units) dynamically, with sizes ranging from 4×4 to 64×64, while H.264 is limited to a maximum of 16×16. However, the improvement of segmentation and spatial prediction requires more computational capacity for the encoding part, while it does not impact too much on the decoding part. HEVC/H.265 is also able to reference blocks of pixels within the same frame (intra prediction) or in different frames (inter prediction).

Even desktop virtualization systems have always benefited from the improvement of streaming systems. From a technical point of view, the technologies used are very similar. For this reason, from version 7.16, Citrix, in its XenApp and XenDesktop product has introduced the possibility of using HEVC/H.265 encoding for desktop streaming.

The setup requires having an NVIDIA card capable of supporting HEVC/H.265 encoding (go to the link). Generally speaking when it comes to enterprise installations, graphics cards that can allow multiple access to their computing power are very expensive, but to have a test lab it is not really necessary to have one of these graphics cards. It is possible to use a consumer NVIDIA card and access the physical PC via the Citrix Workspace App and Desktop.

For the setup of the test environment using HEVC/H.265 encoding I followed this link. In the diagram, instead, I report the hardware/virtual components used.

In the example, the final result of the setup. Connecting through the App workspace, I can play 4K resolution videos without problems.