Since 2003, H2.64 has been the compression scheme of choice. It however is outdated, ergo a replacement was paramount and that is how we got High Efficiency Video Coding.
The idea of HEVC video transmission is to deliver content with the same picture quality as H.264 but with better compression so there’s less data to deal with. HEVC is the future of 4K broadcasts.
Over the course of this article, I will be going through everything about HEVC compression. PS I may occasionally refer to H.264 as Advanced Video Coding.
Evolution of Compression Schemes
With broadcasts, the amount of raw data from the professional HD cameras is massive and there is no way to deal with it all. What’s left to do is compress it to reduce the amount of data to a more manageable form.
In the past, most compression schemes do the job but more often than not, the content ends up being reduced in quality which isn’t so cool. Highly compressed videos before and after uploading will be average in quality at best. Heavy compression can keep the resolution the same although the image may appear softer or noisier.
This problem has necessitated better and smarter compression. Smarter and better compression basically finds better ways to reduce the amount of data in the original content without sacrificing quality.
Every few years the processing power of compression gear has improved to allow for more processor-intensive compression algorithms to broadcast live events without reducing image quality.
HEVC
Image quality in 4K is absolutely crisp and clear which makes 4K even more data intensive than plain HD. HEVC can seamlessly handle 4K video resolutions vis a vis Advanced Video Coding.
How does it do it?
A HEVC video broadcast is at half the bitrate of AVC because HEVC allows video to be compressed at half the bitrate of H.264. Half the bitrate equals double the efficiency delivering significantly better 4K video quality. I have been throwing around the term compression a lot so let me explain what video compression does:
Compression
Compression works on one principle: find out what doesn’t change in consequent frames. In a TV talk show for instance, the shot is constantly the head of the host and their background rarely changes in most of the frames.
You could even make a case for most of the pixels representing their face not changing bar their constantly moving lips of course. Compression encodes an initial frame and then only what is changing instead of encoding every single pixel from every frame. This is how compression works and it is important when you want to broadcast live events.
What Does HEVC Do After Encoding?
HEVC then expands the size of the area that’s looked at for these changers. You may have noticed some blocks in your image when the picture goes haywire in a live broadcast. In a HEVC video broadcast, those blocks can be bigger, smaller and differently shaped compared to older compression schemes. It is worth mentioning that larger blocks were found to be more efficient.
Why We Need HEVC Video Transmission
HEVC promises an improvement in video compression compared to earlier compression techniques. Since the inception of AVC in 2003, digital video has become increasingly omnipresent and the standard has been HD, at the very least. These trends necessitated more efficient compression techniques ergo H.265.
Some other trends that HEVC addresses include:
- Increased use of video resolutions beyond HD which definitely increased the burden on both networks and storage.
- Continued improvements in technology meant improvements in processing capacity so it no longer made sense to use outdated compression techniques. In fact, a mobile device in 2013 is likely to have more computing power than a computer from 2003.
- Widespread use of digital video at constantly increasing resolutions.
