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Where Next for Video Codecs?
As broadcasters and operators move into a streaming-first delivery strategy, codecs like HEVC, AV1, VVC, and EVC show the way forward for reduced bitrates for immersive and ultra HD content

Video compression is a crucial element of broadcasters' and pay TV operators' business; after all, it's what allows them to deliver content to audiences. However, as demand for high-resolution video content increases, the broadcast industry has had no choice but to innovate with new video compression techniques and has begun looking to new solutions to produce further advances in compression. With developments in codecs continuing apace, to fully understand where codecs are heading it's necessary to firstly explore their origins and the current codec landscape. 

Mainstream Codecs: MPEG-2 and AVC

At present, there are two mainstream codecs: MPEG-2, the historic codec used for SD and the first digital deployment, and H.264, otherwise known as Advanced Video Coding (AVC), which was established for the transition to HD. These standards-based codecs have proved to be the two most successful so far and were both primarily formulated for the broadcast market. Initially, International Telecommunication Union (ITU) standards like AVC were designed with TV in mind and have since been extended to over-the-top (OTT). As such, neither codec lends itself to being used for streaming; however, they could be the solution for converged services. 

With streaming overtaking traditional broadcast, the need for new codecs has become apparent and broadcasters and pay TV operators have begun to develop new codecs, including High Efficiency Video Coding (HEVC) and AV1. Yet as broadcasters look to the future, they must remember that a huge number of people are still consuming HD and, therefore, they must continue to pay attention to existing codecs and continue to invest in renewing older codecs to ensure they are still meeting the needs of most audiences. So as work continues on newer codecs, broadcasters and OTT providers should use what they learn from these developments to improve older existing codecs and enhance the viewing experiences of all audiences. 

Emerging Codecs: HEVC and AV1

HEVC was originally seen as the ITU successor to AVC, but its pace has been slowing down owing to limited 4K penetration and royalty issues. Compared to AVC, HEVC delivers high-quality 4K video that is at least 50% smaller than before. A different option has emerged in the form of AV1, which is a royalty-free OTT-centric alternative to HEVC, supported by giant tech groups including FAANG through the Alliance for Open Media. AV1 has been designed primarily with OTT, and therefore progressive scan, in mind which makes it the optimized choice for this type of service.

Whether a broadcaster or pay TV operator uses AV1 or HEVC is dependent on their needs and existing infrastructure, as there are similarities between the two. For example, both provide similar bandwidth efficiency compared to AVC—in the range of 30% to 50%, depending on the resolution. The advantage of AV1 lies in its main value proposition of being royalty-free. Currently, AV1 is seen as the "codec of choice" for streaming media distribution and is supported by the likes of Amazon, Google, and Netflix. 

Codecs Under Development: VVC and EVC

Codecs are set to change even further as the broadcast industry develops new standards to handle new resolutions and more sophisticated content types. One of the codecs currently in development is Versatile Video Coding (VVC) which the Joint Video Experts Team (JVET) expects to be finalised this year. VVC capabilities are expected to support immersive content, resolutions from 4K to 16K and 360° videos. Meanwhile, Essential Video Coding (EVC) has been fast-tracked by MPEG to provide a “licensing-friendly”standardized video coding solution to address business needs, such as video streaming. 

Beyond the usual commitment of reducing the bitrate by 30-50% compared to previous standards (in this case HEVC), it's too soon to determine the exact benefits and advantages of VVC and EVC. Nevertheless, these new codecs are likely to shake up the market over the course of this year and beyond, bringing with them a degree of complexity. As each is due to be set in stone at some point this year, it may take until next year or even 2022 before it's possible to ascertain if they will find their market. 

The Future of Codecs

With each codec boasting different properties, some more suited to streaming and others to traditional broadcast, and with every broadcaster or pay TV operator having different infrastructure and legacy systems, it's unlikely there will be a clear "winner" in the codec domain. Instead, there will be several dominant players per niche. In this scenario, due to the infancy of the standard, its core technology DNA and its supporters, AV1 might cement its position as the "codec of choice" for streaming media distribution, while it's likely that H.264 and HEVC will be among the most popular codecs in use.

The continued development of new and next generation codecs will have a positive impact on all areas of broadcasting as the learnings and technologies generated begin to be used to improve codecs both old and new. Consequently, in the future, all viewers will benefit from an enhanced experience, whether they are watching content in HD or 8K. 

[Editor's note: This is a contributed article from ATEME. Streaming Media accepts vendor bylines based solely on their value to our readers.]