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The evolution of video codecs

Remi Beaudouin, Chief Strategy Officer, ATEME
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When it comes to broadcast and Pay TV operations, video compression is essential in delivering content to audiences. However, as the demand for high-resolution video increases, the need to advance video compression techniques is becoming unavoidable. It’s clear that innovation is the key to evolving compression methods and meeting demand – but to truly understand and influence the future of codecs, it’s vital to look at their origins and the existing requirements for video compression within the broadcast industry.


Existing codecs

There are currently two mainstream codecs, MPEG-2, the historic codec used for SD and initially 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. ITU standards like AVC were designed with TV in mind and have subsequently been extended to over-the-top (OTT). Therefore, neither lend themselves to use for streaming, instead, they could be the answer for converged services.

With the popularity of streaming overtaking traditional broadcast, the need for new video compression technology has become apparent, which has led to the emergence of new codecs. However, while broadcasters are bound to look to the future, it’s vital they don’t forget about the widespread HD audience. As such, existing codecs shouldn’t receive less attention, as they’re still essential to the delivery of this content. Rather, learnings must be taken from these developments to improve older existing codecs to ensure broadcasters are able to meet the needs of most audiences who are still watching standard HD television.


Next generation codecs

High Efficiency Video Coding (HEVC) was originally seen as the ITU successor of AVC, however, 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. Consequently, it is the optimised choice for this type of service.

Whether a broadcaster or Pay TV operator uses AV1 or HEVC is very dependent on their needs and existing infrastructure as there are similarities between the two. Currently, AV1 is seen as the ‘codec of choice’ for streaming media distribution and is supported by the likes of Amazon, Google and Netflix.


Shaking up the market

As the broadcast industry develops new standards to handle new resolutions and more sophisticated content types, codecs are set to change even further to support the rise of OTT consumption and the resulting advancements in technology. One of the codecs currently in development is Versatile Video Coding (VVC) which the JVET expects to be finalised this year. VVC capabilities are expected to support immersive content, resolutions from 4K to 16K and 360 degree videos. Meanwhile, Essential Video Coding (EVC) has been fast-tracked by MPEG to provide a ‘licensing-friendly’ standardised 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 early to ascertain the exact benefits and advantages VVC and EVC could offer. Regardless, these new codecs are likely to shake up the market in 2020 and beyond, and bring with them a degree of complexity, particularly as each of them are due to be set in stone over the course of the next year. As a result, it may take until next year or even 2022 before it’s possible to determine whether they will find their market.


The next decade and beyond

Over the next decade, it’s likely H.264, HEVC and AV1 will be among the most popular codecs in use. Given each codec has different properties and that every broadcaster or Pay TV operator has 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. Due to the infancy of the standard, its core technology DNA and its supporters, AV1 will perhaps cement its position as the ‘codec of choice’ for streaming media distribution.

Improving the landscape of codecs – both old and new – hinges on the learnings and technological innovations taken from ongoing advancement works. So, whether viewers are watching video content in 8K or HD, every audience will benefit from continual enhancements; future-proofing the viewing experience and ensuring that no consumer group gets left behind.

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