What Lies Ahead for Video Codecs?
As demand for high-resolution video content increases, broadcasters are looking to implement new solutions which produce further advances in compression. Consequently, the video codec landscape is going through significant changes as new codecs begin to emerge and existing ones undergo development. So, which codecs are currently available and how is the offering likely to change in the coming years?
Da die Nachfrage nach hochauflösenden Videoinhalten steigt, sind die Broadcaster an noch effzienterer und besserer Videokomprimierung interessiert. Daher exisitiert eine dynamische Videocodec-Landschaft, da neue Codecs aufkommen und bestehende weiterentwickelt werden. Welche Codecs sind derzeit verfügbar und wie wird sich das Angebot in den kommenden Jahren voraussichtlich verändern?
At the moment, there are two mainstream codecs within the broadcast industry, MPEG-2 and H.264. MPEG-2 is the historic codec used for SD and the first digital deployment, while H.264, which is also known as Advanced Video Coding (AVC), 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 codecs lend themselves to being used for streaming, however, they could be the solution for converged services. As streaming overtakes traditional broadcast it has become apparent that current codecs aren’t sufficient to keep up with changes in viewing habits. This has led to new codecs being developed, such as High Efficiency Video Coding (HEVC) and AV1.
However, while there is a need for broadcasters to look to the future, they mustn’t neglect older codecs, in order to meet the needs of the large audiences that are still consuming HD. So, as work continues on newer codecs, the broadcast industry should use what it learns from these developments to improve older existing codecs and enhance the viewing experiences for all viewers.
Originally seen as the ITU successor of AVC, HEVC hasn’t gained pace as expected due 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.
With a number of similarities between AV1 and HEVC, which one a broadcaster or pay-TV operator uses depends largely on their needs and existing infrastructure. For instance, both provide similar bandwidth efficiency compared to AVC – in the range of 30–50 % depending on the resolution. Where they differentiate is that AV1 is royalty-free, which has resulted in it being seen as the ‘codec of choice’ for streaming media distribution and is supported by the likes of Amazon, Google and Netflix.
Codecs in development
Further changes to codecs are expected as the broadcast industry develops new standards to handle new resolutions and more sophisticated content types. This has led to the development of Versatile Video Coding (VVC) which is 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. Other than reducing the bitrate by 30-50 % compared to previous standards (in this case HEVC), it’s currently too soon to determine the exact benefits and advantages of VVC and EVC. Despite this, 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 finalized over the course of this year, it might not be possible until next year or even 2022 to ascertain if they will find their market.
Which codecs will triumph?
Right now, it seems unlikely there will be a clear ‘winner’ in the codec domain owing to each codec having different properties, being suited to different content types, and every broadcaster or pay-TV operator having different infrastructure in place. The likely outcome is that there will be several dominant players per niche. With this in mind, 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 H.264 and HEVC will also 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.