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A Brief Introduction to AV1 Codec

Here is the champion, named "HEVC", who has dominated the codec tournament for more than 5 years. His coach, the grandmaster "MPEG LA" stand behind the stage, pride and confidence, expecting for the next knock out. And here comes a new challenger, the "AV1, Rocky Balboa" for the next generation of Video Codec standard, step to the stage, with the cheer and triumph from his supporters, those "Tech-giants".

The battle is about to begin.

AV1 is the newest video codec launched by the Alliance for the Open Media (AOM). It was first released on 28 March 2018 along with a software-based encoder-decoder as the reference. The initial validated version (1.0.0) was shot out on 25 June 2018, and their pace of updating & evolving to the codec is quick as lightning. Several codec versions were released and some notorious issues for early access versions have been significantly improved. For the year 2020, with only 2 years of R&D, the AV1 has become a quite usable codec with many exciting new features. Many consider the AV1 will dominate the video and streaming market in all probability.

AV1 codec

Why and how this new codec does progressed so agile? They are not something out of nothing. The AOM (Alliance for Open Media) was the man behind the curtain. Established in September 2015, AOM was founded by the leading browser service companies: Google, Mozilla, Apple and Microsoft, along with hardware vendors like AMD, ARM Intel and NVIDIA. Also, Amazon & Netflix joint the birth of this new codec. With all big names on board, Av1 adapted Google's previous VP9 technology and got the utmost support from all AOM alliance members, make AV1 evolving within an uncatchable speed and very promising to become the new standard for a world of content.

These are the core & symbolic characteristics in which differ from H.264, HEVC (H.265), also the main competitor of AV1 codec.

The most eye-catching spot for AV1 is its open and royalty-free strategy. It has become a controversial topic and unraveled the ambition that AOM wants to encroach the market share of HEVC codec, which released in 2013 by the MPEG-LA organization. Why the AOM need to take such an aggressive action against the HEVC from MPEG-LA? There are both technical and market concerns.

The MPEG-LA has dominated video codec standard for decades. A capable competitor did not appear until 2010 when Google VP8 joined the game. Established in the year 1988, the MPEG LA has accumulated a tremendous amount of video codec patent with a gigantic patent pool. As one thing to remind, their patent fee is just about insane.

MPEG-LA and Core Patent
MPEG-LA and their core patent was controlled by non-U.S. companies

At this time, American leading tech companies are united to seek a new codec standard to bypass the existing MPEG codec patents, from an economic view, that will cut off a great amount of cost for online video/streaming contents providers like Google and Netflix. In conclusion, "Royalty-free" is their most distinct competitive advantage when compared to HEVC. Their "patent free" slogan has also attracted periphery companies to release their AV1 applications & add-ons, for example the Radiant media, Digiarty soft, or Mpv player, so on and so forth.

HEVC vs AV1

On the other hand, as a long-run, fully developed codec structure, HEVC codec can hardly adapt its self to modern internet transmission tasks. HEVC is not specifically optimized for internet video transmitting & data storage purpose and end up a result that hardly do improvement on it due to its original purpose (video codec for the broadcast market and streaming irrelevant). With the fact that streaming services are overtaking the previous broadcast business, service providers are eagerly seeking for a compact video format with comparatively decent graphic quality to pose the bandwidth solutions.

AV1 vs HEVC

The technical advantage that AV1 has, with its Achilles's heel in some domain, has become the topic discussed for a long term. Various debates are surrounding the argument that if the AV1 is a codec that capable for the future, with my answer is positive.

Let it be clear: objectively if we need to measure the performance of a codec, we need to check in both two dimensions:

• Bitrate compression capability: with the same graphic quality setting, how compact the digitized video file could be achieved. In another term, a video file is at the highest compress rate, how good the graphic quality could be presented.

• Encoding, decoding: The encoding capability will present on the time taken to encode the raw clip to computer playable video format, it is not acceptable for content creators if it takes forever to encode their video. The decoding capability will significantly affect the user experience, the video play will sluggish/choppy if the decoder is incapable of a fast decoding on end-up devices.

AV1 vs HEVC: The Onslaught

Put it to the practice. The standard for comparing different video codecs, we got to follow certain measurements & metrics. VMAF quality with the Moscow University Video Quality Measurement Tool is one of the greatest criterion which we can do to reference.

The encoding test will be based on four samples that will encode within 4 different codecs through FFmpeg. The encoding scripts will be kept as vanilla as it could be (N-93083-g8522d219ce) with minor adjustment to fit the insignificant, differentiated codec requirement to keep the comparison impartial and reasonable:

AV1 data rate

The vertical axis shows the VMAF scores which representing the graphic quality, a higher score simply means better quality of video (in almost all aspects). The horizontal axis represents the bitrate, again to put that in simple, smaller number means smaller video size & higher compression rate. Reasonably less compact if the coordinate is addressed on the right-hand side.

As a result, AV1 was the champion, H264 the laggard, and x265 and VP9 neck and neck in the middle. A noticeable evidence is AV1 got a very high VMAF grade even it's in an extremely low bitrate, which indicated that AV1 is super effective at a cut off the bandwidth of the video and keep the graphic quality retain a higher baseline.

AV1 bitrate
Research shows AV1 is more concrete than other codecs for approximately 30%

Not only the VMAF prove that AV1 is the winner quality-wise among its competitors. The PSNR (Peak Signal-to-Noise Ratio, see below) tests also regard AV1 codec as the leader of all codecs.

AV1 PSNR

AV1 vs HEVC: The Achilles's Heel:

The encoding/ decoding ability for video codec is a significant factor which end up with the user experience. Imagine a Youtube vlogger need a day or even longer time to encode his/her video before uploading, the time efficiency is literary intolerable. Unfortunately, AV1 is not performing ideally at encoding speed.

We set the initial FFmpeg string (max rate 3000~ 6000K, CPU used 8 cores and 2 passes) both for AV1, HEVC (H.265) and VP9 plus H.264. With a 95.55 VMAP score conformant, the time consumption of AV1 encoding isn't taking the lead.

AV1 encodign time

Data depicts that the AV1 is about 2.5 times slower than x265 and 3 times slower than VP9, and the graphic quality was compromised to 95.55 from 96.18. Even though the sharpest-eyed viewer wouldn't notice this .63 differential, but if we do compare it pin to pin, then the results are embarrassing.

AV1 encoding time

What takes AV1 to such a consequence?

As one of the initial purposes when designing AV1 at the beginning stage, hardware compatibility was in their major concerns. The ultimate solution for compatibility issues will be a "virtual machine" stuff like Java, which idea doesn't fit the computer video industry. So the designers of AV1 codec deducted the hardware dependence, meanwhile, the hardware acceleration is disabled. Their goal is to make AV1 codec video able to run on various devices as possible. But the encoding performance is sacrificed as a result.

But there is hope.

AV1 codec was released in 2018 and still evaluated as an underdevelopment project with pretty much capable for business use. Hundreds and thousands of most topped engineers & developers from AOM are working together with this project. Consider Google, Microsoft, Amazon, and Apple joined this race, with their talented, experienced developers trying their best to ingratiate the market needs, it's highly promising that the problem will be relieved in near future.

AV1 encoding time

Group of test data released in 2018, come with the first usable version of AV1 codec. The figures somehow looks ludicrous.

Since we have witnessed the improvement of the usability of AV1 codec. AV1, as a codec which still on its early stage of life span, it has a lot more space to be optimized & developed compare to other inadequate codecs. From a long term prediction, AV1 has great potential to overturn the video codec industry.

What Makes Different

Considered a high- tech concentrated project the AV1 is, with practically all major tech leaders announcing their technical implementation of amazing new features that make AV1 stand out from the rest video codecs. A closer look at five of its new features will lead us to the observatory of the codec future.

Film Grain Synthesis

AV1 film grain synthesis
A brief sample of the Film grain synthesis process

We've had the experience when film grain appears on over enlarged pictures, but it could also be a form of artist expressiveness. In the previous encoding scenario, the codec could hard to distinguish it from the constant noise and creates a great amount of traffic in the bitstream. High bitrate video compensated for transmitting very little information. Since human brains tend to filter the visual noise and accept them as a bit "emotional" sensation, to find a way to not transfer the noise with the bitstream but re-apply it in the later procedure, could be a desirable solution.

Constrained Directional Enhancement Filter

AV1 constrained directional enhancement filter
Direction search as presented in: Steinar Midtskogen & Jean-Marc Valin: THE AV1 CONSTRAINED DIRECTIONAL ENHANCEMENT FILTER (CDEF). See: https://arxiv.org/abs/1602.05975

As the essential process of all video codecs, the effectiveness of filtering will dramatically influence the quality of encoded video. Each picture will be divided into small units during the encoding process by the lines and blocks. The directional filter is the advanced algorithm, supported by previous filters, CLPF and CDEF, to recognize the edges of each frame with analyzing their direction, low-pass filters along the edges and outlines will be applied and the graphic quality improves since smoother lines and visual effects are adapted.

Frame Super Resolution

AV1 frame super resolution

It is a common practice among video streaming services to adaptively switch the frame resolution based on the current bandwidth. For example, when the available bandwidth is low, a service may send lower resolution frames and then upscale them to the display device resolution. However, such a scaling occurs outside of the video codec as of now. The motivation behind the new Frame Super-resolution framework in AV1 is to make this scaling process more effective by making it a part of the codec itself. The new coding technic allows the lower spatial resolution frames to be coded at first and then super-resolved normatively recursively to adapt to full resolution before rendering the buffers. Later, these super-resolved reference buffers can be used to predict subsequent frames, even if they are at a different resolution.

Non-binary Arithmetic Coding

AV1 non-binary arithmetic coding

AV1 moves to using a symbol-to-symbol adaptive multi-symbol arithmetic coders (up to 8 possible values) instead of traditional HEVC coding (which have only two). The precision is much higher than a binary arithmetic encoder and enhances the tracking capabilities of less common elements of a visual element accurately. Through it's a complex process to coding to merge different values to one, it boosts code performance since multiple bits could process in the same clock cycles sequentially.

The Future of AV1:from the Business View

As a newly rolling out codec standard, a developing technology, the AV1 is now expanding its business territory. As it presented a perfect technological forecast and its business potential isn't hard to discern.

Not only the AOM alliance promoters have acclaimed their support to the future AV1 application, other service providers, open-source project & commercial software solution are released their support of AV1 codec videos: FFmpeg, VLC, CNX players, KMPlayer, Digiarty WinX series…etc. With more and more companies & groups join the AV1 codec family, and we users could more easily watch the AV1 video, accept the benefit from this newest codec standard.

The Tech-leader Enforcement

Need to point out that the bright business outlook of AV1 codec depends on the promotion from AOM members immensely, For instance, AV1 Video Extension beta is added on Microsoft Edge for Windows 10 October 2018 Update (1809), Which indicated the full enhancement from Microsoft on Windows, the world's most popular platform with a tremendous market share for PC, manifests the complete victory in the future of AV1 codec.

AV1 advantages
Source: muvi.com

Google, Microsoft, Mozilla and Apple also successively announced their browser support to AV1. Although the technical framework is still under development, but its outstanding coding performance and royalty-free will be the solid base of the success of AV1 market expansion. And they have a clear, step by step plan for pushing AV1 to become a mature codec standard and to win an ample business achievement.

AV1 evolution
AOM has made a clear Road map for its industry rollout of AV1.

The Things that Have Changed

Commercially the AV1 has got the adoption of many crucial online content providers, including YouTube, Vimeo, Netflix and twitch. And it will drastically change the landscape of the online video market with no doubt.

YouTube adds AV1 support
Google lunching its full support to AV1 codec video

As the leading force of AOM and the main promoter, Google with its YouTube has activelyrolling out AV1 codec video. Begin with their AV1 Beta Launch Playlist with 14 playable videos in 2018, Google claim that there will be 10 to 20 percent out of all Youtube videos will use the AV1 codec by the end of 2020. This ambitious goal also tells us the future widely adaption of AV1 video codec because of Youtube's dominating position in the video-sharing industry. Click here to read more about the following download issue come with the implementation of AV1 codec.

Vimeo adds av1 support
Vimeo Introduces Support for Royalty-Free Video Codec, AV1

Within Mozilla's Rav1e encoder, Vimeo's "Staff picks" channel has added AV1 codec videos. As the major contributor of this encoder technically, Vimeo has a remote plan to implement all uploaded videos with AV1 codec videos.

On Feb 6, 2020, Netflix announced its support of AV1 on android devices and begin to Stream AV1 on Android.

Netflix adds av1 support
Netflix announced their progress AV1 codec steaming services.

And this official announcement also declared that their final goal is to roll out AV1 on all of our platforms. Since Netflix is now the greatest streaming service provider in the United States, which occupied more than 50% of family streaming service subscribers, that could be the decisive move for AOM to promote AV1 codec.

Twitch also plans to roll out AV1 for its header content in 2020, they are ought to solve their "tail content" issue with AV1 codec later but will still in quick.

Twitch adds av1 support
A Roadmap has been announced and on its way going

Additionally, followed by positive test results, Facebook officially presented their favor of AV1 technologies. And the future follow up will be on the schedule. It's a strong signal that AV1 could be popularized among SNS platforms.

Did We Prepared for the AV1 Era?

Hence almost all decisive companies prospected their future with AV1 and we can see the growing implementation of AV1 codec video on various platforms & occasions, have we set to enjoy the changes and exciting content that AV1 brought to us?

Not necessarily we are but surely we could. The adaption of AV1 codec is surely causing trouble to both content creators and audiences; the major flaw, as we mentioned above, the encoding speed was the bottleneck that restrict the performance and user experience for video maker. Good to hear that the AOM is resolving this problem with all their efforts.

As for common users, the audience, things we may have to watch AV1 codec video is a capable player/ download support. Fortunately, there a several noticeable software that we can choose to, like VLC, exoplayer… etc. For downloading purposes, since you can't download & play video after Youtube & Vimeo since the AV1 codec has been widely adopted, the Digiarty WinX video converter would be a decent choice.

In the predictable future, there will be an increased number of implementation of new AV1 codec. Our online video, online streaming, even the Zoom teleconference, and the Facetime will, within my guess, adapt to the new technologies. Keep our eyes on these new things that may change our life, make our mind adapt to this new "AV1 era" and let's begin.

Some FAQ about AV1 Codec

What Is AV1 Codec?

AV1 is the newest video codec launched by the Alliance for the Open Media (AOM). With 2 years of rapid development it has become one of the most concerned video codec and implemented in many websites as the codec for online video streaming.

Does Youtube Adapt AV1?

Yes Youtube does. According to Google official, approximately 20% percent of Youtube video contents will roll out with AV1 codec for better quality and smaller file size. It's a sweet spot for me in the quality/speed trade-off.

How Do We Enable AV1 codec in Youtube Setting?

You may change the setting on the Account Playback page from Auto to either "Prefer AV1 for SD" or "Always prefer AV1".

YouTube av1

Is There a Way to Download AV1 Codec video from Video Sites?

check av1 video setting

Generally speaking, there isn't an official proved measure to download the video files on those video sharing platforms, for example, Youtube, Vimeo. Also there will be technical issues when we try download AV1 codec videos since AV1 codec not yet widely supported by video software solutions; but we can do it with the help of certain third party software, like WinX HD Video Converter Deluxe.

Free Download WinX HD Video Converter Deluxe to Grab AV1 Video Flawlessly

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Decoder that supports AV1 codec on Apple devices.

Extended reading about the comparison between HEVC & AV1

ABOUT THE AUTHOR

Kaley Torres

Kaley Torres is a self-motivated, creative editor with eight years of marketing and SEO experience, specializing in writing on DVD, video, audio, images, new digital contents etc. With a partiality DVD collection, Kaley also enjoys digitizing DVD and is keen to share her DVD video conversion solutions as well as video sharing tips on social media.

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