.AV1 File Extension
|Developer||Alliance for Open Media|
3.0 | 2 Votes
What is an AV1 file?
An AV1 file is a video encoded with AV1 compression, which is an open-source video codec developed by the Alliance for Open Media. AV1 videos are more commonly saved with the .MP4, .MKV, and .WEBM extension(s).
In 2015, several high-profile tech companies, including Amazon, Cisco, Google, Intel, Microsoft, Mozilla, and Netflix, formed the Alliance for Open Media. This non-profit workgroup began developing a number of open-source media technologies and standards, including the AV1 video codec.
The AV1 codec was designed as a freely-available alternative to the widely-used yet royalty-incurring H.264 and HEVC/H.265 codecs developed by the Moving Picture Experts Group (MPEG) and International Telegraph Union (ITU). AV1's creation allowed the Alliance for Open Media and other entities to create and share high-quality videos without paying royalties to MPEG. Notably, in 2020, Netflix began streaming AV1 videos to some Android users, and Google announced that Google Duo will soon begin using AV1 video.
While AV1 is used to create video files, it is not a file format. Rather, it is a compression format that any program that saves video files can use to compress videos. AV1 videos are most commonly saved using one of several more common video container formats, such as MP4, MKV, and WEBM. However, in rare circumstances, you may encounter an AV1 video saved with the .av1 extension.
How do I open an AV1 file?
Because AV1 files are uncommon, most popular media players cannot play them. However, you can open and play AV1 videos in VLC media player, and you can convert them to a more usable video format using FFmpeg.
Programs that open AV1 files
High licensing fees aren’t a new problem. Six years ago, nearly all the major players began work on their own viable alternatives to patented video codecs: Google published VP9, Mozilla launched its Daala project, and Cisco acquired Thor, a codec that is particularly suitable for low-complexity video conferences. Their goal was the same: to create the next generation video codec that would make sharing videos online faster, easier, and cheaper.
In 2015, they joined forces under AOMedia and streaming and hardware giants such as Amazon, Netflix, Intel, AMD,and NVIDIA jumped on board. The result is AV1 codec, which is primarily based on Google VP9, but benefits greatly from the tools and technologies provided by Daala, Thor, and VP10. Since 2018, Google Chrome and Mozilla Firefox – two of the world’s most frequently used browsers – have supported AV1.
Open and royalty-free video coding format developed by the Alliance for Open Media
Not to be confused with AVI, AVC1 or VC-1. For other uses, see AV1 (disambiguation).
AOMedia Video 1 (AV1) is an open, royalty-freevideo coding format initially designed for video transmissions over the Internet. It was developed as a successor to VP9 by the Alliance for Open Media (AOMedia), a consortium founded in 2015 that includes semiconductor firms, video on demand providers, video content producers, software development companies and web browser vendors. The AV1 bitstream specification includes a reference video codec. In 2018, Facebook conducted testing that approximated real world conditions, and the AV1 reference encoder achieved 34%, 46.2% and 50.3% higher data compression than libvpx-vp9, x264 high profile, and x264 main profile respectively.
Like VP9, but unlike H.264/AVC and HEVC, AV1 has a royalty-free licensing model that does not hinder adoption in open-source projects.
AV1 Image File Format (AVIF) is an image file format that uses AV1 compression algorithms.
The Alliance's motivations for creating AV1 included the high cost and uncertainty involved with the patent licensing of HEVC, the MPEG-designed codec expected to succeed AVC. Additionally, the Alliance's seven founding members – Amazon, Cisco, Google, Intel, Microsoft, Mozilla and Netflix – announced that the initial focus of the video format would be delivery of high-quality web video. The official announcement of AV1 came with the press release on the formation of the Alliance for Open Media on 1 September 2015. Only 42 days before, on 21 July 2015, HEVC Advance's initial licensing offer was announced to be an increase over the royalty fees of its predecessor, AVC. In addition to the increased cost, the complexity of the licensing process increased with HEVC. Unlike previous MPEG standards where the technology in the standard could be licensed from a single entity, MPEG-LA, when the HEVC standard was finished, two patent pools had been formed with a third pool was on the horizon. In addition, various patent holders were refusing to license patents via either pool, increasing uncertainty about HEVC's licensing. According to Microsoft's Ian LeGrow, an open-source, royalty-free technology was seen as the easiest way to eliminate this uncertainty around licensing.
The negative effect of patent licensing on free and open-source software has also been cited as a reason for the creation of AV1. For example, building an H.264 implementation into Firefox would prevent it from being distributed free of charge since licensing fees would have to be paid to MPEG-LA.Free Software Foundation Europe has argued that FRAND patent licensing practices make the free software implementation of standards impossible due to various incompatibilities with free software licenses.
Many of the components of the AV1 project were sourced from previous research efforts by Alliance members. Individual contributors started experimental technology platforms years before: Xiph's/Mozilla's Daala already published code in 2010, Google's experimental VP9 evolution project VP10 was announced on 12 September 2014, and Cisco's Thor was published on 11 August 2015. Building on the code base of VP9, AV1 incorporates additional techniques, several of which were developed in these experimental formats. The first version 0.1.0 of the AV1 reference codec was published on 7 April 2016.
Although a soft feature freeze came into effect at the end of October 2017, development continued on several significant features. One of these in-progress features, the bitstream format, was projected to be frozen in January 2018 but was delayed due to unresolved critical bugs as well as further changes to transformations, syntax, the prediction of motion vectors, and the completion of legal analysis. The Alliance announced the release of the AV1 bitstream specification on 28 March 2018, along with a reference, software-based encoder and decoder. On 25 June 2018, a validated version 1.0.0 of the specification was released. On 8 January 2019 a validated version 1.0.0 with Errata 1 of the specification was released.
Martin Smole from AOM member Bitmovin said that the computational efficiency of the reference encoder was the greatest remaining challenge after the bitstream format freeze had been completed. While still working on the format, the encoder was not targeted for production use and speed optimizations were not prioritized. Consequently, the early version of AV1 was orders of magnitude slower than existing HEVC encoders. Much of the development effort was consequently shifted towards maturing the reference encoder. In March 2019, it was reported that the speed of the reference encoder had improved greatly and within the same order of magnitude as encoders for other common formats.
On 21 January 2021, the MIME type of AV1 was defined as video/AV1. The usage of AV1 using this MIME type is restricted to Real-time Transport Protocol purposes only.
AV1 aims to be a video format for the web that is both state of the art and royalty free. According to Matt Frost, head of strategy and partnerships in Google's Chrome Media team, «the mission of the Alliance for Open Media remains the same as the WebM project».
A recurring concern in standards development, not least of royalty-free multimedia formats, is the danger of accidentally infringing on patents that their creators and users didn't know about. The concern has been raised regarding AV1, and previously VP8, VP9, Theora and IVC. The problem is not unique to royalty-free formats, but it uniquely threatens their status as royalty-free.
|Patent licensing||AV1, VP9, Theora||HEVC, AVC||GIF, MP3, MPEG-1, MPEG-2, MPEG-4 Part 2|
|By known patent holders||Royalty-free||Royalty bearing||Patents expired|
|By unknown patent holders||Impossible to ascertain until the format is old|
enough that any patents would have expired
(at least 20 years in WTO countries)
To fulfill the goal of being royalty free, the development process requires that no feature can be adopted before it has been confirmed independently by two separate parties to not infringe on patents of competing companies. In cases where an alternative to a patent-protected technique is not available, owners of relevant patents have been invited to join the Alliance (even if they were already members of another patent pool). For example, Alliance members Apple, Cisco, Google, and Microsoft are also licensors in MPEG-LA's patent pool for H.264. As an additional protection for the royalty-free status of AV1, the Alliance has a legal defense fund to aid smaller Alliance members or AV1 licensees in the event they are sued for alleged patent infringement.
Under patent rules adopted from the World Wide Web Consortium (W3C), technology contributors license their AV1-connected patents to anyone, anywhere, anytime based on reciprocity (i.e. as long as the user does not engage in patent litigation). As a defensive condition, anyone engaging in patent litigation loses the right to the patents of all patent holders.
This treatment of intellectual property rights (IPR), and its absolute priority during development, is contrary to extant MPEG formats like AVC and HEVC. These were developed under an IPR uninvolvement policy by their standardization organisations, as stipulated in the ITU-T's definition of an open standard. However, MPEG's chairman has argued this practice has to change, which it is:EVC is also set to have a royalty-free subset, and will have switchable features in its bitstream to defend against future IPR threats.
The creation of royalty-free web standards has been a long-stated pursuit for the industry. In 2007, the proposal for HTML5 video specified Theora as mandatory to implement. The reason was that public content should be encoded in freely implementable formats, if only as a "baseline format", and that changing such a baseline format later would be hard because of network effects. The Alliance for Open Media is a continuation of Google's efforts with the WebM project, which renewed the royalty-free competition after Theora had been surpassed by AVC. For companies such as Mozilla that distribute free software, AVC can be difficult to support as a per-copy royalty easily is unsustainable given the lack of revenue stream to support these payments in free software (see FRAND § Excluding costless distribution). Similarly, HEVC has not successfully convinced all licensors to allow an exception for freely distributed software (see HEVC § Provision for costless software).
The performance goals include "a step up from VP9 and HEVC" in efficiency for a low increase in complexity. NETVC's efficiency goal is 25% improvement over HEVC. The primary complexity concern is for software decoding, since hardware support will take time to reach users. However, for WebRTC, live encoding performance is also relevant, which is Cisco's agenda: Cisco is a manufacturer of videoconferencing equipment, and their Thor contributions aim at "reasonable compression at only moderate complexity".
Feature-wise, AV1 is specifically designed for real-time applications (especially WebRTC) and higher resolutions (wider color gamuts, higher frame rates, UHD) than typical usage scenarios of the current generation (H.264) of video formats, where it is expected to achieve its biggest efficiency gains. It is therefore planned to support the color space from ITU-R Recommendation BT.2020 and up to 12 bits of precision per color component. AV1 is primarily intended for lossy encoding, although lossless compression is supported as well.
See also: VP9 § Technology, and Daala § Technology
AV1 is a traditional block-based frequency transform format featuring new techniques. Based on Google's VP9, AV1 incorporates additional techniques that mainly give encoders more coding options to enable better adaptation to different types of input.
The Alliance published a reference implementation written in C and assembly language (, ) as free software under the terms of the BSD 2-Clause License. Development happens in public and is open for contributions, regardless of AOM membership.
The development process was such that coding tools were added to the reference code base as experiments, controlled by flags that enable or disable them at build time, for review by other group members as well as specialized teams that helped with and ensured hardware friendliness and compliance with intellectual property rights (TAPAS). When the feature gained some support in the community, the experiment was enabled by default, and ultimately had its flag removed when all of the reviews were passed. Experiment names were lowercased in the configure script and uppercased in conditional compilation flags.
To better and more reliably support HDR and color spaces, corresponding metadata can now be integrated into the video bitstream instead of being signaled in the container.
Frame content is separated into adjacent same-sized blocks referred to as superblocks. Similar to the concept of a macroblock, superblocks are square-shaped and can either be of size 128×128 or 64×64 pixels. Superblocks can be divided in smaller blocks according to different partitioning patterns. The four-way split pattern is the only pattern whose partitions can be recursively subdivided. This allows superblocks to be divided into partitions as small as 4×4 pixels.
"T-shaped" partitioning patterns are introduced, a feature developed for VP10, as well as horizontal or vertical splits into four stripes of 4:1 and 1:4 aspect ratio. The available partitioning patterns vary according to the block size, both 128×128 and 8×8 blocks can't use 4:1 and 1:4 splits. Moreover, 8×8 blocks can't use "T" shaped splits.
Two separate predictions can now be used on spatially different parts of a block using a smooth, oblique transition line (wedge-partitioned prediction). This enables more accurate separation of objects without the traditional staircase lines along the boundaries of square blocks.
More encoder parallelism is possible thanks to configurable prediction dependency between tile rows ().
AV1 performs internal processing in higher precision (10 or 12 bits per sample), which leads to compression improvement due to smaller rounding errors in reference imagery.
Predictions can be combined in more advanced ways (than a uniform average) in a block (compound prediction), including smooth and sharp transition gradients in different directions (wedge-partitioned prediction) as well as implicit masks that are based on the difference between the two predictors. This allows the combination of either two inter predictions or an inter and an intra prediction to be used in the same block.
A frame can reference 6 instead of 3 of the 8 available frame buffers for temporal (inter) prediction while providing more flexibility on bi-prediction ().
The Warped Motion () and Global Motion () tools in AV1 aim to reduce redundant information in motion vectors by recognizing patterns arising from camera motion. They implement ideas that were tried to be exploited in preceding formats like e.g. MPEG-4 ASP, albeit with a novel approach that works in three dimensions. There can be a set of warping parameters for a whole frame offered in the bitstream, or blocks can use a set of implicit local parameters that get computed based on surrounding blocks.
Switch frames (S-frame) are a new inter-frame type that can be predicted using already decoded reference frames from a higher-resolution version of the same video to allow switching to a lower resolution without the need for a full keyframe at the beginning of a video segment in the adaptive bitrate streaming use case.
Intra prediction consists of predicting the pixels of given blocks only using information available in the current frame. Most often, intra predictions are built from the neighboring pixels above and to the left of the predicted block. The DC predictor builds a prediction by averaging the pixels above and to the left of block.
Directional predictors extrapolate these neighboring pixels according to a specified angle. In AV1, 8 main directional modes can be chosen. These modes start at an angle of 45 degrees and increase by a step size of 22.5 degrees up until 203 degrees. Furthermore, for each directional mode, six offsets of 3 degrees can be signaled for bigger blocks, three above the main angle and three below it, resulting in a total of 56 angles ().
The "TrueMotion" predictor got replaced with a Paeth predictor which looks at the difference from the known pixel in the above-left corner to the pixel directly above and directly left of the new one and then chooses the one that lies in direction of the smaller gradient as predictor. A palette predictor is available for blocks with very few (up to 8, dominant) colors like in some computer screen content. Correlations between the luminosity and the color information can now be exploited with a predictor for chroma blocks that is based on samples from the luma plane (). In order to reduce visible boundaries along borders of inter-predicted blocks, a technique called overlapped block motion compensation (OBMC) can be used. This involves extending a block's size so that it overlaps with neighboring blocks by 2 to 32 pixels, and blending the overlapping parts together.
To transform the error remaining after prediction to the frequency domain, AV1 encoders can use square, 2:1/1:2, and 4:1/1:4 rectangular DCTs (), as well as an asymmetric DST for blocks where the top and/or left edge is expected to have lower error thanks to prediction from nearby pixels, or choose to do no transform (identity transform).
It can combine two one-dimensional transforms in order to use different transforms for the horizontal and the vertical dimension ().
AV1 has new optimized quantization matrices (). The eight sets of quantization parameters that can be selected and signaled for each frame now have individual parameters for the two chroma planes and can use spatial prediction. On every new superblock, the quantization parameters can be adjusted by signaling an offset.
For the in-loop filtering step, the integration of Thor's constrained low-pass filter and Daala's directional deringing filter has been fruitful: The combined Constrained Directional Enhancement Filter () exceeds the results of using the original filters separately or together.
It is an edge-directed conditional replacement filter that smooths blocks with configurable (signaled) strength roughly along the direction of the dominant edge to eliminate ringing artifacts.
There is also the loop restoration filter () based on the Wiener filter and self-guided restoration filters to remove blur artifacts due to block processing.
Film grain synthesis () improves coding of noisy signals using a parametric video coding approach. Due to the randomness inherent to film grain noise, this signal component is traditionally either very expensive to code or prone to get damaged or lost, possibly leaving serious coding artifacts as residue. This tool circumvents these problems using analysis and synthesis, replacing parts of the signal with a visually similar synthetic texture based solely on subjective visual impression instead of objective similarity. It removes the grain component from the signal, analyzes its non-random characteristics, and instead transmits only descriptive parameters to the decoder, which adds back a synthetic, pseudorandom noise signal that's shaped after the original component. It is the visual equivalent of the Perceptual Noise Substitution technique used in AC3, AAC, Vorbis, and Opus audio codecs.
Daala's entropy coder (), a non-binary arithmetic coder, was selected for replacing VP9's binary entropy coder. The use of non-binary arithmetic coding helps evade patents but also adds bit-level parallelism to an otherwise serial process, reducing clock rate demands on hardware implementations. This is to say that the effectiveness of modern binary arithmetic coding like CABAC is being approached using a greater alphabet than binary, hence greater speed, as in Huffman code (but not as simple and fast as Huffman code). AV1 also gained the ability to adapt the symbol probabilities in the arithmetic coder per coded symbol instead of per frame ().
Scalable video coding
Main article: Scalable Video Coding
Not to be confused with Scalable Video Technology – Intel's family of software encoders that comprises SVT-HEVC, SVT-VP9 and SVT-AV1.
Of main importance to video conferencing, scalable video coding is a general technique, not unique to AV1, of restricting and structuring video frame dependencies so that one or more lower bitrate video streams are extractable from a higher bitrate stream with better quality. This differs from adaptive bitrate streaming in that some compression efficiency in each higher bitrate adaptation is given up for the benefit of the overall stream. The encoding process is also less redundant and demanding.
AV1 has provisions for temporal and spatial scalability. This is to say that both framerate and resolution are usable ways to define a lower bitrate substream.
Quality and efficiency
A first comparison from the beginning of June 2016[by whom?] found AV1 roughly on par with HEVC, as did one using code from late January 2017.
In April 2017, using the 8 enabled experimental features at the time (of 77 total), Bitmovin was able to demonstrate favorable objective metrics, as well as visual results, compared to HEVC on the Sintel and Tears of Steel short films. A follow-up comparison by Jan Ozer of Streaming Media Magazine confirmed this, and concluded that "AV1 is at least as good as HEVC now". Ozer noted that his and Bitmovin's results contradicted a comparison by Fraunhofer Institute for Telecommunications from late 2016 that had found AV1 65.7% less efficient than HEVC, underperforming even H.264/AVC which they concluded as being 10.5% more efficient. Ozer justified this discrepancy by having used encoding parameters endorsed by each encoder vendor, as well as having more features in the newer AV1 encoder. Decoding performance was at about half the speed of VP9 according to internal measurements from 2017.
Tests from Netflix in 2017, based on measurements with PSNR and VMAF at 720p, showed that AV1 was about 25% more efficient than VP9 (libvpx). Tests from Facebook conducted in 2018, based on PSNR, showed that the AV1 reference encoder was able to achieve 34%, 46.2% and 50.3% higher data compression than libvpx-vp9, x264 high profile, and x264 main profile respectively.
Tests from Moscow State University in 2017 found that VP9 required 31% and HEVC 22% more bitrate than AV1 in order to achieve similar levels of quality. The AV1 encoder was operating at speed "2500–3500 times lower than competitors" due to the lack of optimization (which was not available at that time).
Tests from University of Waterloo in 2020 found that when using a mean opinion score (MOS) for 2160p (4K) video AV1 had bitrate saving of 9.5% compared to HEVC and 16.4% compared to VP9. They also concluded that at the time of the study at 2160p the AV1 video encodes on average took 590× longer compared to encoding with AVC; while HEVC took on average 4.2× longer and VP9 took on average 5.2× longer than AVC respectively.
The latest encoder comparison by Streaming Media Magazine as of September 2020, which used moderate encoding speeds, VMAF, and a diverse set of short clips, indicated that the open-source libaom and SVT-AV1 encoders took about twice as long time to encode as x265 in its "veryslow" preset while using 15-20% less bitrate, or about 45% less bitrate than x264 veryslow. The best-in-test AV1 encoder, Visionular's Aurora1, in its "slower" preset, was as fast as x265 veryslow while saving 50% bitrate over x264 veryslow.
Profiles and levels
AV1 defines three profiles for decoders which are Main, High, and Professional. The Main profile allows for a bit depth of 8- or 10-bits per sample with 4:0:0 (greyscale) and 4:2:0 (quarter) chroma sampling. The High profile further adds support for 4:4:4 chroma sampling (no subsampling). The Professional profile extends capabilities to full support for 4:0:0, 4:2:0, 4:2:2 (half) and 4:4:4 chroma sub-sampling with 8, 10 and 12 bit color depths.
|Main (0)||High (1)||Professional (2)|
|Bit depth||8 or 10-bit||8 or 10-bit||8, 10 & 12 bit|
AV1 defines levels for decoders with maximum variables for levels ranging from 2.0 to 6.3. The levels that can be implemented depend on the hardware capability.
Example resolutions would be 426×[email protected] fps for level 2.0, 854×[email protected] fps for level 3.0, 1920×[email protected] fps for level 4.0, 3840×[email protected] fps for level 5.1, 3840×[email protected] fps for level 5.2, and 7680×[email protected] fps for level 6.2. Level 7 has not been defined yet.
|Min Comp Basis||Max Tiles||Max Tile Cols||Example|
Supported container formats
- MPEG Transport Stream (MPEG TS)
- Real-time Transport Protocol: a preliminary RTP packetization spec by AOMedia defines the transmission of AV1 OBUs directly as the RTP payload. It defines an RTP header extension that carries information about video frames and their dependencies, which is of general usefulness to § scalable video coding. The carriage of raw video data also differs from for example MPEG TS over RTP in that other streams, such as audio, must be carried externally.
- WebM: as a matter of formality, AV1 has not been sanctioned into the subset of Matroska known as WebM as of late 2019.
- On2 IVF: this format was inherited from the first public release of VP8, where it served as a simple development container. rav1e also supports this format.
- Pre-standard WebM: Libaom featured early support for WebM before Matroska containerization was specified; this has since been changed to conform to the Matroska spec.
In October 2016, Netflix stated they expected to be an early adopter of AV1. On 5 February 2020, Netflix began using AV1 to stream select titles on Android, providing 20% improved compression efficiency over their VP9 streams.
In 2018, YouTube began rolling out AV1, starting with its AV1 Beta Launch Playlist. According to the description, the videos are (to begin with) encoded at high bitrate to test decoding performance, and YouTube has "ambitious goals" for rolling out AV1. YouTube for Android TV supports playback of videos encoded in AV1 on capable platforms as of version 2.10.13, released in early 2020.
In February 2019, Facebook, following their own positive test results, said they would gradually roll out AV1 as soon as browser support emerges, starting with their most popular videos.
In June 2019, Vimeo's videos in the "Staff picks" channel were available in AV1. Vimeo is using and contributing to Mozilla's Rav1e encoder and expects, with further encoder improvements, to eventually provide AV1 support for all videos uploaded to Vimeo as well as the company's "Live" offering.
On 30 April 2020, iQIYI announced support for AV1 for users on PC web browsers and Android devices, according to the announcement, as the first Chinese video streaming site to adopt the AV1 format.
Twitch plans to roll out AV1 for its most popular content in 2022 or 2023, with universal support projected to arrive in 2024 or 2025.
- Libaom is the reference implementation. It includes an encoder (aomenc) and a decoder (aomdec). As the former research codec, it has the advantage of being made to justifiably demonstrate efficient use of every feature, but at the general cost of encoding speed. At feature freeze, the encoder had become problematically slow, but speed optimizations with negligible efficiency impact have continued to be made also after that.
- rav1e is an encoder written in Rust and assembly. rav1e takes the opposite developmental approach to Aomenc: start out as the simplest (therefore fastest) conforming encoder, and then improve efficiency over time while remaining fast.
- SVT-AV1 includes an open-source encoder and decoder first released by Intel in February 2019 that is designed especially for usage on data center servers based on Intel Xeon processors. Netflix collaborates with Intel on SVT-AV1.
- dav1d is a decoder written in C99 and assembly focused on speed and portability. The first official version (0.1) was released in December 2018. Version 0.2 was released in March 2019, with users able to "safely use the decoder on all platforms, with excellent performance", according to the developers. Version 0.3 was announced in May 2019 with further optimizations demonstrating performance 2 to 5 times faster than aomdec.; version 0.5 was released in October 2019. Firefox 67 switched from Libaom to dav1d as a default decoder in May 2019. In 2019, dav1d v0.5 was rated the best decoder in comparison to libgav1 and libaom. dav1d 0.9.0 was released on May 17, 2021. dav1d 0.9.2 was released on September 3, 2021.
- Cisco AV1 is a proprietary live encoder that Cisco developed for its Webexteleconference products. The encoder is optimized for latency and the constraint of having a "usable CPU footprint", as with a "commodity laptop". Cisco stressed that at their operating point – high speed, low latency – the large toolset of AV1 does not preclude a low encoding complexity. Rather, the availability of tools for screen content and scalability in all profiles enabled them to find good compression-to-speed tradeoffs, better even than with HEVC. Compared to their previously deployed H.264 encoder, a particular area of improvement was in high resolution screen sharing.
- libgav1 is a decoder written in C++11 released by Google.
Several other parties have announced to be working on encoders, including EVE for AV1 (in beta testing), NGCodec, Socionext, Aurora and MilliCast.
Operating system support
Several Alliance members demonstrated AV1 enabled products at IBC 2018, including Socionext's hardware accelerated encoder. According to Socionext, the encoding accelerator is FPGA based and can run on an Amazon EC2 F1 cloud instance, where it runs 10 times faster than existing software encoders.
According to Mukund Srinivasan, chief business officer of AOM member Ittiam, early hardware support will be dominated by software running on non-CPU hardware (such as GPGPU, DSP or shader programs, as is the case with some VP9 hardware implementations), as fixed-function hardware will take 12–18 months after bitstream freeze until chips are available, plus 6 months for products based on those chips to hit the market. The bitstream was finally frozen on 28 March 2018, meaning chips could be available sometime between March and August 2019. According to the above forecast, products based on chips could then be on the market at the end of 2019 or the beginning of 2020.
- On 7 January 2019, NGCodec announced AV1 support for NGCodec accelerated with Xilinx FPGAs.
- On 18 April 2019, Allegro DVT announced its AL-E210 multi-format video encoder hardware IP, the first publicly announced hardware AV1 encoder.
- On 23 April 2019, Rockchip announced their RK3588 SoC which features AV1 hardware decoding up to 4K 60fps at 10-bit color depth.
- On 9 May 2019, Amphion announced a video decoder with AV1 support up to 4K 60fps On 28 May 2019, Realtek announced the RTD2893, its first integrated circuit with AV1 decoding, up to 8K.
- On 17 June 2019, Realtek announced the RTD1311 SoC for set-top boxes with an integrated AV1 decoder.
- On 20 October 2019, a roadmap from Amlogic shown 3 set-top box SoCs that are able to decode AV1 content, the S805X2, S905X4 and S908X. The S905X4 was used in the SDMC DV8919 by December.
- On 21 October 2019, Chips&Media announced the WAVE510A VPU supporting decoding AV1 at up to 4Kp120.
- On 26 November 2019, MediaTek announced world's first smartphone SoC with an integrated AV1 decoder. The Dimensity 1000 is able to decode AV1 content up to 4K 60fps.
- On 3 January 2020, LG Electronics announced that its 2020 8K TVs, which are based on the α9 Gen 3 processor, support AV1.
- At CES 2020, Samsung announced that its 2020 8K QLED TVs, featuring Samsung's "Quantum Processor 8K SoC," are capable of decoding AV1.
- On 13 August 2020, Intel announced that their Intel Xe-LP GPU in Tiger Lake will be their first product to include AV1 fixed-function hardware decoding.
- On 1 September 2020, Nvidia announced that their Nvidia GeForce RTX 30 Series GPUs will support AV1 fixed-function hardware decoding.
- On 2 September 2020, Intel officially launched Tiger Lake 11th Gen CPUs with AV1 fixed-function hardware decoding.
- On 15 September 2020, AMD merged patches into the amdgpu drivers for Linux which adds support for AV1 decoding support on RDNA2 GPUs.
- On 28 September 2020, Roku refreshed the Roku Ultra including AV1 support.
- On 30 September 2020, Intel released version 20.3.0 for the Intel Media Driver which added support for AV1 decoding on Linux.
- On 10 October 2020, Microsoft confirmed support for AV1 hardware decoding on Xe-LP(Gen12), Ampere and RDNA2 with a blog post.
- On 16 March 2021, Intel officially launched Rocket Lake 11th Gen CPUs with AV1 fixed-function hardware decoding.
Sisvel, a Luxembourg-based company, has formed a patent pool, and are selling a patent license for AV1. The pool was announced in early 2019, but a list of claimed patents was first published on 10 March 2020. This list contains over 1050 patents. The substance of the patent claims remains to be challenged.
Sisvel's prices are .32 Euros for display devices and .11 Euros for non-display devices using AV1. Sisvel has stated that they won't seek content royalties, but their license makes no exemption for software.
As of March 2020[update], the Alliance for Open Media has not responded to the list of patent claims. Their statement after Sisvel's initial announcement reiterated the commitment to their royalty-free patent license and made mention of the "AOMedia patent defense program to help protect AV1 ecosystem participants in the event of patent claims", but did not mention the Sisvel claim by name.
Google is aware of the patent pool, but does not plan to alter their current or upcoming usage plans of AV1.
AV1 Image File Format (AVIF)
AV1 Image File Format (AVIF) () is an image file format specification for storing images or image sequences compressed with AV1 in the HEIF file format. It competes with HEIC which uses the same container format, built upon ISOBMFF, but HEVC for compression. Version 1.0.0 of the AVIF specification was finalized in February 2019.
AVIF supports features like:
On 14 December 2018 Netflix published the first .avif sample images. In November 2020, HDR sample images with PQ transfer function and BT.2020 color primaries were published.
- Web browsers
- Image viewers
- Media player
- VLC reads AVIF files starting with version 4, which is still in development
- Image editors
- Paint.net added support for opening AVIF files in September 2019, and the ability to save AVIF format images in an August 2020 update.
- The Colorist format conversion and Darktable RAW image data have each released support for and provide reference implementations of libavif.
- A GIMP plugin implementation has been developed supporting both 3.x and 2.10.x plugin APIs. Native AVIF import and export was added to GIMP in October 2020.
- Image libraries
- libavif - Portable library for encoding and decoding AVIF files.
- libheif - ISO/IEC 23008-12:2017 HEIF and AVIF decoder and encoder.
- SAIL - Format-agnostic library with support of AVIF implemented on top of libavif.
- Microsoft announced support with the Windows 10 "19H1" preview release, including support in File Explorer, Paint and multiple APIs, together with sample images.
- Android 12 released on October 4, 2021, added native support for AVIF, although it will not be the default image format for the camera app.
- On February 14, 2020, Netflix published a blog article with objective measurements on AVIF's image quality & compression efficiency in comparison to JPEG.
- Cloudflare announced AVIF support in a blog post on 3 October 2020.
- Vimeo announced AVIF support in a blog post on June 3, 2021.
- avif.io is a dedicated database tracking support status on AVIF.
- Exiftool supports AVIF format for read and write EXIF since v11.79.
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AV1 Codec 1.1
With AV1 Video Extension you can play AV1 videos on your Windows 10 device.
This extension is an early beta version of the AV1 software decoder that lets you play videos that have been encoded using the AV1 video coding standard developed by the Alliance for Open Media.
Since this is an early release, you might see some performance issues when playing AV1 videos.
If you allow apps to be updated automatically, you should get the latest updates and improvements when we release them.
YouTube has integrated AV1 and determines which codec to use with a specific algorithm. Though, choosing to stream AV1 in HD is available only for a few videos due to its high resources requirement.
For SD, it will use AV1 up to 480p, and VP9 for higher formats.
AV1 Codec 1.0 - compiled by Chocobo1includes x64 executables for Windows: aomdec.exe and aomenc.exe (AV1 decoder and respectively encoder).
- rav1e allows you to encode video files to the AV1 video format, easily and fast.
- See also How to play Youtube videos with AV1 codec?
Format video av1
What is AV1? The 8K video codec coming soon to streaming services
Move over H.264/AVC and HEVC, there's a new video streaming codec in town and it's got you in its sites. AV1 is here and it's going to be everywhere before you know it.
AV1 is an open, royalty-free video standard with an improved compression system that should allow huge data efficiency savings without reducing video quality – and that could be key going forward into a world of higher frame rates, 8K resolution, HDR standards and audio demands.
As such, AV1 brings implications for those who use services such as Netflix, Disney Plus and Prime Video; people looking to buy a new TV or media streamer; and anyone interested in 8K TV. And as a catch-all compression standard there are many uses beyond, including gaming, realtime applications such as video conferencing and anything else where video streams are required.
What is AV1?
AV1 (AOMedia Video 1) is the the next evolution of the defacto video streaming codec across the internet. It's planned as the successor to the HEVC (H.265) format that is currently used for 4K HDR video on platforms such as Prime Video, Apple TV+, Disney Plus and Netflix.
It was developed by the Alliance for Open Media, which counts Amazon, Apple, ARM, Facebook, Google, Intel, Microsoft, Mozilla, Netflix, Nvidia and Samsung among its members, and is designed to offer internet streaming efficiency upgrades without affecting quality. That makes it an important step in the uptake of streamed 8K video, given the more data-heavy demands of this higher-res format.
The other big advantage to the streaming giants is that AV1 is royalty-free. That means video platforms, device manufacturers and, by proxy, users can avoid the hefty licensing payments previously associated with codecs such as HEVC. With any luck, that should also grease the wheels of AV1's evolution and development by avoiding costly, time consuming and generally prohibitive law suits and patent claims.
At the time of writing, the AV1 video codec shows anywhere up to 30 per cent more efficient compression than HEVC, and those within the Alliance for Open Media will push for even bigger gains still. After all, it's always good to leave room to squeeze more audio and video standards into the bitstream as and when they arise.
But while all sounds good for efficiency of the compression, there is a catch – it takes much, much longer to encode videos in AV1 in the first place. Imagine capturing a video on your mobile then having to wait an age for the AV1 file to be created before you can share it.
The aim for AV1 is for significant improvement here. Realistically, it's a problem that needs to be solved before widespread adoption can happen. Until then, expect AV1 to be a more fringe player.
AV1 decoders are available at different profile settings and levels, depending on each piece of hardware's capabilities. Theoretically, though, there's plenty of scope and the very upper limits of AV1 have not yet been defined.
For the time being, the codec can go as far as 8K at up to 120fps, involving bitrates at up to 800mbps. Bit depth for colour comes in 8-, 10- and 12-bit varieties and with colour sampling up to a 4:4:4 full pixel level.
Can I watch AV1 video now?
Google has already implemented some AV1 use onto YouTube and requires AV1 support to view its 8K videos on TV.
Netflix has also started streaming AV1 content on a few titles. In fact, the subscription giant first took on AV1 as a way of keeping costs down for Android customers. The Netflix 'Save Data' feature on Android devices prioritises the use of the less data-heavy AV1 streams where possible. The company has also committed to take AV1 use across the board going forward.
Vimeo has adopted AV1 for the streams of its 'Staff picks' channel. Facebook has promised a roll out of AV1 as browser support emerges, and Twitch has 2022 or 2023 targeted with universal support projected to arrive in 2024 or 2025.
To watch this AV1 content requires both hardware and software support, which mostly breaks down to which device you've got and what operating system it's using. At the time of writing, there's no AV1 support on MacOS or iOS.
Android (10 onwards), Chrome (70 onwards) and Linux can decode AV1 streams, as can Windows 10 devices (once updated) for certain Windows apps.
What devices support AV1?
Any device looking to support AV1 will need to have an AV1 decoder built-in at the chip level. Compatibility to the codec cannot be added as a firmware update for most devices. That means the very vast majority of devices out there at the time of writing aren't ready for it.
There are one or two that were future-proofed in 2020, though. Of those, the Roku Ultra is probably your best bet to get going with AV1 content straight away, although it's only available in the US for now.
LG's 8K TVs from 2020 are also AV1 compatible with a decoder built into the α9 (Gen 3) processor. It's a similar story for Samsung's 8K sets from the same time – you can actually watch AV1-encoded 8K content from the YouTube app of those sets now.
The other notable AV1-enabled hardware is the Nvidia GeForce RTX 30 Series graphics cards, which would make a very handy video streaming addition to most PCs.
Otherwise, it's a list of AV1 promises but these include a particularly good one. Google recently announced that any device looking to use the Android TV 10 OS produced after the 31st March 2021 deadline will need to have an AV1 decoder built in.
So, expect plenty of set-top boxes and smart TVs launched in 2021 and beyond to be ready to go and, with Google putting its foot down, all sorts of other products and services should fall in line over the next 12 months, and that's good news for everyone. Higher quality video, here we come.
HGiG explained: what is HGiG? How do you get it? And should you use it?
ATSC 3.0: everything you need to know about NextGen TV
3 things you should know about the AV1 codec
The Aomedia Video 1 codec, or AV1, has been making its way into consumer’s hands. In early 2020, Netflix made the headlines when it said it had started streaming AV1 to some Android viewers. Later, Google brought the AV1 codec to its Duo video chat app, and MediaTek enabled AV1 YouTube video streams on its Dimensity 1000 5G SoC.
What is all the fuss about? What is the AV1 codec? Why is it important? Here is a quick look at AV1 and what it means for video streaming over the five years.
AV1 is royalty-free and open source
Inventing technology, designing components, and doing research is expensive. Engineers, materials, and buildings cost money. For a “traditional” company the return on investment comes from sales. If you design a new gadget and it sells in the millions, then you get the money back that was initially spent. That is true of physical products, like smartphones, but it is also true for software development.
A game company spends money developing a game, paying the engineers and the artists along the way, and then it sells the game. It might not even physically exist on a DVD/ROM cartridge/whatever. This might be a digital download. However, the sales pay for its development.
What happens if you design a new algorithm or technique for doing something, say for compressing video? You can’t offer an algorithm as a digital download, it won’t be bought by consumers, but rather by product makers who want to include the algorithm in smartphones, tablets, laptops, TVs, and so on.
If an algorithm’s inventor is able to sell the technique to third parties then one of the business options is to charge a small fee, a royalty charge, for every device that ships with the algorithm. This all seems fair and equitable. However, the system is open to abuse. From unfriendly renegotiations about the fees, to patent trolls, to million-dollar lawsuits, the history of royalty-based businesses is long and full of unexpected wins and losses, for both the “bad guys” and the “good guys.”
Once a technology becomes pervasive then an odd thing happens: products can’t be built without it, but they can’t be built with it, unless the fees are negotiated. Before a product even gets past the initial conception it is already burdened with the prospect of royalty fees. It is like trying to charge a product maker for building a gadget that uses electricity, not the amount of electricity used, but just the fact it uses electricity.
The reaction against this is to look for, and develop, tech which is free from royalty payments and free from the shackles of patents. This is the aim of the AV1 codec.
Many of the current leading and ubiquitous video streaming technologies are not royalty-free. MPEG-2 Video (used in DVDs, satellite TV, digital broadcast TV, and more), H.264/AVC (used in Blu-ray Discs and many internet streaming services), and H.265/HEVC (the recommended codec for 8K TV) are all laden with royalty claims and patents. Sometimes the fees are waived, sometimes they are not. For example, Panasonic has over 1,000 patents related to H.264, and Samsung has over 4,000 patents related to H.265!
The AV1 codec is designed to be royalty-free. It has lots of big names supporting it, which means that a legal challenge against the combined patents pools and financial muscle of Google, Adobe, Microsoft, Facebook, Netflix, Amazon, and Cisco, would be futile. However, that hasn’t stopped some patent trolls, like Sisvel, from rattling their chains.
Also:How to smartphone cameras work?
AV1 codec is 30% better than H.265
Besides being royalty-free and open-source friendly, AV1 needs to actually offer advantages over already established technologies. Aomedia (the guardians of AV1 codec) claim it offers 30% better compression than H.265. That means it uses less data while offering the same quality for 4K UHD video.
There are two important metrics for any video codec. The bitrate (i.e. the size) and the quality. The higher the bitrate, the larger the encoded files. The larger the encoded files, the greater the amount of data that needs to be streamed. As the bitrate changes, so does the quality. In simple terms, if there is less data then the fidelity and accuracy to the original source material will decrease. The more data, the better chance of representing the original.
Video codecs like AV1 (and H.264/H.265) use lossy compression. That means that the encoded version is not the same (pixel by pixel) as the original. The trick is to encode the video in such a way as to make the losses imperceivable to the human eye. There are lots of techniques to do this and it is a complex subject. Three of the principal techniques are to use incremental frame changes, quantization, and motion vectors.
The first is a simple win in terms of compression, rather than send a full frame of video 30 times a second (for a 30fps video), why not just send the changes from one frame to the next. If the scene is two people throwing a ball around then the changes will be the ball and the people. The rest of the scene will remain relatively static. The video encoder need only worry about the difference, a much small data set. Whenever the scene changes, or at forced regular intervals, a full-frame (a keyframe) needs to be included and then the differences are tracked from that last full-frame.
When you take a photo on your smartphone the chances are that it is saved in JPEG format (a .jpg file). JPEG is a lossy image compression format. It works by using a technique called quantization. The basic idea is this, a given segment of a photo (8×8 pixels) can be represented by a fixed sequence of shaded patterns (one for each color channel) layered on top of each other. These patterns are generated using a Discrete Cosine Transform (DCT). Using 64 of these patterns an 8×8 block can be represented by deciding how much of each pattern is needed to get an approximation of the original block. It turns out that maybe only 20% of the patterns are needed to get a convincing imitation of the original block. This means that rather than storing 64 numbers (one per pixel), the image with lossy compression may only need 12 numbers. 64 down to 12, per color channel, is quite a saving.
The number of shaded patterns, the transforms need to generate them, the weighting given to each pattern, the amount of rounding that is done, are all variable and alter the quality and the size of the image. JPEG has one set of rules, H.264 another set, AV1 another set, and so on. But the basic idea is the same. The result is that each frame in the video is, in fact, a lossy representation of the original frame. Compressed and smaller than the original.
Third, there is motion tracking. If we go back to our scene of two people throwing around a ball, then the ball travels across the scene. For some of its travels, it will look exactly the same, so rather than send the same data again and about the ball, it would be better to just note that the block with the ball has how moved a bit. Motion vectors can be complex and finding those vectors and plotting the tracks can be time-consuming during encoding, but not during decoding.
It is all about the bits
The supreme battle for a video encoder is to keep the bitrate low and the quality high. As video encoding has progressed over the years the aim of each successive generation was to decrease the bitrate and maintain the same level of quality. At the same time, there has also been an increase in the display resolutions able to consumers. DVD (NTSC) was 480p, Blu-ray was 1080p and today we have 4K video streaming services and we are edging slowing to 8K. A high screen resolution also means more pixels to represent which means more data is needed for each frame.
The “bitrate” is the number of 1’s and 0’s that are used, per second, by the video codec. As a starting point, a rule of thumb, the higher the bitrate the better the quality. What bitrate you “need” for good quality depends on the codec. But if you use a low bitrate the picture quality can disintegrate quickly.
When the files are store (on a DVD disc, Blu-ray disk, or on a hard drive) the bitrate determines the file size. To make things simple we will ignore any audio tracks and any embedded information inside of a video stream. If a DVD is roughly 4.7GB and you wanted to store a two hour (120 minutes or 7200 seconds) movie, then the maximum bitrate possible would be 5200 kilobits per second or 5.2Mbps.
Megabits vs megabytes:Megabits per second (Mb/s) vs Megabytes per second (MB/s).
In comparison, a 4K video clip straight out of my Android smartphone (in H.264) used 42Mbps, around 8x higher, but while recording at a resolution with around 25x as many pixels per frame. Just looking at those very rough numbers we can see that H.264 offers at least 3x better compression than MPEG-2 Video. The same file encoded in H.265 or AV1 would use roughly around 20Mbps, meaning that both H.265 and the AV1 codec offer twice as much compression as H.264.
These are very much rough estimations about the compression ratios available because the numbers I have given imply a constant bitrate. However, some codecs allow videos to be encoded in a variable bitrate governed by a quality setting. This means that the bitrate changes moment by moment, with a predefined maximum bitrate used when the scenes are complex and lower bitrates when things are less cluttered. It is then this quality setting that determines the overall bitrate.
There are various ways to measure quality. You can look at the peak signal to noise ratio as well as other statistics. Plus you can look at the perceptive quality. If 20 people what the same video clips from different encoders, which ones will be ranked higher for quality.
This is where the 30% better compression claims come from. According to different bits of research, a video stream encoded in AV1 can use a lower bitrate (by 30%) while achieving the same level of quality. From a personal, subjective point of view that is hard to verify and equally hard to dispute.
Above is a montage of a single frame from the same video, encoded in three different ways. The top left is the original video. Next to the right is the AV1 codec, with H.264 below it and H.265 below the original source. The original source was 4K. This is a less than perfect method to visualize the differences, but it should help illustrate the point.
Due to the reduction of the overall resolution (this is a 1,920 x 1,080) image, I find it hard to spot much of a difference between the four images, especially without pixel peeping. Here is the same type of montage but with the image zoomed in, so we can pixel peep, a little.
Here I can see that the original source video probably has the best quality, and the H.264 the worst (relative) to the original. I would struggle to declare a winner between H.265 and AV1. If forced I would say the AV1 codec does a better job of reproducing the colors on petals.
One of the claims that Google made about its use of AVI in its Duo app was that it would, “improve video call quality and reliability, even on very low bandwidth connections.” Back to our montage, this time each encoder has been forced to 10Mbps. This is completely unfair for H.264 as it doesn’t claim to offer the same quality at the same bitrates as H.265/Av1, but it will help us see. Also, the original is unchanged.
H.264 at 10Mbps is clearly the worst of the 3. A quick glance at H.265 and AV1 leaves me feeling that they are very similar. If I go pixel peeping I an see that AV1 is doing a better job with the grass in the top left-hand corner of the frame. So AV1 is the champ, but on points only, it certainly wasn’t a knock-out.
AV1 codec isn’t ready for the masses (yet)
Royalty-free and 30% better. Where do I sign-up? But there is a problem, actually a huge problem. Encoding AV1 files is slow. My original 4K clip from my smartphone is 15 seconds long. To encode it, using software only, into H.264, on my PC takes around 1 minute, so four times longer than the clip length. If I use hardware acceleration available in my NVIDIA video card, then it takes 20 seconds. Just a little longer than the original clip.
For H.265 things are a little slower. Software only encoding takes about 5 minutes, quite a bit longer than the original. Fortunately encoding via hardware into H.265 also takes just 20 seconds. So hardware-enabled encoding of H.264 and H.265 are similar on my setup.
Before all the video geeks start screaming, yes, I know there are a billion different settings that can alter encoding times. I did my best to make sure I was encoding like-for-like.
Next:Does Android use more memory than iOS?
My hardware doesn’t support AV1 encoding, so my only option is software-based. The same 15-second clip, that took five minutes for H.265 in software, takes 10 minutes for Av1. But that wasn’t like-for-like, that was tweaked to get the best performance. I tested several different variations of the quality settings and presets, 10 minutes was the best time. One variation I ran took 44 minutes. 44 minutes for 15 seconds of video. This is using the SVT-AV1 encoder that Netflix is keen about. There are alternatives out there, but they are much slower, like hours and hours, much slower.
|Encoding of 4K 15 sec clip||SW or HW||Time|
Encoding of 4K 15 sec clip:H.264
SW or HW:Software
Encoding of 4K 15 sec clip:H.264
SW or HW:Hardware
Encoding of 4K 15 sec clip:H.265
SW or HW:Software
Encoding of 4K 15 sec clip:H.265
SW or HW:Hardware
Encoding of 4K 15 sec clip:AV1
SW or HW:Software
This means that if I have a one-hour movie I have edited from my vacation way to somewhere exotic, then to convert it to H.265 using hardware acceleration on my PC will take 80 minutes. The same file using the current software AV1 encoders will take 40 hours!
That is why it isn’t ready for the masses (yet). Improvements will come to the encoders. The software will get better and hardware support will start to appear. The decoders are already becoming lean and efficient, that is how Netflix is able to start streaming some content in AV1 to Android devices. But in terms of a ubiquitous replacement for H.264? No, not yet.
One interesting thing about Google’s claims around AV1 for Duo is that it implies AV1 encoding on the client devices and well as AV1 decoding. I emailed Google about this and there were encouraging signs that it was going to tell me some details about its plans for the AV1 codec and Duo, but then everyone on the mailing list fell mysteriously quiet. If anyone from Google does get back to me, then I will let you know!
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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 video codec battle is about to begin. In the post, you are informed of everything regarding to AV1 codec.
Part 1: What Is AV1 Codec
AV1 is the newest video codec launched by the Alliance for the Open Media (AOM). It was first released on March 28, 2018 along with a software-based encoder-decoder as the reference. The initial validated version (1.0.0) was shot out on June 25, 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 2021, with only 3 years of R&D, the AV1 has become a quite usable codec with many exciting new features. Many consider the AV1 codec will dominate the video and streaming market in all probability.
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.
Video Intro: What's AV1 Codec & How to Decode and Encode AV1 Video Files
Part 2: What're the Main Advantages of AV1 Codec
1. Royalty-free and open source. 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.
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, MPV player, so on and so forth.
Royalty Annual Cap
Content Distributoin Fee
US$0.20 per unit
First 100K units each year
• US$25,000 eaech year
Alliance for Open Media
2. Optimized for the Internet. 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.
It is scalable to any modern device at any bandwidth and is designed with a low computational footprint and optimized for the internet and hardware. AV1 is capable of consistent, highest-quality, real-time video delivery, and is flexible for both commercial and non-commercial content, including user-generated content.
Part 3: AV1 vs HEVC: Is AV1 Better than HEVC/H.265?
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 and 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.
Video codec comparison:AV1 vs HEVC/H.265, VVC vs AV1
1. AV1 vs HEVC: Quality and Bitrate Measurement
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:
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.
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. Typically, AV1 codec is 30% better than HEVC in terms of the compression efficiency. It saves up to 30% in bandwidth for the same image quality in HEVC.
Compression performance: AV1 > X265 > VP9 > X264
2. AV1 vs HEVC: The Achilles's Heel - Encoding/Decoding Difficulty
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.
1. 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.
Encoding Time (seconds)
Times Real Time
What can we conclude from the table: Data depicts that the AV1 is about 3x the encoding times of x265 and 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.
2. Decoding Speed
A 6Mbps Elekstra file is converted to Y4M format with FFmpeg script in order to test the decoding speed. From the image, you can see AV1 decoded at .66x real time, with H.264 at 14x, VP9 at 10.5x, and HEVC at 8x real time.
On the other hand, when FFplay is used to play all four files. AV1 won't play at all, which is probably not surprising since it is still in experimental status, while H.264, HEVC and VP9 all played in real time with minimal use of CPU.
What takes AV1 codec 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.
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.
Part 4: What Makes AV1 Different - Innovative Coding Algorithm
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 four of its new features will lead us to the observatory of the codec future.
1. Film Grain Synthesis
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.
2. Constrained Directional Enhancement Filter
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.
3. 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.
4. 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.
Part 5: Can You Watch AV1 Video Now?
As a newly rolling out codec standard, the AV1 is now expanding its business territory. Its bright business outlook 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.
Google, Microsoft, and Mozilla also successively announced their browser support to AV1 codec. 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. Also, the Chrome on desktop adds AV1 encoder to improve video conferencing with WebRTC.
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.
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 2021. 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 to read more about YouTube AV1 video download errors and solution >>
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.
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.
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.
Part 6: How Do You Play AV1 Files?
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? How do you play AV1 file successfully?
Both hardware and software support are required for AV1 content playback. Mostly, it relies on what device and operation system you are working with.
In terms of hardware, NVIDIA has released the specification of their newest NVIDIA RTX 3000 series GPU on september 1st, excitingly announcing their new 3000 series adapt the full AV1 hardware encoder/decoder for better AV1 video watching/streaming experience. GeForce RTX 30 Series are the first discrete GPUs with AV1 decoders (as part of our new 5th generation NVIDIA Decoder), enabling users to take advantage of AV1 on desktops and in media centers. Click to learn more AV1 hardware support >>
In terms of software, Android 10 onwards, chrome 70 onward, linux can decode AV1 video. While at the time of writing, macOS and iOS seem to have no play for AV1 support. Can you play AV1 on any of your Apple device or other gadget?
Yes. There are two ways to play AV1 video.
For the first, any device with an AV1 decoder built-in will be able to play AV1 video. For example, you can play AV1 video on Windows 10 as long as you download and install AV1 codec extension beforehand. 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. For example, we're happy to see 5KPlayer, VLC, CNX players, KMPlayer, and more announce the support of AV1 codec. With these media player in hand, you can play AV1 file without even downloading AV1 decoder.
For the second, AV1 has one major flaw. As we mentioned above, the encoding and decoding speed is the bottleneck that restrict the performance and user experience for video lovers. It is a heavier codec that asks for high-end hardware to decode it. Or else, playing AV1 file will end up with errors. One feasible way to fix the issue is to convert AV1 to MP4 (H.264/HEVC) that is more compatible with your device. To do the task, WinX Video Converter would be a decent choice.
As the leading software provider, WinXDVD announces the timely support of AV1 codec decoding and downloading. That means you can save the online AV1 video from your browser and even convert AV1 video to popular HEVC, H.264, MP4, MOV, MKV, and more for robust playback.
Part 7: Some FAQ about AV1 Codec
1. 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.
2. Does YouTube use AV1 codec?
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.
3. 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".
3. Is there a way to download AV1 codec video from video sites?
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 to download AV1 codec videos since AV1 codec not yet widely supported by video software solutions. But you can do it with the help of certain third party software, like WinX Video Converter.
As stated, AV1 codec isn't yet mature & in lack of hardware support. Digiarty has long-term dedicate to multimedia softwares and the WinX Video Converter is now supporting convert AV1 codec video. At the moment that less video software support AV1 related converting/ modifying, WinX Video Converter Deluxe is one no doubt a good choice.