Eagerly awaited across the tech industry, this week the Alliance for Open Media (AOMedia) has published the first complete version of the bitstream and decoding process specification for their royalty-free AV1 video codec. The release of the AV1 1.0 spec will enable backers of AOMedia to add support for the technology to their products or services, including taking the all-important step of finalizing the designs for the low-power hardware decoders critical for driving the codec's adoption. At least initially, AV1 will be used primarily for streaming video and user-generated content as an alternative to HEVC and its ongoing royalty disputes, but eventually adoption of AV1 may expand to other applications.

The AV1 open-source video codec was developed with 4K+ ultra-high-def resolutions, HDR, and wide color gamut in mind. Among the key features the new codec, AOMedia mentions a 30% more efficient compression algorithm compared to existing methods, predictable requirements for computational capabilities of hardware, and maximum flexibility and scalability. The backers of the AV1 want the codec to be ubiquitous across devices and platforms, therefore expect it to be supported not only by major chipmakers, software designers, and service providers, but also by leading makers of consumer electronics.

AOMedia does not disclose key technological peculiarities of the AV1 video codec in a short whitepaper form, meanwhile parsing through a 600-page bitstream and decoding spec for developers does not necessarily help to explain all the peculiarities of the tech in general. Therefore, I am going to limit technical details about the AV1 to a necessary minimum here.

On a high level, the AV1 is conceptually similar to existing codecs, such as H.264 or H.265. AV1 uses the same basic elements as various codecs have used for well over a decade: block-based coding, variable block sizes (up to 128x128 pixels), block motion compensation, intra-frame compression, forward-integer transform and so on. Meanwhile, since we are talking about compression algorithms more efficient than existing ones, it is natural that the AV1 has a number of advantages over contemporary codecs.

The AV1 performs internal processing in 8, 10 or 12 bits per sample precision, it also supports all three widespread types of chroma subsampling (4:2:0, 4:2:2, 4:4:4), and virtually all major color gamuts and formats (sRGB, BT.2020 (both 10-bit and 12-bit), BT.2100, etc.). The BT.2020 and the BT.2100 recommendations include support not only for 3840×2160, but also for 7680×4320 (8K) resolution, so the AV1 is technically ready for the next-gen monitors and TVs.

AV1 Profiles
seq_profile Bit Depth sRGB Gamut Support Chroma Subsampling
0 8 or 10 No YUV 4:2:0
1 8 or 10 Yes YUV 4:4:4
2 8 or 10 No YUV 4:2:2
2 12 Yes YUV 4:2:0
YUV 4:2:2
YUV 4:4:4

Speaking of displays, it is necessary to note that the AV1 was designed to be compatible with existing interconnections, such as DisplayPort, eDP, HDMI and so on. That said, the technology should also be compatible with contemporary content protection technologies.

The publication of the AV1 spec 1.0 is merely the first step towards adoption of the technology by the market. AOMedia expects content creation tools and desktop browsers to begin to roll out support for AV1 later this year. To ensure this, AOMedia released an unoptimized/experimental AV1 software decoder and encoder for use in software applications. Then, sometimes in 2019, the consortium anticipates select chips and programs to support the tech. More widespread support of the AV1 along with adoption by software is projected for 2020.

Speaking of adoption, the list of AOMedia members includes a variety of influential companies, including Apple, Amazon, AMD, Arm, Broadcom, Facebook, Google, Hulu, Intel, IBM, Microsoft, Netflix, NVIDIA, Realtek, Sigma and many others. These companies either control huge ecosystems themselves, or develop chips that are used by hundreds of millions of customers worldwide. Their support will ensure widespread adoption of the AV1 in the next decade. In the meantime, AOMedia has already started R&D for the AV2, which is to succeed the AV1 codec.

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Source: AOMedia

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  • Santoval - Sunday, April 01, 2018 - link

    "Recording 4-8K with ZERO compression should be allowed if the hardware can handle it"
    Among your many wild dreams/demands that got my eye the most. Although much or most consumer (and *all* prosumer) video recording hardware is capable of zero compression that will never happen due to a thing called "market differentiation". In plain words that means that the camera manufacturers love the very fat profit margins they get from professional video cameras so they would never risk them by moving zero compression down the food chain.

    That looks like it is an unwritten rule that is somehow obeyed even by non professional camera companies. Video/movie professionals require uncompressed video because they can manipulate it, color grade it, edit it, insert special effects in etc much more gracefully. In recent years uncompressed video started being introduced to mid-range prosumer DSLRs (which record video but are not video focused) but that is the current lowest limit I am aware of.
    Reply
  • ಬುಲ್ವಿಂಕಲ್ ಜೆ ಮೂಸ್ - Sunday, April 01, 2018 - link


    Using the calc @ >
    https://www.extron.com/product/videotools.aspx

    4K @ 60fps X 16bit 4:4:4 = 4.45GB/sec
    8K X 60fps X 16 bit 4:4:4 = 17.82 GB/sec

    can you show me any consumer video camera outputting Raw video at more than 4 Gigabytes per second?
    Reply
  • ZeDestructor - Tuesday, April 03, 2018 - link

    That calculator's math is not correct for videocamera raw footage.

    1. That calculator assumes 3 subpixels per pixel. In almost every camera on the market, be it a basic potato you'd have to pay people to take all the way to the $70k RED Monstro you have a bayer pattern sensor with 1 subpixel per pixel, unlike monitors. This significantly reduces the amount data you actually need to record when running with raw.

    2. It uses math that produces the bandwidth needed to drive a monitor at 4K using worse than CVT timings, and that adds a ton (around 20-24%) of overhead that you don't have in a camera raw In a camera raw, you have the raw frame, some metadata about exposure, lenses, shutter speed, location etc and timecodes. Besides, anything past 2560x1600 is using CVT-R2 timings, which have much lower overhead (less than 5% for 4K and up)

    Here's the actual numbers for raw 4K/8K capture, frames only, so add some overhead for metadata (think <10mbit/s, since you don't need blanking intervals here):

    3840 * 2160 * 60fps * 16bit * 1 subpixel @ RGB/4:4:4 chroma: 7.96Gbit/s = ~1GB/s
    7680 * 4320 * 60fps * 16bit * 1 subpixel @ RGB/4:4:4 chroma: 31.85Gbit/s = ~4GB/s

    This all fits just fine using a few SDI cables (remember, those only go up to 12Gbit/s and that's what they use in cinema, TV and live broadcast) to get raw footage off the camera and into some external capture device.

    You can also do that over HDMI or DP just fine (after de-bayering). In fact, this is done right now: the higher-end DSLRs and video cameras all have HDMI output, so you can just feed the live signal into a regular ordinary HDMI capture card and cap it raw that way, but you'll only see that on higher-end kit, because it's expensive to have fast IO in a space as small and oddly-shaped as a camera.
    Reply
  • bill44 - Saturday, March 31, 2018 - link

    Dynamic Metadata support? HFR supported? Reply
  • SeleniumGlow - Sunday, April 01, 2018 - link

    The excessive use of "Speaking of..." phrase to start paragraphs nearly made me think that this was written by Linus G Sebastian. However, I was wondering if there was anything new with audio compression schemes, and I think AV1 is just about video compression? Reply
  • ZeDestructor - Monday, April 02, 2018 - link

    Opus happened not that long ago for audio, and it will be a long while before we see anything better (if ever). The reality is that despite ISP's best efforts, overall internet speed is going up every year, making audio such a small item to optimize for. I mean, what's ~128kbit/s stereo (that's where I've seen audio typically max out at) compared to a 4+mbit/s video stream (4mbit/s is around where 1080p streams sit)? Reply
  • errorr - Monday, April 02, 2018 - link

    The major things about AV1 is that it seems to be really focused on the needs of OTT 4k video. Google and others have stated that it is less efficient at lower than HD resolutions, probably not much better at HD, and somewhere around 30% better at higher resolutions. The real problems left to solve are much more on the encode than the decode end. Netflix is asking for somewhere between 5x-10x more computationally intensive before they will commit to adopting it. Right now they are stating around 200x the computational complexity on current encoders. The next year where they optimize the encoders will determine if AV1 succeeds. Reply
  • errorr - Monday, April 02, 2018 - link

    I also think it is an open question whether consumer devices will ever get powerful enough to have even HW accelerated encoding for consumer produced video. The AV1 codec is focused on large distributors like Google, Netflix, and recently Facebook and their needs. The massive computational needs of AV1 are perfect for these big distribution platforms as cpu cycles are cheap and they are focused on reducing their bandwidth costs. Reply
  • mode_13h - Tuesday, April 03, 2018 - link

    What I don't understand is how they can be so confident some well-resourced patent troll won't come out of the woodwork and submarine the standard, just when it's really gaining momentum.

    It seems to me what we really need is some legal framework around standards that says if you don't state your claim before a standard is ratified by some official body like ISO, then you forfeit your rights to said IP within that context.
    Reply
  • tuxRoller - Wednesday, April 04, 2018 - link

    There's no guarantee for any of these pools (as mpegla discovered) but aom has a massive number of patents under its belt, it was very carefully designed to avoid known patents, and they've setup a legal defense fund.

    http://www.streamingmedia.com/Articles/News/Online...
    Reply

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