Improve video quality and save costs with live AV1 video

What is AV1

AV1 was developed as a state-of-the-art video codec for distribution over the web by the Alliance for Open Media (AOMedia), which consists of representation from several companies including Amazon, Apple, Netflix, Intel, and Nvidia, and others. It’s designed to succeed AVC, VP9, and HEVC as a next generation of natively supported video codes on consumer hardware devices. AV1 supports up to 12-bit color, HDR, and UHD+ frame sizes for distribution of premium content. In addition, AV1 builds into the specification support for web-focused features such built-in security protocols, end-to-end encryption, and film grain synthesis (a method of reducing the bandwidth required to compress and transmit theatrical content while maintaining the texture, look, and feel of the original film).

AOMedia released the formal specification in June 2018; however, the complexity of the encoding techniques used in AV1 required optimizations for several months before it could reach the encoding throughput of other competitive codecs. AV1’s complexity allows for more compressed video streams compared to popular web codecs like AVC and HEVC, so that video can be delivered at the same quality as AVC and HEVC but at lower bitrates.

Live AV1 encoding in the cloud

In 2020, Amazon Web Services (AWS) added support for AV1 in AWS Elemental MediaConvert, a file-based video encoding service. Now, support has been expanded and the AV1 video codec is available across the suite of AWS Media Services. Customers can use AV1 in AWS Elemental MediaLive, AWS Elemental MediaPackage, and AWS Elemental MediaTailor to produce both live and on-demand streams with ad insertion. This means customers can stream and package live AV1 encoded content, prepare AV1 VOD assets and ads, and insert ads into AV1 encoded videos.

With the launch of AV1 in MediaLive, AWS is one of the first cloud providers with live AV1 encoding. MediaLive can encode large adaptive bitrate (ABR) stacks, including AV1 outputs by scaling processing across multiple instances, completely seamlessly to the operator. In the background, AWS has a dedicated team of experts who constantly improve video quality and introduce new video processing features and codecs. This means that customers get continuous video quality improvements and new capabilities by using AWS Media Services, and can delight their viewers with video quality improvements and premium features while also reducing bandwidth and costs.

Viewing device ecosystem and support for AV1

The greater complexity of AV1 carries over to the decoder side of the ecosystem, requiring more hardware resources to decode the video stream and render it on screen. When new codecs are launched, decoding is typically handled at the software level, which leverages the device CPU to reconstruct video frames. While this ensures broad device compatibility since specialized decoder chips are not required, the process is resource intensive and the CPU experiences a heavy workload, leading to heat generation and high energy consumption. CPU-only decoding on mobile devices results in higher battery use, which drains the battery more quickly and causes frustration for the user. While it may not have a major impact on desktop computer users or other devices connected to wall outlets, this energy inefficiency can still result in higher electricity costs and sustainability issues.

New codec adoption typically does not accelerate broadly until consumer devices containing dedicated hardware decoding support begin to saturate the market. These devices offload the complex decoding of a compressed video stream to purpose-built chips or specialized hardware built specifically to efficiently and quickly perform the workload. Not only does this free up the CPU in the device to perform other tasks, the higher efficiency consumes considerably less energy, restoring the battery life expected of mobile devices.

Factors beyond the availability of hardware devices alone influence the extent of new codec adoption. Consumers don’t replace their devices immediately every time manufacturers release a new model, and these device manufactures typically release enhanced features like specialized decoder hardware in higher-end options in the model lineup before trickling down into the entry level models. The economics of scale inherently limit the availability of content using new codecs until these factors converge and the combination of enhanced viewer experience, efficient hardware, and broad consumer device adoption with native decoder support make them economically viable.

In 2024, the majority of new televisions, cell phones, and computers sold have native AV1 decode capabilities, a trend that has been building towards the critical mass required before adoption can accelerate.

AV1 impact on streaming businesses

Running a streaming business has many factors that impact costs. Content acquisition, steaming rights, encoding, hosting, origination, and delivery costs add up. The direct-to-consumer industry has seen a shift in streaming service models with increasing monthly fees and Free Ad-supported Streaming Television (FAST) offerings to keep costs affordable. Any technology that can affect the underlying expenses of running a streaming business will help to ensure competitive end-user pricing and profitability.

In addition to the cost of operation, users with limited bandwidth are often faced with a poor viewing experience, which consists of low-resolution, blocky video quality, and/or frustrating re-buffering during playback. A reduction in bandwidth required to deliver video streams enhances the viewing experience by improving the perceptual video quality within the bandwidth constraints. Technologies that can improve the viewing experience at low bitrates will produce a competitive edge for streaming services that deliver content to users in these low bandwidth environments.

AV1 excels at both reducing the bandwidth required to reproduce a quality video experience and producing a better quality image as the bitrate becomes constrained. In other words, AV1 can both compress the video stream more than commonly used video codecs and degrade in quality when bandwidth is constrained in ways that are less perceptually noticeable and jarring to the viewer.

While the cost of content acquisition and streaming rights are outside of the scope of this blog post, the expenses related to encoding, hosting, origination, and delivery are directly applicable. While higher encoding complexity increases the cost of encoding, lower bitrates and smaller files sizes reduce the cost of the other elements in the operational supply chain. The following example shows how the benefits can outweigh the portion related to encoding.

The operational costs of streaming are heavily influenced by the volume of data delivered to viewers. Content Delivery Network (CDN) expenses are a significant portion of the total bill of running a streaming platform (excluding the expense of acquiring content rights). It is estimated that between stream encoding, packaging, hosting, and delivery, 95% of expenses are directly related to bandwidth consumed and that bitrate reductions of the video stream have a direct impact on reducing the cost of streaming.

Cost modeling example with AV1

Let’s construct a hypothetical streaming event to highlight the savings realized by using an advanced codec like AV1. This streaming event uses an adaptive bitrate (ABR) ladder with six qualities up to 1080p HD at 12Mbps with the H.264/AVC codec. The encoding costs for this ABR output are $3.60 per hour and the CDN charges $0.01 per GB for distribution. The viewing distribution of different bitrates in the ABR ladder results in an average of 8.38Mbps per viewer for the event, which equals 3.68GB per hour.

With these assumptions, for 5,000 viewers and a two-hour event, the total cost would be $375.20.

Encoding: ($3.60 x 2 hours) = $7.20
CDN distribution: (3.68GB x 5,000 viewers x 2 hours x $0.01) = $368.00
Total cost with AVC only: $7.20 + $368.00 = $375.20

Now, let’s add an AV1 ABR ladder to the event stream alongside the AVC version with the assumption that one third of the viewers will be able to watch this version. The encoding cost would increase by an additional $19.20 per hour to encode the AV1 live video. For the AV1 version, let’s also assume that we will be able to lower the bitrate by 40% and match the quality of AVC. For the 33% of the viewers, or 1,650, that can view the AV1 version, they will average 5.03Mbps per viewer for the event, or 2.21GB per hour. With these assumptions, if the two-hour event had 5,000 viewers, the total cost would be $365.09.

Encoding: ($3.60 x 2 hours) + ($19.20 x 2 hours) = $45.60
(3.68GB x 3,350 viewers x 2 hours x $0.01) = $246.56
(2.21GB x 1,650 viewers x 2 hours x $0.01) = $72.93
CDN distribution: $246.56 + $72.93 = $319.49
Total cost with AVC and AV1: $45.60 + $319.49 = $365.09

In this simple example, the savings were $10.11 ($375.20 – $365.09) for the two-hour event. For larger scale events, the encoding cost remains the same, but savings increase as more viewers benefit from the lower bitrates of AV1 without compromising on video quality. To illustrate, if the event had 100,000 viewers (20 times more), the savings would be nearly $500 instead of just $200 (20 x $10).

Conclusion

AV1 is a modern codec with higher complexity, which takes more computing power to encode but provides for more compressed video streams at the same quality compared to AVC and HEVC. Over time, the number of devices with native AV1 decode in hardware will only continue to grow. Because bitrate savings translates directly into CDN savings, lower costs can be achieved by adding AV1 outputs even for small events and these costs decrease even more as viewership increases. Customers can use AV1 in AWS Elemental MediaConvert for VOD workflows, and now MediaLive, MediaPackage, and MediaTailor to produce live streams with ad insertion. To learn more and get started, please visit the AWS Elemental MediaConvert or AWS Elemental MediaLive