Limited Time Free!  Sign up for 14-day trial plan (no credit card needed) with WAF and Bot Management!
Get Started Now 

Understanding AV1: The Next Generation of Video Compression and The Future of Video Coding

EdgeOne-Dev Team
Oct 21, 2024

Understanding  AV1: The Next Generation of Video Compression and The Future of Video Coding
Understanding  AV1: The Next Generation of Video Compression and The Future of Video Coding

In the ever-evolving landscape of digital media, video compression technology plays a crucial role in delivering high-quality content while optimizing bandwidth usage. Among the latest advancements in this field, AV1 (AOMedia Video 1) has emerged as a promising codec that aims to revolutionize video streaming and storage. This article delves into the intricacies of AV1, exploring its features, benefits, and potential impact on the future of video compression. If you are looking to transcode, distribute, and host AV1 videos, you might want to consider our services.

What is AV1?

AV1 was developed by the Alliance for Open Media (AOMedia), a consortium of leading tech companies including Google, Mozilla, Microsoft, and Amazon. Formed in 2015, AOMedia set out to create a next-generation video codec that would be both highly efficient and royalty-free. The primary goals were to improve compression efficiency, reduce bandwidth requirements, and provide a viable alternative to proprietary codecs.

AV1 is designed to be more efficient and flexible than its predecessors, such as H.264 and H.265 (HEVC), and is being adopted by an increasing number of platforms and services, including YouTube, Netflix, and Facebook. It's also supported by several web browsers, such as Google Chrome and Firefox.

AV1 incorporates a wide array of advanced coding tools and techniques. These include improved intra-frame prediction, more flexible partitioning, and enhanced motion compensation. One of AV1's standout features is its ability to adapt to different types of content, optimizing compression for both high-motion scenes and static images within the same video.

AV1 has several advantages that make it an attractive choice for video streaming and encoding. Here are some of them:

  1. Improved Compression Efficiency: AV1 is designed to provide superior video compression efficiency compared to existing standards like H.264, VP9, and HEVC. This means it can deliver similar video quality at lower bitrates, which can lead to significant bandwidth savings.
  2. Royalty-Free: Unlike some other video codecs, AV1 is royalty-free. This means companies can use it without having to pay licensing fees, making it a cost-effective choice, especially for large-scale streaming services.
  3. Broad Industry Support: AV1 has been developed by the Alliance for Open Media, which includes major tech companies like Google, Amazon, Microsoft, and others. This broad industry support helps ensure wide compatibility and adoption.
  4. Future-Proof: AV1 is designed with the future in mind, supporting features like high dynamic range (HDR), wide color gamut (WCG), and high frame rates, making it a suitable choice for next-generation video applications.
  5. Better Streaming Experience: Due to its improved compression efficiency, AV1 can provide a better streaming experience, with less buffering and higher quality video, especially in areas with poor network conditions.
  6. Open Source: Being an open-source project, AV1 encourages innovation and allows for continuous improvements and optimizations by the community.

How does AV1 Codec Work?

1. Video Compression Basics

AV1 uses lossy compression techniques to reduce the size of video files while maintaining visual quality. It achieves this through several key processes:

  • Prediction: AV1 predicts the values of pixels based on the values of neighboring pixels. This is done using various prediction modes, which can be intra-frame (within the same frame) or inter-frame (across different frames).
  • Transformation: After prediction, the residual data (the difference between the predicted and actual pixel values) is transformed using techniques like Discrete Cosine Transform (DCT) or other transforms. This helps to concentrate the energy of the signal into fewer coefficients.
  • Quantization: The transformed coefficients are quantized, which reduces the precision of the values. This step is crucial for reducing the amount of data, but it also introduces some loss of quality.
  • Entropy Coding: The quantized coefficients are then encoded using entropy coding techniques, such as Context-Adaptive Binary Arithmetic Coding (CABAC) or Context-Adaptive Variable-Length Coding (CAVLC). This step further compresses the data by taking advantage of the statistical properties of the data.

2. Key Features of AV1

AV1 incorporates several advanced features that enhance its compression efficiency:

  • Block Partitioning: AV1 allows for flexible partitioning of frames into blocks of various sizes (from 4x4 to 128x128 pixels). This flexibility helps optimize the encoding process based on the content of the video.
  • Multiple Reference Frames: AV1 can use multiple reference frames for inter-frame prediction, which improves the accuracy of motion estimation and reduces artifacts.
  • Adaptive Loop Filter (ALF): AV1 includes an adaptive loop filter that helps to reduce artifacts and improve visual quality by filtering the reconstructed video after decoding.
  • Intra-Prediction Modes: AV1 supports a wide range of intra-prediction modes, allowing for better prediction of pixel values based on neighboring pixels.
  • Tile and Frame Parallelism: AV1 supports tiling, which allows the encoding and decoding processes to be parallelized, improving performance on multi-core processors.

3. AV1 Encoding and Decoding Process

Encoding

The encoding process involves analyzing the video frames, applying the aforementioned techniques, and generating a compressed bitstream. The encoder optimizes the compression based on the content and desired quality. Here's a simplified overview:

  1. Input: The raw video footage is input into the encoder.
  2. Partitioning: The encoder breaks down the video into smaller blocks or "tiles" for more efficient processing.
  3. Prediction: The encoder predicts the content of each block based on the content of neighboring blocks. This is done using intra-frame prediction (for blocks within the same frame) and inter-frame prediction (for blocks in reference frames).
  4. Transform and Quantization: The difference between the predicted and actual content of each block (the "residual") is transformed into the frequency domain and then quantized to reduce its size.
  5. Entropy Coding: The quantized residuals and prediction information are further compressed using entropy coding.
  6. Output: The compressed video stream is output from the encoder.

Decoding

The decoder takes the compressed bitstream and reconstructs the video frames. It reverses the encoding process, applying inverse transformations, de-quantization, and entropy decoding to produce the final video output.

  1. Input: The compressed video stream is input into the decoder.
  2. Entropy Decoding: The entropy-coded data is decoded back into quantized residuals and prediction information.
  3. Dequantization and Inverse Transform: The quantized residuals are dequantized and transformed back into the spatial domain.
  4. Reconstruction: The predicted content of each block is combined with the dequantized and inverse-transformed residuals to reconstruct the original content.
  5. Output: The reconstructed video is output from the decoder.

4. Performance Comparison

Regarding compression efficiency, AV1 consistently outperforms older codecs like H.264 and VP9. Studies have shown that AV1 can achieve the same perceptual quality as HEVC at bitrate savings of around 30%.

At different bitrates, AV1 maintains a quality advantage over its competitors. This is particularly noticeable at lower bitrates, where AV1's advanced prediction and adaptation techniques allow it to preserve more detail and clarity.

When comparing AV1 to other codecs, several key differences emerge:

  • AV1 vs H.264: AV1 offers significantly better compression efficiency, typically achieving the same quality at half the bitrate of H.264. However, H.264 remains more widely supported and less computationally intensive.
  • AV1 vs H.265 (HEVC): While HEVC provides excellent compression, AV1 can achieve similar or better quality at lower bitrates. AV1's royalty-free nature also gives it an advantage over HEVC's complex licensing structure.
  • AV1 vs VP9: As AV1's predecessor, VP9 shares some similarities in approach. However, AV1 offers improved compression efficiency and better performance at lower bitrates.
  • AV1 vs MP4: It's important to note that MP4 is a container format, not a codec. AV1-encoded video can be stored in various container formats, including MP4. The comparison here is more about flexibility and compatibility than compression efficiency.

However, AV1's superior compression comes at the cost of increased computational complexity. Encoding times for AV1 are significantly longer than for H.264 or HEVC, which can be a challenge for live streaming or real-time applications. Decoding speed has improved with hardware acceleration, but support is not yet as widespread as for more established codecs.

How to Play AV1?

Major streaming platforms like YouTube and Netflix have begun adopting AV1 for select content, particularly for mobile and bandwidth-constrained scenarios. Browser support for AV1 is growing, with Chrome, Firefox, and Edge all offering native decoding capabilities. 

Hardware support is expanding on the device front. Many recent smartphones and smart TVs now include AV1 decoding capabilities, and some newer GPUs offer hardware-accelerated AV1 encoding and decoding.

Playing AV1-encoded videos can be done using various media players and web browsers that support the AV1 codec. Here are some ways to play AV1:

Media Players

  • VLC Media Player: VLC is a free and open-source media player that supports a wide range of codecs, including AV1. Make sure you have the latest version installed.
  • MPV: This is another open-source media player that supports AV1.

Windows 10's built-in Movies & TV app also supports AV1, but you might need to download the AV1 Video Extension from the Microsoft Store.

Web Browsers

  • Google Chrome: Chrome has added support for AV1 from version 70 onwards.
  • Mozilla Firefox: Firefox also supports AV1 from version 67 onwards.
  • Microsoft Edge: The newer versions based on Chromium also support AV1.
  • Online Platforms: Many online platforms like YouTube and Netflix have started to support AV1. You can stream AV1 videos directly on these platforms if you're using a compatible web browser.

Remember, decoding AV1 can be more CPU-intensive than other codecs, so make sure your device has sufficient resources to ensure smooth playback. In the future, more hardware devices will likely include dedicated AV1 decoding chips to improve performance.

Use Cases and Future Prospects

AV1 is designed for a variety of applications, including:

  • Streaming Video: AV1 is particularly well-suited for streaming applications, as it provides high-quality video at lower bitrates, which is essential for efficient bandwidth usage.
  • Video Conferencing: The codec's efficiency can improve the quality of video calls, especially in low-bandwidth scenarios.
  • Content Delivery: AV1 is being adopted by major platforms (like YouTube, Netflix, and others) for delivering video content over the Internet.

Despite its advantages, AV1 faces some challenges. The high computational requirements for encoding remain a significant hurdle, particularly for live streaming and user-generated content. However, ongoing development of more efficient encoders and increasing hardware support are gradually addressing this issue.

Looking to the future, work is already underway on AV1's successor, tentatively named AV2. This next-generation codec aims to further improve compression efficiency while addressing some of AV1's current limitations.

The development and success of AV1 also highlight the importance of open standards in driving innovation in video technology. As we move towards increasingly data-intensive applications like 4K streaming, VR, and beyond, codecs like AV1 will play a crucial role in making these technologies accessible and efficient.

In conclusion, while challenges remain, AV1's potential to reshape the landscape of video compression is undeniable. Its continued development and adoption will be a trend worth watching for anyone interested in the future of digital media and internet technologies.

Conclusion

AV1 represents a significant leap forward in video compression technology. Its combination of superior compression efficiency, royalty-free nature, and growing industry support positions it as a key player in the future of digital video. As hardware support increases and encoding efficiency improves, AV1 is likely to see wider adoption across various platforms and use cases.

Tencent EdgeOne VOD (Video on Demand) offers an extensive suite of features such as cloud video storage, video transcoding, and video playback acceleration, ensuring a quick, flexible, and high-quality video delivery. This allows you to focus on your core business, pick and choose services as per your needs, and swiftly adapt to market changes. We also offer a free trial for you to get started. Click here to begin your journey with us.