AOM AV1 3.6 Brings More Performance & Efficiency Optimizations

Google engineers on Tuesday released AOM AV1 v3.6 as the newest version of their open-source, CPU-based AV1 encoder.

As with most AOM AV1 releases, enhancing the compression efficiency and performance optimizations were among the key changes with version 3.6. AOM AV1 3.6 also adds RISC-V architecture support when using the GCC compiler toolchain.

As for the key optimizations with AOM AV1 3.6 worth getting excited about:

- Compression Efficiency Improvements
* Peak compression efficiency in VOD setting is improved by 1%.
* 0.7% - 2.2% RTC encoding BDrate gains for real time speed 8 to 10.
* 15% RTC encoding BDrate gains for screen content speed 10.

- Perceptual Quality Improvements
* Resolved a visual quality issue that was reported for high resolution clips (2K) for speed 4 and above in VOD use case.
* Visual quality improvements to screen content coding.
* Quality improvements to temporal layer RTC coding.

- Speedup and Memory Optimizations
* RTC single-thread encoder speedup:
o ~6% instruction count reduction for speed 5 and 6.
o ~15% instruction count reduction for speed 7.
o ~10% instruction count reduction for speed 8 to 10 (>=360p resolutions).
* RTC multi-thread encoder speedup (beyond single-thread speedup):
o 5-8% encode time reduction for speed 7 to 10.
* RTC screen-content encoder speedup:
o 11% instruction count reduction for speed 9 and 10 (>=720p resolutions).
* ~5% reduction in heap memory requirements for RTC, speed 6 to 10.
* AVIF:
o 4-5% speedup for speed 9 in still-picture encoding mode.
o 3-4% heap memory reduction in still-picture encoding mode for 360p-720p resolutions with multiple threads.

There is also a variety of bug fixes to this AV1 encoder and various other improvements over prior versions. More information on AOM AV1 3.6 via the Google AOMedia Git repository.