libaom v3.12.0 North Star release
2025-02-10 v3.12.0
This release includes new codec interfaces, compression efficiency and
perceptual improvements, speedup and memory optimizations, and bug
fixes. This release is ABI compatible with the last release.
Five internal functions (aom_free, aom_malloc, aom_wb_bytes_written,
aom_wb_write_bit, aom_wb_write_literal) that were exported by mistake
are no longer exported from the libaom shared library. The removal of
these internal functions from the ABI is a bug fix and does not break
ABI compatibility.
Acknowledgments: The image quality optimizations in the new tuning
mode AOM_TUNE_IQ were originally developed for SVT-AV1-PSY by
Cole Ogaard, Gianni Rosato, Julio Barba, and Zakaria Djebrouni.
- New Features
* New tuning mode AOM_TUNE_IQ (image quality) for the
AOME_SET_TUNING codec control (--tune=iq) in all-intra mode. The
feature detection macro AOM_HAVE_TUNE_IQ, if defined, indicates
that AOM_TUNE_IQ is available. The image quality optimizations in
AOM_TUNE_IQ were developed by using the SSIMULACRA 2 metric for
guidance and validated with subjective visual quality checks.
* New value 6 for the AV1E_SET_DELTAQ_MODE codec control
(--deltaq-mode): use modulation for all intra using Variance
Boost. Variance Boost is a variance adaptive quantization
implementation that modulates qindex depending on the ratio of
low-variance to high-variance 8x8 subblocks within a 64x64
superblock, as well as the actual variance of the subblocks
themselves.
* New value 3 for the AV1E_SET_ENABLE_CDEF codec control
(--enable-cdef): Enable CDEF adaptively based on frame qindex.
* In all-intra mode, the AOME_SET_SHARPNESS codec control now also
sets the loop_filter_sharpness syntax element in the bitstream.
Larger values increasingly reduce how much the filtering can
change the sample values on block edges to favor perceived
sharpness.
* In all-intra mode, the default value of the AV1E_SET_QM_MIN codec
control is decreased to 4, and the default value of the
AV1E_SET_QM_MAX codec control is increased to 10. The default
values in good-quality and realtime modes remain unchanged (5 and
9, respectively).
- Compression Efficiency Improvements
* Tuning mode AOM_TUNE_IQ improves image compression efficiency on
the CLIC dataset by up to 12% for the same SSIMULACRA 2 score, up
to 14% for the same DSSIM score, and up to 17% for the same
Butteraugli score.
* ~3% BD-rate gains for speed 11 VGA camera mode.
* ~5% BD-rate gains for speed 11 on scroll clips screen mode.
- Perceptual Quality Improvements
* Adjust temporal filter strength for better visual quality.
* RTC screen: visual quality improvements for scrolling and for
scene/slide changes.
* RTC camera mode: visual quality improvements for speed 11 VGA.
- Speedup and Memory Optimizations
* Optimize the Arm Neon implementation of the loop filter functions
with an average uplift of 15 - 25% in microbenchmarks.
* Add the CDEF optimization for RISC-V.
* Help the compiler generate better vectorized code for variance
calculation and warped motion in generic CPU builds.
* Make several arrays const.
- Other Improvements
* Binary size reduction: 1 - 2% compared with last release, with
CONFIG_REALTIME_ONLY enabled, CONFIG_AV1_DECODER and
CONFIG_AV1_HIGHBITDEPTH disabled.
* Build: compile source files in parallel under MSVC.
- Bug Fixes
* Fix bug where metadata added with aom_img_add_metadata was lost
when frame scaling was used.
* Bug b:383306740: RTC: Fix to issues with scrolling for screen
content.
* Bug b:382465458: RTC: Fix to artifact for grayscale input.
* Bug b:380247338: RTC: Fix to encode_time spikes on scene/slide
changes.
* RTC: Fix to rate correction factor update for VBR screen mode.
https://groups.google.com/a/aomedia.org/g/av1-discuss/c/nJxECdg-7P8
* Bug b:378401081: RTC: Fix to cyclic refresh update for external RC
(rate control).
Bug: 394596176
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