AOMediaCodec/SVT-AV1 v4.3.0

on GitLab

[4.3.0] - 2026-11-01

Encoder (general)

• Improved the quality vs. speed tradeoffs across all presets:
  
  • ~5-8% improvement in cycle efficiency at similar quality levels
    
  • ~10-11% run time reduction in multi-threaded mode
    
• Speed optimizations in MD pruning, RDOQ and coefficient cost, MV cost and subpel search, loop filter parameter derivation, and block copies
  
• Run anti-aliasing-aware screen content detection only on I-frames in multi-threaded mode
  

VOD / Random Access / Still Image

• Added experimental --fast-decode 3 (ENABLE_FAST_DECODE_3 CMake option): a decode-speed level for still images, with decoder-complexity terms in the mode decision RD cost
  
• Added timed film grain tables (--fgs-table) and per-picture film grain parameters through a new FILM_GRAIN_EVENT API
  
• Lossless coding fixes and speedups (recode, RDOQ, light PD1)
  
• Fixed bitrate inversion at fractional CRF/QP above 63
  

RTC / Low Delay

• Added low-delay tile parallelism
  
• Added opt-in CBR pre-encode frame skipping (max_allowed_consecutive_frames_skips, EB_NoErrorFrameSkipped)
  
• Added screen content tools for RTC: IntraBC on I-frames and palette on intra blocks of inter frames
  
• Signal AV1 frame_id for application-managed LTR streams, and keep LTR anchors in a dedicated half of the DPB
  
• Added max_hierarchical_levels to size buffer pools for runtime mini-GOP size changes
  
• Allow re-encoding of key frames and on max frame size conditions
  
• RTC preset retuning (hierarchical levels 1-2, CDEF strength selection, ME segmentation right-sizing at 540p and below)
  

Build

• Added MOBILE_BUILD CMake option (build.sh --mobile-build): one 8-bit library for RTC, VOD and AVIF at a fraction of the default binary size
  
• Added CONFIG_ENABLE_* switches to compile out unused coding tools, and further binary size reduction for RTC and minimal builds (const-folding, dead-code stripping, PGO build script)
  
• Reduced stack usage by hoisting large buffers off the stack
  

x86

• Added native 8-bit CDEF kernels (AVX2, SSE4.1) and int16 lowbd forward transforms (AVX2, AVX-512)
  
• Added an SSE4.1 tier for intra predictors, CfL, SAD, Hadamard, palette, and transform kernels
  
• Optimized quantize, memcpy, block copy, full distortion, and sub-pixel variance kernels
  

Arm

• Added Neon kernels for fwht4x4, highbd variance, k-means, OBMC weighted prediction, down2_symeven, and interpolate_core
  
• Added Neon and SVE2 Hadamard SATD and psy distortion kernels
  
• Optimized VMAF tune, variance, and sub-pixel variance kernels
  
• Only read MIDR_EL1 where the kernel advertises it
  

Bug fixes and documentation

• Fixed multi-instance and TSan data races, and nondeterministic output with --enable-overlays 1 or --lookahead 0
  
• Fixed a low-delay deadlock, an Apple teardown SIGTRAP, and single-core encoding without --lp
  
• Fixed out-of-bounds reads, a high bit depth Hadamard overflow, UBSan findings, and NaN/overflow in film grain and temporal filtering noise estimation
  
• Fixed hidden-frame T.35 metadata output and recon output changing the deblocking level search
  
• Fixed the --tier parameter being ignored when writing the sequence header
  
• Fixed an encoder/decoder mismatch when quantization matrices were enabled on frames coded losslessly
  
• Stricter configuration validation (switch frames with all-intra, forward key frames with CBR, RTC build settings)
  
• Fixed Visual Studio 2026 and Windows Server 2016 issues
  
• General code cleanup, CI and test improvements, and reformatting with clang-format 22