[4.2.0] - 2026-07-14

VOD / Random Access

• Added TUNE-VMAF mode targeting ~15% VMAF BD-rate improvement at minimal PSNR loss
• Implemented single-thread processing mode with RA handling
• RA preset tuning and bitrate optimization for M3-M5
• New CLI options: --cqp, --enable-intrabc, --hbd-mds, --enable-kf-tf
• Added raw OBU output format as an alternative to IVF
• Signal initial_display_delay in sequence header to fix A/V sync on seek

RTC / Low Delay

• Added CBR rate control with Kalman-filter QP estimation, cyclic refresh, and frame re-encode
• Added on-the-fly MG size, preset, bitrate, and frame rate changes
• Added reference frame management API with LTR support and two-layer RPS structure
• Exposed --max-intra-bitrate-pct and --max-inter-bitrate-pct parameters
• Improved compression efficiency vs. cycle tradeoff across RTC presets
• Optimized memory footprint for RTC mode with small resolutions
• Further speed and quality tuning for RTC

Encoder (general)

• Refactored entropy coding: direct tile-buffer writes, arithmetic coder simplifications, coefficient shaving
• CDEF optimizations: 8-bit boundary-aware filter, persistent scratch buffers, luma/chroma specialization
• MD and ME optimizations (LPD1 early-skip, VLPD0 fast path, static-block ME bypass)
• Optimized still-image screen content detection
• Optimized TPL dispatch when TPL is disabled
• Added ENABLE_STACK_PROTECTOR CMake option to prevent the stack protector flag from being added

Arm

• Added lowbd (8-bit) int16 forward transform NEON kernels (4x4 through 32x32)
• Added Neon SAD, quantize-matrix, SSIM, VMAF, variance, and pixel projection error kernels
• Added SVE2 VMAF kernels and hardware CRC-32C for hash-based ME
• Optimized convolution, full distortion, and SAD calculation functions

Bug fixes and documentation

• Fixed superres recode crash, RESIZE_DYNAMIC under --rtc, RTC candidate-count overflow, recon output, and memory leak
• Fixed signed left-shift UB, OOB reads, and race conditions in rate control
• Added NVTX/Nsight Systems profiling hooks, PPC toolchain, and macOS universal binary support
• Addressed cppcheck warnings and rewrote affected unit tests
• Addressed USAN and MSAN warnings
• Reduced OBMC stack usage to fix a crash with PGO
• General code cleanup, documentation updates, and test improvements

cross-posted from: https://lemmy.ml/post/48174535

AV2 is the next-generation video coding specification from the Alliance for Open Media (AOMedia). Building on the foundation of AV1, AV2 is engineered to provide superior compression efficiency, enabling high-quality video delivery at significantly lower bitrates. It is optimized for the evolving demands of streaming, broadcasting, and real-time video conferencing.

This specification serves as the definitive technical reference for AV2 implementations. It outlines the bitstream syntax, semantics, and decoding processes required to ensure full conformance.

AV2 provides enhanced support for AR/VR applications, split-screen delivery of multiple programs, improved handling of screen content, and an ability to operate over a wider visual quality range.

[4.1] - 2026-03-23

Encoder

• Refactor MD, EncDec, and Entropy Coding kernels (!2604)
• Improve Still Image coding efficiency (!2612, !2614)
• Change Wiener Filter level for chroma for presets M3 and below (!2620)
• Optimize Screen Content coding for Still Image (!2630)

Arm

• Refactor Subpixel Variance kernels (!2608)
• Optimize 16b SAD kernel (!2610)
• Fixed Neoverse V2 unit test detection (!2622)
• Update Arm build guide (!2625)

Bug fixes and documentation

• Fixed a hang caused by improper variable looping (#2338, !2600)
• Add missing option 2 for --enable-dlf's help output (!2601)
• Depth Refinement algorithmic bug fix (!2602)
• Add mutexes to fix hangs when running multiple instances of the encoder in one process (!2603, !2605, !2619)
• Fix motion calculation for cyclic QP refresh (!2613)
• Fixed a Debug vs Release mismatch (!2618)
• Fixed some new warnings with newer GCC versions (!2621, !2636)
• Changed Temporal Filtering distortion calculation to not include padding (!2623)
• Cleanup some dead unit tests (!2626)
• Benchmark framework improvements (!2627)
• CI/CD improvements (!2628)
• Fixed some niche crashes (!2629)
• Readd missing PredStructure enum without SVT_AV1 prefix (!2635)
• Rename svt_log to prevent conflict with SVT-JPEG-XS (!2634)
• General code and doc cleanup (!2606, !2607, !2609, !2611, !2616, !2617, !2624, !2631, !2633, !2637)

[4.0.0] - 2026-1-23

API updates

• Major release with new API updates that are not backwards compatible.
• Extended the crf range to 70 reducing the impact or QP scaling allowing the encoder to reach lower bitrates
• Added quarter steps between crf increments to allow for further granularity in qp selection
• Added support for setting a custom global logger for library consumers (!2570 (merged), !2579 (merged))
• Cleaned up public API headers including removal of deprecated macros, structs, and fields (!2565 (merged), !2568 (merged))
  • Additionally cleaned up anything marked using SVT_AV1_CHECK_VERSION().
• Added ability to calculate per-frame PSNR and SSIM metrics (!2521 (merged))
• Allow sending more than 1 but less than 4 frames with avif mode (This is not for AVIF image sequence, but for encoding an alpha layer) (!2551 (merged), !2560 (merged))
• Added tune IQ and MS-SSIM for Still Image coding mode

Encoder

• Significant improvements in AVIF and still image modes (!2552 (merged),!2567 (merged)):
• ~5-8x speedup M11-M0 at the same quality levels with tune MS-SSIM
• ~5-8% BD-Rate improvements at the same complexity with tune MS-SSIM
• Tradeoff improvements for the RTC modes (!2558 (merged)):
• ~5-15% speedup at similar quality levels in --rtc mode across presets 7 - 11
• Tradeoff improvements for the Random Access mode (VOD use case) showing a 10-25% speedup across presets M7 down to M0 for --fast-decode 1 and 2 (!2558 (merged))
• Major feature updates for the visual quality mode with the completion porting all SVT-AV1-PSY applicable features for --tune vq for video and --tune iq for avif (!2484 (merged), !2489 (merged), !2491 (merged), !2494 (merged), !2496 (merged), !2503 (merged), !2504 (merged), !2507 (merged), !2514 (merged), !2522 (merged) , !2561 (merged), !2562 (merged), !2576 (merged)):
• Added AC Bias, a psychovisual feature that improves detail preservation and film grain retention
• Update S-Frame support to allow setting it in a specific decode order option and with more qp options (!2477 (merged) !2523 (merged) !2534 (merged))
• Further Arm Neon and SVE2 optimizations that improve high bitdepth encoding by an average of ~5% in low resolutions

More info:

VP9: https://www.twoorioles.com/eve-vp9

AV1: https://www.twoorioles.com/eve-av1

The last time these numbers were updated was ~2019, so it has been a while.

GitHub: https://github.com/gianni-rosato/svt-av1-psy/releases/tag/v2.3.0-B

I'm proud to announce that 8 SVT-AV1-PSY features will be making it into the next mainline SVT-AV1 release!

The 8 features are:

• Variance boost curve selection (adopted from our "enable alt curve")
• Sub-64px dimension support
• TF strength + adaptive TF
• Color help for help with printing encoder colorspace information
• Odd resolution support
• Luminance QP Bias (adopted from luma bias)
• Adaptive film grain
• User-configurable sharpness through --sharpness

We are beyond excited to have mainline behind our perceptual methodology & the features we've authored to support it, and I expect even bigger feature integrations stemming from deeper collaboration in the future. The mainline team have been amazing to work with – looking forward to more in the future!

GitHub: https://github.com/gianni-rosato/svt-av1-psy/releases/tag/v2.3.0-A

Also, come say hi on Matrix! URL: https://matrix.to/#/#av1-for-dummies:matrix.org

cross-posted from: https://lemmy.ml/post/22744274

The Vulkan Working Group at The Khronos Group has delivered a series of video decode and encode extensions since 2022 collectively referred to as "Vulkan Video." These extensions integrate hardware-accelerated stream compression and decompression using widely adopted codecs with the full power of Vulkan, enabling developers to seamlessly combine GPU-powered rendering and compute acceleration with video processing in a single highly efficient runtime.

Today, with the release of Vulkan 1.3.302, Khronos is proud to announce two new encode extensions. First, the highly anticipated Encode AV1 extension enhances Vulkan Video by adding AV1 encode functionality to complement its existing AV1 decode support. This milestone means that Vulkan Video now provides full decode AND encode acceleration for the H.264, H.265 and AV1 codec standards. Additionally, the new Encode Quantization Map extension introduces advanced encoding features for all supported codecs to Vulkan Video developers for the first time. We are confident these extensions provide the necessary building blocks for your advanced Vulkan Video applications!

How does SVT-AV1 2.2.x stack up against the encoder's previous version?

GitHub: https://github.com/gianni-rosato/svt-av1-psy/releases/tag/v2.3.0

Also, come say hi on Matrix! URL: https://matrix.to/#/#av1-for-dummies:matrix.org

Changes for 1.5.0 'Sonic':

1.5.0 is a major release of dav1d, that:

• WARNING: we removed some of the SSE2 optimizations, so if you care about systems without SSSE3, you should be careful when updating!
• Add Arm OpenBSD run-time CPU feature
• Optimize index offset calculations for decode_coefs
• picture: copy HDR10+ and T35 metadata only to visible frames
• SSSE3 new optimizations for 6-tap (8bit and hbd)
• AArch64/SVE: Add HBD subpel filters using 128-bit SVE2
• AArch64: Add USMMLA implempentation for 6-tap H/HV
• AArch64: Optimize Armv8.0 NEON for HBD horizontal filters and 6-tap filters
• Power9: Optimized ITX till 16x4.
• Loongarch: numerous optimizations
• RISC-V optimizations for pal, cdef_filter, ipred, mc_blend, mc_bdir, itx
• Allow playing videos in full-screen mode in dav1dplay

GitHub: https://github.com/gianni-rosato/svt-av1-psy/releases/tag/v2.2.1-B

GitHub: https://github.com/gianni-rosato/svt-av1-psy/releases/tag/v2.2.1-A

cross-posted from: https://lemmy.world/post/19262772

Good morning my fellow video encoding afficionados.

As usual, I was trying to find interesting stuff on the web, and I finally did!

Someone in our wonderful AV1 enthusiast community has spent a lot of time working on natively adding svt-av1-psy to Handbrake; this is done through specific patches that add the additional functionality of svt-av1-psy in Handbrake.

This allows for Windows, macOS, Linux (Flatpak) and native Linux builds of Handbrake to be built with nearly complete svt-av1-psy support.

It's truly a great addition as it allows many more people to be at the leading edge of high fidelity AV1 encoding.

Note that these are based on Nightly Handbrake, but this shouldn't pose a problem.

Head over to the "Releases" page to find the full builds, CLI versions and even dynamic library replacement: https://github.com/Nj0be/HandBrake-SVT-AV1-PSY/releases

That'll be all from me. Thank you for your attention and have a great Saturday.

Give the issue & upvote and comment to show your support - every like helps!

SVT-AV1-PSY v2.2.0

Long time no see! We're back with another exciting release: SVT-AV1-PSY v2.2.0! 🎉

PSY Updates

Features

• --tf-strength parameter for manually adjusting temporal filtering strength. By default, reduces temporal filtering strength by 4x
• --chroma-qm-min & --chroma-qm-max parameters for adjusting quantization matrix flatness for chroma planes
• --tune 4 - A new Tune called Still Picture has been introduced for AVIF encoding, with promising gains observed over aomenc, aomenc 4:4:4, and mainline SVT-AV1

Quality & Performance

• Enable 10-bit subpixel motion estimation processing for 10-bit inputs on Preset 3 & below
• Enable SUPERRES_AUTO_ALL for Tune 3 when superres-mode=4
  • Disables ALT-REF superres for speed and quality
• Add unipred bias for SSIM full mode decision cost when using Tune 3
• New perceptual QM curve when using Tune 3
  • Better chroma QM adjustment & better high fidelity performance
• Vastly improved screen content detection when --scm 2 is set. Currently only enabled in Tune 4

Documentation

• --help menu correctly prints maximum CRF value (70)
• Default Tune 2 is better reflected across documentation
• Updated build documentation
• Additional featured projects

Bug Fixes

• Scoped down QM disablement to only affect NEON-enabled systems
• Scoped down global sharpness features to --sharpness 1, as was the original intention

Mainline Updates

API updates

• No API changes on this release

Encoder

• Improve the tradeoffs for the random access mode across presets:
  • Speedup of ~15% across presets M0 - M8 while maintaining similar quality levels
• Improve the tradeoffs for the low-delay mode across presets
• Increased temporal resolution setting to 6L for 4k resolutions by default
• Added ARM optimizations for functions with c_only equivalent yielding an average speedup of ~13% for 4k 10-bit

Cleanup Build & bug fixes & documentation

• Profile-guided-optimized helper build overhaul
• Major cleanup and fixing of Neon unit test suite
• Address stylecheck dependence on public repositories

Support Us

As SVT-AV1-PSY's codebase has become more complex and the encoder's capabilities have increased dramatically, our efforts have scaled in kind. We have poured hours into coding, testing, distributing, and supporting this piece of open-source software entirely for free, and our work isn't stopping any time soon.

If you appreciate the work that we do and you'd like to support us, we are always excited to see code contributions from outside of the core development team. Otherwise, you can support us monetarily via the links below.

Gianni Rosato: Donate

Julio Barba: Donate Soon

BlueSwordM: Coming Soon

Clybius: Coming Soon

Any support you can offer goes a long way, and we sincerely appreciate it. ♥️

Thanks for using SVT-AV1-PSY! <3

Full Changelog: https://github.com/gianni-rosato/svt-av1-psy/commits/v2.2.0

[2.2.0] - 2024-08-19

API updates

• No API changes on this release

Encoder

• Improve the tradeoffs for the random access mode across presets:
• Speedup of ~15% across presets M0 - M8 while maintaining similar quality levels (!2253)
• Improve the tradeoffs for the low-delay mode across presets (!2260)
• Increased temporal resolution setting to 6L for 4k resolutions by default
• Added ARM optimizations for functions with c_only equivalent yielding an average speedup of ~13% for 4k10bit

Cleanup Build and bug fixes and documentation

• Profile-guided-optimized helper build overhaul
• Major cleanup and fixing of Neon unit test suite
• Address stylecheck dependence on public repositories

bdr-ssimu2

Encode, analyze, & plot SSIMULACRA2 scores using a source video file that is encoded with FFmpeg.

This Python script generates BD-Rate (Bjøntegaard-Delta Rate) graphs for comparing the performance of different encoding commands. It encodes a source video with various specified Constant Rate Factor (CRF) values, calculates SSIMULACRA2 scores, and plots the results via matplotlib.

Features

• Encodes a source video using two user-configurable FFmpeg commands
• Calculates SSIMULACRA2 scores (and soon XPSNR scores as well)
• Generates BD-Rate curves comparing the two encoding commands
• Outputs both average and harmonic mean SSIMULACRA2 plots
• Allows for temporal metric analysis subsampling (sampling every nth frame)

Prerequisites

• Python 3.x
• FFmpeg
• VapourSynth with:
  • VSZip Plugin
  • FFMS2
  • fmtconv
• Required Python packages:
  • vapoursynth
  • matplotlib
  • tqdm

See more in the linked Git repo's README!

Introducing SVT-AV1-PSY v2.1.0-A

Features

• New parameter --max-32-tx-size, which restricts block transform sizes to a maximum of 32x32 pixels. This can be useful in very specific scenarios for improving overall efficiency
• Added support for HDR10+ JSON files via a new --hdr10plus-json parameter (thanks @quietvoid!). In order to build a binary with support for HDR10+, see our PSY Development page.
• New parameter --adaptive-film-grain, which helps remedy perceptually harmful grain patterns caused by extracting grain from blocks that are too large for a given video resolution. This parameter is enabled by default

Quality & Performance

• Disabled SSIM-cost transform decisions while keeping SSIM-cost mode decisions, generally improving Tune 3's efficiency & consistency
• Additional NEON optimizations for ARM platforms, providing a speed increase

Documentation

• All of the features present in this release have been documented, so associated documentation has been updated accordingly
• Build documentation updated to reflect the HDR10+ build option

Bug Fixes

• Disabled quantization matrices for presets 5 and higher due to a visual consistency bug (#56)

Full Changelog: https://github.com/gianni-rosato/svt-av1-psy/commits/v2.1.0-A

SVT-AV1 2.1.0 just released, how does it compare to SVT-AV1 2.0.0? Well-known encoder Trix attempts to answer this question with metrics, graphs, and detailed analysis.

[2.1.0] - 2024-05-17

API updates

• One config parameter added within the padding size. Config param structure size remains unchanged
• Presets 6 and 12 are now pointing to presets 7 and 13 respectively due to the lack of spacing between the presets
• Further preset shuffling is being discussed in #2152

Encoder

• Added variance boost support to improve visual quality for the tune vq mode
• Improve the tradeoffs for the random access mode across presets:
• Speedup of 12-40% presets M0, M3, M5 and M6 while maintaining similar quality levels
• Improved the compression efficiency of presets M11-M13 by 1-2% (!2213)
• Added ARM optimizations for functions with c_only equivalent

Cleanup Build and bug fixes and documentation

• Use nasm as a default assembler and yasm as a fallback
• Fix performance regression for systems with multiple processor groups
• Enable building SvtAv1ApiTests and SvtAv1E2ETests for arm
• Added variance boost documentation
• Added a mailmap file to map duplicate git generated emails to the appropriate author

Hi there! We're back with a new micro-release format to announce some exciting changes in SVT-AV1-PSY v2.0.0-A! 🎉

PSY Updates

Features

• The CRF range, previously capped at 63, has been extended to a maximum value of 70. It can also be incremented in quarter increments of 0.25
• New option: --enable-dlf 2 for a slower, more accurate deblocking loop filter
• New option: --qp-scale-compress-strength (0 to 3) which sets a strength for the QP scale algorithm to compress values across all temporal layers. Higher values result in more consistent video quality
• New option: --frame-luma-bias (0 to 100) enables experimental frame-level luma bias to improve quality in dark scenes by adjusting frame-level QP based on average luminance across each frame

Quality & Performance

• A temporal layer qindex offset has been added to Tune 3 for more consistent quality across frames when encoding
• Minor speed bump to Preset 8
• Dynamic delta_q_res switching implemented to help reduce signaling overhead, which should improve quality especially at CRF ≥40
• Other general improvements to Tune 3

Documentation

• PNG images have been replaced with smaller lossless WebP images, resulting in faster loading & repository cloning times.
• More consistent & thorough PSY Development page, including build instructions

Bug Fixes

• Help menu formatting adjusted for less frequent underlining
• --progress 2 no longer reports the same information as --progress 3

Other

• Introducing PSY Micro-releases! Each micro-release will be marked with a letter, bringing a bundle of new features & improvements. The release letter will reset back to the initial A each time our mainline version is updated. More info can be found in this project's README & the PSY Development page

Thanks for using SVT-AV1-PSY! ♥️

Full Changelog: https://github.com/gianni-rosato/svt-av1-psy/commits/v2.0.0-A

From the GitHub releases:

Hello, everyone! We've been hard at work enhancing SVT-AV1 with our additions to the encoder improving visual fidelity. Little by little, we are working on trying to bring many of them to mainline! For the time being, I want to note that major SVT-AV1-PSY releases & mainline releases are not the same, and the codebases differ due to our changes; the version numbers may be identical, but the versions themselves are not, which is disclosed within the encoder's version information. With that, we're excited to announce SVT-AV1-PSY v2.0.0! 🎉

PSY Updates

Variance boost

• Moved varboost delta-q adjusting code to happen before TPL, giving TPL the opportunity to work with more accurate superblock delta-q priors, and produce better final rdmult lambda values
  • Fixed rare cases of pulsing at high CRFs (>=40) and strengths (3-4)
  • 2% avg. bitrate reduction for comparable image quality
• Added an alternative boosting curve (--enable-alt-curve), with different variance/strength tradeoffs
• Refactored boost code so it internally works with native q-step ratios
• Removed legacy variance boosting method based on 64x64 values
  • Parameter --new-variance-octile -> --variance-octile

Excitingly, a var-boost mainline merge has been marked with the highest priority issue label by the mainline development team, so we may see this in mainline SVT-AV1 soon! Congrats @juliobbv! 🎉

Other

• Presets got faster, so in addition to Preset -2, we have an even slower Preset -3
• --sharpness now accepts negative values
• The SVT-AV1-PSY encoder now supports Dolby Vision encoding via Dolby Vision RPUs. To build with Dolby Vision support, install libdovi & pass --enable-libdovi to ./build.sh on macOS/Linux (or enable-libdovi to ./build.bat on Windows).

Mainline Updates

Major API updates

• Changed the API signaling the End Of Stream (EOS) with the last frame vs with an empty frame
• OPT_LD_LATENCY2 making the change above is kept in the code to help devs with integration
• The support of this API change has been merged to ffmpeg with a 2.0 version check
• Removed the 3-pass VBR mode which changed the calling mechanism of multi-pass VBR
• Moved to a new versioning scheme where the project major version will be updated every time API/ABI is changed

Encoder

• Improve the tradeoffs for the random access mode across presets:
• Speedup presets MR by ~100% and improved quality along with tradeoff improvements across the higher quality presets (!2179,#2158)
• Improved the compression efficiency of presets M9-M13 by 1-4% (!2179)
• Simplified VBR multi-pass to use 2 passes to allow integration with ffmpeg
• Continued adding ARM optimizations for functions with c_only equivalent
• Replaced the 3-pass VBR with a 2-pass VBR to ease the multi-pass integration with ffmpeg
• Memory savings of 20-35% for LP 8 mode in preset M6 and below and 1-5% in other modes / presets
• Film grain table support via --fgs-table (already in SVT-AV1-PSY) (link)
• Disable film grain denoise by default (already in SVT-AV1-PSY) (link)

Cleanup, bug fixes & documentation

• Various cleanups and functional bug fixes
• Update the documentation to reflect the rate control

Thanks for using SVT-AV1-PSY! ♥️

Full Changelog: https://github.com/gianni-rosato/svt-av1-psy/commits/v2.0.0