tag	eaa6cef362f196dd4c4dc2c51d436826627a9ec3
tagger	Urvang Joshi <urvang@google.com>	Wed Oct 29 13:34:18 2025 -0700
object	069d53c4c136054b920cd1c8b20fc363d204d2a1

Research-v12.0.0 anchor.

Includes the following since the previous anchor:

Candidate Tools
---------------
- CWG-F332 "On 64x64 Transform Block Coding Order"  (turn on by default)
- CWG-F284 "Deblocking DQP control" (turn on by default)
- CWG-F334 "Decoder-Side Normative Constraint on Motion Vector Values"
- CWG-F336 "Bugfix for 4x4 Warp Padding"
- CWG-F338 "Block size constraint for MHCCP"
- CWG-F344 "GDF padding alignment with LR"
- CWG-F265 Part 1 "On disabling loop-filters across tile-boundaries" (Test 2)
  (turn on by default)
- CWG-F265 Part 2 "On disabling loop-filters across lossless segments" (turn on
  by default)
- CWG-F348 "On high level signaling of motion modes"
- CWG-F353 "Decoder-side Constraints on Intra BAWP”
- CWG-F266 “On 64-Point Transform” (option 2, Test1)
- CWG-F354 “Uniform tile distribution”
- CWG-F371 “RU size restriction based on super_block size”
- CWG-F370 “Bitstream Constraint on Inter BAWP mode”
- CWG-F365 "On Optical Flow Auto Mode" (Test 2)
- CWG-F303 "On Division Handling" (DC Pred aspect)
- CWG-F374 "MHCCP bitdepth constraints" (Test 1)
- CWG-F380 "Bugfix for IntraBC Local Search Range on Frame Boundary”
- CWG-F300 update "enable_idtx_intra sequence level flag”

High-level Syntax
-----------------
- CWG-F298 Test A.1 “Multi-Frame Header” (from CWG-F070)
- CWG-F298 Test A.2 “Removal of redundant frame header” (from CWG-F097)
- CWG-F298 A.3 Introduce sequence header ID” (from CWG-E242)
- CWG-F298 A.7 “Rename the reduced_still_picture_hdr_flag” (from CWG-E242)
- CWG-F298 A.9 “Signal bitdepth with a UVLC code and LUT” (from CWG-E242)
- CWG-F298 A.10 “Signal tile information at sequence, multi-frame and frame
  level” (from CWG-E242)
- CWG-F298 A.11 “Scaling function improvements for film grain synthesis” (from
  CWG-F109)
- CWG-F298 A.15 + A.18 “uvlc() for mfh_id and mfh_id_in_frame_header”
- CWG-F298 Test B “Introduce chroma_format_idc” (from CWG-E242)
- CWG-F298 Test C “Use Tilegroup OBU, add Switch OBU, SEF OBU, and TIP OBU”
  (from CWG-F106)
- CWG-F298 Test E “Parsing independence on the Multi Frame header” (from
  CWG-E242)
- CWG-F298 Test G “Extension of frame buffer pool size” (from CWG-F172)
- CWG-F298 Test L “Random Access Switch frame” (from CWG-F147 and CWG-F231)
- CWG-F298 Test M “Temporal unit update” (from CWG-F232)
- CWG-F298 Test R “On the signaling of multi-view, multi-layer and multi-stream
  information” (from CWG-F221)
- CWG-F298 Test S “Render size signalling and derivation” (from CWG-F248)
- CWG-F220 "Sequence Cropping Window”
- CWG-F293 “Buffer Removal Timing Info OBU”
- CWG-F342 "Making multi-frame header OBU optional"
- CWG-F317 "An approach to increase the reference picture resolution
  constraints"
- CWG-F318 "Guided debanding metadata”
- CWG-F350 "On the interaction between the AVM output marking process and
  multi-layer coding"
- CWG-F362 "AV2 HLS: implicit frame tool flags for reduced still pictures”
- CWG-F367 "On OBU ordering in TU”
- CWG-F322 "On Switch and Error Resilient Frames" (Aspects 2.1, 2.2, 2.3.5 and
  2.4)
- CWG-F341 “On the xlayer_id value”
- CWG-F349 "Signaling improvements for tile configuration in frame header"
- CWG-F160 "Optional Temporal Unit Delimiters"
- CWG-F369 "Short metadata header"
- CWG-F364 "background color information in the atlas obu"
- CWG-F220 "Sequence Cropping Window”
- CWG-F298 Test F “Reorder sequence header flags” (from CWG-E242)
- CWG-F298 Test U “Adding metadata support” (from CWG-E195 and CWG-F161)

Encoder-only Improvements (Non-normative)
-----------------------------------------
- CWG-F347 "Further Improvement of model RD based inter mode decision of AVM
  random access configuration" (Test 2)

Encoder / Decoder Speedups (Non-normative)
------------------------------------------
- Do not initialize wedge masks until the first inter frame
- Non-normative improvements in CDEF, LR, CCSO and inv_txfm
- DIP: Add AVX2 optimization for `resample_output`
- CFL: Add new SIMD functions for CFL downsampling functions.
- Enable row-level multithreading support for CDEF frame in decoder
- Add AVX2 for refinemv_highbd_pad_mc_border
- Optimize set_lpf_parameters() function

Code Cleanups
-------------
- CWG-F366: Removal of Compile-time Macros
- CWG-F058: Remove large scale tile code

Gitlab CI Improvements
----------------------
- Wiki section on running large tests from Nightly CI
- Speed-up some unit tests in CI
- Add build check for bitstream and mismatch debug tools

Bugfixes
--------
https://gitlab.com/AOMediaCodec/avm/-/milestones/16#tab-issues

commit	069d53c4c136054b920cd1c8b20fc363d204d2a1	[log] [tgz]
author	Hilmi Egilmez <hegilmez@apple.com>	Tue Oct 28 01:23:36 2025 +0000
committer	Urvang Joshi <urvang@google.com>	Tue Oct 28 01:23:36 2025 +0000
tree	c6627cf704454c77f1b8b59444ee42727267d8b3
parent	34f70ed459a5d3384c058987f7e59eca67ae03b5 [diff]

Use correct maximum value for MAX_OPS_COUNT

Fixes #1015

av1/common/enums.h[diff]

1 file changed

tree: c6627cf704454c77f1b8b59444ee42727267d8b3

README.md

AVM

Building

Prerequisites

CMake version 3.16 or higher.
Git.
Perl.
For x86 targets, yasm, which is preferred, or a recent version of nasm. If you download yasm with the intention to work with Visual Studio, please download win32.exe or win64.exe and rename it into yasm.exe. DO NOT download or use vsyasm.exe.
Building the documentation requires doxygen version 1.8.10 or newer.
Building the unit tests requires Python.

Get the code

The AVM project source code is stored in the Alliance of Open Media’s GitLab repository. To get the code,

    $ git clone https://gitlab.com/AOMediaCodec/avm.git
    # By default, the above command stores the source in the avm directory:
    $ cd avm

Basic build

CMake replaces the configure step typical of many projects. Running CMake will produce configuration and build files for the currently selected CMake generator. For most systems the default generator is Unix Makefiles. The basic form of a makefile build is the following:

    $ cmake path/to/avm
    $ make

The above will generate a makefile build that produces the AVM library and applications for the current host system after the make step completes successfully. The compiler chosen varies by host platform, but a general rule applies: On systems where cc and c++ are present in $PATH at the time CMake is run the generated build will use cc and c++ by default.

Configuration options

The AVM codec library has a great many configuration options. These come in two varieties:

Build system configuration options. These have the form ENABLE_FEATURE.
AVM codec configuration options. These have the form CONFIG_FEATURE.

Both types of options are set at the time CMake is run. The following example enables ccache and disables the AVM encoder:

    $ cmake path/to/avm -DENABLE_CCACHE=1 -DCONFIG_MULTITHREAD=0
    $ make

The available configuration options are too numerous to list here. Build system configuration options can be found at the top of the CMakeLists.txt file found in the root of the AVM repository, and AVM codec configuration options can currently be found in the file build/cmake/aom_config_defaults.cmake.

Dylib builds

A dylib (shared object) build of the AVM codec library can be enabled via the CMake built in variable BUILD_SHARED_LIBS:

    $ cmake path/to/avm -DBUILD_SHARED_LIBS=1
    $ make

This is currently only supported on non-Windows targets.

Debugging

Depending on the generator used there are multiple ways of going about debugging AVM components. For single configuration generators like the Unix Makefiles generator, setting CMAKE_BUILD_TYPE to Debug is sufficient:

    $ cmake path/to/avm -DCMAKE_BUILD_TYPE=Debug

For Xcode, mainly because configuration controls for Xcode builds are buried two configuration windows deep and must be set for each subproject within the Xcode IDE individually, CMAKE_CONFIGURATION_TYPES should be set to Debug:

    $ cmake path/to/avm -G Xcode -DCMAKE_CONFIGURATION_TYPES=Debug

For Visual Studio the in-IDE configuration controls should be used. Simply set the IDE project configuration to Debug to allow for stepping through the code.

In addition to the above it can sometimes be useful to debug only C and C++ code. To disable all assembly code and intrinsics set AOM_TARGET_CPU to generic at generation time:

    $ cmake path/to/avm -DAOM_TARGET_CPU=generic

Cross compiling

For the purposes of building the AVM codec and applications, relative to the scope of this guide, all builds for architectures differing from the native host architecture will be considered cross compiles. The AVM CMake build handles cross compiling via the use of toolchain files included in the AVM repository. The available toolchain files can be found at cmake folder in the AVM repository. The following example demonstrates use of the x86-linux.cmake toolchain file on a x86_64 linux host:

    $ cmake path/to/avm \
      -DCMAKE_TOOLCHAIN_FILE=path/to/avm/build/cmake/toolchains/x86-linux.cmake
    $ make

Sanitizers

Sanitizer integration is built-in to the CMake build system. To enable a sanitizer, add -DSANITIZE=<type> to the CMake command line. For example, to enable address sanitizer:

    $ cmake path/to/avm -DSANITIZE=address
    $ make

Sanitizers available vary by platform, target, and compiler. Consult your compiler documentation to determine which, if any, are available.

Microsoft Visual Studio builds

Building the AVM codec library in Microsoft Visual Studio is supported. Visual Studio 2019 (16.7) or later is required. The following example demonstrates generating projects and a solution for the Microsoft IDE:

    # This does not require a bash shell; Command Prompt (cmd.exe) is fine.
    # This assumes the build host is a Windows x64 computer.

    # To build with Visual Studio 2019 for the x64 target:
    $ cmake path/to/avm -G "Visual Studio 16 2019"
    $ cmake --build .

    # To build with Visual Studio 2019 for the 32-bit x86 target:
    $ cmake path/to/avm -G "Visual Studio 16 2019" -A Win32
    $ cmake --build .

NOTE: The build system targets Windows 7 or later by compiling files with -D_WIN32_WINNT=0x0601.

Xcode builds

Building the AVM codec library in Xcode is supported. The following example demonstrates generating an Xcode project:

    $ cmake path/to/avm -G Xcode

Build with VMAF support

After installing libvmaf.a, you can use it with the encoder:

    $ cmake path/to/avm -DCONFIG_TUNE_VMAF=1

Please note that the default VMAF model will be used unless you set the following flag when running the encoder:

    # --vmaf-model-path=path/to/model

Testing

Testing basics

There are several methods of testing the AVM codec. All of these methods require the presence of the AVM source code and a working build of the AVM library and applications.

1. Unit tests:

The unit tests can be run at build time:

    # Before running the make command the LIBAOM_TEST_DATA_PATH environment
    # variable should be set to avoid downloading the test files to the
    # cmake build configuration directory.
    $ cmake path/to/avm
    # Note: The AVM CMake build creates many test targets. Running make
    # with multiple jobs will speed up the test run significantly.
    $ make runtests

2. Example tests:

The example tests require a bash shell and can be run in the following manner:

    # See the note above about LIBAOM_TEST_DATA_PATH above.
    $ cmake path/to/avm
    $ make
    # It's best to build the testdata target using many make jobs.
    # Running it like this will verify and download (if necessary)
    # one at a time, which takes a while.
    $ make testdata
    $ path/to/avm/test/examples.sh --bin-path examples

Downloading the test data

The fastest and easiest way to obtain the test data is to use CMake to generate a build using the Unix Makefiles generator, and then to build only the testdata rule:

    $ cmake path/to/avm -G "Unix Makefiles"
    # 28 is used because there are 28 test files as of this writing.
    $ make -j28 testdata

The above make command will only download and verify the test data.

Additional input data for testing the encoder can be obtained from: AV2 - CTC

Sharded testing

The AVM codec library unit tests are built upon gtest which supports sharding of test jobs. Sharded tests can be achieved as follows for example:

   # Set the environment variable GTEST_TOTAL_SHARDS to control the number of
   # shards.
   $ export GTEST_TOTAL_SHARDS=10
   # (GTEST shard indexing is 0 based).
   $ seq 0 $(( $GTEST_TOTAL_SHARDS - 1 )) \
       | xargs -n 1 -P 0 -I{} env GTEST_SHARD_INDEX={} ./test_libaom

To create a test shard for each CPU core available on the current system set GTEST_TOTAL_SHARDS to the number of CPU cores on your system minus one. The maximum number of test targets that can run concurrently is determined by the number of CPUs on the system where the build is configured as detected by CMake. A system with 24 cores can run 24 test shards using a value of 24 with the -j parameter. When CMake is unable to detect the number of cores 10 shards is the default maximum value.

Coding style

We are using the Google C Coding Style defined by the Google C++ Style Guide.

The coding style used by this project is enforced with clang-format and cmake-format.

clang-format can be installed with your system's package manager, or directly from llvm.org. For best results, your version should match the one used by Gitlab CI, noted as a comment in .clang-format.
cmake-format can be obtained by installing cmakelang. Again, for best results, your version should match the one used by Gitlab CI, noted as a comment in .cmake-format.py

Before pushing changes for review, format your code using the tools above.

We recommend automating the formatting by adding a pre-commit hook at .git/hooks/pre-commit. An example pre-commit hook is provided below:

#!/bin/bash
# Replace 'VERSION' below to match clang-format version in the CI.
CLANG_FORMAT_PATH=/usr/lib/llvm-VERSION/bin
CMAKE_FORMAT_PATH=${HOME}/.local/bin/

echo "Applying clang-format ..."
for file in $(git diff-index --cached --name-only HEAD -- "*.[hc]pp" "*.cc" "*.[ch]") ; do
  ${CLANG_FORMAT_PATH}/clang-format -i --style=file ${file}
  git add ${file}
  echo "Formatted file: $file"
done
echo "Done."

echo "Applying cmake-format ..."
for file in $(git diff-index --cached --name-only HEAD -- '*.cmake' CMakeLists.txt) ; do
  ${CMAKE_FORMAT_PATH}/cmake-format -i ${file}
  git add ${file}
  echo "Formatted file: $file"
done
echo "Done."

Submitting patches

We manage the submission of patches using Gitlab's merge request process. This tool implements a workflow on top of the Git version control system to ensure that all changes get peer reviewed and tested prior to their distribution. If you are not able to submit an MR, please contact SW coordinators to make sure necessary contributor agreements are signed for the AOMedia Project.

Follow the one-time set-up steps as detailed here.
For pushing your code modifications, follow the steps detailed here.
Once the code is pushed into a branch, create a merge request as detailed here.
- The code review, approval and CI/CD process will be initiated after the MR is created.
- Once the MR is approved, the software co-ordinators will merge the MR to the main branch.

Follow the Merge request page to check the status of the changes, review comments etc.

Support

This library is an open source project supported by its community. Please email https://aomedia.org/contact/ for help.

Bug reports

Bug reports can be filed in the Alliance for Open Media Gitlab issue tracker.