Add wmf h265 support

[Bernini0]

Summary

Add H.265 (HEVC) hardware-accelerated encoding and decoding support on Windows
using the Media Foundation Transform (MFT) pipeline. This enables H.265 codec
negotiation and media processing through the OS-provided HEVC MFTs, which
delegate to GPU vendor hardware (NVENC/NVDEC, Intel QSV, AMD AMF) transparently.

Motivation

WebRTC M137 includes H.265 SDP/RTP infrastructure (rtc_use_h265=true) but
ships no encoder/decoder implementations. This PR fills that gap on Windows
without introducing any third-party codec dependencies.

Changes

New files (src/win/)

• wmf_h265_encoder.h/.cc — VideoEncoder implementation using HEVC encoder MFT
• wmf_h265_decoder.h/.cc — VideoDecoder implementation using HEVC decoder MFT
• wmf_h265_factory.h/.cc — Decorator factories that add H.265 to the builtin codec list

Modified files

• BUILD.gn — Conditionally compile WMF sources when is_win && !libwebrtc_intel_media_sdk && rtc_use_h265
• src/rtc_peerconnection_factory_impl.cc — Wire WMF factories into CreatePeerConnectionFactory

Implementation details

• Codec discovery: MFTEnumEx with MFT_ENUM_FLAG_HARDWARE | MFT_ENUM_FLAG_SORTANDFILTER to prefer HW-accelerated MFTs
• Pixel format: I420 → NV12 conversion via libyuv (input), NV12/I420 → I420 (output)
• Rate control: CBR mode via CODECAPI_AVEncCommonRateControlMode; dynamic bitrate updates via CODECAPI_AVEncCommonMeanBitRate
• Keyframe requests: Forced IDR via CODECAPI_AVEncVideoForceKeyFrame
• Low latency: MF_LOW_LATENCY attribute set on both encoder and decoder MFTs
• QP reporting: H265BitstreamParser extracts per-frame QP into EncodedImage::qp_
• Resolution alignment: Reports requested_resolution_alignment = 2 (NV12 requirement)
• COM safety: CoInitializeEx is called in IsSupported() and InitMediaFoundation() so the code works regardless of whether the calling thread has COM initialized
• Dynamic resolution change: Decoder handles MF_E_TRANSFORM_STREAM_CHANGE and updates cached dimensions from the new output media type
• SDP parameters: Advertises Main profile (profile-id=1), Main tier (tier-flag=0), Level 4.0 (level-id=120)
• Hardware acceleration: Both GetEncoderInfo() and GetDecoderInfo() report is_hardware_accelerated = true

Build flags

rtc_use_h265=true
proprietary_codecs=true
ffmpeg_branding="Chrome"

No additional flags required. The WMF path activates automatically on Windows when libwebrtc_intel_media_sdk is not set (default).

Requirements

• Windows 10 1709+ with HEVC Video Extensions (free from Microsoft Store for OEMs, or $0.99 for HEVC Video Extensions from Device Manufacturer)
• GPU with HEVC encode/decode support (NVIDIA Kepler+, Intel Skylake+, AMD Polaris+)

[orchidflower]

@Bernini0 Hi, thank you for providing this patch. I tried it with webrtc m137, it worked. :)

But when I tried to compile it with webrtc m144, it failed. Can you provide new patch to fix this? Thanks!

Here is the error messages:

E:\work\libwebrtc_m144\src>ninja -C out-release/Windows-x64 libwebrtc ninja: Entering directory out-release/Windows-x64'
[4339/4347] CXX obj/libwebrtc/libwebrtc/wmf_h265_encoder.obj
FAILED: [code=1] obj/libwebrtc/libwebrtc/wmf_h265_encoder.obj
....\third_party\llvm-build\Release+Asserts\bin\clang-cl.exe /c ../../libwebrtc/src/win/wmf_h265_encoder.cc /Foobj/libwebrtc/libwebrtc/wmf_h265_encoder.obj /nologo /showIncludes:user "-imsvcC:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.44.35207\include" "-imsvcC:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.44.35207\ATLMFC\include" "-imsvcC:\Program Files\Microsoft Visual Studio\2022\Community\VC\Auxiliary\VS\include" "-imsvcC:\Program Files (x86)\Windows Kits\10\include\10.0.26100.0\ucrt" "-imsvcC:\Program Files (x86)\Windows Kits\10\include\10.0.26100.0\um" "-imsvcC:\Program Files (x86)\Windows Kits\10\include\10.0.26100.0\shared" "-imsvcC:\Program Files (x86)\Windows Kits\10\include\10.0.26100.0\winrt" "-imsvcC:\Program Files (x86)\Windows Kits\10\include\10.0.26100.0\cppwinrt" "-imsvcC:\Program Files (x86)\Windows Kits\NETFXSDK\4.8\include\um" -DUSE_LIBYUV -DWEBRTC_INCLUDE_INTERNAL_AUDIO_DEVICE -DLIB_WEBRTC_API_EXPORTS -DWEBRTC_WIN -DRTC_DESKTOP_DEVICE -D_HAS_NODISCARD -D_CRT_NONSTDC_NO_WARNINGS -D_WINSOCK_DEPRECATED_NO_WARNINGS "-DCR_CLANG_REVISION="llvmorg-22-init-14273-gea10026b-2"" -D_LIBCPP_HARDENING_MODE=LIBCPP_HARDENING_MODE_EXTENSIVE -D_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS -D_LIBCPP_INSTRUMENTED_WITH_ASAN=0 -DCR_LIBCXX_REVISION=fa224989fd9c52f68042d7fd6824302c33cb68c0 -D__STD_C -D_CRT_RAND_S -D_CRT_SECURE_NO_DEPRECATE -D_SCL_SECURE_NO_DEPRECATE -D_ATL_NO_OPENGL -D_WINDOWS -DCERT_CHAIN_PARA_HAS_EXTRA_FIELDS -DPSAPI_VERSION=2 -DWIN32 -D_SECURE_ATL -DWINAPI_FAMILY=WINAPI_FAMILY_DESKTOP_APP -DUSE_AURA=1 -DWIN32_LEAN_AND_MEAN -DNOMINMAX -D_UNICODE -DUNICODE -DNTDDI_VERSION=NTDDI_WIN11_GE -D_WIN32_WINNT=0x0A00 -DWINVER=0x0A00 -DNDEBUG -DNVALGRIND -DDYNAMIC_ANNOTATIONS_ENABLED=0 -DWEBRTC_ENABLE_PROTOBUF=1 -DWEBRTC_STRICT_FIELD_TRIALS=0 -DRTC_ENABLE_VP9 -DRTC_ENABLE_H265 -DRTC_DAV1D_IN_INTERNAL_DECODER_FACTORY -DWEBRTC_HAVE_SCTP -DWEBRTC_USE_H264 -DWEBRTC_ENCODER_PSNR_STATS -DPROTOBUF_ENABLE_DEBUG_LOGGING_MAY_LEAK_PII=0 -DWEBRTC_ENABLE_AVX2 -DRTC_ENABLE_WIN_WGC -DWEBRTC_NON_STATIC_TRACE_EVENT_HANDLERS=0 -DABSL_ALLOCATOR_NOTHROW=1 -DLIB_WEBRTC_API_DLL -DCHROMIUM -DLIBYUV_DISABLE_NEON -DLIBYUV_DISABLE_SVE -DLIBYUV_DISABLE_SME -DLIBYUV_DISABLE_LSX -DLIBYUV_DISABLE_LASX -DHAVE_WEBRTC_VIDEO -DMANGLE_JPEG_NAMES -I../../libwebrtc -I../../libwebrtc/include -I../.. -Igen -I../../buildtools/third_party/libc++ -I../../third_party/abseil-cpp -I../../third_party/perfetto/include -Igen/third_party/perfetto/build_config -Igen/third_party/perfetto -I../../third_party/libyuv/include -I../../third_party/boringssl/src/include -I../../third_party/libjpeg_turbo/src -Wno-microsoft-extra-qualification -Wno-reorder /W4 -Wimplicit-fallthrough -Wextra-semi -Wunreachable-code-aggressive -Wgnu -Wno-gnu-anonymous-struct -Wno-gnu-conditional-omitted-operand -Wno-gnu-include-next -Wno-gnu-label-as-value -Wno-gnu-redeclared-enum -Wno-gnu-statement-expression -Wno-gnu-zero-variadic-macro-arguments -Wno-zero-length-array -Wthread-safety -Wno-missing-field-initializers -Wno-unused-parameter -Wno-psabi -Wloop-analysis -Wno-unneeded-internal-declaration -Wno-cast-function-type -Wno-thread-safety-reference-return -Wno-nontrivial-memcall -Wno-uninitialized-const-pointer -Wno-nonportable-include-path -Wshadow /WX -fno-delete-null-pointer-checks /clang:-fno-strict-overflow -fno-ident /clang:-fno-math-errno -fcolor-diagnostics -fmerge-all-constants /Zc:sizedDealloc- -fcrash-diagnostics-dir=../../out/clang-crashreports -mllvm -instcombine-lower-dbg-declare=0 -mllvm -split-threshold-for-reg-with-hint=0 /clang:-ffp-contract=off -fcomplete-member-pointers /Gy /FS /bigobj /utf-8 /Zc:twoPhase -ffile-reproducible /D__WRL_ENABLE_FUNCTION_STATICS_ -fmsc-version=1934 -m64 -msse3 /Brepro -Wno-builtin-macro-redefined -D__DATE__= -D__TIME__= -D__TIMESTAMP__= -ffile-compilation-dir=. -no-canonical-prefixes -ftrivial-auto-var-init=pattern /O2 /clang:-O2 /Oy- /Zc:inline /Gw /Z7 -gno-codeview-command-line -mllvm -pick-merged-source-locations -gcodeview-ghash -gomit-unreferenced-methods -Xclang -fuse-ctor-homing -fsanitize=array-bounds -fsanitize-trap=array-bounds /guard:cf /MT -Wheader-hygiene -Wstring-conversion -Wtautological-overlap-compare -Wshadow -Wctad-maybe-unsupported -Wc++11-narrowing -Wundef -Wunused-lambda-capture /TP -Wno-invalid-offsetof -Wenum-compare-conditional -Wno-nullability-completeness /std:c++20 -Wno-trigraphs /GR- -I../../third_party/libc++/src/include /Fd"obj/libwebrtc/libwebrtc_cc.pdb"
../../libwebrtc/src/win/wmf_h265_encoder.cc(313,3): error: use of undeclared identifier 'rtc'
313 | rtc::scoped_refptr i420_buffer =
| ^
../../libwebrtc/src/win/wmf_h265_encoder.cc(313,22): error: 'I420BufferInterface' does not refer to a value
313 | rtc::scoped_refptr i420_buffer =
| ^
../..\api/video/video_frame_buffer.h(183,18): note: declared here
183 | class RTC_EXPORT I420BufferInterface : public PlanarYuv8Buffer {
| ^
../../libwebrtc/src/win/wmf_h265_encoder.cc(313,43): error: use of undeclared identifier 'i420_buffer'
313 | rtc::scoped_refptr i420_buffer =
| ^~~~~~~~~~~
../../libwebrtc/src/win/wmf_h265_encoder.cc(316,18): error: use of undeclared identifier 'i420_buffer'
316 | int y_stride = i420_buffer->StrideY();
| ^~~~~~~~~~~
../../libwebrtc/src/win/wmf_h265_encoder.cc(317,18): error: use of undeclared identifier 'i420_buffer'
317 | int u_stride = i420_buffer->StrideU();
| ^~~~~~~~~~~
../../libwebrtc/src/win/wmf_h265_encoder.cc(318,18): error: use of undeclared identifier 'i420_buffer'
318 | int v_stride = i420_buffer->StrideV();
| ^~~~~~~~~~~
../../libwebrtc/src/win/wmf_h265_encoder.cc(325,7): error: use of undeclared identifier 'i420_buffer'
325 | i420_buffer->DataY(), y_stride, i420_buffer->DataU(), u_stride,
| ^~~~~~~~~~~
../../libwebrtc/src/win/wmf_h265_encoder.cc(325,39): error: use of undeclared identifier 'i420_buffer'
325 | i420_buffer->DataY(), y_stride, i420_buffer->DataU(), u_stride,
| ^~~~~~~~~~~
../../libwebrtc/src/win/wmf_h265_encoder.cc(326,7): error: use of undeclared identifier 'i420_buffer'
326 | i420_buffer->DataV(), v_stride, nv12_buffer_.data(), width_,
| ^~~~~~~~~~~
../../libwebrtc/src/win/wmf_h265_encoder.cc(492,9): error: use of undeclared identifier 'rtc'
492 | rtc::ArrayView(data, data_length));
| ^
../../libwebrtc/src/win/wmf_h265_encoder.cc(492,24): error: expected expression
492 | rtc::ArrayView(data, data_length));
| ^
11 errors generated.
[4340/4347] CXX obj/libwebrtc/libwebrtc/wmf_h265_decoder.obj
FAILED: [code=1] obj/libwebrtc/libwebrtc/wmf_h265_decoder.obj
....\third_party\llvm-build\Release+Asserts\bin\clang-cl.exe /c ../../libwebrtc/src/win/wmf_h265_decoder.cc /Foobj/libwebrtc/libwebrtc/wmf_h265_decoder.obj /nologo /showIncludes:user "-imsvcC:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.44.35207\include" "-imsvcC:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.44.35207\ATLMFC\include" "-imsvcC:\Program Files\Microsoft Visual Studio\2022\Community\VC\Auxiliary\VS\include" "-imsvcC:\Program Files (x86)\Windows Kits\10\include\10.0.26100.0\ucrt" "-imsvcC:\Program Files (x86)\Windows Kits\10\include\10.0.26100.0\um" "-imsvcC:\Program Files (x86)\Windows Kits\10\include\10.0.26100.0\shared" "-imsvcC:\Program Files (x86)\Windows Kits\10\include\10.0.26100.0\winrt" "-imsvcC:\Program Files (x86)\Windows Kits\10\include\10.0.26100.0\cppwinrt" "-imsvcC:\Program Files (x86)\Windows Kits\NETFXSDK\4.8\include\um" -DUSE_LIBYUV -DWEBRTC_INCLUDE_INTERNAL_AUDIO_DEVICE -DLIB_WEBRTC_API_EXPORTS -DWEBRTC_WIN -DRTC_DESKTOP_DEVICE -D_HAS_NODISCARD -D_CRT_NONSTDC_NO_WARNINGS -D_WINSOCK_DEPRECATED_NO_WARNINGS "-DCR_CLANG_REVISION="llvmorg-22-init-14273-gea10026b-2"" -D_LIBCPP_HARDENING_MODE=LIBCPP_HARDENING_MODE_EXTENSIVE -D_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS -D_LIBCPP_INSTRUMENTED_WITH_ASAN=0 -DCR_LIBCXX_REVISION=fa224989fd9c52f68042d7fd6824302c33cb68c0 -D__STD_C -D_CRT_RAND_S -D_CRT_SECURE_NO_DEPRECATE -D_SCL_SECURE_NO_DEPRECATE -D_ATL_NO_OPENGL -D_WINDOWS -DCERT_CHAIN_PARA_HAS_EXTRA_FIELDS -DPSAPI_VERSION=2 -DWIN32 -D_SECURE_ATL -DWINAPI_FAMILY=WINAPI_FAMILY_DESKTOP_APP -DUSE_AURA=1 -DWIN32_LEAN_AND_MEAN -DNOMINMAX -D_UNICODE -DUNICODE -DNTDDI_VERSION=NTDDI_WIN11_GE -D_WIN32_WINNT=0x0A00 -DWINVER=0x0A00 -DNDEBUG -DNVALGRIND -DDYNAMIC_ANNOTATIONS_ENABLED=0 -DWEBRTC_ENABLE_PROTOBUF=1 -DWEBRTC_STRICT_FIELD_TRIALS=0 -DRTC_ENABLE_VP9 -DRTC_ENABLE_H265 -DRTC_DAV1D_IN_INTERNAL_DECODER_FACTORY -DWEBRTC_HAVE_SCTP -DWEBRTC_USE_H264 -DWEBRTC_ENCODER_PSNR_STATS -DPROTOBUF_ENABLE_DEBUG_LOGGING_MAY_LEAK_PII=0 -DWEBRTC_ENABLE_AVX2 -DRTC_ENABLE_WIN_WGC -DWEBRTC_NON_STATIC_TRACE_EVENT_HANDLERS=0 -DABSL_ALLOCATOR_NOTHROW=1 -DLIB_WEBRTC_API_DLL -DCHROMIUM -DLIBYUV_DISABLE_NEON -DLIBYUV_DISABLE_SVE -DLIBYUV_DISABLE_SME -DLIBYUV_DISABLE_LSX -DLIBYUV_DISABLE_LASX -DHAVE_WEBRTC_VIDEO -DMANGLE_JPEG_NAMES -I../../libwebrtc -I../../libwebrtc/include -I../.. -Igen -I../../buildtools/third_party/libc++ -I../../third_party/abseil-cpp -I../../third_party/perfetto/include -Igen/third_party/perfetto/build_config -Igen/third_party/perfetto -I../../third_party/libyuv/include -I../../third_party/boringssl/src/include -I../../third_party/libjpeg_turbo/src -Wno-microsoft-extra-qualification -Wno-reorder /W4 -Wimplicit-fallthrough -Wextra-semi -Wunreachable-code-aggressive -Wgnu -Wno-gnu-anonymous-struct -Wno-gnu-conditional-omitted-operand -Wno-gnu-include-next -Wno-gnu-label-as-value -Wno-gnu-redeclared-enum -Wno-gnu-statement-expression -Wno-gnu-zero-variadic-macro-arguments -Wno-zero-length-array -Wthread-safety -Wno-missing-field-initializers -Wno-unused-parameter -Wno-psabi -Wloop-analysis -Wno-unneeded-internal-declaration -Wno-cast-function-type -Wno-thread-safety-reference-return -Wno-nontrivial-memcall -Wno-uninitialized-const-pointer -Wno-nonportable-include-path -Wshadow /WX -fno-delete-null-pointer-checks /clang:-fno-strict-overflow -fno-ident /clang:-fno-math-errno -fcolor-diagnostics -fmerge-all-constants /Zc:sizedDealloc- -fcrash-diagnostics-dir=../../out/clang-crashreports -mllvm -instcombine-lower-dbg-declare=0 -mllvm -split-threshold-for-reg-with-hint=0 /clang:-ffp-contract=off -fcomplete-member-pointers /Gy /FS /bigobj /utf-8 /Zc:twoPhase -ffile-reproducible /D__WRL_ENABLE_FUNCTION_STATICS_ -fmsc-version=1934 -m64 -msse3 /Brepro -Wno-builtin-macro-redefined -D__DATE__= -D__TIME__= -D__TIMESTAMP__= -ffile-compilation-dir=. -no-canonical-prefixes -ftrivial-auto-var-init=pattern /O2 /clang:-O2 /Oy- /Zc:inline /Gw /Z7 -gno-codeview-command-line -mllvm -pick-merged-source-locations -gcodeview-ghash -gomit-unreferenced-methods -Xclang -fuse-ctor-homing -fsanitize=array-bounds -fsanitize-trap=array-bounds /guard:cf /MT -Wheader-hygiene -Wstring-conversion -Wtautological-overlap-compare -Wshadow -Wctad-maybe-unsupported -Wc++11-narrowing -Wundef -Wunused-lambda-capture /TP -Wno-invalid-offsetof -Wenum-compare-conditional -Wno-nullability-completeness /std:c++20 -Wno-trigraphs /GR- -I../../third_party/libc++/src/include /Fd"obj/libwebrtc/libwebrtc_cc.pdb"
../../libwebrtc/src/win/wmf_h265_decoder.cc(401,3): error: use of undeclared identifier 'rtc'
401 | rtc::scoped_refptr i420_buffer =
| ^
../../libwebrtc/src/win/wmf_h265_decoder.cc(401,22): error: 'I420Buffer' does not refer to a value
401 | rtc::scoped_refptr i420_buffer =
| ^
../..\api/video/i420_buffer.h(27,18): note: declared here
27 | class RTC_EXPORT I420Buffer : public I420BufferInterface {
| ^
../../libwebrtc/src/win/wmf_h265_decoder.cc(401,34): error: use of undeclared identifier 'i420_buffer'
401 | rtc::scoped_refptr i420_buffer =
| ^~~~~~~~~~~
../../libwebrtc/src/win/wmf_h265_decoder.cc(407,24): error: use of undeclared identifier 'i420_buffer'
407 | i420_buffer->MutableDataY(), i420_buffer->StrideY(),
| ^~~~~~~~~~~
../../libwebrtc/src/win/wmf_h265_decoder.cc(407,53): error: use of undeclared identifier 'i420_buffer'
407 | i420_buffer->MutableDataY(), i420_buffer->StrideY(),
| ^~~~~~~~~~~
../../libwebrtc/src/win/wmf_h265_decoder.cc(408,24): error: use of undeclared identifier 'i420_buffer'
408 | i420_buffer->MutableDataU(), i420_buffer->StrideU(),
| ^~~~~~~~~~~
../../libwebrtc/src/win/wmf_h265_decoder.cc(408,53): error: use of undeclared identifier 'i420_buffer'
408 | i420_buffer->MutableDataU(), i420_buffer->StrideU(),
| ^~~~~~~~~~~
../../libwebrtc/src/win/wmf_h265_decoder.cc(409,24): error: use of undeclared identifier 'i420_buffer'
409 | i420_buffer->MutableDataV(), i420_buffer->StrideV(),
| ^~~~~~~~~~~
../../libwebrtc/src/win/wmf_h265_decoder.cc(409,53): error: use of undeclared identifier 'i420_buffer'
409 | i420_buffer->MutableDataV(), i420_buffer->StrideV(),
| ^~~~~~~~~~~
../../libwebrtc/src/win/wmf_h265_decoder.cc(418,22): error: use of undeclared identifier 'i420_buffer'
418 | i420_buffer->MutableDataY(), i420_buffer->StrideY(),
| ^~~~~~~~~~~
../../libwebrtc/src/win/wmf_h265_decoder.cc(418,51): error: use of undeclared identifier 'i420_buffer'
418 | i420_buffer->MutableDataY(), i420_buffer->StrideY(),
| ^~~~~~~~~~~
../../libwebrtc/src/win/wmf_h265_decoder.cc(419,22): error: use of undeclared identifier 'i420_buffer'
419 | i420_buffer->MutableDataU(), i420_buffer->StrideU(),
| ^~~~~~~~~~~
../../libwebrtc/src/win/wmf_h265_decoder.cc(419,51): error: use of undeclared identifier 'i420_buffer'
419 | i420_buffer->MutableDataU(), i420_buffer->StrideU(),
| ^~~~~~~~~~~
../../libwebrtc/src/win/wmf_h265_decoder.cc(420,22): error: use of undeclared identifier 'i420_buffer'
420 | i420_buffer->MutableDataV(), i420_buffer->StrideV(),
| ^~~~~~~~~~~
../../libwebrtc/src/win/wmf_h265_decoder.cc(420,51): error: use of undeclared identifier 'i420_buffer'
420 | i420_buffer->MutableDataV(), i420_buffer->StrideV(),
| ^~~~~~~~~~~
../../libwebrtc/src/win/wmf_h265_decoder.cc(437,37): error: use of undeclared identifier 'i420_buffer'
437 | .set_video_frame_buffer(i420_buffer)
| ^~~~~~~~~~~
16 errors generated.
[4346/4347] CXX obj/libwebrtc/libwebrtc/rtc_desktop_media_list_impl.obj
ninja: build stopped: subcommand failed.`