feat: encode H.264 with VA-API on Intel and AMD GPUs on Linux

docs/guide/advanced/video-codecs.md

@@ -27,14 +27,14 @@ PeerConnectionFactory factory = PeerConnectionFactory.builder()
 | Platform | Hardware encoding |
 |---|---|
 | Windows | H.264 with NVENC on NVIDIA GPUs, otherwise through the Media Foundation encoder of the GPU driver (AMD, Intel) |
-| Linux | H.264 with NVENC on NVIDIA GPUs; other GPUs encode in software |
+| Linux | H.264 with NVENC on NVIDIA GPUs, otherwise through the VA-API encoder of the GPU driver (Intel, AMD) |
 | macOS | H.264 through VideoToolbox, as with `DefaultVideoEncoderFactory` |
 
-NVENC needs an NVIDIA driver of version 522 or newer on Windows, 520 or newer on Linux; it is loaded at run time, so nothing needs to be installed on machines without one.
+NVENC needs an NVIDIA driver of version 522 or newer on Windows, 520 or newer on Linux. VA-API needs libva 2 and a driver that encodes H.264, such as Intel's `intel-media-va-driver` (iHD) or Mesa's `mesa-va-drivers` for AMD, and access to a render node in `/dev/dri`. All of them are loaded at run time, so nothing needs to be installed on machines without them.
 
-The hardware encoders take over H.264 Constrained Baseline and Baseline with packetization mode 1, formats the software encoder offers too, so encoding in hardware never changes what is negotiated. When a hardware encoder fails to start, for example because the GPU has no encoder sessions left, or fails while encoding, the stream switches to the next encoder in line (on Windows, from NVENC to Media Foundation), and finally to the software encoder, and continues with a key frame. On a machine without a hardware encoder, the factory encodes like `DefaultVideoEncoderFactory`.
+The hardware encoders take over H.264 Constrained Baseline and Baseline with packetization mode 1, formats the software encoder offers too, so encoding in hardware never changes what is negotiated. When a hardware encoder fails to start, for example because the GPU has no encoder sessions left, or fails while encoding, the stream switches to the next encoder in line (e.g. from NVENC to Media Foundation on Windows), and finally to the software encoder, and continues with a key frame. On a machine without a hardware encoder, the factory encodes like `DefaultVideoEncoderFactory`.
 
-Which encoder a stream uses shows in the `encoderImplementation` statistic of its `outbound-rtp` stats, e.g. `NVENC (NVIDIA GeForce RTX 4070)`, `MediaFoundation (AMDh264Encoder)` or `OpenH264`.
+Which encoder a stream uses shows in the `encoderImplementation` statistic of its `outbound-rtp` stats, e.g. `NVENC (NVIDIA GeForce RTX 4070)`, `MediaFoundation (AMDh264Encoder)`, `VA-API (Intel iHD driver ...)` or `OpenH264`.
 
 ### Native Codecs
 

webrtc-jni/src/main/cpp/CMakeLists.txt

@@ -110,6 +110,10 @@ target_include_directories(${PROJECT_NAME}
 if(WIN32 OR LINUX)
     target_include_directories(${PROJECT_NAME} PRIVATE dependencies/nvenc/include)
 endif()
+if(LINUX)
+    # libva is loaded at run time, so building needs its headers only.
+    target_include_directories(${PROJECT_NAME} PRIVATE dependencies/libva/include)
+endif()
 
 set_target_properties(${PROJECT_NAME} PROPERTIES
     OUTPUT_NAME "${PROJECT_NAME}-${OUTPUT_NAME_SUFFIX}"
@@ -170,3 +174,10 @@ if(WIN32 OR LINUX)
         COMPONENT Runtime
     )
 endif()
+if(LINUX)
+    install(FILES
+        "${CMAKE_CURRENT_SOURCE_DIR}/dependencies/libva/COPYING"
+        DESTINATION "${CMAKE_INSTALL_PREFIX}/META-INF/licenses/libva"
+        COMPONENT Runtime
+    )
+endif()

webrtc-jni/src/main/cpp/dependencies/libva/COPYING

@@ -0,0 +1,19 @@
+    Permission is hereby granted, free of charge, to any person obtaining a
+    copy of this software and associated documentation files (the
+    "Software"), to deal in the Software without restriction, including
+    without limitation the rights to use, copy, modify, merge, publish,
+    distribute, sub license, and/or sell copies of the Software, and to
+    permit persons to whom the Software is furnished to do so, subject to
+    the following conditions:
+
+    The above copyright notice and this permission notice (including the
+    next paragraph) shall be included in all copies or substantial portions
+    of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+    OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+    IN NO EVENT SHALL PRECISION INSIGHT AND/OR ITS SUPPLIERS BE LIABLE FOR
+    ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+    TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+    SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

webrtc-jni/src/main/cpp/dependencies/libva/README.md

@@ -0,0 +1,12 @@
+# libva headers
+
+`include/va/` holds the public headers of libva 2.17.0 (VA-API 1.17), taken
+unchanged from https://github.com/intel/libva/tree/2.17.0/va, except:
+
+- `va_drm.h` comes from `va/drm/va_drm.h`;
+- `va_version.h` is generated from `va/va_version.h.in` with version 1.17.0,
+  as the libva build does.
+
+The library loads `libva.so.2` and `libva-drm.so.2` at run time, so the
+headers are all the build needs, including for the cross-compiled targets.
+libva is licensed under the MIT license in `COPYING`.