docs/linux_hw_video_decode.md

# Enabling hardware 

<video>

 decode codepaths on linux

Hardware acceleration of video decode on linux is [unsupported](http://crbug.com/137247) in Chrome for user-facing builds.  During development (targeting other platforms) it can be useful to be able to trigger the code-paths used on HW-accelerated platforms (such as CrOS and win7) in a linux-based development environment.  Here's one way to do so, with details based on a gprecise setup.

  * Install pre-requisites: On Ubuntu Precise, at least, this includes:
```
sudo apt-get install libtool libvdpau1 libvdpau-dev
```

  * Install and configure [libva](http://cgit.freedesktop.org/libva/)
```
DEST=${HOME}/apps/libva
cd /tmp
git clone git://anongit.freedesktop.org/libva
cd libva
git reset --hard libva-1.2.1
./autogen.sh && ./configure --prefix=${DEST}
make -j32 && make install
```
  * Install and configure the [VDPAU](http://cgit.freedesktop.org/vaapi/vdpau-driver) VAAPI driver
```
DEST=${HOME}/apps/libva
cd /tmp
git clone git://anongit.freedesktop.org/vaapi/vdpau-driver
cd vdpau-driver
export PKG_CONFIG_PATH=${DEST}/lib/pkgconfig/:$PKG_CONFIG_PATH
export LIBVA_DRIVERS_PATH=${DEST}/lib/dri
export LIBVA_X11_DEPS_CFLAGS=-I${DEST}/include
export LIBVA_X11_DEPS_LIBS=-L${DEST}/lib
export LIBVA_DEPS_CFLAGS=-I${DEST}/include
export LIBVA_DEPS_LIBS=-L${DEST}/lib
make distclean
unset CC CXX
./autogen.sh && ./configure --prefix=${DEST} --enable-debug
find . -name Makefile |xargs sed -i 'sI/usr/lib/xorg/modules/driversI${DEST}/lib/driIg'
sed -i -e 's/_(\(VAEncH264VUIBufferType\|VAEncH264SEIBufferType\));//' src/vdpau_dump.c
make -j32 && rm -f ${DEST}/lib/dri/{nvidia_drv_video.so,s3g_drv_video.so} && make install
```
  * Add to `$GYP_DEFINES`:
    * `chromeos=1` to link in `VaapiVideoDecodeAccelerator`
    * `proprietary_codecs=1 ffmpeg_branding=Chrome` to allow Chrome to play h.264 content, which is the only codec VAVDA knows about today.
  * Re-run gyp (`./build/gyp_chromium` or `gclient runhooks`)
  * Rebuild chrome
  * Run chrome with `LD_LIBRARY_PATH=${HOME}/apps/libva/lib` in the environment, and with the --no-sandbox command line flag.
  * If things don't work, a Debug build (to include D\*LOG's) with `--vmodule=*content/common/gpu/media/*=10,gpu_video*=1` might be enlightening.

# NOTE THIS IS AN UNSUPPORTED CONFIGURATION AND LIKELY TO BE BROKEN AT ANY POINT IN TIME

This page is purely here to help developers targeting supported HW 

<video>

 decode platforms be more effective.  Do not expect help if this setup fails to work.