1# Enabling hardware <video> decode codepaths on linux
2
3Hardware acceleration of video decode on Linux is
4[unsupported](https://crbug.com/137247) in Chrome for user-facing builds. During
5development (targeting other platforms) it can be useful to be able to trigger
6the code-paths used on HW-accelerated platforms (such as CrOS and win7) in a
7linux-based development environment. Here's one way to do so, with details based
8on a gprecise setup.
9
10*   Install pre-requisites: On Ubuntu Precise, at least, this includes:
11
12    ```shell
13    sudo apt-get install libtool libvdpau1 libvdpau-dev
14    ```
15
16*   Install and configure [libva](http://cgit.freedesktop.org/libva/)
17
18    ```shell
19    DEST=${HOME}/apps/libva
20    cd /tmp
21    git clone git://anongit.freedesktop.org/libva
22    cd libva
23    git reset --hard libva-1.2.1
24    ./autogen.sh && ./configure --prefix=${DEST}
25    make -j32 && make install
26    ```
27
28*   Install and configure the
29    [VDPAU](http://cgit.freedesktop.org/vaapi/vdpau-driver) VAAPI driver
30
31    ```shell
32    DEST=${HOME}/apps/libva
33    cd /tmp
34    git clone git://anongit.freedesktop.org/vaapi/vdpau-driver
35    cd vdpau-driver
36    export PKG_CONFIG_PATH=${DEST}/lib/pkgconfig/:$PKG_CONFIG_PATH
37    export LIBVA_DRIVERS_PATH=${DEST}/lib/dri
38    export LIBVA_X11_DEPS_CFLAGS=-I${DEST}/include
39    export LIBVA_X11_DEPS_LIBS=-L${DEST}/lib
40    export LIBVA_DEPS_CFLAGS=-I${DEST}/include
41    export LIBVA_DEPS_LIBS=-L${DEST}/lib
42    make distclean
43    unset CC CXX
44    ./autogen.sh && ./configure --prefix=${DEST} --enable-debug
45    find . -name Makefile |xargs sed -i 'sI/usr/lib/xorg/modules/driversI${DEST}/lib/driIg'
46    sed -i -e 's/_(\(VAEncH264VUIBufferType\|VAEncH264SEIBufferType\));//' src/vdpau_dump.c
47    make -j32 && rm -f ${DEST}/lib/dri/{nvidia_drv_video.so,s3g_drv_video.so} && make install
48    ```
49
50*   Add to args.gn:
51    *   `target_os = "chromeos"` to link in `VaapiVideoDecodeAccelerator`
52    *   `proprietary_codecs = true` and `ffmpeg_branding = "Chrome"` to
53        allow Chrome to play h.264 content, which is the only codec
54        VAVDA knows about today.
55*   Rebuild chrome
56*   Run chrome with `LD_LIBRARY_PATH=${HOME}/apps/libva/lib` in the environment,
57    and with the `--no-sandbox` command line flag.
58*   If things don't work, a Debug build (to include D\*LOG's) with
59    `--vmodule=*content/common/gpu/media/*=10,gpu_video*=1` might be
60    enlightening.
61
62** note
63NOTE THIS IS AN UNSUPPORTED CONFIGURATION AND LIKELY TO BE BROKEN AT ANY
64POINT IN TIME
65**
66
67This page is purely here to help developers targeting supported HW `<video>`
68decode platforms be more effective. Do not expect help if this setup fails to
69work.
70