Overview

This layer enables hardware assisted video decoding in Chromium via the Chromium V4L2VDA, using the v4l-gst libv4l plugin to connect it to the Renesas H/W video decoder available through GStreamer.

Currently, only the H264 video codec is supported.

Building

1. Add this layer to your bblayers.conf file

2. Add the following packages to your IMAGE_INSTALL_append variable in your local.conf

   • v4l-gst
   • libv4l
   • libv4l-dev

3. Add the following define to your local.conf

PACKAGECONFIG_append_pn-chromium = " proprietary-codecs"

bitbake as usual.

Configuration

The settings file for the v4l-gst bridge is located at /etc/xdg/libv4l-gst.conf. This file allows for specifying the GStreamer pipeline that the plugin will attempt to use to decode the video frames that it receives from the V4L2 interface.

Example settings for an R-Car board are show below, but they may be updated to use more generic settings.

[libv4l-gst]
pipeline=h264parse ! omxh264dec no-reorder=true ! queue max-size-bytes=0 max-size-time=0 max-size-buffers=0 ! vspfilter output-io-mode=0

Running

Create a dummy V4L2 device file under /dev

# touch /dev/video-gst
# chsmack -a \* /dev/video-gst

Accessing the /dev/video-gst file will allow an application to use the v4l-gst plugin using the same API as a regular V4L2 device file.

Running with Chromium

Link to the video decoder device file that Chromium uses

# ln -s /dev/video-gst /dev/video-dec
# chsmack -a \* /dev/video-dec

Hardware video decoding is blacklisted by default on Chromium. Add the --ignore-gpu-blacklist to the Chromium command line to enable video decoding via the V4L2 interface.