Presented by

  • Nicolas Dufresne

    Nicolas Dufresne

    Nicolas Dufresne is a Principal Multimedia Engineer at Collabora. Based in Montréal, he was initially a generalist developer with a background in STB development. Nicolas began contributing to the GStreamer Multimedia Framework in 2011, adding infrastructure and primitives to support accelerated upload of buffers to GL textures. Today, Nicolas is actively involved in both the GStreamer and Linux Media communities to help create a solid support for CODECs on Linux.


Surveys of children from age 6 to 17 years old are showing a majority want to become either a professional vlogger, or YouTuber. These new generations, beginning with millennials, are consuming video content like never before. To make video editing and production easier, transitions with transparency capability have become very common. These transitions have their own marketplaces. They are mostly encoded using the royalty-free CODECs VP8 and VP9, and are stored into a WebM (Matroska for Web) container. Unfortunately, these CODEC implementations do not support the alpha plane that provides transparency. In this talk, Nicolas will introduce the audience to retro alpha support, a workaround specification designed by the Google WebM team to enable VP8 & VP9 to support transparency, and will dive into the architecture he has implemented in GStreamer to support this type of video, both with software decoders and hardware-accelerated V4L2 decoders.