Cairo is “slow”

Here’s the pipeline:

gst-launch-0.10 filesrc location=/home/lvs/The\ Matrix\ -\ Theatrical\ Trailer.avi ! decodebin ! queue ! cairomixer sink_0::xx=0.5 sink_0::xy=0.273151 sink_0::yx=-0.273151 sink0::yy=0.5 sink_0::alpha=0.6 sink_0::xpos=72 sink_0::ypos=48 sink_2:xx=1.38582 sink_2::xy=-0.574025 sink_2::yx=0.574025 sink2::yy=1.38582 sink_2::alpha=0.7 sink_2::xpos=20 sink_2::ypos=150 sink_2::zorder=10 sink_1::xpos=300 sink_1::ypos=100 ! video/x-cairo,width=800,height=500 ! pangotimeoverlay ! cairoxsink filesrc location=/home/lvs/the_incredibles-tlr_m480.mov ! decodebin ! cairocolorspace ! video/x-cairo ! queue ! cairomixer0. filesrc location=/home/lvs/transformers.trailer.480.mov ! decodebin ! cairocolorspace ! video/x-cairo ! queue ! cairomixer0.

Here’s the result:

CPU utilization when playing this is roughly 30%, which I attribute mostly to the video decoding. The Intel 945 GPU takes 25% doing this. If I use the sync=false property, the video is done after 59s. It’s also completely backwards compatible when no hardware acceleration is available. In fact I used the same pipeline to record the video, just replacing the sink with a theoraenc.

Implementation details are here and here. Total amount of code written is roughly 10.000 lines, put into the right spots in gstreamer, cairo, pixman and the xserver. Of course, the code is not limited to GStreamer. I expect Webkit and Mozilla will use it too, once it’s properly integrated. And then we can do these effects in Javascript.