On Wed, 2018-10-17 at 14:33 -0700, Steve Longerbeam wrote: [...] > > I'm also interested in looking at Philipps' 'i.MX media mem2mem > > scaler' series (https://patchwork.kernel.org/cover/10603881/) and am > > wondering if anyone has some example pipelines showing that in use. > > I'm hoping that is what is needed to be able to use hardware > > scaling/CSC and coda based encoding on streams from v4l2 PCI capture > > devices. > > Yes exactly, I'll let Philipp answer. I'm also interested in the gstreamer > element needed to make use of h/w scaling/CSC from the mem2mem > device. GStreamer should create a GstV4l2Transform element "v4l2videoXconvert" for the /dev/videoX mem2mem scaler device. > For coda encode, my understanding is that the v4l2h264enc element will > make use of coda h/w encode, something like this example which encodes to > a h.264 file (I haven't verified this works, still need to build a later > version of gst-plugins-good that has the vl2h264enc support): > > gst-launch-1.0 v4l2src io-mode=dmabuf device=/dev/video$dev !\ "video/x-raw,format=$fmt,width=$w,height=$h" ! \ > v4l2h264enc output-io-mode=dmabuf-import ! queue ! matroskamux ! \ > filesink location=$filename With GStreamer 1.14 the capture side io-mode parameter is not necessary anymore to export dmabufs. The output-io-mode parameter is currently still needed though, as the V4L2 elements don't support negotiating dmabuf using caps via video/x-raw(memory:DMABuf) yet. Also there's a h264parse missing to convert the video/x-h264,stream- format=byte-stream from v4l2h264enc to video/x-h264,stream-format=avc as required by matroskamux: gst-launch-1.0 \ v4l2src ! \ v4l2video10convert output-io-mode=dmabuf-import ! \ v4l2h264enc output-io-mode=dmabuf-import ! \ h264parse ! \ matroskamux ! \ filesink > > Lastly, is there any hope to use IMX6 hardware compositing to say > > stitch together multiple streams from a v4l2 PCI capture device into a > > single stream for coda based hw encoding? > > The IPUv3 Image Converter has a combining unit that can combine pixels from > two images, but there is no support for that in mainline AFAIK. I don't think there is any V4L2 API for compositing yet. regards Philipp
