gistfile1.txt

#!/bin/bash -ex

    gst-launch-1.0 \
        v4l2src device=$HDMI2USB !\
            image/jpeg,width=1280,height=720 !\
            jpegdec !\
            videoconvert !\
            videorate !\
            video/x-raw,format=I420,width=1280,height=720,framerate=30/1,pixel-aspect-ratio=1/1 !\
            queue !\
            intervideosink channel=v \
        \
        alsasrc device='hw:1,0' !\
            audio/x-raw,format=S16LE,channels=2,layout=interleaved,rate=48000 !\
            queue !\
            interaudiosink channel=a \
        \
        intervideosrc channel=v ! mux. \
        interaudiosrc channel=a ! mux. \
        \
        matroskamux name=mux !\
            fdsink | pv >/dev/null