meta,
    args = {
        "gltestsrc ! gldownload ! autovideoconvert name=convert ! capsfilter name=capsfilter caps=\"video/x-raw(memory:GLMemory)\" ! fakevideosink name=sink",
    },
    configs = {
       "$(validateflow), pad=convert:src, record-buffers=true, ignored-fields=\"stream-start={stream-id,group-id,stream},buffer={meta}\"",
    }

crank-clock, repeat=2
wait, on-clock=true
foreach,
    caps = <
            "video/x-raw",
            "video/x-raw(memory:GLMemory)",
            "video/x-raw",
           >,
    actions = {
        [set-properties, capsfilter::caps="$(caps)"],
        [crank-clock, repeat=2],
        [wait, on-clock=true],
    }
stop