VA: Fail to convert the video format twice.
The command line:
gst-launch-1.0 -vf videotestsrc num-buffers=15 ! video/x-raw,format=I420_10LE,width=1920,height=1080 ! videoconvert ! vapostproc ! glimagesink
fails with reason not-negotiated (-4)
The I420_10LE is not supported in the vapostproc's format list. So the correct way is that videoconvert should convert it to some format such as P010_10LE which is supported by vapostproc, or just directly convert to NV12/I420 which is supported by glimagesink and make vapostproc in passthrough mode.
But in fact, the videoconvert still decide to use I420_10LE format.
/GstPipeline:pipeline0/GstVideoConvert:videoconvert0.GstPad:src: caps = video/x-raw, format=(string)I420_10LE, width=(int)1920, height=(int)1080, framerate=(fraction)30/1, multiview-mode=(string)mono, pixel-aspect-ratio=(fraction)1/1, interlace-mode=(string)progressive