Mine

#/bin/bash
#casio_prototype.sh
gst-launch \
videotestsrc pattern=2 ! \
videorate ! \
videoscale ! \
video/x-raw-yuv,format=\(fourcc\)I420,width=112,height=80,rate=\(fraction\)4/1 ! \
ffmpegcolorspace ! \
textoverlay ! \
ffmpegcolorspace ! \
tee ! \
queue ! \
mix. \
filesrc location=video.ogg ! \
decodebin ! \
queue ! \
ffmpegcolorspace ! \
videoscale ! \
video/x-raw-yuv,format=\(fourcc\)AYUV,width=320,height=240 ! \
ffmpegcolorspace ! \
videomixer name=mix ! \
ffmpegcolorspace ! \
videoscale ! \
sdlvideosink \
videotestsrc pattern=1 ! \
videoscale ! \
video/x-raw-yuv,format=\(fourcc\)I420,width=320,height=240 ! \
ffmpegcolorspace ! \
tee ! \
queue ! \
mix. \

$ ./casio_prototype.sh 2>&1 | grep -i error
0:00:05.560454000 18821 0x8a496c8 DEBUG             GST_PADS gstpad.c:2674:gst_pad_buffer_alloc_unchecked:<src1:proxypad2> alloc function returned error (-1) not-linked
0:00:05.560485000 18821 0x8a496c8 LOG         GST_SCHEDULING gstpad.c:2757:gst_pad_alloc_buffer_full:<vorbisdec1:src> alloc function returned error not-linked
0:00:06.223157000 18821 0x819e440 INFO      GST_ERROR_SYSTEM gstelement.c:1619:gst_element_message_full:<sdlvideosink0> posting message: Internal data flow problem.
0:00:06.223287000 18821 0x819e440 DEBUG              GST_BUS gstbus.c:335:gst_bus_post:<bus1> [msg 0x8b59d98] posting on bus, type warning, GstMessageWarning, gerror=(GstGError)(NULL), debug=(string)"gstbasesink.c\(2123\):\ gst_base_sink_chain_unlocked\ \(\):\ /pipeline0/sdlvideosink0:\012Received\ buffer\ without\ a\ new-segment.\ Assuming\ timestamps\ start\ from\ 0."
0:00:06.223394000 18821 0x819e440 DEBUG              GST_BUS gstbus.c:335:gst_bus_post:<bus2> [msg 0x8b59d98] posting on bus, type warning, GstMessageWarning, gerror=(GstGError)(NULL), debug=(string)"gstbasesink.c\(2123\):\ gst_base_sink_chain_unlocked\ \(\):\ /pipeline0/sdlvideosink0:\012Received\ buffer\ without\ a\ new-segment.\ Assuming\ timestamps\ start\ from\ 0."
0:00:06.223522000 18821 0x819e440 INFO      GST_ERROR_SYSTEM gstelement.c:1642:gst_element_message_full:<sdlvideosink0> posted warning message: Internal data flow problem.