Linux/AM5728: AM5728 GStreamer Ducatih264dec0 cannot link with Matroska Muxer

Part Number:AM5728

Tool/software: Linux

I am using the latest TI AM5728 Processor SDK ( 05.00.00.15 ) on the AM5728 EVM.

I have 2 USB Web Cams hooked up to the SDK and I can successfully run simultaneous gst-launch processes for each webpage as shown below:

GST_DEBUG=3 gst-launch-1.0 v4l2src device=/dev/video1 ! 'video/x-raw, format=(string)YUY2, width=(int)640, height=(int)480, framerate=30/1' ! videoconvert !  'video/x-raw, format=(string)NV12, width=(int)640, height=(int)480' ! ducatih264enc ! h264parse ! ducatih264dec ! waylandsink sync=false

GST_DEBUG=1 gst-launch-1.0 -e -v v4l2src device=/dev/video2 io-mode=4 ! 'video/x-raw, format=(string)UYVY, width=(int)160, height=(int)120' ! videoconvert !  'video/x-raw, format=(string)NV12, width=(int)160, height=(int)120' ! ducatih264enc ! h264parse ! ducatih264dec ! waylandsink sync=false

Now I want to mux both streams into a matroska file as shown below. However, it fails with the error "WARNING: erroneous pipeline: could not link ducatih264dec0 to mux":

gst-launch-1.0 -v -e \
    v4l2src device=/dev/video2 io-mode=4 \
	! 'video/x-raw, format=(string)UYVY, width=(int)160, height=(int)120' \
	! videoconvert \
	! 'video/x-raw, format=(string)NV12, width=(int)160, height=(int)120' \
	! ducatih264enc \
	! h264parse \
	! ducatih264dec \
	! mux. \
    v4l2src device=/dev/video1 \
        ! queue max-size-buffers=0 max-size-time=0 max-size-bytes=0 \
        ! 'video/x-raw, format=(string)YUY2, width=(int)640, height=(int)480, framerate=30/1' \
	! videoconvert \
	! 'video/x-raw, format=(string)NV12, width=(int)640, height=(int)480' \
	! ducatih264enc \
	! h264parse \
	! ducatih264dec \
        ! mux. \
    matroskamux name=mux min-index-interval=1000000000 \
        ! queue max-size-buffers=0 max-size-time=0 max-size-bytes=0 \
        ! filesink location=test-vid.mkv

How can I do this? Thanks.