HAP video codec

I'm able to use FFmpeg ffplay to play HAP encoded videos and it's supported in libav, but it seems that the caps mapping for AV_CODEC_ID_HAP is missing from gst-libav.

$ gst-inspect-1.0 | grep hap libav: avdec_hap: libav Vidvox Hap decoder

Here's what I received when I play a HAP encoded video (audio plays fine):

ERROR Your GStreamer installation is missing a plug-in. for file:///C:/Users/james/Downloads/VDMX_Halloween_Hap_4K/projection_zigzag_zoom_hap.mov ERROR debug information: ../gst/playback/gsturidecodebin.c(988): no_more_pads_full (): /GstPlayBin:playbin/GstURIDecodeBin:uridecodebin18: no suitable plugins found: ../gst/playback/gstdecodebin2.c(4679): gst_decode_bin_expose (): /GstPlayBin:playbin/GstURIDecodeBin:uridecodebin18/GstDecodeBin:decodebin18: no suitable plugins found: Missing decoder: video/x-gst-fourcc-Hap1 (video/x-gst-fourcc-Hap1, width=(int)3840, height=(int)2160, framerate=(fraction)30/1, pixel-aspect-ratio=(fraction)1/1)

This happens with Hap1, HapY, HapM, and Hap5 encoded videos from this sample: https://s3.amazonaws.com/vidvox/hap/Hap_Test_Vidvox_QuickTime_Codec.zip

Is there any easy way I can add support for libav HAP decoding? It would be a huge help for a current project I'm involved with ;)