The latest VLC development code now supports zero-copy GStreamer video decoding. With the zero-copy comes increased efficiency and performance.
The commit by Vikram Fugro explains, "Implements the interface to provide the VLC pictures from vout mapped to GstBuffers, along with per video plane stride/offsets info, to the upstream gstreamer video decoder. If the stride/offsets info of the vlc pictures (created by vout) matches the video decoder's expectations, the decoder will directly decode into the vout allocated pictures, enabling zero-copy. Else it will continue to use it's own bufferpool."