As　the　projection　of　the　real　world,　videos　usually　have　many　repeated　patterns　with　similar　structures　cross　regions,　presenting　strong　non-local　correlations.　Moreover,　different　videos　own　different　characteristics.　Exploitation　of　the　non-local　correlations　by　off-line　training　of　transforms　has　attracted　considerable　attention　over　the　past　years　for　compression.　However,　the　samples　used　for　training　the　transforms　are　usually　collected　from　a　predefined　set　of　training　videos　to　avoid　the　transmission　of　transform　matrixes.　There　is　no　guarantee　that　the　characteristics　of　those　training　videos　and　the　corresponding　transforms　fit　the　current　coding　video　very　well.　To　address　that,　this　paper　proposes　an　internal-video　mode　dependent　directional　transform　in　HEVC　for　intra　coding.　In　this　scheme,　for　coding　a　video　clip,　based　on　different　directions,　a　set　of　sample　blocks　is　collected　for　each　direction　to　train　a　Karhunen-Loeve　transform　at　the　video　clip　level.　During　encoding,　the　better　transform　between　the　proposed　transform　and　original　DCT/DST　in　HEVC　is　determined　based　on　rate-distortion　optimization.　These　transform　matrixes　are　entropy　coded　to　the　bitstream.　The　proposed　method　can　capture　the　statistical　characteristics　of　the　coded　video　clip　and　provide　efficient　transforms.　Experimental　results　show　that　the　proposed　method　achieves　significant　performance　improvements　in　comparison　with　HEVC　for　intra　coding,　up　to　13%　BD-rate　savings　for　the　all　intra　configuration.　©　2016　IEEE.