check norm6 vlc validity as there are some bit sequences which dont corespond...

check norm6 vlc validity as there are some bit sequences which dont corespond to any codeword, the other vlc tables all seem to be huffman tables though


git-svn-id: file:///var/local/repositories/ffmpeg/trunk@3883 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

libavcodec/vc9.c

@@ -852,6 +852,10 @@ static int bitplane_decoding(BitPlane *bp, VC9Context *v)
         for(y=  bp->height%tile_h; y< bp->height; y+=tile_h){
             for(x=  bp->width%tile_w; x< bp->width; x+=tile_w){
                 code = get_vlc2(&v->gb, vc9_norm6_vlc.table, VC9_NORM6_VLC_BITS, 2);
+                if(code<0){
+                    av_log(v->avctx, AV_LOG_DEBUG, "inavlid NORM-6 VLC\n");
+                    return -1;
+                }
                 //FIXME following is a pure guess and probably wrong
                 //FIXME A bitplane (0 | !0), so could the shifts be avoided ?
                 planep[x     + 0*bp->stride]= (code>>0)&1;