mlp: Only initialize VLC tables once. This caused a crash when multiple

instances of the decoder were started at different times.
Bug reported by Maxim Anisiutkin.

Originally committed as revision 20254 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/mlpdec.c

@@ -155,6 +155,7 @@ static VLC huff_vlc[3];
 
 static av_cold void init_static(void)
 {
+    if (!huff_vlc[0].bits) {
     INIT_VLC_STATIC(&huff_vlc[0], VLC_BITS, 18,
                 &ff_mlp_huffman_tables[0][0][1], 2, 1,
                 &ff_mlp_huffman_tables[0][0][0], 2, 1, 512);
@@ -164,6 +165,7 @@ static av_cold void init_static(void)
     INIT_VLC_STATIC(&huff_vlc[2], VLC_BITS, 15,
                 &ff_mlp_huffman_tables[2][0][1], 2, 1,
                 &ff_mlp_huffman_tables[2][0][0], 2, 1, 512);
+    }
 
     ff_mlp_init_crc();
 }