Make decode_init fail if the huffman tables are invalid and thus init_vlc fails.

Otherwise this will crash during decoding because the vlc tables are NULL.
Partially fixes ogv/smclock.ogv.1.101.ogv from issue 1240.

Originally committed as revision 19355 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/vp3.c

@@ -1788,29 +1788,34 @@ static av_cold int vp3_decode_init(AVCodecContext *avctx)
         for (i = 0; i < 16; i++) {
 
             /* DC histograms */
-            init_vlc(&s->dc_vlc[i], 5, 32,
+            if (init_vlc(&s->dc_vlc[i], 5, 32,
                 &s->huffman_table[i][0][1], 4, 2,
-                &s->huffman_table[i][0][0], 4, 2, 0);
+                &s->huffman_table[i][0][0], 4, 2, 0) < 0)
+                goto vlc_fail;
 
             /* group 1 AC histograms */
-            init_vlc(&s->ac_vlc_1[i], 5, 32,
+            if (init_vlc(&s->ac_vlc_1[i], 5, 32,
                 &s->huffman_table[i+16][0][1], 4, 2,
-                &s->huffman_table[i+16][0][0], 4, 2, 0);
+                &s->huffman_table[i+16][0][0], 4, 2, 0) < 0)
+                goto vlc_fail;
 
             /* group 2 AC histograms */
-            init_vlc(&s->ac_vlc_2[i], 5, 32,
+            if (init_vlc(&s->ac_vlc_2[i], 5, 32,
                 &s->huffman_table[i+16*2][0][1], 4, 2,
-                &s->huffman_table[i+16*2][0][0], 4, 2, 0);
+                &s->huffman_table[i+16*2][0][0], 4, 2, 0) < 0)
+                goto vlc_fail;
 
             /* group 3 AC histograms */
-            init_vlc(&s->ac_vlc_3[i], 5, 32,
+            if (init_vlc(&s->ac_vlc_3[i], 5, 32,
                 &s->huffman_table[i+16*3][0][1], 4, 2,
-                &s->huffman_table[i+16*3][0][0], 4, 2, 0);
+                &s->huffman_table[i+16*3][0][0], 4, 2, 0) < 0)
+                goto vlc_fail;
 
             /* group 4 AC histograms */
-            init_vlc(&s->ac_vlc_4[i], 5, 32,
+            if (init_vlc(&s->ac_vlc_4[i], 5, 32,
                 &s->huffman_table[i+16*4][0][1], 4, 2,
-                &s->huffman_table[i+16*4][0][0], 4, 2, 0);
+                &s->huffman_table[i+16*4][0][0], 4, 2, 0) < 0)
+                goto vlc_fail;
         }
     }
 
@@ -1844,6 +1849,10 @@ static av_cold int vp3_decode_init(AVCodecContext *avctx)
     }
 
     return 0;
+
+vlc_fail:
+    av_log(avctx, AV_LOG_FATAL, "Invalid huffman table\n");
+    return -1;
 }
 
 /*