[FFmpeg-cvslog] r20560 - trunk/libavcodec/apedec.c

[kostya]

Author: kostya
Date: Fri Nov 20 08:49:53 2009
New Revision: 20560

Log:
Implement missing case for decoding samples with large pivot value in APE
decoder.
This fixes issue 1555

Modified:
   trunk/libavcodec/apedec.c

Modified: trunk/libavcodec/apedec.c
==============================================================================
--- trunk/libavcodec/apedec.c	Fri Nov 20 08:26:17 2009	(r20559)
+++ trunk/libavcodec/apedec.c	Fri Nov 20 08:49:53 2009	(r20560)
@@ -408,8 +408,24 @@ static inline int ape_decode_value(APECo
             overflow |= range_decode_bits(ctx, 16);
         }
 
-        base = range_decode_culfreq(ctx, pivot);
-        range_decode_update(ctx, 1, base);
+        if (pivot < 0x10000) {
+            base = range_decode_culfreq(ctx, pivot);
+            range_decode_update(ctx, 1, base);
+        } else {
+            int base_hi = pivot, base_lo;
+            int bbits = 0;
+
+            while (base_hi & ~0xFFFF) {
+                base_hi >>= 1;
+                bbits++;
+            }
+            base_hi = range_decode_culfreq(ctx, base_hi + 1);
+            range_decode_update(ctx, 1, base_hi);
+            base_lo = range_decode_culfreq(ctx, 1 << bbits);
+            range_decode_update(ctx, 1, base_lo);
+
+            base = (base_hi << bbits) + base_lo;
+        }
 
         x = base + overflow * pivot;
     }