From 76267e4e90a3b64f98ca0e4517eff44e963d5e18 Mon Sep 17 00:00:00 2001
From: Kostya Shishkov <kostya.shishkov@gmail.com>
Date: Fri, 20 Nov 2009 07:49:53 +0000
Subject: [PATCH] Implement missing case for decoding samples with large pivot
value in APE decoder. This fixes issue 1555
Originally committed as revision 20560 to svn://svn.ffmpeg.org/ffmpeg/trunk
---
libavcodec/apedec.c | 20 ++++++++++++++++++--
1 file changed, 18 insertions(+), 2 deletions(-)
diff --git a/libavcodec/apedec.c b/libavcodec/apedec.c
index 1e21e6a401a..20ebe9ed673 100644
--- a/libavcodec/apedec.c
+++ b/libavcodec/apedec.c
@@ -408,8 +408,24 @@ static inline int ape_decode_value(APEContext * ctx, APERice *rice)
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;
}
--
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