avcodec/dnxhddec: fix decoding of DNxHR HQX 10-bit

[ffmpeg] / libavcodec / get_bits.h

diff --git a/libavcodec/get_bits.h b/libavcodec/get_bits.h
index 0f183e0358359e400fdcab91e1368d28bbc764fb..c530015169e1c8939265658ef5bf0694e3e45be4 100644 (file)
--- a/libavcodec/get_bits.h
+++ b/libavcodec/get_bits.h
@@ -229,6 +229,20 @@ static inline int get_xbits(GetBitContext *s, int n)
     return (NEG_USR32(sign ^ cache, n) ^ sign) - sign;
 }
 
+static inline int get_xbits_le(GetBitContext *s, int n)
+{
+    register int sign;
+    register int32_t cache;
+    OPEN_READER(re, s);
+    av_assert2(n>0 && n<=25);
+    UPDATE_CACHE_LE(re, s);
+    cache = GET_CACHE(re, s);
+    sign  = sign_extend(~cache, n) >> 31;
+    LAST_SKIP_BITS(re, s, n);
+    CLOSE_READER(re, s);
+    return (zero_extend(sign ^ cache, n) ^ sign) - sign;
+}
+
 static inline int get_sbits(GetBitContext *s, int n)
 {
     register int tmp;
@@ -331,6 +345,7 @@ static inline void skip_bits1(GetBitContext *s)
  */
 static inline unsigned int get_bits_long(GetBitContext *s, int n)
 {
+    av_assert2(n>=0 && n<=32);
     if (!n) {
         return 0;
     } else if (n <= MIN_CACHE_BITS) {
@@ -369,6 +384,10 @@ static inline uint64_t get_bits64(GetBitContext *s, int n)
  */
 static inline int get_sbits_long(GetBitContext *s, int n)
 {
+    // sign_extend(x, 0) is undefined
+    if (!n)
+        return 0;
+
     return sign_extend(get_bits_long(s, n), n);
 }