[FFmpeg-devel] [PATCH] avformat/mp3dec: Fix definition of MIDDLE_BITS

Ingo Brückl ib at wupperonline.de
Tue Oct 3 16:50:37 EEST 2017


The number of bits from bit #m to #n is n - m plus 1.

Signed-off-by: Ingo Brückl <ib at wupperonline.de>
---
 libavformat/mp3dec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavformat/mp3dec.c b/libavformat/mp3dec.c
index 0924a57843..a5c4f2ea12 100644
--- a/libavformat/mp3dec.c
+++ b/libavformat/mp3dec.c
@@ -142,7 +142,7 @@ static void mp3_parse_info_tag(AVFormatContext *s, AVStream *st,
                                MPADecodeHeader *c, uint32_t spf)
 {
 #define LAST_BITS(k, n) ((k) & ((1 << (n)) - 1))
-#define MIDDLE_BITS(k, m, n) LAST_BITS((k) >> (m), ((n) - (m)))
+#define MIDDLE_BITS(k, m, n) LAST_BITS((k) >> (m), ((n) - (m) + 1))

     uint16_t crc;
     uint32_t v;
--
2.14.2


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