avutil/softfloat: Fix sign error in and improve documentation of av_int2sf()

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

diff --git a/libavutil/softfloat.h b/libavutil/softfloat.h
index 32b33d9dfd6b3457d9f908003ba9b09402130a33..b13d728f308273641aadc1a884cfaa6910314b50 100644 (file)
--- a/libavutil/softfloat.h
+++ b/libavutil/softfloat.h
@@ -176,8 +176,10 @@ static inline av_const SoftFloat av_sub_sf(SoftFloat a, SoftFloat b){
 //FIXME log, exp, pow
 
 /**
- * Converts a mantisse and exponent to a SoftFloat
- * @returns a SoftFloat with value v * 2^frac_bits
+ * Converts a mantisse and exponent to a SoftFloat.
+ * This converts a fixed point value v with frac_bits fractional bits to a
+ * SoftFloat.
+ * @returns a SoftFloat with value v * 2^-frac_bits
  */
 static inline av_const SoftFloat av_int2sf(int v, int frac_bits){
     int exp_offset = 0;