Commit dd4fb233 authored by Luca Barbato's avatar Luca Barbato Committed by Derek Buitenhuis

ape: Unbreak adaptcoeffs computation

And simplify and explain the expression.

Fault introduced in f3fdef10Signed-off-by: 's avatarDerek Buitenhuis <derek.buitenhuis@gmail.com>
parent 5b9a4476
...@@ -1284,8 +1284,16 @@ static void do_apply_filter(APEContext *ctx, int version, APEFilter *f, ...@@ -1284,8 +1284,16 @@ static void do_apply_filter(APEContext *ctx, int version, APEFilter *f,
/* Update the adaption coefficients */ /* Update the adaption coefficients */
absres = FFABS(res); absres = FFABS(res);
if (absres) if (absres)
*f->adaptcoeffs = ((res & INT32_MIN) ^ ((~0UL) << 30)) >> *f->adaptcoeffs = APESIGN(res) *
(25 + (absres <= f->avg*3) + (absres <= f->avg*4/3)); (8 << ((absres > f->avg * 3) + (absres > f->avg * 4 / 3)));
/* equivalent to the following code
if (absres <= f->avg * 4 / 3)
*f->adaptcoeffs = APESIGN(res) * 8;
else if (absres <= f->avg * 3)
*f->adaptcoeffs = APESIGN(res) * 16;
else
*f->adaptcoeffs = APESIGN(res) * 32;
*/
else else
*f->adaptcoeffs = 0; *f->adaptcoeffs = 0;
......
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