From: Luca Barbato Date: Thu, 21 Apr 2016 14:09:38 +0000 (+0200) Subject: ape: Unbreak adaptcoeffs computation X-Git-Tag: n3.1~37^2~82 X-Git-Url: https://git.videolan.org/?p=ffmpeg.git;a=commitdiff_plain;h=4012fe1ee819edc7689e182189e66c5401fb4b41 ape: Unbreak adaptcoeffs computation And simplify and explain the expression. Fault introduced in f3fdef108eb06b1e71b29152bf6822519e787efe --- diff --git a/libavcodec/apedec.c b/libavcodec/apedec.c index 85d26aef27..d7cf8a2708 100644 --- a/libavcodec/apedec.c +++ b/libavcodec/apedec.c @@ -1305,8 +1305,16 @@ static void do_apply_filter(APEContext *ctx, int version, APEFilter *f, /* Update the adaption coefficients */ absres = FFABS(res); if (absres) - *f->adaptcoeffs = ((res & ((~0UL) << 31)) ^ ((~0UL) << 30)) >> - (25 + (absres <= f->avg*3) + (absres <= f->avg*4/3)); + *f->adaptcoeffs = APESIGN(res) * + (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 *f->adaptcoeffs = 0;