X-Git-Url: https://git.sesse.net/?p=fjl;a=blobdiff_plain;f=idct_float.c;h=34ff5b690cabb463f1e156ba573b6cd3e865895c;hp=c8bde1b236ac80c3bc5f5380fc5adcbd9569bc77;hb=75e1e46dafe538990da0ea3b021c82d5ed6d5e21;hpb=56779091c47e5c61376d7f942cc58b831673e1d7

diff --git a/idct_float.c b/idct_float.c
index c8bde1b..34ff5b6 100644
--- a/idct_float.c
+++ b/idct_float.c
@@ -50,9 +50,11 @@ static inline void idct1d_float(double y0, double y1, double y2, double y3, doub
 	// constants
 	static const double a1 = 0.7071067811865474;   // sqrt(2)
 	static const double a2 = 0.5411961001461971;   // cos(3/8 pi) * sqrt(2)
-	static const double a3 = a1;
+	// static const double a3 = a1;
+	static const double a3 = 0.7071067811865474;
 	static const double a4 = 1.3065629648763766;   // cos(pi/8) * sqrt(2)
-	static const double a5 = 0.5 * (a4 - a2);
+	// static const double a5 = 0.5 * (a4 - a2);
+	static const double a5 = 0.3826834323650897;
 
 	// phase 1
 	const double p1_0 = y0;
@@ -157,12 +159,12 @@ void idct_float(const int16_t* input, const void* userdata, uint8_t* output)
 		             temp2);
 		for (unsigned x = 0; x < DCTSIZE; ++x) {
 			const double val = temp2[x];
-			if (val < 0.0) {
+			if (val < -128.0) {
 				output[y * DCTSIZE + x] = 0;
-			} else if (val >= 255.0) {
+			} else if (val >= 127.0) {
 				output[y * DCTSIZE + x] = 255;
 			} else {
-				output[y * DCTSIZE + x] = (uint8_t)(val + 0.5);
+				output[y * DCTSIZE + x] = (uint8_t)(val + 128.5);
 			}
 		}
 	}