X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=qdc.cpp;h=41ef04df00f95f3714e1617326fb4d4c4f5ddefa;hb=79aa73c43af43f8f497e5920c83459f3e94d3612;hp=094f3b6b7e0e80b451b288bcce4d458cbcabde45;hpb=447dce35641fc3ae6194cfe0221577281b04ae5b;p=narabu

diff --git a/qdc.cpp b/qdc.cpp
index 094f3b6..41ef04d 100644
--- a/qdc.cpp
+++ b/qdc.cpp
@@ -507,6 +507,9 @@ int main(int argc, char **argv)
 	//double last_cb_cfl_fac = 0.0;
 	//double last_cr_cfl_fac = 0.0;
 
+	int max_val_x[8] = {0}, min_val_x[8] = {0};
+	int max_val_y[8] = {0}, min_val_y[8] = {0};
+
 	// DCT and quantize luma
 	for (unsigned yb = 0; yb < HEIGHT; yb += 8) {
 		for (unsigned xb = 0; xb < WIDTH; xb += 8) {
@@ -527,6 +530,11 @@ int main(int argc, char **argv)
 					int k = quantize(in_y[coeff_idx], coeff_idx);
 					coeff_y[(yb + y) * WIDTH + (xb + x)] = k;
 
+					max_val_x[x] = std::max(max_val_x[x], k);
+					min_val_x[x] = std::min(min_val_x[x], k);
+					max_val_y[y] = std::max(max_val_y[y], k);
+					min_val_y[y] = std::min(min_val_y[y], k);
+
 					// Store back for reconstruction / PSNR calculation
 					in_y[coeff_idx] = unquantize(k, coeff_idx);
 				}
@@ -961,4 +969,18 @@ int main(int argc, char **argv)
 		extra_bits,
 		extra_bits / 8,
 		tot_bytes);
+
+#if 0
+	printf("Max coefficient ranges (as a function of x):\n\n");
+	for (unsigned x = 0; x < 8; ++x) {
+		int range = std::max(max_val_x[x], -min_val_x[x]);
+		printf("  [%4d, %4d] (%.2f bits)\n", min_val_x[x], max_val_x[x], log2(range * 2 + 1));
+	}
+
+	printf("Max coefficient ranges (as a function of y):\n\n");
+	for (unsigned y = 0; y < 8; ++y) {
+		int range = std::max(max_val_y[y], -min_val_y[y]);
+		printf("  [%4d, %4d] (%.2f bits)\n", min_val_y[y], max_val_y[y], log2(range * 2 + 1));
+	}
+#endif
 }