Add some code for calculating maximum coefficent ranges, for bit allocation.

diff --git a/qdc.cpp b/qdc.cpp
index 094f3b6b7e0e80b451b288bcce4d458cbcabde45..41ef04df00f95f3714e1617326fb4d4c4f5ddefa 100644 (file)
--- 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
 }