Allow one-sided scan count down sampling

Change-Id: I164add43e9d75af82312b464a176cdf0045ef9e1

av1/common/scan.c

@@ -6620,18 +6620,47 @@ void av1_down_sample_scan_count(uint32_t *non_zero_count_ds,
                                 TX_SIZE tx_size) {
   const int tx_w = tx_size_wide[tx_size];
   const int tx_h = tx_size_high[tx_size];
-  const int tx_w_ds = tx_w >> 1;
-  const int tx_h_ds = tx_h >> 1;
-  for (int r_ds = 0; r_ds < tx_h_ds; ++r_ds) {
-    for (int c_ds = 0; c_ds < tx_w_ds; ++c_ds) {
-      const int ci_ds = r_ds * tx_w_ds + c_ds;
-      const int r = r_ds << 1;
-      const int c = c_ds << 1;
-      const int ci = r * tx_w + c;
-      non_zero_count_ds[ci_ds] = non_zero_count[ci] + non_zero_count[ci + 1] +
-                                 non_zero_count[ci + tx_w] +
-                                 non_zero_count[ci + 1 + tx_w];
+  if (tx_w > 8 && tx_h > 8) {
+    const int tx_w_ds = tx_w >> 1;
+    const int tx_h_ds = tx_h >> 1;
+    for (int r_ds = 0; r_ds < tx_h_ds; ++r_ds) {
+      for (int c_ds = 0; c_ds < tx_w_ds; ++c_ds) {
+        const int ci_ds = r_ds * tx_w_ds + c_ds;
+        const int r = r_ds << 1;
+        const int c = c_ds << 1;
+        const int ci = r * tx_w + c;
+        non_zero_count_ds[ci_ds] = non_zero_count[ci] + non_zero_count[ci + 1] +
+                                   non_zero_count[ci + tx_w] +
+                                   non_zero_count[ci + 1 + tx_w];
+      }
+    }
+  } else if (tx_w > 8 && tx_h <= 8) {
+    const int tx_w_ds = tx_w >> 1;
+    const int tx_h_ds = tx_h;
+    for (int r_ds = 0; r_ds < tx_h_ds; ++r_ds) {
+      for (int c_ds = 0; c_ds < tx_w_ds; ++c_ds) {
+        const int ci_ds = r_ds * tx_w_ds + c_ds;
+        const int r = r_ds;
+        const int c = c_ds << 1;
+        const int ci = r * tx_w + c;
+        non_zero_count_ds[ci_ds] = non_zero_count[ci] + non_zero_count[ci + 1];
+      }
     }
+  } else if (tx_w <= 8 && tx_h > 8) {
+    const int tx_w_ds = tx_w;
+    const int tx_h_ds = tx_h >> 1;
+    for (int r_ds = 0; r_ds < tx_h_ds; ++r_ds) {
+      for (int c_ds = 0; c_ds < tx_w_ds; ++c_ds) {
+        const int ci_ds = r_ds * tx_w_ds + c_ds;
+        const int r = r_ds << 1;
+        const int c = c_ds;
+        const int ci = r * tx_w + c;
+        non_zero_count_ds[ci_ds] =
+            non_zero_count[ci] + non_zero_count[ci + tx_w];
+      }
+    }
+  } else {
+    assert(0);
   }
 }
 
@@ -6640,21 +6669,55 @@ void av1_up_sample_scan_count(uint32_t *non_zero_count,
                               TX_SIZE tx_size, unsigned int block_num) {
   const int tx_w = tx_size_wide[tx_size];
   const int tx_h = tx_size_high[tx_size];
-  const int tx_w_ds = tx_w >> 1;
-  const int tx_h_ds = tx_h >> 1;
-  for (int r_ds = 0; r_ds < tx_h_ds; ++r_ds) {
-    for (int c_ds = 0; c_ds < tx_w_ds; ++c_ds) {
-      const int ci_ds = r_ds * tx_w_ds + c_ds;
-      const int r = r_ds << 1;
-      const int c = c_ds << 1;
-      const int ci = r * tx_w + c;
-      uint32_t count = ROUND_POWER_OF_TWO(non_zero_count_ds[ci_ds], 2);
-      clamp64(count, 0, block_num);
-      non_zero_count[ci] = count;
-      non_zero_count[ci + 1] = count;
-      non_zero_count[ci + tx_w] = count;
-      non_zero_count[ci + tx_w + 1] = count;
+  if (tx_w > 8 && tx_h > 8) {
+    const int tx_w_ds = tx_w >> 1;
+    const int tx_h_ds = tx_h >> 1;
+    for (int r_ds = 0; r_ds < tx_h_ds; ++r_ds) {
+      for (int c_ds = 0; c_ds < tx_w_ds; ++c_ds) {
+        const int ci_ds = r_ds * tx_w_ds + c_ds;
+        const int r = r_ds << 1;
+        const int c = c_ds << 1;
+        const int ci = r * tx_w + c;
+        uint32_t count = ROUND_POWER_OF_TWO(non_zero_count_ds[ci_ds], 2);
+        count = clamp64(count, 0, block_num);
+        non_zero_count[ci] = count;
+        non_zero_count[ci + 1] = count;
+        non_zero_count[ci + tx_w] = count;
+        non_zero_count[ci + tx_w + 1] = count;
+      }
+    }
+  } else if (tx_w > 8 && tx_h <= 8) {
+    const int tx_w_ds = tx_w >> 1;
+    const int tx_h_ds = tx_h;
+    for (int r_ds = 0; r_ds < tx_h_ds; ++r_ds) {
+      for (int c_ds = 0; c_ds < tx_w_ds; ++c_ds) {
+        const int ci_ds = r_ds * tx_w_ds + c_ds;
+        const int r = r_ds;
+        const int c = c_ds << 1;
+        const int ci = r * tx_w + c;
+        uint32_t count = ROUND_POWER_OF_TWO(non_zero_count_ds[ci_ds], 1);
+        count = clamp64(count, 0, block_num);
+        non_zero_count[ci] = count;
+        non_zero_count[ci + 1] = count;
+      }
     }
+  } else if (tx_w <= 8 && tx_h > 8) {
+    const int tx_w_ds = tx_w;
+    const int tx_h_ds = tx_h >> 1;
+    for (int r_ds = 0; r_ds < tx_h_ds; ++r_ds) {
+      for (int c_ds = 0; c_ds < tx_w_ds; ++c_ds) {
+        const int ci_ds = r_ds * tx_w_ds + c_ds;
+        const int r = r_ds << 1;
+        const int c = c_ds;
+        const int ci = r * tx_w + c;
+        uint32_t count = ROUND_POWER_OF_TWO(non_zero_count_ds[ci_ds], 1);
+        count = clamp64(count, 0, block_num);
+        non_zero_count[ci] = count;
+        non_zero_count[ci + tx_w] = count;
+      }
+    }
+  } else {
+    assert(0);
   }
 }
 #endif