only the immediate above right pixel is needed; this removes a
conditional from the inner loop
the final average calculated currently relies on above[] being extended,
it could be reduced to use above[block_size - 2] + 3 * above_right
Change-Id: Ica4f2b8d25eec3ca1d6fa52ef0d4adc228eeea3f
static INLINE void d45_predictor(uint8_t *dst, ptrdiff_t stride, int bs,
const uint8_t *above, const uint8_t *left) {
static INLINE void d45_predictor(uint8_t *dst, ptrdiff_t stride, int bs,
const uint8_t *above, const uint8_t *left) {
- int r, c;
- (void) left;
- for (r = 0; r < bs; ++r) {
- for (c = 0; c < bs; ++c)
- dst[c] = r + c + 2 < bs * 2 ? ROUND_POWER_OF_TWO(above[r + c] +
- above[r + c + 1] * 2 +
- above[r + c + 2], 2)
- : above[bs * 2 - 1];
+ const uint8_t above_right = above[bs - 1];
+ int x, size;
+ uint8_t avg[31]; // TODO(jzern): this could be block size specific
+ (void)left;
+
+ for (x = 0; x < bs - 1; ++x) {
+ avg[x] = AVG3(above[x], above[x + 1], above[x + 2]);
+ }
+ for (x = 0, size = bs - 1; x < bs; ++x, --size) {
+ memcpy(dst, avg + x, size);
+ memset(dst + size, above_right, x + 1);