Add 4 to 3 scaling NEON optimization

Speed comparing with the one calling vpx_scaled_2d_neon()
  ~1.7 x in general
  ~2.8x for BILINEAR filter

BUG=webm:1419

Change-Id: I8f0a54c2013e61ea086033010f97c19ecf47c7c6

2 files changed, 346 insertions, 1 deletions

diff --git a/vp9/encoder/arm/neon/vp9_frame_scale_neon.c b/vp9/encoder/arm/neon/vp9_frame_scale_neon.c
index ce19e6cd1..ff4de3ea1 100644
--- a/vp9/encoder/arm/neon/vp9_frame_scale_neon.c
+++ b/vp9/encoder/arm/neon/vp9_frame_scale_neon.c
@@ -170,6 +170,14 @@ static INLINE void scale_plane_4_to_1_bilinear_phase_non_0_neon(
   } while (--y);
 }
 
+static INLINE uint8x8_t scale_filter_bilinear(const uint8x8_t *const s,
+                                              const uint8x8_t *const coef) {
+  const uint16x8_t h0 = vmull_u8(s[0], coef[0]);
+  const uint16x8_t h1 = vmlal_u8(h0, s[1], coef[1]);
+
+  return vrshrn_n_u16(h1, 7);
+}
+
 static void scale_plane_2_to_1_general_neon(const uint8_t *src,
                                             const int src_stride, uint8_t *dst,
                                             const int dst_stride, const int w,
@@ -392,6 +400,310 @@ static void scale_plane_4_to_1_general_neon(const uint8_t *src,
   } while (x);
 }
 
+// Notes for 4 to 3 scaling:
+//
+// 1. 6 rows are calculated in each horizontal inner loop, so width_hor must be
+// multiple of 6, and no less than w.
+//
+// 2. 8 rows are calculated in each vertical inner loop, so width_ver must be
+// multiple of 8, and no less than w.
+//
+// 3. 8 columns are calculated in each horizontal inner loop for further
+// vertical scaling, so height_hor must be multiple of 8, and no less than
+// 4 * h / 3.
+//
+// 4. 6 columns are calculated in each vertical inner loop, so height_ver must
+// be multiple of 6, and no less than h.
+//
+// 5. The physical location of the last row of the 4 to 3 scaled frame is
+// decided by phase_scaler, and are always less than 1 pixel below the last row
+// of the original image.
+
+static void scale_plane_4_to_3_bilinear_neon(const uint8_t *src,
+                                             const int src_stride, uint8_t *dst,
+                                             const int dst_stride, const int w,
+                                             const int h,
+                                             const int phase_scaler,
+                                             uint8_t *const temp_buffer) {
+  static const int step_q4 = 16 * 4 / 3;
+  const int width_hor = (w + 5) - ((w + 5) % 6);
+  const int stride_hor = width_hor + 2;  // store 2 extra pixels
+  const int width_ver = (w + 7) & ~7;
+  // We only need 1 extra row below because there are only 2 bilinear
+  // coefficients.
+  const int height_hor = (4 * h / 3 + 1 + 7) & ~7;
+  const int height_ver = (h + 5) - ((h + 5) % 6);
+  int x, y = height_hor;
+  uint8_t *t = temp_buffer;
+  uint8x8_t s[9], d[8], c[6];
+
+  assert(w && h);
+
+  c[0] = vdup_n_u8((uint8_t)vp9_filter_kernels[BILINEAR][phase_scaler][3]);
+  c[1] = vdup_n_u8((uint8_t)vp9_filter_kernels[BILINEAR][phase_scaler][4]);
+  c[2] = vdup_n_u8(
+      (uint8_t)vp9_filter_kernels[BILINEAR][(phase_scaler + 1 * step_q4) &
+                                            SUBPEL_MASK][3]);
+  c[3] = vdup_n_u8(
+      (uint8_t)vp9_filter_kernels[BILINEAR][(phase_scaler + 1 * step_q4) &
+                                            SUBPEL_MASK][4]);
+  c[4] = vdup_n_u8(
+      (uint8_t)vp9_filter_kernels[BILINEAR][(phase_scaler + 2 * step_q4) &
+                                            SUBPEL_MASK][3]);
+  c[5] = vdup_n_u8(
+      (uint8_t)vp9_filter_kernels[BILINEAR][(phase_scaler + 2 * step_q4) &
+                                            SUBPEL_MASK][4]);
+
+  d[6] = vdup_n_u8(0);
+  d[7] = vdup_n_u8(0);
+
+  // horizontal 6x8
+  do {
+    load_u8_8x8(src, src_stride, &s[0], &s[1], &s[2], &s[3], &s[4], &s[5],
+                &s[6], &s[7]);
+    src += 1;
+    transpose_u8_8x8(&s[0], &s[1], &s[2], &s[3], &s[4], &s[5], &s[6], &s[7]);
+    x = width_hor;
+
+    do {
+      load_u8_8x8(src, src_stride, &s[1], &s[2], &s[3], &s[4], &s[5], &s[6],
+                  &s[7], &s[8]);
+      src += 8;
+      transpose_u8_8x8(&s[1], &s[2], &s[3], &s[4], &s[5], &s[6], &s[7], &s[8]);
+
+      // 00 10 20 30 40 50 60 70
+      // 01 11 21 31 41 51 61 71
+      // 02 12 22 32 42 52 62 72
+      // 03 13 23 33 43 53 63 73
+      // 04 14 24 34 44 54 64 74
+      // 05 15 25 35 45 55 65 75
+      d[0] = scale_filter_bilinear(&s[0], &c[0]);
+      d[1] =
+          scale_filter_bilinear(&s[(phase_scaler + 1 * step_q4) >> 4], &c[2]);
+      d[2] =
+          scale_filter_bilinear(&s[(phase_scaler + 2 * step_q4) >> 4], &c[4]);
+      d[3] = scale_filter_bilinear(&s[4], &c[0]);
+      d[4] = scale_filter_bilinear(&s[4 + ((phase_scaler + 1 * step_q4) >> 4)],
+                                   &c[2]);
+      d[5] = scale_filter_bilinear(&s[4 + ((phase_scaler + 2 * step_q4) >> 4)],
+                                   &c[4]);
+
+      // 00 01 02 03 04 05 xx xx
+      // 10 11 12 13 14 15 xx xx
+      // 20 21 22 23 24 25 xx xx
+      // 30 31 32 33 34 35 xx xx
+      // 40 41 42 43 44 45 xx xx
+      // 50 51 52 53 54 55 xx xx
+      // 60 61 62 63 64 65 xx xx
+      // 70 71 72 73 74 75 xx xx
+      transpose_u8_8x8(&d[0], &d[1], &d[2], &d[3], &d[4], &d[5], &d[6], &d[7]);
+      // store 2 extra pixels
+      vst1_u8(t + 0 * stride_hor, d[0]);
+      vst1_u8(t + 1 * stride_hor, d[1]);
+      vst1_u8(t + 2 * stride_hor, d[2]);
+      vst1_u8(t + 3 * stride_hor, d[3]);
+      vst1_u8(t + 4 * stride_hor, d[4]);
+      vst1_u8(t + 5 * stride_hor, d[5]);
+      vst1_u8(t + 6 * stride_hor, d[6]);
+      vst1_u8(t + 7 * stride_hor, d[7]);
+
+      s[0] = s[8];
+
+      t += 6;
+      x -= 6;
+    } while (x);
+    src += 8 * src_stride - 4 * width_hor / 3 - 1;
+    t += 7 * stride_hor + 2;
+    y -= 8;
+  } while (y);
+
+  // vertical 8x6
+  x = width_ver;
+  t = temp_buffer;
+  do {
+    load_u8_8x8(t, stride_hor, &s[0], &s[1], &s[2], &s[3], &s[4], &s[5], &s[6],
+                &s[7]);
+    t += stride_hor;
+    y = height_ver;
+
+    do {
+      load_u8_8x8(t, stride_hor, &s[1], &s[2], &s[3], &s[4], &s[5], &s[6],
+                  &s[7], &s[8]);
+      t += 8 * stride_hor;
+
+      d[0] = scale_filter_bilinear(&s[0], &c[0]);
+      d[1] =
+          scale_filter_bilinear(&s[(phase_scaler + 1 * step_q4) >> 4], &c[2]);
+      d[2] =
+          scale_filter_bilinear(&s[(phase_scaler + 2 * step_q4) >> 4], &c[4]);
+      d[3] = scale_filter_bilinear(&s[4], &c[0]);
+      d[4] = scale_filter_bilinear(&s[4 + ((phase_scaler + 1 * step_q4) >> 4)],
+                                   &c[2]);
+      d[5] = scale_filter_bilinear(&s[4 + ((phase_scaler + 2 * step_q4) >> 4)],
+                                   &c[4]);
+      vst1_u8(dst + 0 * dst_stride, d[0]);
+      vst1_u8(dst + 1 * dst_stride, d[1]);
+      vst1_u8(dst + 2 * dst_stride, d[2]);
+      vst1_u8(dst + 3 * dst_stride, d[3]);
+      vst1_u8(dst + 4 * dst_stride, d[4]);
+      vst1_u8(dst + 5 * dst_stride, d[5]);
+
+      s[0] = s[8];
+
+      dst += 6 * dst_stride;
+      y -= 6;
+    } while (y);
+    t -= stride_hor * (4 * height_ver / 3 + 1);
+    t += 8;
+    dst -= height_ver * dst_stride;
+    dst += 8;
+    x -= 8;
+  } while (x);
+}
+
+static void scale_plane_4_to_3_general_neon(const uint8_t *src,
+                                            const int src_stride, uint8_t *dst,
+                                            const int dst_stride, const int w,
+                                            const int h,
+                                            const InterpKernel *const coef,
+                                            const int phase_scaler,
+                                            uint8_t *const temp_buffer) {
+  static const int step_q4 = 16 * 4 / 3;
+  const int width_hor = (w + 5) - ((w + 5) % 6);
+  const int stride_hor = width_hor + 2;  // store 2 extra pixels
+  const int width_ver = (w + 7) & ~7;
+  // We need (SUBPEL_TAPS - 1) extra rows: (SUBPEL_TAPS / 2 - 1) extra rows
+  // above and (SUBPEL_TAPS / 2) extra rows below.
+  const int height_hor = (4 * h / 3 + SUBPEL_TAPS - 1 + 7) & ~7;
+  const int height_ver = (h + 5) - ((h + 5) % 6);
+  const int16x8_t filters0 =
+      vld1q_s16(coef[(phase_scaler + 0 * step_q4) & SUBPEL_MASK]);
+  const int16x8_t filters1 =
+      vld1q_s16(coef[(phase_scaler + 1 * step_q4) & SUBPEL_MASK]);
+  const int16x8_t filters2 =
+      vld1q_s16(coef[(phase_scaler + 2 * step_q4) & SUBPEL_MASK]);
+  int x, y = height_hor;
+  uint8_t *t = temp_buffer;
+  uint8x8_t s[15], d[8];
+
+  assert(w && h);
+
+  src -= (SUBPEL_TAPS / 2 - 1) * src_stride + SUBPEL_TAPS / 2;
+  d[6] = vdup_n_u8(0);
+  d[7] = vdup_n_u8(0);
+
+  // horizontal 6x8
+  do {
+    load_u8_8x8(src + 1, src_stride, &s[0], &s[1], &s[2], &s[3], &s[4], &s[5],
+                &s[6], &s[7]);
+    transpose_u8_8x8(&s[0], &s[1], &s[2], &s[3], &s[4], &s[5], &s[6], &s[7]);
+    x = width_hor;
+
+    do {
+      src += 8;
+      load_u8_8x8(src, src_stride, &s[7], &s[8], &s[9], &s[10], &s[11], &s[12],
+                  &s[13], &s[14]);
+      transpose_u8_8x8(&s[7], &s[8], &s[9], &s[10], &s[11], &s[12], &s[13],
+                       &s[14]);
+
+      // 00 10 20 30 40 50 60 70
+      // 01 11 21 31 41 51 61 71
+      // 02 12 22 32 42 52 62 72
+      // 03 13 23 33 43 53 63 73
+      // 04 14 24 34 44 54 64 74
+      // 05 15 25 35 45 55 65 75
+      d[0] = scale_filter_8(&s[0], filters0);
+      d[1] = scale_filter_8(&s[(phase_scaler + 1 * step_q4) >> 4], filters1);
+      d[2] = scale_filter_8(&s[(phase_scaler + 2 * step_q4) >> 4], filters2);
+      d[3] = scale_filter_8(&s[4], filters0);
+      d[4] =
+          scale_filter_8(&s[4 + ((phase_scaler + 1 * step_q4) >> 4)], filters1);
+      d[5] =
+          scale_filter_8(&s[4 + ((phase_scaler + 2 * step_q4) >> 4)], filters2);
+
+      // 00 01 02 03 04 05 xx xx
+      // 10 11 12 13 14 15 xx xx
+      // 20 21 22 23 24 25 xx xx
+      // 30 31 32 33 34 35 xx xx
+      // 40 41 42 43 44 45 xx xx
+      // 50 51 52 53 54 55 xx xx
+      // 60 61 62 63 64 65 xx xx
+      // 70 71 72 73 74 75 xx xx
+      transpose_u8_8x8(&d[0], &d[1], &d[2], &d[3], &d[4], &d[5], &d[6], &d[7]);
+      // store 2 extra pixels
+      vst1_u8(t + 0 * stride_hor, d[0]);
+      vst1_u8(t + 1 * stride_hor, d[1]);
+      vst1_u8(t + 2 * stride_hor, d[2]);
+      vst1_u8(t + 3 * stride_hor, d[3]);
+      vst1_u8(t + 4 * stride_hor, d[4]);
+      vst1_u8(t + 5 * stride_hor, d[5]);
+      vst1_u8(t + 6 * stride_hor, d[6]);
+      vst1_u8(t + 7 * stride_hor, d[7]);
+
+      s[0] = s[8];
+      s[1] = s[9];
+      s[2] = s[10];
+      s[3] = s[11];
+      s[4] = s[12];
+      s[5] = s[13];
+      s[6] = s[14];
+
+      t += 6;
+      x -= 6;
+    } while (x);
+    src += 8 * src_stride - 4 * width_hor / 3;
+    t += 7 * stride_hor + 2;
+    y -= 8;
+  } while (y);
+
+  // vertical 8x6
+  x = width_ver;
+  t = temp_buffer;
+  do {
+    load_u8_8x8(t, stride_hor, &s[0], &s[1], &s[2], &s[3], &s[4], &s[5], &s[6],
+                &s[7]);
+    t += 7 * stride_hor;
+    y = height_ver;
+
+    do {
+      load_u8_8x8(t, stride_hor, &s[7], &s[8], &s[9], &s[10], &s[11], &s[12],
+                  &s[13], &s[14]);
+      t += 8 * stride_hor;
+
+      d[0] = scale_filter_8(&s[0], filters0);
+      d[1] = scale_filter_8(&s[(phase_scaler + 1 * step_q4) >> 4], filters1);
+      d[2] = scale_filter_8(&s[(phase_scaler + 2 * step_q4) >> 4], filters2);
+      d[3] = scale_filter_8(&s[4], filters0);
+      d[4] =
+          scale_filter_8(&s[4 + ((phase_scaler + 1 * step_q4) >> 4)], filters1);
+      d[5] =
+          scale_filter_8(&s[4 + ((phase_scaler + 2 * step_q4) >> 4)], filters2);
+      vst1_u8(dst + 0 * dst_stride, d[0]);
+      vst1_u8(dst + 1 * dst_stride, d[1]);
+      vst1_u8(dst + 2 * dst_stride, d[2]);
+      vst1_u8(dst + 3 * dst_stride, d[3]);
+      vst1_u8(dst + 4 * dst_stride, d[4]);
+      vst1_u8(dst + 5 * dst_stride, d[5]);
+
+      s[0] = s[8];
+      s[1] = s[9];
+      s[2] = s[10];
+      s[3] = s[11];
+      s[4] = s[12];
+      s[5] = s[13];
+      s[6] = s[14];
+
+      dst += 6 * dst_stride;
+      y -= 6;
+    } while (y);
+    t -= stride_hor * (4 * height_ver / 3 + 7);
+    t += 8;
+    dst -= height_ver * dst_stride;
+    dst += 8;
+    x -= 8;
+  } while (x);
+}
+
 void vp9_scale_and_extend_frame_neon(const YV12_BUFFER_CONFIG *src,
                                      YV12_BUFFER_CONFIG *dst,
                                      INTERP_FILTER filter_type,
@@ -501,6 +813,39 @@ void vp9_scale_and_extend_frame_neon(const YV12_BUFFER_CONFIG *src,
         scaled = 0;
       }
     }
+  } else if (4 * dst_w == 3 * src_w && 4 * dst_h == 3 * src_h) {
+    // 4 to 3
+    const int buffer_stride = (dst_w + 5) - ((dst_w + 5) % 6) + 2;
+    const int buffer_height = (4 * dst_h / 3 + SUBPEL_TAPS - 1 + 7) & ~7;
+    uint8_t *const temp_buffer =
+        (uint8_t *)malloc(buffer_stride * buffer_height);
+    if (temp_buffer) {
+      scaled = 1;
+      if (filter_type == BILINEAR) {
+        scale_plane_4_to_3_bilinear_neon(src->y_buffer, src->y_stride,
+                                         dst->y_buffer, dst->y_stride, dst_w,
+                                         dst_h, phase_scaler, temp_buffer);
+        scale_plane_4_to_3_bilinear_neon(
+            src->u_buffer, src->uv_stride, dst->u_buffer, dst->uv_stride,
+            dst_uv_w, dst_uv_h, phase_scaler, temp_buffer);
+        scale_plane_4_to_3_bilinear_neon(
+            src->v_buffer, src->uv_stride, dst->v_buffer, dst->uv_stride,
+            dst_uv_w, dst_uv_h, phase_scaler, temp_buffer);
+      } else {
+        scale_plane_4_to_3_general_neon(
+            src->y_buffer, src->y_stride, dst->y_buffer, dst->y_stride, dst_w,
+            dst_h, vp9_filter_kernels[filter_type], phase_scaler, temp_buffer);
+        scale_plane_4_to_3_general_neon(
+            src->u_buffer, src->uv_stride, dst->u_buffer, dst->uv_stride,
+            dst_uv_w, dst_uv_h, vp9_filter_kernels[filter_type], phase_scaler,
+            temp_buffer);
+        scale_plane_4_to_3_general_neon(
+            src->v_buffer, src->uv_stride, dst->v_buffer, dst->uv_stride,
+            dst_uv_w, dst_uv_h, vp9_filter_kernels[filter_type], phase_scaler,
+            temp_buffer);
+      }
+      free(temp_buffer);
+    }
   }
 
   if (scaled) {
diff --git a/vp9/encoder/vp9_frame_scale.c b/vp9/encoder/vp9_frame_scale.c
index 9d2639338..832df18c8 100644
--- a/vp9/encoder/vp9_frame_scale.c
+++ b/vp9/encoder/vp9_frame_scale.c
@@ -28,7 +28,7 @@ void vp9_scale_and_extend_frame_c(const YV12_BUFFER_CONFIG *src,
   const InterpKernel *const kernel = vp9_filter_kernels[filter_type];
   int x, y, i;
 
-#if 0
+#if HAVE_NEON
   // TODO(linfengz): The 4:3 specialized C code is disabled by default since
   // it's much slower than the general version which calls vpx_scaled_2d() even
   // if vpx_scaled_2d() is not optimized. It will only be enabled as a reference