Reland of Optimize Android NV12 capture

webrtc/common_video/libyuv/webrtc_libyuv.cc

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 323 matching lines @@
                           ref_frame->video_frame_buffer()->DataV(),
                           ref_frame->video_frame_buffer()->StrideV(),
                           test_frame->video_frame_buffer()->DataY(),
                           test_frame->video_frame_buffer()->StrideY(),
                           test_frame->video_frame_buffer()->DataU(),
                           test_frame->video_frame_buffer()->StrideU(),
                           test_frame->video_frame_buffer()->DataV(),
                           test_frame->video_frame_buffer()->StrideV(),
                           test_frame->width(), test_frame->height());
 }
+
+void NV12ToI420Scaler::NV12ToI420Scale(
+    const uint8_t* src_y, int src_stride_y,
+    const uint8_t* src_uv, int src_stride_uv,
+    int src_width, int src_height,
+    uint8_t* dst_y, int dst_stride_y,
+    uint8_t* dst_u, int dst_stride_u,
+    uint8_t* dst_v, int dst_stride_v,
+    int dst_width, int dst_height) {
+  if (src_width == dst_width && src_height == dst_height) {
+    // No scaling.
+    tmp_uv_planes_.clear();
+    tmp_uv_planes_.shrink_to_fit();
+    libyuv::NV12ToI420(
+        src_y, src_stride_y,
+        src_uv, src_stride_uv,
+        dst_y, dst_stride_y,
+        dst_u, dst_stride_u,
+        dst_v, dst_stride_v,
+        src_width, src_height);
+    return;
+  }
+
+  // Scaling.
+  // Allocate temporary memory for spitting UV planes.
+  const int src_uv_width = (src_width + 1) / 2;
+  const int src_uv_height = (src_height + 1) / 2;
+  tmp_uv_planes_.resize(src_uv_width * src_uv_height * 2);
+  tmp_uv_planes_.shrink_to_fit();
+
+  // Split source UV plane into separate U and V plane using the temporary data.
+  uint8_t* const src_u = tmp_uv_planes_.data();
+  uint8_t* const src_v = tmp_uv_planes_.data() + src_uv_width * src_uv_height;
+  libyuv::SplitUVPlane(src_uv, src_stride_uv,
+                       src_u, src_uv_width,
+                       src_v, src_uv_width,
+                       src_uv_width, src_uv_height);
+
+  // Scale the planes into the destination.
+  libyuv::I420Scale(src_y, src_stride_y,
+                    src_u, src_uv_width,
+                    src_v, src_uv_width,
+                    src_width, src_height,
+                    dst_y, dst_stride_y,
+                    dst_u, dst_stride_u,
+                    dst_v, dst_stride_v,
+                    dst_width, dst_height,
+                    libyuv::kFilterBox);
+}
+
 }  // namespace webrtc