Optimize Android NV12 capture

webrtc/common_video/libyuv/include/webrtc_libyuv.h

 /*
  *  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 105 matching lines @@
                     VideoType dst_video_type,
                     int dst_sample_size,
                     uint8_t* dst_frame);
 
 // Compute PSNR for an I420 frame (all planes).
 // Returns the PSNR in decibel, to a maximum of kInfinitePSNR.
 double I420PSNR(const VideoFrame* ref_frame, const VideoFrame* test_frame);
 // Compute SSIM for an I420 frame (all planes).
 double I420SSIM(const VideoFrame* ref_frame, const VideoFrame* test_frame);
 
+// Helper function for directly converting and scaling NV12 to I420. The
+// |tmp_data| argument will be used for intermediary splitting the UV plane into
+// separate U and V planes, so the size of that memory region must be at least
+// 2 * ((src_width + 1) / 2) * ((src_height + 1) / 2).
+void NV12ToI420Scale(uint8_t* tmp_data,
+                     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);
+
 }  // namespace webrtc
 
 #endif  // WEBRTC_COMMON_VIDEO_LIBYUV_INCLUDE_WEBRTC_LIBYUV_H_