NV12 allow NULL for Y

source/convert.cc

 /*
  *  Copyright 2011 The LibYuv 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 26 matching lines @@
                       int src_y_width, int src_y_height,
                       int src_uv_width, int src_uv_height) {
   const int dst_y_width = Abs(src_y_width);
   const int dst_y_height = Abs(src_y_height);
   const int dst_uv_width = SUBSAMPLE(dst_y_width, 1, 1);
   const int dst_uv_height = SUBSAMPLE(dst_y_height, 1, 1);
   if (src_y_width == 0 || src_y_height == 0 ||
       src_uv_width == 0 || src_uv_height == 0) {
     return -1;
   }
+  // TODO(fbarchard): make Y optional.
   ScalePlane(src_y, src_stride_y, src_y_width, src_y_height,
              dst_y, dst_stride_y, dst_y_width, dst_y_height,
              kFilterBilinear);
   ScalePlane(src_u, src_stride_u, src_uv_width, src_uv_height,
              dst_u, dst_stride_u, dst_uv_width, dst_uv_height,
              kFilterBilinear);
   ScalePlane(src_v, src_stride_v, src_uv_width, src_uv_height,
              dst_v, dst_stride_v, dst_uv_width, dst_uv_height,
              kFilterBilinear);
   return 0;
@@ skipping 249 matching lines @@
 //   this as well as the two Y planes.
 static int X420ToI420(const uint8* src_y,
                       int src_stride_y0, int src_stride_y1,
                       const uint8* src_uv, int src_stride_uv,
                       uint8* dst_y, int dst_stride_y,
                       uint8* dst_u, int dst_stride_u,
                       uint8* dst_v, int dst_stride_v,
                       int width, int height) {
   int halfwidth = (width + 1) >> 1;
   int halfheight = (height + 1) >> 1;
-  if (!src_y || !src_uv ||
-      !dst_y || !dst_u || !dst_v ||
+  if (!src_uv || !dst_u || !dst_v ||
       width <= 0 || height == 0) {
     return -1;
   }
   // Negative height means invert the image.
   if (height < 0) {
     height = -height;
     halfheight = (height + 1) >> 1;
     dst_y = dst_y + (height - 1) * dst_stride_y;
     dst_u = dst_u + (halfheight - 1) * dst_stride_u;
     dst_v = dst_v + (halfheight - 1) * dst_stride_v;
@@ skipping 1155 matching lines @@
     dst_u += dst_stride_u;
     dst_v += dst_stride_v;
   }
   return 0;
 }
 
 #ifdef __cplusplus
 }  // extern "C"
 }  // namespace libyuv
 #endif