1 files changed, 89 insertions, 0 deletions
diff --git a/tensorflow/examples/android/jni/rgb2yuv.cc b/tensorflow/examples/android/jni/rgb2yuv.cc
new file mode 100755
index 0000000000..428f311eb8
--- /dev/null
+++ b/tensorflow/examples/android/jni/rgb2yuv.cc
@@ -0,0 +1,89 @@
+// These utility functions allow for the conversion of RGB data to YUV data.
+
+#include "tensorflow/examples/android/jni/rgb2yuv.h"
+
+#include "tensorflow/core/platform/port.h"
+
+using namespace tensorflow;
+
+static inline void WriteYUV(const int x, const int y, const int width,
+                            const int r8, const int g8, const int b8,
+                            uint8* const pY,
+                            uint8* const pUV) {
+  // Using formulas from http://msdn.microsoft.com/en-us/library/ms893078
+  *pY = ((66 * r8 + 129 * g8 + 25 * b8 + 128) >> 8) + 16;
+
+  // Odd widths get rounded up so that UV blocks on the side don't get cut off.
+  const int blocks_per_row = (width + 1) / 2;
+
+  // 2 bytes per UV block
+  const int offset = 2 * (((y / 2) * blocks_per_row + (x / 2)));
+
+  // U and V are the average values of all 4 pixels in the block.
+  if (!(x & 1) && !(y & 1)) {
+    // Explicitly clear the block if this is the first pixel in it.
+    pUV[offset] = 0;
+    pUV[offset + 1] = 0;
+  }
+
+  // V (with divide by 4 factored in)
+#ifdef __APPLE__
+  const int u_offset = 0;
+  const int v_offset = 1;
+#else
+  const int u_offset = 1;
+  const int v_offset = 0;
+#endif
+  pUV[offset + v_offset] += ((112 * r8 - 94 * g8 - 18 * b8 + 128) >> 10) + 32;
+
+  // U (with divide by 4 factored in)
+  pUV[offset + u_offset] += ((-38 * r8 - 74 * g8 + 112 * b8 + 128) >> 10) + 32;
+}
+
+void ConvertARGB8888ToYUV420SP(const uint32* const input, uint8* const output,
+                               int width, int height) {
+  uint8* pY = output;
+  uint8* pUV = output + (width * height);
+  const uint32* in = input;
+
+  for (int y = 0; y < height; y++) {
+    for (int x = 0; x < width; x++) {
+      const uint32 rgb = *in++;
+#ifdef __APPLE__
+      const int nB = (rgb >> 8) & 0xFF;
+      const int nG = (rgb >> 16) & 0xFF;
+      const int nR = (rgb >> 24) & 0xFF;
+#else
+      const int nR = (rgb >> 16) & 0xFF;
+      const int nG = (rgb >> 8) & 0xFF;
+      const int nB = rgb & 0xFF;
+#endif
+      WriteYUV(x, y, width, nR, nG, nB, pY++, pUV);
+    }
+  }
+}
+
+void ConvertRGB565ToYUV420SP(const uint16* const input, uint8* const output,
+                             const int width, const int height) {
+  uint8* pY = output;
+  uint8* pUV = output + (width * height);
+  const uint16* in = input;
+
+  for (int y = 0; y < height; y++) {
+    for (int x = 0; x < width; x++) {
+      const uint32 rgb = *in++;
+
+      const int r5 = ((rgb >> 11) & 0x1F);
+      const int g6 = ((rgb >> 5) & 0x3F);
+      const int b5 = (rgb & 0x1F);
+
+      // Shift left, then fill in the empty low bits with a copy of the high
+      // bits so we can stretch across the entire 0 - 255 range.
+      const int r8 = r5 << 3 | r5 >> 2;
+      const int g8 = g6 << 2 | g6 >> 4;
+      const int b8 = b5 << 3 | b5 >> 2;
+
+      WriteYUV(x, y, width, r8, g8, b8, pY++, pUV);
+    }
+  }
+}