RGB YUV420

Author: xhp

android/src/main/java/cn/jiguang/imui/messagelist/DecodeUtil.java

@@ -18,6 +18,82 @@
 
 public class DecodeUtil {
 
+    public  byte[] getYUV420sp(int inputWidth, int inputHeight,
+                               Bitmap scaled) {
+        int[] argb = new int[inputWidth * inputHeight];
+
+        scaled.getPixels(argb, 0, inputWidth, 0, 0, inputWidth, inputHeight);
+
+        byte[] yuv = new byte[inputWidth * inputHeight * 3 / 2];
+
+        encodeYUV420SP(yuv, argb, inputWidth, inputHeight);
+
+        scaled.recycle();
+
+        return yuv;
+    }
+
+
+    private void encodeYUV420SP(byte[] yuv420sp, int[] argb, int width,
+                                int height) {
+        // 帧图片的像素大小
+        final int frameSize = width * height;
+        // ---YUV数据---
+        int Y, U, V;
+        // Y的index从0开始
+        int yIndex = 0;
+        // UV的index从frameSize开始
+        int uvIndex = frameSize;
+
+        // ---颜色数据---
+//      int a, R, G, B;
+        int R, G, B;
+        //
+        int argbIndex = 0;
+        //
+
+        // ---循环所有像素点，RGB转YUV---
+        for (int j = 0; j < height; j++) {
+            for (int i = 0; i < width; i++) {
+
+                // a is not used obviously
+//              a = (argb[argbIndex] & 0xff000000) >> 24;
+                R = (argb[argbIndex] & 0xff0000) >> 16;
+                G = (argb[argbIndex] & 0xff00) >> 8;
+                B = (argb[argbIndex] & 0xff);
+                //
+                argbIndex++;
+
+                // well known RGB to YUV algorithm
+                Y = ((66 * R + 129 * G + 25 * B + 128) >> 8) + 16;
+                U = ((-38 * R - 74 * G + 112 * B + 128) >> 8) + 128;
+                V = ((112 * R - 94 * G - 18 * B + 128) >> 8) + 128;
+
+                //
+                Y = Math.max(0, Math.min(Y, 255));
+                U = Math.max(0, Math.min(U, 255));
+                V = Math.max(0, Math.min(V, 255));
+
+                // NV21 has a plane of Y and interleaved planes of VU each
+                // sampled by a factor of 2
+                // meaning for every 4 Y pixels there are 1 V and 1 U. Note the
+                // sampling is every other
+                // pixel AND every other scanline.
+                // ---Y---
+                yuv420sp[yIndex++] = (byte) Y;
+
+                // ---UV---
+//              if ((j % 2 == 0) && (i % 2 == 0)) {
+//
+//
+//
+//                  yuv420sp[uvIndex++] = (byte) V;
+//
+//                  yuv420sp[uvIndex++] = (byte) U;
+//              }
+            }
+        }
+    }
     private static byte[] getRGB(Bitmap bitmap) {
         int width = bitmap.getWidth();
         int height = bitmap.getHeight();