Feature: add yuv to rgb

app/CMakeLists.txt

@@ -42,6 +42,7 @@ add_library( # Sets the name of the library.
             src/main/cpp/metadata/media_retriever_jni.cpp
             src/main/cpp/metadata/metadata_util.c
             src/main/cpp/metadata/ffmpeg_media_retriever.c
+            src/main/cpp/yuv2rgb/yuv_2_rgb.cpp
         )
 
 add_library( ffmpeg

app/src/main/cpp/yuv2rgb/yuv_2_rgb.cpp

@@ -0,0 +1,60 @@
+//
+// Created by xu fulong on 2022/7/8.
+//
+
+#include "yuv_to_rgb.h"
+
+static int range(int val) {
+    if (val < 0) {
+        return 0;
+    } else if (val > 255) {
+        return 255;
+    } else {
+        return val;
+    }
+}
+
+static void YCbCr_to_RGB(uint8_t *dst, const uint8_t *src, int length) {
+    if (length < 1) return;
+    int R, G, B;
+    int Y, Cb, Cr;
+    int i, offset;
+    for (i = 0; i < length; i++) {
+        offset = (i << 1) + i;
+        Y = src[offset];
+        Cb = src[offset + 1] - 128;
+        Cr = src[offset + 2] - 128;
+        R = Y + ((RGBRCrI * Cr + half_shift) >> shift);
+        G = Y + ((RGBGCbI * Cb + RGBGCrI * Cr + half_shift) >> shift);
+        B = Y + ((RGBBCbI * Cb + half_shift) >> shift);
+        R = range(R);
+        G = range(G);
+        B = range(B);
+        offset = i << 2;
+        dst[offset] = (uint8_t) B;
+        dst[offset + 1] = (uint8_t) G;
+        dst[offset + 2] = (uint8_t) R;
+        dst[offset + 3] = 0xff;
+    }
+}
+
+static void RGB_to_YCbCr(uint8_t *dst, const uint8_t *src, int length) {
+    if (length < 1) return;
+    int R, G, B;
+    int i, offset;
+    for (i = 0; i < length; i++) {
+        offset = i << 2;
+        B = src[offset];
+        G = src[offset + 1];
+        R = src[offset + 2];
+        offset = (i << 1) + i;
+        dst[offset] = (uint8_t) ((YCbCrYRI * R + YCbCrYGI * G + YCbCrYBI * B + half_shift)
+                >> shift);
+        dst[offset + 1] = (uint8_t) (128 +
+                                     ((YCbCrCbRI * R + YCbCrCbGI * G + YCbCrCbBI * B + half_shift)
+                                             >> shift));
+        dst[offset + 2] = (uint8_t) (128 +
+                                     ((YCbCrCrRI * R + YCbCrCrGI * G + YCbCrCrBI * B + half_shift)
+                                             >> shift));
+    }
+}

app/src/main/cpp/yuv2rgb/yuv_to_rgb.h

@@ -0,0 +1,47 @@
+//
+// Created by xu fulong on 2022/7/8.
+//
+
+#ifndef FFMPEGANDROID_YUV_TO_RGB_H
+#define FFMPEGANDROID_YUV_TO_RGB_H
+
+#include <cstdint>
+
+const float YCbCrYRF = 0.299F;
+const float YCbCrYGF = 0.587F;
+const float YCbCrYBF = 0.114F;
+const float YCbCrCbRF = -0.168736F;
+const float YCbCrCbGF = -0.331264F;
+const float YCbCrCbBF = 0.500000F;
+const float YCbCrCrRF = 0.500000F;
+const float YCbCrCrGF = -0.418688F;
+const float YCbCrCrBF = -0.081312F;
+
+const float RGBRCrF = 1.40200F;
+const float RGBGCbF = -0.34414F;
+const float RGBGCrF = -0.71414F;
+const float RGBBCbF = 1.77200F;
+
+const int shift = 20;
+const int half_shift = 1 << (shift - 1);
+
+const int YCbCrYRI = (int)(YCbCrYRF * (1 << shift) + 0.5);
+const int YCbCrYGI = (int)(YCbCrYGF * (1 << shift) + 0.5);
+const int YCbCrYBI = (int)(YCbCrYBF * (1 << shift) + 0.5);
+const int YCbCrCbRI = (int)(YCbCrCbRF * (1 << shift) + 0.5);
+const int YCbCrCbGI = (int)(YCbCrCbGF * (1 << shift) + 0.5);
+const int YCbCrCbBI = (int)(YCbCrCbBF * (1 << shift) + 0.5);
+const int YCbCrCrRI = (int)(YCbCrCrRF * (1 << shift) + 0.5);
+const int YCbCrCrGI = (int)(YCbCrCrGF * (1 << shift) + 0.5);
+const int YCbCrCrBI = (int)(YCbCrCrBF * (1 << shift) + 0.5);
+
+const int RGBRCrI = (int)(RGBRCrF * (1 << shift) + 0.5);
+const int RGBGCbI = (int)(RGBGCbF * (1 << shift) + 0.5);
+const int RGBGCrI = (int)(RGBGCrF * (1 << shift) + 0.5);
+const int RGBBCbI = (int)(RGBBCbF * (1 << shift) + 0.5);
+
+static void YCbCr_to_RGB(uint8_t* dst, const uint8_t* src, int length);
+
+static void RGB_to_YCbCr(uint8_t* dst, const uint8_t* src, int length);
+
+#endif //FFMPEGANDROID_YUV_TO_RGB_H