安卓YUV转灰度的性能优化主要可以通过以下几个方面来实现:
// native-lib.cpp
#include
#include
extern "C" {
JNIEXPORT void JNICALL
Java_com_example_yuvconverter_YUVConverter_YUVtoGray(JNIEnv *env, jobject thiz, jbyteArray yuvData,
jbyteArray grayData, jint width, jint height) {
jbyte *pYUVData = env->GetByteArrayElements(yuvData, NULL);
jbyte *pGrayData = env->GetByteArrayElements(grayData, NULL);
int yuvSize = width * height * 3 / 2;
int graySize = width * height;
jbyte *pY = pYUVData;
jbyte *pUV = pYUVData + graySize;
jbyte *pGray = pGrayData;
for (int i = 0; i < height; i++) {
for (int j = 0; j < width; j++) {
int y = pY[i * width + j] & 0xff;
int u = pUV[(i / 2) * (width / 2) + (j / 2) * 2] & 0xff;
int v = pUV[(i / 2) * (width / 2) + (j / 2) * 2 + 1] & 0xff;
int r = (int) (y + 1.402 * (v - 128));
int g = (int) (y - 0.344136 * (u - 128) - 0.714136 * (v - 128));
int b = (int) (y + 1.772 * (u - 128));
int gray = (r + g + b) / 3;
pGray[i * width + j] = gray;
}
}
env->ReleaseByteArrayElements(yuvData, pYUVData, 0);
env->ReleaseByteArrayElements(grayData, pGrayData, 0);
}
}
public class YUVConverter {
private static final int NUM_THREADS = 4;
public static byte[] convertYUVtoGray(byte[] yuvData, int width, int height) {
byte[] grayData = new byte[width * height];
int yuvSize = width * height * 3 / 2;
Thread[] threads = new Thread[NUM_THREADS];
for (int i = 0; i < NUM_THREADS; i++) {
final int threadId = i;
threads[i] = new Thread(new Runnable() {
@Override
public void run() {
int start = threadId * width * height / NUM_THREADS;
int end = (threadId + 1) * width * height / NUM_THREADS;
for (int i = start; i < end; i++) {
// Convert YUV to gray here
byte y = yuvData[i];
grayData[i] = y;
}
}
});
threads[i].start();
}
try {
for (Thread thread : threads) {
thread.join();
}
} catch (InterruptedException e) {
e.printStackTrace();
}
return grayData;
}
}
public class YUVConverter {
public static Bitmap convertYUVtoGray(Context context, byte[] yuvData, int width, int height) {
RenderScript rs = RenderScript.create(context);
ScriptC_yuv_to_gray script = new ScriptC_y
上一篇:安卓与ubuntu