截屏、录像、同屏（通过libyuv进行像素转换、裁剪）
本篇文章借鉴的博客比较多，有些忘记原出处了，还请原作者谅解
主要用到ImageReader、VitrualDisplay、libyuv库
ImageReader接收VirtualDisplay投屏的手机屏幕数据，然后通过libyuv进行像素转换 、裁剪 （RGBA_8888 -> I420 -> 裁剪I420 -> NV21）
直接上核心代码
//获取imageReader中的最新数据
image = mImageReader.acquireLatestImage();
//非空判断，如果为空，使用缓存的上一帧数据
if (image == null) {
return lastFrame;
}
final Image.Plane[] planes = image.getPlanes();
final int width = image.getWidth();
final int height = image.getHeight();
int pixelStride = planes[0].getPixelStride();//像素之间间隔
final int rowStride = planes[0].getRowStride();//行与之间间隔，也就是行长度
int rowPadding = rowStride - pixelStride * width;//行尾填充=每行长度-像素间隔*图片宽度
final int planeWidth = width + rowPadding / pixelStride;
final ByteBuffer buffer = planes[0].getBuffer();
buffer.rewind();
final byte[] planeData = new byte[buffer.capacity()];
buffer.get(planeData);
byte[] yuvData = new byte[planeWidth * height * 3 / 2];
//RABG转I420
YuvUtils.RgbaToI420(Key.RGBA_TO_I420,
planeData,yuvData,planeWidth,height);
byte[] cutData = new byte[width*height*3/2];
//裁剪
YuvUtils.CutI420(yuvData,planeWidth,height,cutData,0,0,width,height);
lastFrame = new byte[width *height * 3 / 2];
//I420转NV21
YuvUtils.I420ToNV21(cutData,lastFrame,width,height,false);
lastData = lastFrame;
return lastData;
上面是java的主要代码
接下来是jni的，由于初次接触libyuv，所以用了两周时间才搜集（照抄）到合适资料，最终勉强能够使用，废话不多说，直接上代码（大部分代码是一个大佬四年前的博客上的，用到的只有三个方法，上面java已经说明了）
#include <assert.h>
#include "libyuv.h"
#include "jni.h"
#include "android/log.h"
#define YUV_UTILS_JAVA "com/wuwang/libyuv/YuvUtils"
#ifdef __cplusplus
extern "C" {
#endif
static int (*rgbaToI420Func[])(const uint8 *,int,uint8 *,int,uint8 *,int ,uint8 *,int,int,int)={
libyuv::ABGRToI420,libyuv::RGBAToI420,libyuv::ARGBToI420,libyuv::BGRAToI420,
libyuv::RGB24ToI420,libyuv::RGB565ToI420
};
static int (*i420ToRgbaFunc[])(const uint8 *,int, const uint8 *,int,const uint8 *,int,uint8 *,
int ,int ,int )={
libyuv::I420ToABGR,libyuv::I420ToRGBA,libyuv::I420ToARGB,libyuv::I420ToBGRA,
libyuv::I420ToRGB24,libyuv::I420ToRGB565
};
static void (*rotatePlaneFunc[])(const uint8* src,int src_stride,uint8* dst,int dst_stride,
int width,int height)={
libyuv::RotatePlane90,libyuv::RotatePlane180,libyuv::RotatePlane270,
};
static void (*rotateUVFunc[])(const uint8* src, int src_stride, uint8* dst_a, int dst_stride_a,
uint8* dst_b, int dst_stride_b, int width, int height)={
libyuv::RotateUV90,libyuv::RotateUV180,libyuv::RotateUV270,
};
//RGBA转I420
int rgbaToI420(JNIEnv * env,jclass clazz,jbyteArray rgba,jint rgba_stride,
jbyteArray yuv,jint y_stride,jint u_stride,jint v_stride,
jint width,jint height,
int (*func)(const uint8 *,int,uint8 *,int,uint8 *,int ,uint8 *,int,int,int)){
size_t ySize=(size_t) (y_stride * height);
size_t uSize=(size_t) (u_stride * height >> 1);
jbyte * rgbaData= env->GetByteArrayElements(rgba,JNI_FALSE);
jbyte * yuvData=env->GetByteArrayElements(yuv,JNI_FALSE);
int ret=func((const uint8 *) rgbaData, rgba_stride, (uint8 *) yuvData, y_stride,
(uint8 *) (yuvData) + ySize, u_stride, (uint8 *) (yuvData )+ ySize + uSize,
v_stride, width, height);
env->ReleaseByteArrayElements(rgba,rgbaData,JNI_OK);
env->ReleaseByteArrayElements(yuv,yuvData,JNI_OK);
return ret;
}
int i420ToRgba(JNIEnv * env,jclass clazz,jbyteArray yuv,jint y_stride,jint u_stride,jint v_stride,
jbyteArray rgba,jint rgba_stride,jint width,jint height,
int (*func)(const uint8 *,int, const uint8 *,int,const uint8 *,int,uint8 *,
int ,int ,int )){
size_t ySize=(size_t) (y_stride * height);
size_t uSize=(size_t) (u_stride * height >> 1);
jbyte * rgbaData= env->GetByteArrayElements(rgba,JNI_FALSE);
jbyte * yuvData=env->GetByteArrayElements(yuv,JNI_FALSE);
int ret=func((const uint8 *) yuvData, y_stride, (uint8 *) yuvData + ySize, u_stride,
(uint8 *) (yuvData)+ ySize + uSize, v_stride, (uint8 *) (rgbaData),
rgba_stride, width, height);
env->ReleaseByteArrayElements(rgba,rgbaData,JNI_OK);
env->ReleaseByteArrayElements(yuv,yuvData,JNI_OK);
return ret;
}
//I420转nv21
int Jni_I420ToNV21(JNIEnv * env,jclass clazz,jbyteArray yuv420p,jbyteArray yuv420sp,jint width,jint height,jboolean swapUV){
size_t ySize=(size_t) (width * height);
size_t uSize=(size_t) (width * height >> 2);
size_t stride[]={0,uSize};
jbyte * yuv420pData=env->GetByteArrayElements(yuv420p,JNI_FALSE);
jbyte * yuv420spData=env->GetByteArrayElements(yuv420sp,JNI_FALSE);
int ret=libyuv::I420ToNV21((const uint8 *) yuv420pData, width,
(const uint8 *) (yuv420pData + ySize + stride[swapUV]), width >> 1,
(const uint8 *) (yuv420pData + ySize + stride[1-swapUV]), width >> 1,
(uint8 *) yuv420spData, width, (uint8 *) (yuv420spData + ySize), width, width, height);
env->ReleaseByteArrayElements(yuv420p,yuv420pData,JNI_OK);
env->ReleaseByteArrayElements(yuv420sp,yuv420spData,JNI_OK);
return ret;
}
int Jni_Rgba2NV21(JNIEnv * env,jclass clazz,jbyteArray rgba,jbyteArray yuv,jint width,jint height){
return 1;
}
int Jni_NV21ToI420(JNIEnv * env,jclass clazz,jbyteArray yuv420p,jbyteArray yuv420sp,jint width,jint height,jboolean swapUV){
size_t ySize=(size_t) (width * height);
size_t uSize=(size_t) (width * height >> 2);
size_t stride[]={0,uSize};
jbyte * yuv420pData=env->GetByteArrayElements(yuv420p,JNI_FALSE);
jbyte * yuv420spData=env->GetByteArrayElements(yuv420sp,JNI_FALSE);
int ret=libyuv::NV21ToI420((const uint8 *) yuv420spData, width, (const uint8 *) (yuv420spData + ySize), width,
(uint8 *) yuv420pData, width,
(uint8 *) (yuv420pData + ySize + stride[swapUV]), width >> 1,
(uint8 *) (yuv420pData + ySize + stride[1-swapUV]), width >> 1, width, height);
env->ReleaseByteArrayElements(yuv420p,yuv420pData,JNI_OK);
env->ReleaseByteArrayElements(yuv420sp,yuv420spData,JNI_OK);
return ret;
}
void Jni_NV21Scale(JNIEnv * env,jclass clazz,jbyteArray src,jint width,jint height,jbyteArray dst,jint dst_width,jint dst_height,int mode){
size_t ySize=(size_t) (width * height);
size_t dstYSize=(size_t) (dst_width*dst_height);
jbyte * srcData=env->GetByteArrayElements(src,JNI_FALSE);
jbyte * dstData=env->GetByteArrayElements(dst,JNI_FALSE);
libyuv::ScalePlane((const uint8 *) srcData, width, width, height,
(uint8 *) dstData, dst_width, dst_width, dst_height,(libyuv::FilterMode) mode);
libyuv::ScalePlane((const uint8 *)(srcData+ySize) , width, width, height>>1,
(uint8 *)(dstData+dstYSize), dst_width, dst_width, dst_height>>1,
(libyuv::FilterMode) mode);
env->ReleaseByteArrayElements(src,srcData,JNI_OK);
env->ReleaseByteArrayElements(dst,dstData,JNI_OK);
}
void Jni_I420Scale(JNIEnv * env,jclass clazz,jbyteArray src,jint width,jint height,jbyteArray dst,jint dst_width,jint dst_height,int mode,jboolean swapUV){
int ySize=width * height;
int swap[]={0,ySize>>2};
size_t dstYSize=(size_t) (dst_width*dst_height);
jbyte * srcData=env->GetByteArrayElements(src,JNI_FALSE);
jbyte * dstData=env->GetByteArrayElements(dst,JNI_FALSE);
libyuv::I420Scale((const uint8 *) srcData, width, (const uint8 *) (srcData + ySize), width >> 1,
(uint8 *)(srcData + ySize + (ySize >> 2)), width >> 1, width, height,
(uint8 *) dstData, dst_width, (uint8 *) (dstData + dstYSize+swap[swapUV]), dst_width >> 1,
(uint8 *) (dstData + dstYSize + swap[1-swapUV]), dst_width >> 1,
dst_width, dst_height, (libyuv::FilterMode) mode);
env->ReleaseByteArrayElements(src,srcData,JNI_OK);
env->ReleaseByteArrayElements(dst,dstData,JNI_OK);
}
void Jni_RgbaScale(JNIEnv * env,jclass clazz,jint type,jbyteArray src,jint src_width,jint src_height,jbyteArray dst,jint dst_width,jint dst_height,jint mode){
int bytes=(type&0x0F000000)>>24;
jbyte * srcData=env->GetByteArrayElements(src,JNI_FALSE);
jbyte * dstData=env->GetByteArrayElements(dst,JNI_FALSE);
libyuv::ARGBScale((const uint8 *) srcData, bytes * src_width, src_width, src_height,
(uint8 *) dstData, bytes*dst_width, dst_width, dst_height,
(libyuv::FilterMode) mode);
env->ReleaseByteArrayElements(src,srcData,JNI_OK);
env->ReleaseByteArrayElements(dst,dstData,JNI_OK);
}
void Jni_NV21ToI420Rotate(JNIEnv * env,jclass clazz,jbyteArray src,jint width,jint height,jbyteArray dst,jint de,jboolean swapUV){
int dst_stride[]={height,width,height};
size_t ySize=(size_t) (width * height);
size_t swap[]={0,ySize>>2};
jbyte * srcData=env->GetByteArrayElements(src,JNI_FALSE);
jbyte * dstData=env->GetByteArrayElements(dst,JNI_FALSE);
rotatePlaneFunc[de]((const uint8 *) srcData, width, (uint8 *) dstData, dst_stride[de], width, height);
rotateUVFunc[de]((const uint8 *) (srcData+ySize), width, (uint8 *)(dstData+ySize+swap[swapUV]), dst_stride[de]>>1,
(uint8*)(dstData+ySize+swap[1-swapUV]),dst_stride[de]>>1,width>>1, height>>1);
env->ReleaseByteArrayElements(src,srcData,JNI_OK);
env->ReleaseByteArrayElements(dst,dstData,JNI_OK);
}
int Jni_RgbaToI420WithStride(JNIEnv * env,jclass clazz,jint type,jbyteArray rgba,jint rgba_stride,
jbyteArray yuv,jint y_stride,jint u_stride,jint v_stride,
jint width,jint height){
uint8 cType= (uint8) (type & 0x0F);
return rgbaToI420(env,clazz,rgba,rgba_stride,yuv,y_stride,u_stride,v_stride,width,height,rgbaToI420Func[cType]);
}
int Jni_RgbaToI420(JNIEnv * env,jclass clazz,jint type,jbyteArray rgba,jbyteArray yuv,jint width,jint height){
uint8 cType=(uint8) (type & 0x0F);
int rgba_stride= ((type & 0xF0) >> 4)*width;
int y_stride=width;
int u_stride=width>>1;
int v_stride=u_stride;
return rgbaToI420(env,clazz,rgba,rgba_stride,yuv,y_stride,u_stride,v_stride,width,height,rgbaToI420Func[cType]);
}
int Jni_I420ToRgbaWithStride(JNIEnv * env,jclass clazz,jint type,jbyteArray yuv,jint y_stride,jint u_stride,jint v_stride,
jbyteArray rgba,jint rgba_stride,
jint width,jint height){
uint8 cType=(uint8) (type & 0x0F);
return i420ToRgba(env,clazz,yuv,y_stride,u_stride,v_stride,rgba,rgba_stride,width,height,i420ToRgbaFunc[cType]);
}
int Jni_I420ToRgba(JNIEnv * env,jclass clazz,jint type,jbyteArray yuv,jbyteArray rgba,jint width,jint height){
uint8 cType=(uint8) (type & 0x0F);
int rgba_stride= ((type & 0xF0) >> 4)*width;
int y_stride=width;
int u_stride=width>>1;
int v_stride=u_stride;
return i420ToRgba(env,clazz,yuv,y_stride,u_stride,v_stride,rgba,rgba_stride,width,height,i420ToRgbaFunc[cType]);
}
int Jni_ScalePlane(JNIEnv * env,jclass clazz,jbyteArray src,jint srcStride,jint srcWidth,jint srcHeight,jbyteArray dst,jint dstStride,jint dstWidth,jint dstHeight,jint mode){
jbyte * src_=env->GetByteArrayElements(src,JNI_FALSE);
jbyte * dst_=env->GetByteArrayElements(dst,JNI_FALSE);
libyuv::ScalePlane((uint8 *)src_,srcStride,srcWidth,srcHeight,(uint8 *)dst_,dstStride,dstWidth,dstHeight,(libyuv::FilterMode)mode);
env->ReleaseByteArrayElements(src,src_,JNI_OK);
env->ReleaseByteArrayElements(dst,dst_,JNI_OK);
return 0;
}
//i420裁剪
int Jni_CutI420(JNIEnv * env,jclass clazz,jbyteArray src,jint srcWidth,jint srcHeight,jbyteArray dst,jint xStart,jint yStart,jint xSize,jint ySize){
jbyte * src_=env->GetByteArrayElements(src,JNI_FALSE);
jbyte * dst_=env->GetByteArrayElements(dst,JNI_FALSE);
libyuv::ConvertToI420(
(uint8 *)src_,
srcWidth*srcHeight*3/2,
(uint8 *)dst_,
xSize,
(uint8 *)dst_+xSize*ySize,
(xSize+1)/2,
(uint8 *)dst_+xSize*ySize+((xSize+1)/2)*((ySize+1)/2),
(xSize+1)/2,
xStart,
yStart,
srcWidth,
srcHeight,
xSize,
ySize,
libyuv::kRotate0,
libyuv::FOURCC_YU12);
env->ReleaseByteArrayElements(src,src_,JNI_OK);
env->ReleaseByteArrayElements(dst,dst_,JNI_OK);
return 0;
}
//libyuv中，rgba表示abgrabgrabgr这样的顺序写入文件，java使用的时候习惯rgba表示rgbargbargba写入文件
static JNINativeMethod g_methods[]={
{"RgbaToI420","(I[BI[BIIIII)I", (void *)Jni_RgbaToI420WithStride},
{"RgbaToI420","(I[B[BII)I", (void *)Jni_RgbaToI420},
{"Rgba2NV21","([B[BII)I",(void *)Jni_Rgba2NV21},
{"ScalePlane","([BIII[BIIII)I",(void *)Jni_ScalePlane},
{"CutI420","([BII[BIIII)I",(void *)Jni_CutI420},
{"I420ToRgba","(I[BIII[BIII)I", (void *)Jni_I420ToRgbaWithStride},
{"I420ToRgba", "(I[B[BII)I", (void *)Jni_I420ToRgba},
{"I420ToNV21","([B[BIIZ)I",(void *)Jni_I420ToNV21},
{"NV21ToI420","([B[BIIZ)I",(void *)Jni_NV21ToI420},
{"NV21Scale","([BII[BIII)V",(void *)Jni_NV21Scale},
{"I420Scale","([BII[BIIIZ)V",(void *)Jni_I420Scale},
{"RgbaScale","([BII[BIII)V",(void *)Jni_RgbaScale},
{"NV21ToI420Rotate","([BII[BIZ)V",(void *)Jni_NV21ToI420Rotate},
};
JNIEXPORT jint JNI_OnLoad(JavaVM *vm, void *reserved)
{
JNIEnv* env = nullptr;
if (vm->GetEnv((void**)&env, JNI_VERSION_1_4) != JNI_OK) {
return JNI_ERR;
}
assert(env != nullptr);
jclass clazz=env->FindClass(YUV_UTILS_JAVA);
env->RegisterNatives(clazz, g_methods, (int) (sizeof(g_methods) / sizeof((g_methods)[0])));
return JNI_VERSION_1_4;
}
JNIEXPORT void JNI_OnUnload(JavaVM *jvm, void *reserved){
JNIEnv* env = nullptr;
if (jvm->GetEnv((void**)&env, JNI_VERSION_1_4) != JNI_OK) {
return;
}
jclass clazz=env->FindClass(YUV_UTILS_JAVA);
env->UnregisterNatives(clazz);
}
#ifdef __cplusplus
}
#endif
jni只用到了 Rgba转i420，i420裁剪，i420转nva21，其他方法没有验证，毕竟是借鉴（照抄）的，以后有空再看看吧
这种jni写法也是第一次见，所以留作记录，通过学习libyuv也算是有一点点收获，恶补了关于像素、byte存储、补齐方面的知识。
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