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Android用surface直接显示yuv数据(2)

热度:42   发布时间:2016-04-28 04:54:50.0
Android用surface直接显示yuv数据(二)

    上一篇文章主要是参照AwesomePlayer直接用SoftwareRenderer类来显示yuv,为了能用到这个类,不惜依赖了libstagefright、libstagefright_color_conversion等动态静态库,从而造成程序具有很高的耦合度,也不便于我们理解yuv数据直接显示的深层次原因。

    于是我开始研究SoftwareRenderer的具体实现,我们来提取SoftwareRenderer的核心代码,自己来实现yuv的显示。

    SoftwareRenderer就只有三个方法,一个构造函数,一个析构函数,还有一个负责显示的render方法。构造方法里有个很重要的地方native_window_set_buffers_geometry这里是配置即将申请的图形缓冲区的宽高和颜色空间,忽略了这个地方,画面将用默认的值显示,将造成显示不正确。render函数里最重要的三个地方,一个的dequeBuffer,一个是mapper,一个是queue_buffer。

native_window_set_buffers_geometry;//设置宽高以及颜色空间yuv420native_window_dequeue_buffer_and_wait;//根据以上配置申请图形缓冲区mapper.lock(buf->handle, GRALLOC_USAGE_SW_WRITE_OFTEN, bounds, &dst));//将申请到的图形缓冲区跨进程映射到用户空间memcpy(dst, data, dst_y_size + dst_c_size*2);//填充yuv数据到图形缓冲区mNativeWindow->queueBuffer;//显示

以上五步是surface显示图形必不可少的五步。

有了以上分析,我们直接上代码:(yuv数据下载地址点击打开链接,放到sdcard)

main.cpp

#include <cutils/memory.h>#include <unistd.h>#include <utils/Log.h>#include <binder/IPCThreadState.h>#include <binder/ProcessState.h>#include <binder/IServiceManager.h>#include <media/stagefright/foundation/ADebug.h>#include <gui/Surface.h>#include <gui/SurfaceComposerClient.h>#include <gui/ISurfaceComposer.h>#include <ui/DisplayInfo.h>#include <android/native_window.h>#include <system/window.h>#include <ui/GraphicBufferMapper.h>//ANativeWindow 就是surface,对应surface.cpp里的codeusing namespace android;//将x规整为y的倍数,也就是将x按y对齐static int ALIGN(int x, int y) {    // y must be a power of 2.    return (x + y - 1) & ~(y - 1);}void render(        const void *data, size_t size, const sp<ANativeWindow> &nativeWindow,int width,int height) {    sp<ANativeWindow> mNativeWindow = nativeWindow;    int err;	int mCropWidth = width;	int mCropHeight = height;		int halFormat = HAL_PIXEL_FORMAT_YV12;//颜色空间    int bufWidth = (mCropWidth + 1) & ~1;//按2对齐    int bufHeight = (mCropHeight + 1) & ~1;		CHECK_EQ(0,            native_window_set_usage(            mNativeWindow.get(),            GRALLOC_USAGE_SW_READ_NEVER | GRALLOC_USAGE_SW_WRITE_OFTEN            | GRALLOC_USAGE_HW_TEXTURE | GRALLOC_USAGE_EXTERNAL_DISP));    CHECK_EQ(0,            native_window_set_scaling_mode(            mNativeWindow.get(),            NATIVE_WINDOW_SCALING_MODE_SCALE_TO_WINDOW));    // Width must be multiple of 32???	//很重要,配置宽高和和指定颜色空间yuv420	//如果这里不配置好,下面deque_buffer只能去申请一个默认宽高的图形缓冲区    CHECK_EQ(0, native_window_set_buffers_geometry(                mNativeWindow.get(),                bufWidth,                bufHeight,                halFormat));			ANativeWindowBuffer *buf;//描述buffer	//申请一块空闲的图形缓冲区    if ((err = native_window_dequeue_buffer_and_wait(mNativeWindow.get(),            &buf)) != 0) {        ALOGW("Surface::dequeueBuffer returned error %d", err);        return;    }    GraphicBufferMapper &mapper = GraphicBufferMapper::get();    Rect bounds(mCropWidth, mCropHeight);    void *dst;    CHECK_EQ(0, mapper.lock(//用来锁定一个图形缓冲区并将缓冲区映射到用户进程                buf->handle, GRALLOC_USAGE_SW_WRITE_OFTEN, bounds, &dst));//dst就指向图形缓冲区首地址    if (true){        size_t dst_y_size = buf->stride * buf->height;        size_t dst_c_stride = ALIGN(buf->stride / 2, 16);//1行v/u的大小        size_t dst_c_size = dst_c_stride * buf->height / 2;//u/v的大小                memcpy(dst, data, dst_y_size + dst_c_size*2);//将yuv数据copy到图形缓冲区    }    CHECK_EQ(0, mapper.unlock(buf->handle));    if ((err = mNativeWindow->queueBuffer(mNativeWindow.get(), buf,            -1)) != 0) {        ALOGW("Surface::queueBuffer returned error %d", err);    }    buf = NULL;}bool getYV12Data(const char *path,unsigned char * pYUVData,int size){	FILE *fp = fopen(path,"rb");	if(fp == NULL){		printf("read %s fail !!!!!!!!!!!!!!!!!!!\n",path);		return false;	}	fread(pYUVData,size,1,fp);	fclose(fp);	return true;}int main(void){	// set up the thread-pool    sp<ProcessState> proc(ProcessState::self());    ProcessState::self()->startThreadPool();		// create a client to surfaceflinger    sp<SurfaceComposerClient> client = new SurfaceComposerClient();	sp<IBinder> dtoken(SurfaceComposerClient::getBuiltInDisplay(            ISurfaceComposer::eDisplayIdMain));	DisplayInfo dinfo;	//获取屏幕的宽高等信息    status_t status = SurfaceComposerClient::getDisplayInfo(dtoken, &dinfo);	printf("w=%d,h=%d,xdpi=%f,ydpi=%f,fps=%f,ds=%f\n",         dinfo.w, dinfo.h, dinfo.xdpi, dinfo.ydpi, dinfo.fps, dinfo.density);    if (status)        return -1;	//创建surface    sp<SurfaceControl> surfaceControl = client->createSurface(String8("testsurface"),            dinfo.w, dinfo.h, PIXEL_FORMAT_RGBA_8888, 0);			/*************************get yuv data from file;****************************************/				printf("[%s][%d]\n",__FILE__,__LINE__);	int width,height;	width = 320;	height = 240;	int size = width * height * 3/2;	unsigned char *data = new unsigned char[size];	const char *path = "/mnt/sdcard/yuv_320_240.yuv";	getYV12Data(path,data,size);//get yuv data from file;	/*********************配置surface*******************************************************************/    SurfaceComposerClient::openGlobalTransaction();    surfaceControl->setLayer(100000);//设定Z坐标	surfaceControl->setPosition(100, 100);//以左上角为(0,0)设定显示位置	surfaceControl->setSize(width, height);//设定视频显示大小    SurfaceComposerClient::closeGlobalTransaction();	sp<Surface> surface = surfaceControl->getSurface();	printf("[%s][%d]\n",__FILE__,__LINE__);	/**********************显示yuv数据******************************************************************/		render(data,size,surface,width,height);	printf("[%s][%d]\n",__FILE__,__LINE__);		IPCThreadState::self()->joinThreadPool();//可以保证画面一直显示,否则瞬间消失    IPCThreadState::self()->stopProcess();	return 0;}

Android.mk (这次依赖的库少了很多)

LOCAL_PATH:= $(call my-dir)include $(CLEAR_VARS)LOCAL_SRC_FILES:= \	main.cpp	LOCAL_SHARED_LIBRARIES := \	libcutils \	libutils \	libbinder \    libui \    libgui \	libstagefright_foundation	LOCAL_MODULE:= MyShowYUVLOCAL_MODULE_TAGS := testsinclude $(BUILD_EXECUTABLE)
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