Android用surface直接顯示yuv資料(二)
阿新 • • 發佈:2019-02-17
上一篇文章主要是參照AwesomePlayer直接用SoftwareRenderer類來顯示yuv,為了能用到這個類,不惜依賴了libstagefright、libstagefright_color_conversion等動態靜態庫,從而造成程式具有很高的耦合度,也不便於我們理解yuv資料直接顯示的深層次原因。
於是我開始研究SoftwareRenderer的具體實現,我們來提取SoftwareRenderer的核心程式碼,自己來實現yuv的顯示。
SoftwareRenderer就只有三個方法,一個建構函式,一個解構函式,還有一個負責顯示的render方法。構造方法裡有個很重要的地方native_window_set_buffers_geometry這裡是配置即將申請的圖形緩衝區的寬高和顏色空間,忽略了這個地方,畫面將用預設的值顯示,將造成顯示不正確。render函式裡最重要的三個地方,一個的dequeBuffer,一個是mapper,一個是queue_buffer。
- native_window_set_buffers_geometry;//設定寬高以及顏色空間yuv420
- native_window_dequeue_buffer_and_wait;//根據以上配置申請圖形緩衝區
- mapper.lock(buf->handle, GRALLOC_USAGE_SW_WRITE_OFTEN, bounds, &dst));//將申請到的圖形緩衝區跨程序對映到使用者空間
- memcpy(dst, data, dst_y_size + dst_c_size*2);//填充yuv資料到圖形緩衝區
- mNativeWindow->queueBuffer;//顯示
以上五步是surface顯示圖形必不可少的五步。
有了以上分析,我們直接上程式碼:(yuv資料下載地址點選開啟連結,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,對應surface.cpp裡的code
- usingnamespace android;
- //將x規整為y的倍數,也就是將x按y對齊
- staticint ALIGN(int x, int y) {
- // y must be a power of 2.
- return (x + y - 1) & ~(y - 1);
- }
- void render(
- constvoid *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;//顏色空間
- int bufWidth = (mCropWidth + 1) & ~1;//按2對齊
- 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,配置寬高和和指定顏色空間yuv420
- //如果這裡不配置好,下面deque_buffer只能去申請一個預設寬高的圖形緩衝區
- CHECK_EQ(0, native_window_set_buffers_geometry(
- mNativeWindow.get(),
- bufWidth,
- bufHeight,
- halFormat));
- ANativeWindowBuffer *buf;//描述buffer
- //申請一塊空閒的圖形緩衝區
- 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(//用來鎖定一個圖形緩衝區並將緩衝區對映到使用者程序
- buf->handle, GRALLOC_USAGE_SW_WRITE_OFTEN, bounds, &dst));//dst就指向圖形緩衝區首地址
- 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);//將yuv資料copy到圖形緩衝區
- }
- 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(constchar *path,unsigned char * pYUVData,int size){
- FILE *fp = fopen(path,"rb");
- if(fp == NULL){
- printf("read %s fail !!!!!!!!!!!!!!!!!!!\n",path);
- returnfalse;
- }
- fread(pYUVData,size,1,fp);
- fclose(fp);
- returntrue;
- }
- 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;
- //獲取螢幕的寬高等資訊
- 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;
- //建立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];
- constchar *path = "/mnt/sdcard/yuv_320_240.yuv";
- getYV12Data(path,data,size);//get yuv data from file;
- /*********************配置surface*******************************************************************/
- SurfaceComposerClient::openGlobalTransaction();
- surfaceControl->setLayer(100000);//設定Z座標
- surfaceControl->setPosition(100, 100);//以左上角為(0,0)設定顯示位置
- surfaceControl->setSize(width, height);//設定視訊顯示大小
- SurfaceComposerClient::closeGlobalTransaction();
- sp<Surface> surface = surfaceControl->getSurface();
- printf("[%s][%d]\n",__FILE__,__LINE__);
- /**********************顯示yuv資料******************************************************************/
- render(data,size,surface,width,height);
- printf("[%s][%d]\n",__FILE__,__LINE__);
- IPCThreadState::self()->joinThreadPool();//可以保證畫面一直顯示,否則瞬間消失
- IPCThreadState::self()->stopProcess();
- return 0;
- }
Android.mk (這次依賴的庫少了很多)
- 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:= MyShowYUV
- LOCAL_MODULE_TAGS := tests
- include $(BUILD_EXECUTABLE)