轉自:http://blog.csdn.net/tung214/article/details/36887041
研究了一段時間Android的surface系統,一直執着地認爲所有在surface或者屏幕上顯示的畫面,必須要轉換成RGB才能顯示,yuv數據也要通過顏色空間轉換成RGB才能顯示。可最近在研究stagefright視頻顯示時發現,根本找不到omx解碼後的yuv是怎麼轉換成RGB的代碼,yuv數據在render之後就找不到去向了,可畫面確確實實的顯示出來了,這從此顛覆了yuv必須要轉換成RGB才能顯示的真理了。
稍微看一下AsomePlayer的代碼,不難發現,視頻的每一幀是通過調用了SoftwareRenderer來渲染顯示的,我也嘗試用利用SoftwareRenderer來直接render yuv數據顯示,竟然成功了,這是一個很大的突破,比如以後攝像頭採集到的yuv,可以直接丟yuv數據到surface顯示,無需耗時耗效率的yuv轉RGB了。
代碼原創,貼出來與大家分享:Android 4.4平臺 (其中yuv數據的地址可以從這裏下載點擊打開鏈接,放到/mnt/sdcard目錄)
- #include<include/SoftwareRenderer.h>
- #include <cutils/memory.h>
- #include <unistd.h>
- #include <utils/Log.h>
- #include <binder/IPCThreadState.h>
- #include <binder/ProcessState.h>
- #include <binder/IServiceManager.h>
- #include <gui/Surface.h>
- #include <gui/SurfaceComposerClient.h>
- #include <gui/ISurfaceComposer.h>
- #include <ui/DisplayInfo.h>
- #include <android/native_window.h>
- #include <media/stagefright/MetaData.h>
- using namespace android;
- 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;
- //獲取屏幕的寬高等信息
- 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;
- //創建surface,有些系統可能報錯,dinfo.w和dinfo.h也可以寫成固定值
- sp<SurfaceControl> surfaceControl = client->createSurface(String8("showYUV"),
- 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];
- 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);//設定Z座標
- surfaceControl->setPosition(100, 100);//以左上角爲(0,0)設定顯示位置
- surfaceControl->setSize(width, height);//設定視頻顯示大小
- SurfaceComposerClient::closeGlobalTransaction();
- sp<Surface> surface = surfaceControl->getSurface();
- printf("[%s][%d]\n",__FILE__,__LINE__);
- /****************************************************************************************/
- sp<MetaData> meta = new MetaData;
- meta->setInt32(kKeyWidth, width);
- meta->setInt32(kKeyHeight, height);
- /*指定yuv格式,支持以下yuv格式
- * OMX_COLOR_FormatYUV420Planar:
- * OMX_TI_COLOR_FormatYUV420PackedSemiPlanar:
- * HAL_PIXEL_FORMAT_YV12:
- * 其他的貌似會轉換成OMX_COLOR_Format16bitRGB565
- */
- meta->setInt32(kKeyColorFormat, HAL_PIXEL_FORMAT_YV12);
- //setRect不要也可以,我也不知道設置了有什麼用,原理是什麼,但是設置,參數一定要正確
- meta->setRect(
- kKeyCropRect,
- 0,//left
- 0,//top
- width -1,//right
- height -1);//bottom
- printf("[%s][%d]\n",__FILE__,__LINE__);
- SoftwareRenderer* sr = new SoftwareRenderer(surface,meta);//初始化
- printf("[%s][%d]\n",__FILE__,__LINE__);
- sr->render(data,size,NULL);//關鍵在這裏,顯示到屏幕上
- delete[] data;
- 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 如果你有完整編譯過的Android編譯環境,那沒問題,如果是NDK,可能有點麻煩,因爲其中很多靜態動態庫。
- LOCAL_PATH:= $(call my-dir)
- include $(CLEAR_VARS)
- LOCAL_SRC_FILES:= \
- main.cpp
- LOCAL_STATIC_LIBRARIES := \
- libstagefright_color_conversion
- LOCAL_SHARED_LIBRARIES := \
- libcutils \
- libutils \
- libbinder \
- libui \
- libgui \
- libstagefright\
- libstagefright_foundation
- LOCAL_C_INCLUDES := \
- frameworks/native/include/media/openmax \
- frameworks/av/media/libstagefright
- LOCAL_MODULE:= showYUV
- LOCAL_MODULE_TAGS := tests
- include $(BUILD_EXECUTABLE)