windows mobile用sdl做视频显示(附sdl lib for mobile)(转)

http://blog.csdn.net/lius1984/article/details/4420786?

使用的sdl库及头文件已上传至http://download.csdn.net/source/1775400
sdl是开源的跨平台多媒体开发包，主要用在快速的视频格式转换和显示，以及封装了键盘/鼠标/手机按键/触屏等各个平台的用户交互响应，广泛应用在游戏，多媒体播放器等应用中。目前支持windows,linux, wince,mac os,非正式地支持symbian os。

一般视频解码器输出图像的是yuv420格式，而屏幕显示大都是rgb42规格。mobile上画面显示一般经由decode>>yuv2rgb>>scale>>directDraw直接写屏。采用SDL可以加速这一过程，且更方便响应全屏缩放等用户操作。

下面介绍mobile上用sdl来加速显示视频的全过程。

1. 把主对话框的窗口句柄传给显示类。

2. 初始化sdl，设置显示视频模式

SDL_Surface *screen;

SDL_Rect sdl_rect;

SDL_Overlay *bmp;

bool InitSdl()

{

char sdl_var[64];

sprintf(sdl_var,"SDL_WINDOWID=0x%lx", m_hWnd);//主窗口句柄

SDL_putenv(sdl_var);

char *myvalue =SDL_getenv("SDL_WINDOWID");

atexit(SDL_Quit);

//根据解码后的视频尺寸来初始化sdl

screen =SDL_SetVideoMode(ImageWidth, ImageHeight, 0,SDL_ANYFORMAT|SDL_RESIZABLE|SDL_DOUBLEBUF|SDL_HWSURFACE);//注意用到的参数flags

if(!screen)

{

TRACE(L"error SDL SetVideoMode!");

return false;

}

bmp = SDL_CreateYUVOverlay(ImageWidth,ImageHeight, ,SDL_YV12_OVERLAY,screen);

if(!bmp)

{

TRACE(L"error SDL CreateYUVOverlay!");

return false;

}

return TRUE;

}

3. 在屏幕上绘制像素

void SdlDisplayFrame()

{

AVPicture pict;

pict.data[0] = bmp->pixels[0];

pict.data[1] = bmp->pixels[2];

pict.data[2] = bmp->pixels[1];

pict.linesize[0] = bmp->pitches[0];

pict.linesize[1] = bmp->pitches[2];

pict.linesize[2] = bmp->pitches[1];

//pFrame是ffmpeg存放解码后yuv数据的struct

img_convert(&pict, PIX_FMT_YUV420P,(AVPicture *)pFrame,pContext->pix_fmt, iImage_Width, iImage_Height);

SDL_LockSurface(screen);

SDL_LockYUVOverlay(bmp);

{

sdl_rect.x = 0;

sdl_rect.y = 0;

sdl_rect.w =m_width; //pContext->width;

sdl_rect.h =m_height; //pContext->height;

}

SDL_UnlockYUVOverlay(bmp);

SDL_UnlockSurface(screen);

SDL_DisplayYUVOverlay(bmp,&sdl_rect);//显示图片到屏幕

}

4. 事件轮询和按键响应

void SdlEvent()

{

SDL_Event event;

while ( SDL_PollEvent(&event))

{

TRACE(L"========SDL VIDEORESIZEEVENT START");

switch (event.type)

{

caseSDL_VIDEORESIZE:

// 响应图像缩放事件

if(m_iImage_Width == Image_Primary_Width && m_iImage_Height == Image_Primary_Height)

{

TRACE(L"event.resize.w= %d",event.resize.w);

TRACE(L"event.resize.h= %d",event.resize.h);

m_width=event.resize.w;

m_height= event.resize.h;

SDL_FreeYUVOverlay(bmp);

bmp= NULL;

SDL_FreeSurface(screen);

screen= NULL;

if(!IsQcif)

{

m_height= m_height * 2;

m_width= m_width * 2;

screen=SDL_SetVideoMode(MobileFullScreenWidth,MobileFullScreenHeight,

0,SDL_ANYFORMAT|SDL_RESIZABLE|SDL_DOUBLEBUF|SDL_HWSURFACE);

if(screen == NULL)

{

TRACE(L"screen=NULL");

return;

}

bmp=SDL_CreateYUVOverlay(MobileFullScreenWidth,MobileFullScreenHeight,

SDL_YV12_OVERLAY,screen);

if(bmp == NULL)

{

TRACE(L"bm1= NULL");

return;

}

IsQcif= true;

}

else

{

screen= SDL_SetVideoMode(Image_Primary_Width,Image_Primary_Height,

0,SDL_ANYFORMAT|SDL_RESIZABLE|SDL_DOUBLEBUF|SDL_HWSURFACE);

if(screen == NULL)

{

TRACE(L"screen1=NULL");

return;

}

bmp=SDL_CreateYUVOverlay(Image_Primary_Width,Image_Primary_Height,

SDL_YV12_OVERLAY,screen);

if(bmp == NULL)

{

TRACE(L"bm1= NULL");

return;

}

IsQcif= false;

}

break;

}

caseSDL_MOUSEBUTTONDOWN:

//响应触屏笔点击事件

break;

}

case SDL_QUIT:

//响应退出事件

break;

default:

break;

}

}

}