九乡新闻网黄一琳天天向上:stagefright框架（五）-Video Rendering
来源：百度文库 编辑：九乡新闻网 时间：2024/04/28 01:03:56
(1) 要将mVideoBuffer中的资料输出之前，必须先建立mVideoRenderer
void AwesomePlayer::onVideoEvent()
{
...
if (mVideoRenderer == NULL)
{
initRenderer_l();
}
...
}
void AwesomePlayer::initRenderer_l()
{
if (!strncmp("OMX.", component, 4))
{
mVideoRenderer = new AwesomeRemoteRenderer(
mClient.interface()->createRenderer(
mISurface,
component,
...)); .......... (2)
}
else
{
mVideoRenderer = new AwesomeLocalRenderer(
...,
component,
mISurface); ............................ (3)
}
}
(2) 如果video decoder是OMX component，则建立一个AwesomeRemoteRenderer作为mVideoRenderer
从上段的程序(1)来看，AwesomeRemoteRenderer的本质是由OMX::createRenderer所创建的。createRenderer会先建立一个hardware renderer -- SharedVideoRenderer (libstagefrighthw.so)；若失败，则建立software renderer -- SoftwareRenderer (surface)。
sp
{
VideoRenderer *impl = NULL;
libHandle = dlopen("libstagefrighthw.so", RTLD_NOW);
if (libHandle)
{
CreateRendererFunc func = dlsym(libHandle, ...);
impl = (*func)(...); <----------------- Hardware Renderer
}
if (!impl)
{
impl = new SoftwareRenderer(...); <---- Software Renderer
}
}
(3) 如果video decoder是software component，则建立一个AwesomeLocalRenderer作为mVideoRenderer
AwesomeLocalRenderer的constructor会呼叫本身的init函数，其所做的事和OMX::createRenderer一模一样。
void AwesomeLocalRenderer::init(...)
{
mLibHandle = dlopen("libstagefrighthw.so", RTLD_NOW);
if (mLibHandle)
{
CreateRendererFunc func = dlsym(...);
mTarget = (*func)(...); <---------------- Hardware Renderer
}
if (mTarget == NULL)
{
mTarget = new SoftwareRenderer(...); <--- Software Renderer
}
}
(4) mVideoRenderer一经建立就可以开始将解码后的资料传给它
void AwesomePlayer::onVideoEvent()
{
if (!mVideoBuffer)
{
mVideoSource->read(&mVideoBuffer, ...);
}
[Check Timestamp]
if (mVideoRenderer == NULL)
{
initRenderer_l();
}
mVideoRenderer->render(mVideoBuffer); <----- Render Data
}
