stagefright 架构分析(八) 如何获取ComponentHandle，plugin与omx_core桥接
目前基于高通的code分析：
1. 引入libOmxCore.so
根据stagefright 架构分析(七) 动态加载libstagefrighthw.so中的描述
Plugin会加载libOmxCore.so，并调用相应的functions
OMX_Init
OMX_Deinit
OMX_ComponentNameEnum
OMX_GetHandle
OMX_FreeHandle
OMX_GetRolesOfComponent
2. libOmxCore.so 编译内容
LOCAL_SRC_FILES := src/common/omx_core_cmp.cpp
LOCAL_SRC_FILES += src/common/qc_omx_core.c
LOCAL_SRC_FILES += src/$(MM_CORE_TARGET)/qc_registry_table_android.c
3. Plugin调用functions
调用的functions在qc_omx_core.c实现QComOMXPlugin中通过dlsym得到的函数指针，是在qc_omx_core.c中实现的。
例如 mInit = (InitFunc)dlsym(mLibHandle, "OMX_Init");
(*mInit)();
最终调用的是
OMX_API OMX_ERRORTYPE OMX_APIENTRY
OMX_Init()
{
DEBUG_PRINT("OMXCORE API - OMX_Init \n");
/* Nothing to do here ; shared objects shall be loaded at the get handle method */
return OMX_ErrorNone;
}
4. OMX_COMPONENTTYPE interface
component interface在omx_core_cmp.cpp中实现：
具体看这个函数，就容易理解了
void * qc_omx_create_component_wrapper(OMX_PTR obj_ptr)
{
qc_omx_component *pThis = (qc_omx_component *)obj_ptr;
OMX_COMPONENTTYPE* component = &(pThis->m_cmp);
memset(&pThis->m_cmp,0,sizeof(OMX_COMPONENTTYPE));
component->nSize = sizeof(OMX_COMPONENTTYPE);
component->nVersion.nVersion = OMX_SPEC_VERSION;
component->pApplicationPrivate = 0;
component->pComponentPrivate = obj_ptr;
component->AllocateBuffer = &qc_omx_component_allocate_buffer;
component->FreeBuffer = &qc_omx_component_free_buffer;
component->GetParameter = &qc_omx_component_get_parameter;
component->SetParameter = &qc_omx_component_set_parameter;
component->SendCommand = &qc_omx_component_send_command;
component->FillThisBuffer = &qc_omx_component_fill_this_buffer;
component->EmptyThisBuffer = &qc_omx_component_empty_this_buffer;
component->GetState = &qc_omx_component_get_state;
component->GetComponentVersion = &qc_omx_component_get_version;
component->GetConfig = &qc_omx_component_get_config;
component->SetConfig = &qc_omx_component_set_config;
component->GetExtensionIndex = &qc_omx_component_get_extension_index;
component->ComponentTunnelRequest = &qc_omx_component_tunnel_request;
component->UseBuffer = &qc_omx_component_use_buffer;
component->SetCallbacks = &qc_omx_component_set_callbacks;
component->UseEGLImage = &qc_omx_component_use_EGL_image;
component->ComponentRoleEnum = &qc_omx_component_role_enum;
component->ComponentDeInit = &qc_omx_component_deinit;
return (void *)component;
}
5. 如何获取ComponentHandle
OMX_ERRORTYPE QComOMXPlugin::makeComponentInstance(const char *name,
const OMX_CALLBACKTYPE *callbacks,
OMX_PTR appData,
OMX_COMPONENTTYPE **component) {
//调用GetHandle,注册callbacks，并用name得到component句柄
return (*mGetHandle)(
reinterpret_cast<OMX_HANDLETYPE *>(component),
const_cast<char *>(name),
appData, const_cast<OMX_CALLBACKTYPE *>(callbacks));
}
OMX_API OMX_ERRORTYPE OMX_APIENTRY
OMX_GetHandle(OMX_OUT OMX_HANDLETYPE* handle,
OMX_IN OMX_STRING componentName,
OMX_IN OMX_PTR appData,
OMX_IN OMX_CALLBACKTYPE* callBacks)
{
//根据componentName获得对应的component的index
cmp_index = get_cmp_index(componentName);
// dynamically load the so
core[cmp_index].fn_ptr =
omx_core_load_cmp_library(core[cmp_index].so_lib_name,
&core[cmp_index].so_lib_handle);
//创建instance指针地址
void* pThis = (*(core[cmp_index].fn_ptr))();
if(pThis)
{
void *hComp = NULL;
//这就是前面注册component
hComp = qc_omx_create_component_wrapper((OMX_PTR)pThis);
//初始化component
if((eRet = qc_omx_component_init(hComp, core[cmp_index].name)) !=
OMX_ErrorNone)
qc_omx_component_set_callbacks(hComp,callBacks,appData);
//得到component handle的index
hnd_index = get_comp_handle_index(componentName);
if(hnd_index >= 0)
{
//最终将创建好的component handle返回
core[cmp_index].inst[hnd_index]= *handle = (OMX_HANDLETYPE) hComp;
}
}
6. 如何根据ComponentName找到对应的handle呢？
static int get_cmp_index(char *cmp_name){
for(i=0; i< (int)SIZE_OF_CORE; i++)
{
if(!strcmp(cmp_name, core[i].name))
{
rc = i;
break;
}
}
return rc;
}
可以看到，是根据全局数组core中找到的
core的定义在$(MM_CORE_TARGET)/qc_registry_table_android.c
不同的TARGET有不同的定义
omx_core_cb_type core[] =
{
{
"OMX.qcom.video.decoder.avc",
NULL, // Create instance function
// Unique instance handle
{
NULL,
NULL,
NULL,
NULL
},
NULL, // Shared object library handle
"libOmxVdec.so",
{
"video_decoder.avc"
}
},
{
"OMX.qcom.video.decoder.avc.secure",
NULL, // Create instance function
// Unique instance handle
{
NULL,
NULL,
NULL,
NULL
},
NULL, // Shared object library handle
"libOmxVdec.so",
{
"video_decoder.avc"
}
},
{
"OMX.qcom.video.decoder.divx4",
NULL, // Create instance function
// Unique instance handle
{
NULL,
NULL,
NULL,
NULL
},
NULL, // Shared object library handle
"libOmxVdec.so",
{
"video_decoder.divx"
}
},
{
"OMX.qcom.video.decoder.divx",
NULL, // Create instance function
// Unique instance handle
{
NULL,
NULL,
NULL,
NULL
},
NULL, // Shared object library handle
"libOmxVdec.so",
{
"video_decoder.divx"
}
},
{
"OMX.qcom.video.decoder.divx311",
NULL, // Create instance function
// Unique instance handle
{
NULL,
NULL,
NULL,
NULL
},
NULL, // Shared object library handle
"libOmxVdec.so",
{
"video_decoder.divx"
}
},
{
"OMX.qcom.video.decoder.mpeg4",
NULL, // Create instance function
// Unique instance handle
{
NULL,
NULL,
NULL,
NULL
},
NULL, // Shared object library handle
"libOmxVdec.so",
{
"video_decoder.mpeg4"
}
},
{
"OMX.qcom.video.decoder.mpeg2",
NULL, // Create instance function
// Unique instance handle
{
NULL,
NULL,
NULL,
NULL
},
NULL, // Shared object library handle
"libOmxVdec.so",
{
"video_decoder.mpeg2"
}
},
{
"OMX.qcom.video.decoder.vc1",
NULL, // Create instance function
// Unique instance handle
{
NULL,
NULL,
NULL,
NULL
},
NULL, // Shared object library handle
"libOmxVdec.so",
{
"video_decoder.vc1"
}
},
{
"OMX.qcom.video.decoder.wmv",
NULL, // Create instance function
// Unique instance handle
{
NULL,
NULL,
NULL,
NULL
},
NULL, // Shared object library handle
"libOmxVdec.so",
{
"video_decoder.vc1"
}
},
{
"OMX.qcom.video.decoder.h263",
NULL, // Create instance function
// Unique instance handle
{
NULL,
NULL,
NULL,
NULL
},
NULL, // Shared object library handle
"libOmxVdec.so",
{
"video_decoder.h263"
}
},
{
"OMX.qcom.video.encoder.mpeg4",
NULL, // Create instance function
// Unique instance handle
{
NULL,
NULL,
NULL,
NULL
},
NULL, // Shared object library handle
"libOmxVenc.so",
{
"video_encoder.mpeg4"
}
},
{
"OMX.qcom.video.encoder.h263",
NULL, // Create instance function
// Unique instance handle
{
NULL,
NULL,
NULL,
NULL
},
NULL, // Shared object library handle
"libOmxVenc.so",
{
"video_encoder.h263"
}
},
{
"OMX.qcom.video.encoder.avc",
NULL, // Create instance function
// Unique instance handle
{
NULL,
NULL,
NULL,
NULL
},
NULL, // Shared object library handle
"libOmxVenc.so",
{
"video_encoder.avc"
}
},
{
"OMX.qcom.audio.decoder.Qcelp13",
NULL, // Create instance function
// Unique instance handle
{
NULL,
NULL,
NULL,
NULL
},
NULL, // Shared object library handle
"libOmxQcelp13Dec.so",
{
"audio_decoder.Qcelp13"
}
},
{
"OMX.qcom.audio.decoder.evrc",
NULL, // Create instance function
// Unique instance handle
{
NULL,
NULL,
NULL,
NULL
},
NULL, // Shared object library handle
"libOmxEvrcDec.so",
{
"audio_decoder.evrc"
}
},
{
"OMX.qcom.audio.decoder.wma",
NULL, // Create instance function
// Unique instance handle
{
NULL,
NULL,
NULL,
NULL
},
NULL, // Shared object library handle
"libOmxWmaDec.so",
{
"audio_decoder.wma"
}
},
{
"OMX.qcom.audio.decoder.wma10Pro",
NULL, // Create instance function
// Unique instance handle
{
NULL,
NULL,
NULL,
NULL
},
NULL, // Shared object library handle
"libOmxWmaDec.so",
{
"audio_decoder.wma"
}
},
{
"OMX.qcom.audio.decoder.aac",
NULL, // Create instance function
// Unique instance handle
{
NULL,
NULL,
NULL,
NULL
},
NULL, // Shared object library handle
"libOmxAacDec.so",
{
"audio_decoder.aac"
}
},
{
"OMX.qcom.audio.encoder.aac",
NULL, // Create instance function
// Unique instance handle
{
NULL,
NULL,
NULL,
NULL
},
NULL, // Shared object library handle
"libOmxAacEnc.so",
{
"audio_encoder.aac"
}
},
{
"OMX.qcom.audio.encoder.qcelp13",
NULL, // Create instance function
// Unique instance handle
{
NULL,
NULL,
NULL,
NULL
},
NULL, // Shared object library handle
"libOmxQcelp13Enc.so",
{
"audio_encoder.qcelp13"
}
},
{
"OMX.qcom.audio.encoder.evrc",
NULL, // Create instance function
// Unique instance handle
{
NULL,
NULL,
NULL,
NULL
},
NULL, // Shared object library handle
"libOmxEvrcEnc.so",
{
"audio_encoder.evrc"
}
},
{
"OMX.qcom.audio.encoder.amrnb",
NULL, // Create instance function
// Unique instance handle
{
NULL,
NULL,
NULL,
NULL
},
NULL, // Shared object library handle
"libOmxAmrEnc.so",
{
"audio_encoder.amrnb"
}
},
{
"OMX.qcom.audio.decoder.aac",
NULL, // Create instance function
// Unique instance handle
{
NULL,
NULL,
NULL,
NULL
},
NULL, // Shared object library handle
"libOmxAacDec.so",
{
"audio_decoder.aac"
}
},
{
"OMX.qcom.audio.decoder.multiaac",
NULL, // Create instance function
// Unique instance handle
{
NULL,
NULL,
NULL,
NULL
},
NULL, // Shared object library handle
"libOmxAacDec.so",
{
"audio_decoder.aac"
}
},
{
"AIV.play",
NULL, // Create instance function
// Unique instance handle
{
NULL,
NULL,
NULL,
NULL
},
NULL, // Shared object library handle
"libAivPlay.so",
{
"AIV.play.101"
}
},
{
"OMX.qcom.file.muxer",
NULL, // Create instance function
// Unique instance handle
{
NULL,
NULL,
NULL,
NULL
},
NULL, // Shared object library handle
"libOmxMux.so",
{
"container_muxer.mp2"
}
}
};
const unsigned int SIZE_OF_CORE = sizeof(core) / sizeof(omx_core_cb_type);