本文共 23177 字,大约阅读时间需要 77 分钟。
这几天一直在研究android 的omx机制,我针对的android是4.0.3,主要是TI 的4430,4460的omx方式实现,这里还是简单的说一下为什么要研究这个文件
之前有一篇文章已经比较详细的说过了OMAP4系列芯片了,这里这个OMXCameraAdapter其实就是omap4 A9端的omx client,通过这个client与ducati端(也就是omap4的DSP端)的omx进行通信,可以把ducati端的这个omx简单理解为omx servicer,之前已经说了很多了andriod camera了,但是之前文章都是针对V4LCameraAdapter这个适配器进行的,这是大家都比较了解的,就是app通过V4L2这种方式与kernel camera driver实现交互,进而实现camera 的使用,包括数据回调等过程,但是这里的OMX方法完全颠覆了我之前的想法,开始在研究OMX的时候自己就是调用这个死胡同里了,一直在试图在OMX的实现中找到他到底是在哪么访问设备的,本来我是以后最终他还是通过V4L2这种方式,事实证明我错了,OMX是一种完全不同于V4L2 的访问camera的策略,他通过A9端的omx client和DSP端的omx通信,而且最终访问camera的方法是在DSP端omx server接到到A9端的omx client配置后按照指定方法实现camera 的控制的,这里ducati端到底是怎么处理的我暂时没有关注,暂时精力有限啊!
以上是我自己的见解,也许是完全错误的,待确认,这里只是总结我的分析过程
经过上面我的概述,自然A9端的这个OMXCameraAdapter对于我来说就是一切了,分析它是必经之路啊
现在就开始:
首先要知道在哪里实例化了这个类的对象,这个在之前已经说到过了,这个不在说明,重点看看他的initialize方法都干了些甚么 ?
- /*--------------------Camera Adapter Class STARTS here-----------------------------*/
-
- status_t OMXCameraAdapter::initialize(CameraProperties::Properties* caps)
- {
- LOG_FUNCTION_NAME;
-
- char value[PROPERTY_VALUE_MAX];
- const char *mountOrientationString = NULL;
-
- property_get("debug.camera.showfps", value, "0");
- mDebugFps = atoi(value);
- property_get("debug.camera.framecounts", value, "0");
- mDebugFcs = atoi(value);
-
- #ifdef CAMERAHAL_OMX_PROFILING
-
- property_get("debug.camera.profile", value, "0");
- mDebugProfile = atoi(value);
-
- #endif
-
- TIMM_OSAL_ERRORTYPE osalError = OMX_ErrorNone;
- OMX_ERRORTYPE eError = OMX_ErrorNone;
- status_t ret = NO_ERROR;
-
- mLocalVersionParam.s.nVersionMajor = 0x1;
- mLocalVersionParam.s.nVersionMinor = 0x1;
- mLocalVersionParam.s.nRevision = 0x0 ;
- mLocalVersionParam.s.nStep = 0x0;
-
- mPending3Asettings = 0;//E3AsettingsAll;
- mPendingCaptureSettings = 0;
- mPendingPreviewSettings = 0;
-
- if ( 0 != mInitSem.Count() )
- {
- CAMHAL_LOGEB("Error mInitSem semaphore count %d", mInitSem.Count());
- LOG_FUNCTION_NAME_EXIT;
- return NO_INIT;
- }
-
- ///Update the preview and image capture port indexes
- mCameraAdapterParameters.mPrevPortIndex = OMX_CAMERA_PORT_VIDEO_OUT_PREVIEW;
- // temp changed in order to build OMX_CAMERA_PORT_VIDEO_OUT_IMAGE;
- mCameraAdapterParameters.mImagePortIndex = OMX_CAMERA_PORT_IMAGE_OUT_IMAGE;
- mCameraAdapterParameters.mMeasurementPortIndex = OMX_CAMERA_PORT_VIDEO_OUT_MEASUREMENT;
- //currently not supported use preview port instead
- mCameraAdapterParameters.mVideoPortIndex = OMX_CAMERA_PORT_VIDEO_OUT_VIDEO;
- mCameraAdapterParameters.mVideoInPortIndex = OMX_CAMERA_PORT_VIDEO_IN_VIDEO;
- // 1.OMX_Init
- eError = OMX_Init();
- if (eError != OMX_ErrorNone) {
- CAMHAL_LOGEB("OMX_Init() failed, error: 0x%x", eError);
- return ErrorUtils::omxToAndroidError(eError);
- }
- mOmxInitialized = true;
-
- // 2.Initialize the callback handles
- OMX_CALLBACKTYPE callbacks;
- callbacks.EventHandler = android::OMXCameraAdapterEventHandler;
- callbacks.EmptyBufferDone = android::OMXCameraAdapterEmptyBufferDone;
- callbacks.FillBufferDone = android::OMXCameraAdapterFillBufferDone;
-
- // 3.Get the handle to the OMX Component
- eError = OMXCameraAdapter::OMXCameraGetHandle(&mCameraAdapterParameters.mHandleComp, this, callbacks);
- if(eError != OMX_ErrorNone) {
- CAMHAL_LOGEB("OMX_GetHandle -0x%x", eError);
- }
- GOTO_EXIT_IF((eError != OMX_ErrorNone), eError);
-
- // 4.设置component的初始状态
- mComponentState = OMX_StateLoaded;
-
- CAMHAL_LOGVB("OMX_GetHandle -0x%x sensor_index = %lu", eError, mSensorIndex);
- initDccFileDataSave(&mCameraAdapterParameters.mHandleComp, mCameraAdapterParameters.mPrevPortIndex);
-
- // 5.disable所以的component
- eError = OMX_SendCommand(mCameraAdapterParameters.mHandleComp,
- OMX_CommandPortDisable,
- OMX_ALL,
- NULL);
-
- if(eError != OMX_ErrorNone) {
- CAMHAL_LOGEB("OMX_SendCommand(OMX_CommandPortDisable) -0x%x", eError);
- }
- GOTO_EXIT_IF((eError != OMX_ErrorNone), eError);
-
- // 6.Register for port enable event
- ret = RegisterForEvent(mCameraAdapterParameters.mHandleComp,
- OMX_EventCmdComplete,
- OMX_CommandPortEnable,
- mCameraAdapterParameters.mPrevPortIndex,
- mInitSem);
- if(ret != NO_ERROR) {
- CAMHAL_LOGEB("Error in registering for event %d", ret);
- goto EXIT;
- }
-
- // 7.Enable PREVIEW Port
- eError = OMX_SendCommand(mCameraAdapterParameters.mHandleComp,
- OMX_CommandPortEnable,
- mCameraAdapterParameters.mPrevPortIndex,
- NULL);
- if(eError != OMX_ErrorNone) {
- CAMHAL_LOGEB("OMX_SendCommand(OMX_CommandPortEnable) -0x%x", eError);
- }
- GOTO_EXIT_IF((eError!=OMX_ErrorNone), eError);
-
- // 8.Wait for the port enable event to occur
- ret = mInitSem.WaitTimeout(OMX_CMD_TIMEOUT);
- if ( NO_ERROR == ret ) {
- CAMHAL_LOGDA("-Port enable event arrived");
- } else {
- ret |= RemoveEvent(mCameraAdapterParameters.mHandleComp,
- OMX_EventCmdComplete,
- OMX_CommandPortEnable,
- mCameraAdapterParameters.mPrevPortIndex,
- NULL);
- CAMHAL_LOGEA("Timeout for enabling preview port expired!");
- goto EXIT;
- }
-
- // 9.Select the sensor
- OMX_CONFIG_SENSORSELECTTYPE sensorSelect;
- OMX_INIT_STRUCT_PTR (&sensorSelect, OMX_CONFIG_SENSORSELECTTYPE);
- sensorSelect.eSensor = (OMX_SENSORSELECT) mSensorIndex;
- eError = OMX_SetConfig(mCameraAdapterParameters.mHandleComp, ( OMX_INDEXTYPE ) OMX_TI_IndexConfigSensorSelect, &sensorSelect);
- if ( OMX_ErrorNone != eError ) {
- CAMHAL_LOGEB("Error while selecting the sensor index as %d - 0x%x", mSensorIndex, eError);
- return BAD_VALUE;
- } else {
- CAMHAL_LOGDB("Sensor %d selected successfully", mSensorIndex);
- }
-
- #ifdef CAMERAHAL_DEBUG
-
- printComponentVersion(mCameraAdapterParameters.mHandleComp);
-
- #endif
- // 10.初始化默认参数
- mBracketingEnabled = false;
- mZoomBracketingEnabled = false;
- mBracketingBuffersQueuedCount = 0;
- mBracketingRange = 1;
- mLastBracetingBufferIdx = 0;
- mBracketingBuffersQueued = NULL;
- mOMXStateSwitch = false;
- mBracketingSet = false;
- #ifdef CAMERAHAL_USE_RAW_IMAGE_SAVING
- mRawCapture = false;
- mYuvCapture = false;
- #endif
-
- mCaptureSignalled = false;
- mCaptureConfigured = false;
- mReprocConfigured = false;
- mRecording = false;
- mWaitingForSnapshot = false;
- mPictureFormatFromClient = NULL;
-
- mCapabilitiesOpMode = MODE_MAX;
- mCapMode = INITIAL_MODE;
- mIPP = IPP_NULL;
- mVstabEnabled = false;
- mVnfEnabled = false;
- mBurstFrames = 1;
- mBurstFramesAccum = 0;
- mCapturedFrames = 0;
- mFlushShotConfigQueue = false;
- mPictureQuality = 100;
- mCurrentZoomIdx = 0;
- mTargetZoomIdx = 0;
- mPreviousZoomIndx = 0;
- mReturnZoomStatus = false;
- mZoomInc = 1;
- mZoomParameterIdx = 0;
- mExposureBracketingValidEntries = 0;
- mZoomBracketingValidEntries = 0;
- mSensorOverclock = false;
- mAutoConv = OMX_TI_AutoConvergenceModeMax;
- mManualConv = 0;
- mDeviceOrientation = 0;
- mCapabilities = caps;
- mZoomUpdating = false;
- mZoomUpdate = false;
- mGBCE = BRIGHTNESS_OFF;
- mGLBCE = BRIGHTNESS_OFF;
- mParameters3A.ExposureLock = OMX_FALSE;
- mParameters3A.WhiteBalanceLock = OMX_FALSE;
-
- mEXIFData.mGPSData.mAltitudeValid = false;
- mEXIFData.mGPSData.mDatestampValid = false;
- mEXIFData.mGPSData.mLatValid = false;
- mEXIFData.mGPSData.mLongValid = false;
- mEXIFData.mGPSData.mMapDatumValid = false;
- mEXIFData.mGPSData.mProcMethodValid = false;
- mEXIFData.mGPSData.mVersionIdValid = false;
- mEXIFData.mGPSData.mTimeStampValid = false;
- mEXIFData.mModelValid = false;
- mEXIFData.mMakeValid = false;
-
- //update the mDeviceOrientation with the sensor mount orientation.
- //So that the face detect will work before onOrientationEvent()
- //get triggered.
- CAMHAL_ASSERT(mCapabilities);
- mountOrientationString = mCapabilities->get(CameraProperties::ORIENTATION_INDEX);
- CAMHAL_ASSERT(mountOrientationString);
- mDeviceOrientation = atoi(mountOrientationString);
-
- if (mSensorIndex != 2) {
- mCapabilities->setMode(MODE_HIGH_SPEED);
- }
-
- if (mCapabilities->get(CameraProperties::SUPPORTED_ZOOM_STAGES) != NULL) {
- mMaxZoomSupported = mCapabilities->getInt(CameraProperties::SUPPORTED_ZOOM_STAGES) + 1;
- } else {
- mMaxZoomSupported = 1;
- }
-
- // 11.initialize command handling thread
- if(mCommandHandler.get() == NULL)
- mCommandHandler = new CommandHandler(this);
-
- if ( NULL == mCommandHandler.get() )
- {
- CAMHAL_LOGEA("Couldn't create command handler");
- return NO_MEMORY;
- }
-
- ret = mCommandHandler->run("CallbackThread", PRIORITY_URGENT_DISPLAY);
- if ( ret != NO_ERROR )
- {
- if( ret == INVALID_OPERATION){
- CAMHAL_LOGDA("command handler thread already runnning!!");
- ret = NO_ERROR;
- } else {
- CAMHAL_LOGEA("Couldn't run command handlerthread");
- return ret;
- }
- }
-
- // 12.initialize omx callback handling thread
- if(mOMXCallbackHandler.get() == NULL)
- mOMXCallbackHandler = new OMXCallbackHandler(this);
-
- if ( NULL == mOMXCallbackHandler.get() )
- {
- CAMHAL_LOGEA("Couldn't create omx callback handler");
- return NO_MEMORY;
- }
-
- ret = mOMXCallbackHandler->run("OMXCallbackThread", PRIORITY_URGENT_DISPLAY);
- if ( ret != NO_ERROR )
- {
- if( ret == INVALID_OPERATION){
- CAMHAL_LOGDA("omx callback handler thread already runnning!!");
- ret = NO_ERROR;
- } else {
- CAMHAL_LOGEA("Couldn't run omx callback handler thread");
- return ret;
- }
- }
-
- OMX_INIT_STRUCT_PTR (&mRegionPriority, OMX_TI_CONFIG_3A_REGION_PRIORITY);
- OMX_INIT_STRUCT_PTR (&mFacePriority, OMX_TI_CONFIG_3A_FACE_PRIORITY);
- mRegionPriority.nPortIndex = OMX_ALL;
- mFacePriority.nPortIndex = OMX_ALL;
-
- //Setting this flag will that the first setParameter call will apply all 3A settings
- //and will not conditionally apply based on current values.
- mFirstTimeInit = true;
-
- //Flag to avoid calling setVFramerate() before OMX_SetParameter(OMX_IndexParamPortDefinition)
- //Ducati will return an error otherwise.
- mSetFormatDone = false;
-
- memset(mExposureBracketingValues, 0, EXP_BRACKET_RANGE*sizeof(int));
- memset(mZoomBracketingValues, 0, ZOOM_BRACKET_RANGE*sizeof(int));
- mMeasurementEnabled = false;
- mFaceDetectionRunning = false;
- mFaceDetectionPaused = false;
- mFDSwitchAlgoPriority = false;
-
- memset(&mCameraAdapterParameters.mCameraPortParams[mCameraAdapterParameters.mImagePortIndex], 0, sizeof(OMXCameraPortParameters));
- memset(&mCameraAdapterParameters.mCameraPortParams[mCameraAdapterParameters.mPrevPortIndex], 0, sizeof(OMXCameraPortParameters));
- memset(&mCameraAdapterParameters.mCameraPortParams[mCameraAdapterParameters.mVideoPortIndex], 0, sizeof(OMXCameraPortParameters));
- memset(&mCameraAdapterParameters.mCameraPortParams[mCameraAdapterParameters.mVideoInPortIndex], 0, sizeof(OMXCameraPortParameters));
-
- // 13.initialize 3A defaults
- mParameters3A.Effect = getLUTvalue_HALtoOMX(OMXCameraAdapter::DEFAULT_EFFECT, EffLUT);
- mParameters3A.FlashMode = getLUTvalue_HALtoOMX(OMXCameraAdapter::DEFAULT_FLASH_MODE, FlashLUT);
- mParameters3A.SceneMode = getLUTvalue_HALtoOMX(OMXCameraAdapter::DEFAULT_SCENE_MODE, SceneLUT);
- mParameters3A.EVCompensation = atoi(OMXCameraAdapter::DEFAULT_EV_COMPENSATION);
- mParameters3A.Focus = getLUTvalue_HALtoOMX(OMXCameraAdapter::DEFAULT_FOCUS_MODE, FocusLUT);
- mParameters3A.ISO = getLUTvalue_HALtoOMX(OMXCameraAdapter::DEFAULT_ISO_MODE, IsoLUT);
- mParameters3A.Flicker = getLUTvalue_HALtoOMX(OMXCameraAdapter::DEFAULT_ANTIBANDING, FlickerLUT);
- mParameters3A.Brightness = atoi(OMXCameraAdapter::DEFAULT_BRIGHTNESS);
- mParameters3A.Saturation = atoi(OMXCameraAdapter::DEFAULT_SATURATION) - SATURATION_OFFSET;
- mParameters3A.Sharpness = atoi(OMXCameraAdapter::DEFAULT_SHARPNESS) - SHARPNESS_OFFSET;
- mParameters3A.Contrast = atoi(OMXCameraAdapter::DEFAULT_CONTRAST) - CONTRAST_OFFSET;
- mParameters3A.WhiteBallance = getLUTvalue_HALtoOMX(OMXCameraAdapter::DEFAULT_WB, WBalLUT);
- mParameters3A.Exposure = getLUTvalue_HALtoOMX(OMXCameraAdapter::DEFAULT_EXPOSURE_MODE, ExpLUT);
- mParameters3A.ExposureLock = OMX_FALSE;
- mParameters3A.FocusLock = OMX_FALSE;
- mParameters3A.WhiteBalanceLock = OMX_FALSE;
-
- mParameters3A.ManualExposure = 0;
- mParameters3A.ManualExposureRight = 0;
- mParameters3A.ManualGain = 0;
- mParameters3A.ManualGainRight = 0;
-
- mParameters3A.AlgoFixedGamma = OMX_TRUE;
- mParameters3A.AlgoNSF1 = OMX_TRUE;
- mParameters3A.AlgoNSF2 = OMX_TRUE;
- mParameters3A.AlgoSharpening = OMX_TRUE;
- mParameters3A.AlgoThreeLinColorMap = OMX_TRUE;
- mParameters3A.AlgoGIC = OMX_TRUE;
-
- LOG_FUNCTION_NAME_EXIT;
- return ErrorUtils::omxToAndroidError(eError);
-
- EXIT:
-
- CAMHAL_LOGDB("Exiting function %s because of ret %d eError=%x", __FUNCTION__, ret, eError);
- performCleanupAfterError();
- LOG_FUNCTION_NAME_EXIT;
- return ErrorUtils::omxToAndroidError(eError);
- }
这里就是针对上面的这个过程进行全面分析,上面已经很清楚的标出了每一步,下面开始进入正题,唉,这个第二遍写这篇文章了,不知道怎么回事,之前写完了发布了,然后提示要审核,后来就再也没有消息了,我辛辛苦苦写好的文章啊!就这样没了,心痛,一直把这里当做学习的记事本,把自己的技术思路总结出来,希望ChinaUnix改进吧,越做越好!!
现在开始正文:
/ / 1 . OMX_Init 这里从字面就可以知道这个方法到底是干什么的,看看TI给他的说明吧
- /** The OMX_Init method is used to initialize the OMX core. It shall be the
- first call made into OMX and it should only be executed one time without
- an interviening OMX_Deinit call.
-
- The core should return from this call within 20 msec.
-
- @return OMX_ERRORTYPE
- If the command successfully executes, the return code will be
- OMX_ErrorNone. Otherwise the appropriate OMX error will be returned.
- @ingroup core
- */
- OMX_API OMX_ERRORTYPE OMX_APIENTRY OMX_Init(void);
上面说的很清楚,这个方法用来initialize OMX core,只能调用一次除非使用过了OMX_Diniit
/ / 2 . Initialize the callback handles callbacks.EventHandler = android::OMXCameraAdapterEventHandler;
callbacks.EmptyBufferDone = android::OMXCameraAdapterEmptyBufferDone;
callbacks.FillBufferDone = android::OMXCameraAdapterFillBufferDone;
这里这三个函数的引入很低调,但是却很重要,那叫相当重要啊
- typedef struct OMX_CALLBACKTYPE
- {
- /** The EventHandler method is used to notify the application when an
- event of interest occurs. Events are defined in the OMX_EVENTTYPE
- enumeration. Please see that enumeration for details of what will
- be returned for each type of event. Callbacks should not return
- an error to the component, so if an error occurs, the application
- shall handle it internally. This is a blocking call.
-
- The application should return from this call within 5 msec to avoid
- blocking the component for an excessively long period of time.
-
- @param hComponent
- handle of the component to access. This is the component
- handle returned by the call to the GetHandle function.
- @param pAppData
- pointer to an application defined value that was provided in the
- pAppData parameter to the OMX_GetHandle method for the component.
- This application defined value is provided so that the application
- can have a component specific context when receiving the callback.
- @param eEvent
- Event that the component wants to notify the application about.
- @param nData1
- nData will be the OMX_ERRORTYPE for an error event and will be
- an OMX_COMMANDTYPE for a command complete event and OMX_INDEXTYPE for a OMX_PortSettingsChanged event.
- @param nData2
- nData2 will hold further information related to the event. Can be OMX_STATETYPE for
- a OMX_CommandStateSet command or port index for a OMX_PortSettingsChanged event.
- Default value is 0 if not used. )
- @param pEventData
- Pointer to additional event-specific data (see spec for meaning).
- */
-
- OMX_ERRORTYPE (*EventHandler)(
- OMX_IN OMX_HANDLETYPE hComponent,
- OMX_IN OMX_PTR pAppData,
- OMX_IN OMX_EVENTTYPE eEvent,
- OMX_IN OMX_U32 nData1,
- OMX_IN OMX_U32 nData2,
- OMX_IN OMX_PTR pEventData);
-
- /** The EmptyBufferDone method is used to return emptied buffers from an
- input port back to the application for reuse. This is a blocking call
- so the application should not attempt to refill the buffers during this
- call, but should queue them and refill them in another thread. There
- is no error return, so the application shall handle any errors generated
- internally.
-
- The application should return from this call within 5 msec.
-
- @param hComponent
- handle of the component to access. This is the component
- handle returned by the call to the GetHandle function.
- @param pAppData
- pointer to an application defined value that was provided in the
- pAppData parameter to the OMX_GetHandle method for the component.
- This application defined value is provided so that the application
- can have a component specific context when receiving the callback.
- @param pBuffer
- pointer to an OMX_BUFFERHEADERTYPE structure allocated with UseBuffer
- or AllocateBuffer indicating the buffer that was emptied.
- @ingroup buf
- */
- OMX_ERRORTYPE (*EmptyBufferDone)(
- OMX_IN OMX_HANDLETYPE hComponent,
- OMX_IN OMX_PTR pAppData,
- OMX_IN OMX_BUFFERHEADERTYPE* pBuffer);
-
- /** The FillBufferDone method is used to return filled buffers from an
- output port back to the application for emptying and then reuse.
- This is a blocking call so the application should not attempt to
- empty the buffers during this call, but should queue the buffers
- and empty them in another thread. There is no error return, so
- the application shall handle any errors generated internally. The
- application shall also update the buffer header to indicate the
- number of bytes placed into the buffer.
-
- The application should return from this call within 5 msec.
-
- @param hComponent
- handle of the component to access. This is the component
- handle returned by the call to the GetHandle function.
- @param pAppData
- pointer to an application defined value that was provided in the
- pAppData parameter to the OMX_GetHandle method for the component.
- This application defined value is provided so that the application
- can have a component specific context when receiving the callback.
- @param pBuffer
- pointer to an OMX_BUFFERHEADERTYPE structure allocated with UseBuffer
- or AllocateBuffer indicating the buffer that was filled.
- @ingroup buf
- */
- OMX_ERRORTYPE (*FillBufferDone)(
- OMX_OUT OMX_HANDLETYPE hComponent,
- OMX_OUT OMX_PTR pAppData,
- OMX_OUT OMX_BUFFERHEADERTYPE* pBuffer);
-
- } OMX_CALLBACKTYPE;
第二遍写就是没动力啊,不翻译了,很容易理解的,三个很重要的回调函数
/ / 3 . Get the handle to the OMX Component 通过这个方法获得组件的handle,在相当于应用程序访问文件获得的句柄fd
- OMX_ERRORTYPE OMXCameraAdapter::OMXCameraGetHandle(OMX_HANDLETYPE *handle, OMX_PTR pAppData,
- const OMX_CALLBACKTYPE & callbacks)
- {
- OMX_ERRORTYPE eError = OMX_ErrorUndefined;
-
- for ( int i = 0; i < 5; ++i ) {
- if ( i > 0 ) {
- // sleep for 100 ms before next attempt
- usleep(100000);
- }
-
- // setup key parameters to send to Ducati during init
- OMX_CALLBACKTYPE oCallbacks = callbacks;
-
- // get handle
- eError = OMX_GetHandle(handle, (OMX_STRING)"OMX.TI.DUCATI1.VIDEO.CAMERA", pAppData, &oCallbacks);
- if ( eError == OMX_ErrorNone ) {
- return OMX_ErrorNone;
- }
-
- CAMHAL_LOGEB("OMX_GetHandle() failed, error: 0x%x", eError);
- }
-
- *handle = 0;
- return eError;
- }
上面直接调用接口中的方法获取handle
- /** The OMX_GetHandle method will locate the component specified by the
- component name given, load that component into memory and then invoke
- the component's methods to create an instance of the component.
-
- The core should return from this call within 20 msec.
-
- @param [out] pHandle
- pointer to an OMX_HANDLETYPE pointer to be filled in by this method.
- @param [in] cComponentName
- pointer to a null terminated string with the component name. The
- names of the components are strings less than 127 bytes in length
- plus the trailing null for a maximum size of 128 bytes. An example
- of a valid component name is "OMX.TI.AUDIO.DSP.MIXER\0". Names are
- assigned by the vendor, but shall start with "OMX." and then have
- the Vendor designation next.
- @param [in] pAppData
- pointer to an application defined value that will be returned
- during callbacks so that the application can identify the source
- of the callback.
- @param [in] pCallBacks
- pointer to a OMX_CALLBACKTYPE structure that will be passed to the
- component to initialize it with.
- @return OMX_ERRORTYPE
- If the command successfully executes, the return code will be
- OMX_ErrorNone. Otherwise the appropriate OMX error will be returned.
- @ingroup core
- */
- OMX_API OMX_ERRORTYPE OMX_APIENTRY OMX_GetHandle(
- OMX_OUT OMX_HANDLETYPE* pHandle,
- OMX_IN OMX_STRING cComponentName,
- OMX_IN OMX_PTR pAppData,
- OMX_IN OMX_CALLBACKTYPE* pCallBacks);
自己看注释吧
// 4.设置component的初始状态 前面介绍OMX的时候已经说过了,使用OMX要按照规矩办事,有指定的流程的
这里就是初始化这个状态,使组件状态为最初状态,就好像睡觉前先脱好衣服一样
// 5.disable所有的component
这里调用了一个方法是我们关注的重点,调用这个方法实现的功能其实已经说的很清楚了,不就是disable 所有组件吗
但是这个还是很有必要分析一下这个OMX_SendCommand的,算了还是看注释吧,之前我也只是翻译总结一下而已
- /** Send a command to the component. This call is a non-blocking call.
- The component should check the parameters and then queue the command
- to the component thread to be executed. The component thread shall
- send the EventHandler() callback at the conclusion of the command.
- This macro will go directly from the application to the component (via
- a core macro). The component will return from this call within 5 msec.
-
- When the command is "OMX_CommandStateSet" the component will queue a
- state transition to the new state idenfied in nParam.
-
- When the command is "OMX_CommandFlush", to flush a port's buffer queues,
- the command will force the component to return all buffers NOT CURRENTLY
- BEING PROCESSED to the application, in the order in which the buffers
- were received.
-
- When the command is "OMX_CommandPortDisable" or
- "OMX_CommandPortEnable", the component's port (given by the value of
- nParam) will be stopped or restarted.
-
- When the command "OMX_CommandMarkBuffer" is used to mark a buffer, the
- pCmdData will point to a OMX_MARKTYPE structure containing the component
- handle of the component to examine the buffer chain for the mark. nParam1
- contains the index of the port on which the buffer mark is applied.
-
- Specification text for more details.
-
- @param [in] hComponent
- handle of component to execute the command
- @param [in] Cmd
- Command for the component to execute
- @param [in] nParam
- Parameter for the command to be executed. When Cmd has the value
- OMX_CommandStateSet, value is a member of OMX_STATETYPE. When Cmd has
- the value OMX_CommandFlush, value of nParam indicates which port(s)
- to flush. -1 is used to flush all ports a single port index will
- only flush that port. When Cmd has the value "OMX_CommandPortDisable"
- or "OMX_CommandPortEnable", the component's port is given by
- the value of nParam. When Cmd has the value "OMX_CommandMarkBuffer"
- the components pot is given by the value of nParam.
- @param [in] pCmdData
- Parameter pointing to the OMX_MARKTYPE structure when Cmd has the value
- "OMX_CommandMarkBuffer".
- @return OMX_ERRORTYPE
- If the command successfully executes, the return code will be
- OMX_ErrorNone. Otherwise the appropriate OMX error will be returned.
- @ingroup comp
- */
- #define OMX_SendCommand( \
- hComponent, \
- Cmd, \
- nParam, \
- pCmdData) \
- ((OMX_COMPONENTTYPE*)hComponent)->SendCommand( \
- hComponent, \
- Cmd, \
- nParam, \
- pCmdData) /* Macro End */
// 6.Register for port enable event
这里还是坚持说一下吧
RegisterForEvent(mCameraAdapterParameters.mHandleComp,
OMX_EventCmdComplete,
OMX_CommandPortEnable,
mCameraAdapterParameters.mPrevPortIndex,
mInitSem);
上面的这几个传入的参数还是先有个印象吧,之后要有用的
- status_t OMXCameraAdapter::RegisterForEvent(OMX_IN OMX_HANDLETYPE hComponent,
- OMX_IN OMX_EVENTTYPE eEvent,
- OMX_IN OMX_U32 nData1,
- OMX_IN OMX_U32 nData2,
- OMX_IN Semaphore &semaphore)
- {
- status_t ret = NO_ERROR;
- ssize_t res;
- Mutex::Autolock lock(mEventLock);
-
- LOG_FUNCTION_NAME;
- TIUTILS::Message * msg = ( struct TIUTILS::Message * ) malloc(sizeof(struct TIUTILS::Message));
- if ( NULL != msg )
- {
- msg->command = ( unsigned int ) eEvent;
- msg->arg1 = ( void * ) nData1;
- msg->arg2 = ( void * ) nData2;
- msg->arg3 = ( void * ) &semaphore;
- msg->arg4 = ( void * ) hComponent;
- res = mEventSignalQ.add(msg);
- if ( NO_MEMORY == res )
- {
- CAMHAL_LOGEA("No ressources for inserting OMX events");
- free(msg);
- ret = -ENOMEM;
- }
- }
-
- LOG_FUNCTION_NAME_EXIT;
-
- return ret;
- }
这里只是把我们传入的数据打包成一个Message,让后把这个消息添加到mEventSignalQ队列中,接着往下看,重点在后面呢?
/ / 7 . Enable PREVIEW Port 这个调用之前分析过的OMX_SendCommand方法enable 组件的preview port
/ / 8 . Wait for the port enable event to occur 这里到了我们的重点了,上面第七步调用了OMX_SendCommand这个方法,组件在完成处理后实际上会给应用层一个应答,这个应答是通过我们上面说过的一个callback来通知应用层的,所以这里我们看看这个处理回调方法的实现:
/ / 9 . Select the sensor / / 10 . 初始化默认参数 / / 11 . initialize command handling thread / / 12 . initialize omx callback handling thread / / 13 . initialize 3A defaults 待填充内容。。。。。。
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