2025年MTK平台闪光灯相关信息

大家好，我是讯享网，很高兴认识大家。

（1）概念

MTK打闪一般分为预闪、主闪两个阶段。相应的执行一次拍照会有预闪、主闪两次开灯。预闪可以用来防红眼(red-eye reduction)。闪光时使环境发生变化，会按新的光线条件（有闪光时）重新测光，来实现更精确；
预闪是开灯让AE/AF收敛，其持续的时间取决于AF/AF收敛的速度，Flash本身没有控制预闪时间长短的能力。理论上环境亮度越暗，对应的Sensor Framerate越低，AE/AF收敛的时间就越长(AE收敛完之后，才会做AF收敛)。预闪阶段会提前计算主闪时会使用的参数(AE/AWB/AF/Duty)。
主闪是在Capture阶段去开灯，一般flow至少会亮三张Frame，在第三帧P1 Done关灯。主闪Duty, doCap要使用的AE参数、AWB权重、AF lock focus都是在预闪阶段就决定了。所以主闪的持续时间相对比预闪的会短一些，电流强度也会稍微高一点。

这里我们以普通的mt6761为例，可以查看部分代码的设置。

（2）闪光灯Hal逻辑代码

//vendor/mediatek/proprietary/hardware/mtkcam/aaa/source/common/flash_mgr/flash_hal.cpp int FlashHal::getTorchStatus() { 
    logI("getTorchStatus(): torch status(%d).", mTorchStatus); return mTorchStatus; } int FlashHal::setTorchOnOff(MBOOL enable) { 
    logI("[CAT][flash] setTorchOnOff(): type:%d enable:%d", mStrobeTypeId, enable); if (mStrobeTypeId == STROBE_TYPE_FRONT && !cust_isSubFlashSupport()) return 1; if (enable == 1) { 
    init(); setInCharge(1); setOnOff(enable, FLASH_HAL_SCENARIO_TORCH); mTorchStatus = 1; } else { 
    setOnOff(enable, FLASH_HAL_SCENARIO_TORCH); setInCharge(0); uninit(); mTorchStatus = 0; } return 0; } int FlashHal::setVideoTorchOnOff(int enable) { 
    logI("setVideoTorchOnOff(): enable(%d).", enable); setOnOff(enable, FLASH_HAL_SCENARIO_VIDEO_TORCH); return 0; } int FlashHal::setAfLampOnOff(int enable) { 
    logI("setAfLampOnOff(): enable(%d).", enable); setOnOff(enable, FLASH_HAL_SCENARIO_AF_LAMP); return 0; } int FlashHal::setPfOnOff(int enable) { 
    logI("setPfOnOff(): enable(%d).", enable); setOnOff(enable, FLASH_HAL_SCENARIO_PRE_FLASH); return 0; } int FlashHal::setCaptureFlashOnOff(int enable) { 
    logI("setCaptureFlashOnOff(): enable(%d).", enable); setOnOff(enable, FLASH_HAL_SCENARIO_MAIN_FLASH); return 0; } int FlashHal::setTorchDuty(int level) { 
    int duty = 0, dutyLt = 0; logI("setTorchLevel(): level(%d).", level); mTorchLevel = level; FlashCustomAdapter::getInstance(mSensorDev)->getTorchDuty(level, &duty, &dutyLt); mpStrobe->setDuty(duty); if (mStrobeCtNum > 1) { 
    mpStrobe2->setDuty(dutyLt); } return 0; } //setOnOff int FlashHal::setOnOff(int enable, FLASH_HAL_SCENARIO_ENUM scenario) { 
    logI("[CAT][flash] setOnOff(): type:%d enable:%d scenario:%d", mStrobeTypeId, enable, scenario); /* verify arguments */ if (verifyScenario(scenario)) { 
    logE("setOnOff(): invalid arguments."); return -1; } if (!isAvailable()) { 
    logI("setOnOff(): sensorDev(%d) not available.", mSensorDev); return -1; } if (scenario == FLASH_HAL_SCENARIO_MAIN_FLASH) { 
    //... } else if (scenario == FLASH_HAL_SCENARIO_VIDEO_TORCH) { 
    //... } if (enable) return setFlashOn(mFlashHalInfo[scenario]); else return setFlashOff(); }

讯享网

（3）关闭真闪配置

讯享网//vendor/mediatek/proprietary/custom/mt6761/hal/camera_3a/flashawb_tuning_custom.cpp MBOOL isFlashAWBv2Enabled(MINT32 i4SensorDev) { 
    switch (i4SensorDev) { 
    case NSIspTuning::ESensorDev_Main: // Main Sensor return MTRUE;//MFALSE case NSIspTuning::ESensorDev_MainSecond: // Main Second Sensor return MTRUE; case NSIspTuning::ESensorDev_Sub: // Sub Sensor return MTRUE; case NSIspTuning::ESensorDev_SubSecond: // Sub Second Sensor return MTRUE; default: return MTRUE; } }

（4）默认关闭双闪通道，并进行闪光灯校准

//kernel-4.19/arch/arm64/boot/dts/mediatek/mt6761.dts flashlight_core: flashlight_core { 
    compatible = "mediatek,flashlight_core"; }; flashlights_mt6370: flashlights_mt6370 { 
    compatible = "mediatek,flashlights_mt6370"; decouple = <1>;//默认为0，需要配置为1 channel@1 { 
    type = <0>; ct = <0>; part = <0>; }; }; flashlights_aw3644: flashlights_aw3644 { 
    compatible = "mediatek,flashlights_aw3644"; };

讯享网//vendor/mediatek/proprietary/custom/mt6761/hal/flashlight/flash_custom.cpp int cust_isDualFlashSupport(int sensorDev) { 
    if(sensorDev == DUAL_CAMERA_MAIN_SENSOR || sensorDev == DUAL_CAMERA_MAIN_2_SENSOR) return 0; else return 0; return 0; }

如下修改为闪光灯校准：vendor/mediatek/proprietary/custom/mt6761/hal/flashlight/flash_tuning_custom_cct.cpp

在这里插入图片描述
讯享网

（5）闪光灯亮度相关参数

//vendor/mediatek/proprietary/custom/mt6761/hal/flashlight //flash_tuning_custom_cct.cpp //-------------------- //eng level //index mode //torch p->engLevel.torchDuty = 6;//手电筒亮度 //af p->engLevel.afDuty = 6;//对焦闪光灯亮度 //pf, mf, normal p->engLevel.pfDuty = 6;//预闪亮度 p->engLevel.mfDutyMax = 27;//主闪亮度范围值 p->engLevel.mfDutyMin = 0; //...

（6）闪光灯打闪Log分析

（A）main Log查看（3次打闪）

打闪几次可通过如下Log判断。

讯享网W TaskMgr : [sendEvent] TaskEvent:TouchAEStart, fgLampflashCond(1)/bCustEnableFlash(1)/bStrobeBVTrigger(1) W TaskMgr : [sendEvent] TaskEvent:TouchAEStart, fgLampflashCond(1)/bCustEnableFlash(1)/bStrobeBVTrigger(1) W TaskMgr : [sendEvent] TaskEvent:TouchAEStart, fgLampflashCond(1)/bCustEnableFlash(1)/bStrobeBVTrigger(1)

另可通过如下源码查看调用过程。

//vendor/mediatek/proprietary/hardware/mtkcam/aaa/source/isp_30/ae_mgr/ae_mgr.cpp MBOOL AeMgr::IsStrobeBVTrigger() { 
    MBOOL bStrobeBVTrigger; MINT32 i4Bv = 0; if (m_rAEInitInput.rAEPARAM.strAEParasetting.bEV0TriggerStrobe == MTRUE) { 
    // The strobe trigger by the EV 0 index i4Bv = m_BVvalueWOStrobe; } else { 
    if (m_rAEInitInput.rAEPARAM.pEVValueArray[m_eAEEVcomp]) { 
    if (m_pIAeAlgo != NULL) { 
    i4Bv = m_BVvalueWOStrobe + m_pIAeAlgo->getSenstivityDeltaIndex(1024 * 1024 / m_rAEInitInput.rAEPARAM.pEVValueArray[m_eAEEVcomp]); } else { 
    i4Bv = m_BVvalueWOStrobe; AE_LOG("[%s()] The AE algo class is NULL, i4SensorDev:%d line:%d\n", __FUNCTION__, m_eSensorDev, __LINE__); } } } bStrobeBVTrigger = (i4Bv < m_CurrentCaptureTable.i4StrobeTrigerBV)?MTRUE:MFALSE; AE_LOG_IF(m_3ALogEnable, "[%s()] i4SensorDev:%d bStrobeBVTrigger:%d BV:%d %d\n", __FUNCTION__, m_eSensorDev, bStrobeBVTrigger, i4Bv, m_CurrentCaptureTable.i4StrobeTrigerBV); return bStrobeBVTrigger; }

可通过如上Code中的bStrobeBVTrigger字段来查看当前环境值和打闪阈值。

讯享网D ae_mgr : [IsStrobeBVTrigger()] i4SensorDev:1 bStrobeBVTrigger:0 BV:11 -28 D ae_mgr : [IsStrobeBVTrigger()] i4SensorDev:1 bStrobeBVTrigger:0 BV:10 -28 D ae_mgr : [IsStrobeBVTrigger()] i4SensorDev:1 bStrobeBVTrigger:1 BV:-36 -28 D ae_mgr : [IsStrobeBVTrigger()] i4SensorDev:1 bStrobeBVTrigger:0 BV:-2 -28

备注：具体打闪阈值通过效果文件来控制。

//camera_AE_PLineTable_xxxxraw.h static constexpr strAETable g_AE_PreviewAutoTable = { 
    AETABLE_RPEVIEW_AUTO, //eAETableID 147, //u4TotalIndex -28, //i4StrobeTrigerBV //为当前配置的打闪阈值 102, //i4MaxBV -44, //i4MinBV, Original:-45 90, //i4EffectiveMaxBV -30, //i4EffectiveMinBV LIB3A_AE_ISO_SPEED_AUTO, //ISO sPreviewPLineTable_60Hz, sPreviewPLineTable_50Hz, NULL, };

（B）kernel Log查看（3次打闪）

讯享网//预闪 kernel_log_6__2023_0613_:10220: <7>[ 2188.] (0)[7550:3AEventThd]flashlight: _flashlight_ioctl: FLASH_IOC_SET_ONOFF(0,0,0): 1 kernel_log_6__2023_0613_:11035: <7>[ 2189.] (2)[7550:3AEventThd]flashlight: _flashlight_ioctl: FLASH_IOC_SET_ONOFF(0,0,0): 0 //主闪 kernel_log_6__2023_0613_:11260: <7>[ 2190.] (0)[7467:3ATHREAD]flashlight: _flashlight_ioctl: FLASH_IOC_SET_ONOFF(0,0,0): 1 kernel_log_6__2023_0613_:11305: <7>[ 2190.] (3)[7512:CAM_P1]flashlight: _flashlight_ioctl: FLASH_IOC_SET_ONOFF(0,0,0): 0 kernel_log_6__2023_0613_:11463: <7>[ 2190.] (1)[7467:3ATHREAD]flashlight: _flashlight_ioctl: FLASH_IOC_SET_ONOFF(0,0,0): 0 kernel_log_6__2023_0613_:12779: <7>[ 2193.] (1)[7639:3AEventThd]flashlight: _flashlight_ioctl: FLASH_IOC_SET_ONOFF(0,0,0): 1 kernel_log_6__2023_0613_:13307: <7>[ 2194.] (3)[7639:3AEventThd]flashlight: _flashlight_ioctl: FLASH_IOC_SET_ONOFF(0,0,0): 0 kernel_log_6__2023_0613_:13497: <7>[ 2194.] (0)[7467:3ATHREAD]flashlight: _flashlight_ioctl: FLASH_IOC_SET_ONOFF(0,0,0): 1 kernel_log_6__2023_0613_:13542: <7>[ 2195.016548] (1)[7512:CAM_P1]flashlight: _flashlight_ioctl: FLASH_IOC_SET_ONOFF(0,0,0): 0 kernel_log_6__2023_0613_:13705: <7>[ 2195.] (2)[7467:3ATHREAD]flashlight: _flashlight_ioctl: FLASH_IOC_SET_ONOFF(0,0,0): 0 kernel_log_6__2023_0613_:15349: <7>[ 2198.] (2)[7653:3AEventThd]flashlight: _flashlight_ioctl: FLASH_IOC_SET_ONOFF(0,0,0): 1 kernel_log_6__2023_0613_:15942: <7>[ 2200.] (3)[7653:3AEventThd]flashlight: _flashlight_ioctl: FLASH_IOC_SET_ONOFF(0,0,0): 0 kernel_log_6__2023_0613_:16129: <7>[ 2200.] (3)[7467:3ATHREAD]flashlight: _flashlight_ioctl: FLASH_IOC_SET_ONOFF(0,0,0): 1 kernel_log_6__2023_0613_:16174: <7>[ 2200.] (0)[7512:CAM_P1]flashlight: _flashlight_ioctl: FLASH_IOC_SET_ONOFF(0,0,0): 0 kernel_log_6__2023_0613_:16347: <7>[ 2201.] (1)[7467:3ATHREAD]flashlight: _flashlight_ioctl: FLASH_IOC_SET_ONOFF(0,0,0): 0