android camera API1调用camera HAL3流程学习总结_hal1 hal3

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于 2024-05-16 14:05:52 发布

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通过上述代码分析发现API1+HAL3对用的client是Camera2Client
其类图如下：
在这里插入图片描述
从上边看Camera2Client继承实现了ICamera定义的camera API1接口，但是其内部的成员变量mDevice是`Camera3Device 类型,其是针对HAL3设计的，其类的备注如下：

/\*\*
 \* CameraDevice for HAL devices with version CAMERA\_DEVICE\_API\_VERSION\_3\_0 or higher.
 \*/
class Camera3Device :
            public CameraDeviceBase,
            virtual public hardware::camera::device::V3_2::ICameraDeviceCallback,
            private camera3_callback_ops

Camera3Device类图如下：

在这里插入图片描述
Camera3Device内部类HalInterface中的sp<hardware::camera::device::V3_2::ICameraDeviceSession>mHidlSession成员变量，是在opencamera是获取的对象，之后所有的constructDefaultRequestSettings，configureStreams等操作，都是通过该对象与HAL3进行通信完成的。
下边给出ICameraDeviceSession类图：
在这里插入图片描述
该类是定义在hardware\interfaces\camera\device中，是cameraservice与cameraprovider通信的接口。
下边分析 openCamera具体流程

从流程图上看，opencamera主要完成了两件事：

makeclient 创建camera2client对象及Camera3Device对象
初始化camera2client，真正完成打开相机的地方

从上述过程看，Camera2Client实现的是Camera API1的接口，在opencamera时，通过Camera3Device中的BpHwCameraDevice类型对象deviceInfo3->mInterface的open方法完成与HAL3通信来打开相机，并该方法返回结果为ICameraDeviceSession类型对象session，表示相机成功打开，之后所有的相机相关操作全是通过该对象完成。

2. startpreview

startPreview时序图如下：
在这里插入图片描述
从上述时序图看，startpreive过程主要有两个过程，

configureStreams
将request插入到mRepeatingRequests队列中，并启动RequestThread，向HAL层不断发送processCaptureRequest申请

3. takepicture

开启相机后会启动一个拍照处理线程mCaptureSequencer:

template<typename TProviderPtr>
status_t Camera2Client::initializeImpl(TProviderPtr providerPtr)
{
    ATRACE\_CALL();
    ALOGV("%s: Initializing client for camera %d", __FUNCTION__, mCameraId);
    status_t res;

res = Camera2ClientBase::initialize(providerPtr);
...

#ifdef USE_QTI_CAMERA2CLIENT
mQTICamera2Client = new QTICamera2Client(this);
#endif

mStreamingProcessor <span class="token operator">=</span> new <span class="token function">StreamingProcessor</span><span class="token punctuation">(</span>this<span class="token punctuation">)</span><span class="token punctuation">;</span>
threadName <span class="token operator">=</span> String8<span class="token punctuation">:</span><span class="token punctuation">:</span><span class="token function">format</span><span class="token punctuation">(</span><span class="token string">"C2-%d-StreamProc"</span><span class="token punctuation">,</span>
        mCameraId<span class="token punctuation">)</span><span class="token punctuation">;</span>

mFrameProcessor <span class="token operator">=</span> new <span class="token function">FrameProcessor</span><span class="token punctuation">(</span>mDevice<span class="token punctuation">,</span> this<span class="token punctuation">)</span><span class="token punctuation">;</span>
threadName <span class="token operator">=</span> String8<span class="token punctuation">:</span><span class="token punctuation">:</span><span class="token function">format</span><span class="token punctuation">(</span><span class="token string">"C2-%d-FrameProc"</span><span class="token punctuation">,</span>
        mCameraId<span class="token punctuation">)</span><span class="token punctuation">;</span>
mFrameProcessor<span class="token operator">-&gt;</span><span class="token function">run</span><span class="token punctuation">(</span>threadName<span class="token punctuation">.</span><span class="token function">string</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token comment">//创建拍照处理线程并启动</span>
mCaptureSequencer <span class="token operator">=</span> new <span class="token function">CaptureSequencer</span><span class="token punctuation">(</span>this<span class="token punctuation">)</span><span class="token punctuation">;</span>
threadName <span class="token operator">=</span> String8<span class="token punctuation">:</span><span class="token punctuation">:</span><span class="token function">format</span><span class="token punctuation">(</span><span class="token string">"C2-%d-CaptureSeq"</span><span class="token punctuation">,</span>
        mCameraId<span class="token punctuation">)</span><span class="token punctuation">;</span>
mCaptureSequencer<span class="token operator">-&gt;</span><span class="token function">run</span><span class="token punctuation">(</span>threadName<span class="token punctuation">.</span><span class="token function">string</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

mJpegProcessor <span class="token operator">=</span> new <span class="token function">JpegProcessor</span><span class="token punctuation">(</span>this<span class="token punctuation">,</span> mCaptureSequencer<span class="token punctuation">)</span><span class="token punctuation">;</span>
threadName <span class="token operator">=</span> String8<span class="token punctuation">:</span><span class="token punctuation">:</span><span class="token function">format</span><span class="token punctuation">(</span><span class="token string">"C2-%d-JpegProc"</span><span class="token punctuation">,</span>
        mCameraId<span class="token punctuation">)</span><span class="token punctuation">;</span>
mJpegProcessor<span class="token operator">-&gt;</span><span class="token function">run</span><span class="token punctuation">(</span>threadName<span class="token punctuation">.</span><span class="token function">string</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

#ifdef USE_QTI_CAMERA2CLIENT
mRawProcessor = new RawProcessor(this, mCaptureSequencer);
threadName = String8::format(“C2-%d-RawProc”,
mCameraId);
mRawProcessor->run(threadName.string());
#endif

mZslProcessor <span class="token operator">=</span> new <span class="token function">ZslProcessor</span><span class="token punctuation">(</span>this<span class="token punctuation">,</span> mCaptureSequencer<span class="token punctuation">)</span><span class="token punctuation">;</span>

threadName <span class="token operator">=</span> String8<span class="token punctuation">:</span><span class="token punctuation">:</span><span class="token function">format</span><span class="token punctuation">(</span><span class="token string">"C2-%d-ZslProc"</span><span class="token punctuation">,</span>
        mCameraId<span class="token punctuation">)</span><span class="token punctuation">;</span>
mZslProcessor<span class="token operator">-&gt;</span><span class="token function">run</span><span class="token punctuation">(</span>threadName<span class="token punctuation">.</span><span class="token function">string</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

mCallbackProcessor <span class="token operator">=</span> new <span class="token function">CallbackProcessor</span><span class="token punctuation">(</span>this<span class="token punctuation">)</span><span class="token punctuation">;</span>
threadName <span class="token operator">=</span> String8<span class="token punctuation">:</span><span class="token punctuation">:</span><span class="token function">format</span><span class="token punctuation">(</span><span class="token string">"C2-%d-CallbkProc"</span><span class="token punctuation">,</span>
        mCameraId<span class="token punctuation">)</span><span class="token punctuation">;</span>
mCallbackProcessor<span class="token operator">-&gt;</span><span class="token function">run</span><span class="token punctuation">(</span>threadName<span class="token punctuation">.</span><span class="token function">string</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token punctuation">.</span>
<span class="token keyword">return</span> OK<span class="token punctuation">;</span>

}

线程中包含有一个状态机，不断检测是否有拍照命令下发，
状态机状态定义如下：

    enum CaptureState {
        IDLE,
        START,
        ZSL_START,
        ZSL_WAITING,
        ZSL_REPROCESSING,
        STANDARD_START,
        STANDARD_PRECAPTURE_WAIT,
        STANDARD_CAPTURE,
        STANDARD_CAPTURE_WAIT,
        DONE,
        ERROR,
        NUM_CAPTURE_STATES
    } mCaptureState;

对应的状态处理函数定义如下：

const CaptureSequencer::StateManager
        CaptureSequencer::kStateManagers[CaptureSequencer::NUM_CAPTURE_STATES-1] = {
    &CaptureSequencer::manageIdle,
    &CaptureSequencer::manageStart,
    &CaptureSequencer::manageZslStart,
    &CaptureSequencer::manageZslWaiting,
    &CaptureSequencer::manageZslReprocessing,
    &CaptureSequencer::manageStandardStart,
    &CaptureSequencer::manageStandardPrecaptureWait,
    &CaptureSequencer::manageStandardCapture,
    &CaptureSequencer::manageStandardCaptureWait,
    &CaptureSequencer::manageDone,
};

在有拍照命令下发时，状态机进入下一状态START，否则一直停留在IDLE状态


bool CaptureSequencer::threadLoop() {

sp<Camera2Client> client = mClient.promote();
if (client == 0) return false;

CaptureState currentState;
{
Mutex::Autolock l(mStateMutex);
currentState = mCaptureState;
}
//状态机处理流程
currentState = (this->*kStateManagers[currentState])(client);