第17讲 初始化vendortags, flashlight和perfclass -凯发k8手机登录

本讲是android camera native framework专题的第17讲，我们介绍cameraserver进程启动之初始化vendortags, flashlight和perfclass。

更多资源：

创建vendortagdescriptorcache

vendortagdescriptorcache是一个manager，管理不同provider里面的vendor tag descriptor，vendortagdescriptor维护管理所有vendor tags的section、name、type，id之间的关系：

android 13 代码逻辑：cameraprovidermanager::setupvendortags()

status_t cameraprovidermanager::setupvendortags() {
    sp tagcache = new vendortagdescriptorcache();
    for (auto& provider : mproviders) {
        tagcache->addvendordescriptor(provider->mprovidertagid, provider->mvendortagdescriptor);
    }
    vendortagdescriptorcache::setasglobalvendortagcache(tagcache);
    return ok;
}

flashlight初始化

cameraserver通过cameraflashlight来管理各cameradevice的flashlight，类图如下：

通过cameraflashlight::findflashunits完成flashlight的初始化，流程如下：

android 13代码，cameraflashlight::findflashunits：

status_t cameraflashlight::findflashunits() {
    mutex::autolock l(mlock);
    status_t res;
    std::vector cameraids;
    std::vector ids = mprovidermanager->getcameradeviceids();
    int numberofcameras = static_cast(ids.size());
    cameraids.resize(numberofcameras);
    // no module, must be provider
    for (size_t i = 0; i < cameraids.size(); i  ) {
        cameraids[i] = string8(ids[i].c_str());
    }
    mflashcontrol.clear();
    for (auto &id : cameraids) {
        ssize_t index = mhasflashlightmap.indexofkey(id);
        if (0 <= index) {
            continue;
        }
        bool hasflash = false;
        res = createflashlightcontrol(id);
        if (res) {
            aloge("%s: failed to create flash control for %s", __function__,
                    id.string());
        } else {
            res = mflashcontrol->hasflashunit(id, &hasflash);
            if (res == -eusers || res == -ebusy) {
                aloge("%s: failed to check if camera %s has a flash unit. some "
                        "camera devices may be opened", __function__,
                        id.string());
                return res;
            } else if (res) {
                aloge("%s: failed to check if camera %s has a flash unit. %s"
                        " (%d)", __function__, id.string(), strerror(-res),
                        res);
            }
            mflashcontrol.clear();
        }
        mhasflashlightmap.add(id, hasflash);
    }
    mflashlightmapinitialized = true;
    return ok;
}

为sperfclass过滤characteristics

执行条件：

• ro.odm.build.media_performance_class >= 31

执行动作：

• 针对主后置和主前置，过滤掉<1080p的jpeg尺寸

cts(sperfclasstest.java)：

• testsperfclassjpegsizesbycamera

流程：

android 13代码：

void cameraservice::filtersperfclasscharacteristicslocked() {
    // to claim to be s performance primary cameras, the cameras must be
    // backward compatible. so performance class primary camera ids must be api1
    // compatible.
    bool firstrearcameraseen = false, firstfrontcameraseen = false;
    for (const auto& cameraid : mnormaldeviceidswithoutsystemcamera) {
        int facing = -1;
        int orientation = 0;
        string8 cameraid8(cameraid.c_str());
        getdeviceversion(cameraid8, /*out*/&facing, /*out*/&orientation);
        if (facing == -1) {
            aloge("%s: unable to get camera device \"%s\" facing", __function__, cameraid.c_str());
            return;
        }
        if ((facing == hardware::camera_facing_back && !firstrearcameraseen) ||
                (facing == hardware::camera_facing_front && !firstfrontcameraseen)) {
            status_t res = mcameraprovidermanager->filtersmalljpegsizes(cameraid);
            if (res == ok) {
                mperfclassprimarycameraids.insert(cameraid);
            } else {
                aloge("%s: failed to filter small jpeg sizes for performance class primary "
                        "camera %s: %s(%d)", __function__, cameraid.c_str(), strerror(-res), res);
                break;
            }
            if (facing == hardware::camera_facing_back) {
                firstrearcameraseen = true;
            }
            if (facing == hardware::camera_facing_front) {
                firstfrontcameraseen = true;
            }
        }
        if (firstrearcameraseen && firstfrontcameraseen) {
            break;
        }
    }
}