diff --git a/camera/device/default/ExternalCameraUtils.h b/camera/device/default/ExternalCameraUtils.h
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+++ b/camera/device/default/ExternalCameraUtils.h
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+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef HARDWARE_INTERFACES_CAMERA_DEVICE_DEFAULT_EXTERNALCAMERAUTILS_H_
+#define HARDWARE_INTERFACES_CAMERA_DEVICE_DEFAULT_EXTERNALCAMERAUTILS_H_
+
+#include <CameraMetadata.h>
+#include <HandleImporter.h>
+#include <aidl/android/hardware/camera/common/Status.h>
+#include <aidl/android/hardware/camera/device/CaptureResult.h>
+#include <aidl/android/hardware/camera/device/ErrorCode.h>
+#include <aidl/android/hardware/camera/device/NotifyMsg.h>
+#include <aidl/android/hardware/graphics/common/BufferUsage.h>
+#include <aidl/android/hardware/graphics/common/PixelFormat.h>
+#include <tinyxml2.h>
+#include <unordered_map>
+#include <unordered_set>
+
+using ::aidl::android::hardware::camera::common::Status;
+using ::aidl::android::hardware::camera::device::CaptureResult;
+using ::aidl::android::hardware::camera::device::ErrorCode;
+using ::aidl::android::hardware::camera::device::NotifyMsg;
+using ::aidl::android::hardware::graphics::common::BufferUsage;
+using ::aidl::android::hardware::graphics::common::PixelFormat;
+using ::android::hardware::camera::common::V1_0::helper::CameraMetadata;
+using ::android::hardware::camera::common::V1_0::helper::HandleImporter;
+
+namespace android {
+namespace hardware {
+namespace camera {
+
+namespace external {
+namespace common {
+
+struct Size {
+    int32_t width;
+    int32_t height;
+
+    bool operator==(const Size& other) const {
+        return (width == other.width && height == other.height);
+    }
+};
+
+struct SizeHasher {
+    size_t operator()(const Size& sz) const {
+        size_t result = 1;
+        result = 31 * result + sz.width;
+        result = 31 * result + sz.height;
+        return result;
+    }
+};
+
+struct ExternalCameraConfig {
+    static const char* kDefaultCfgPath;
+    static ExternalCameraConfig loadFromCfg(const char* cfgPath = kDefaultCfgPath);
+
+    // CameraId base offset for numerical representation
+    uint32_t cameraIdOffset;
+
+    // List of internal V4L2 video nodes external camera HAL must ignore.
+    std::unordered_set<std::string> mInternalDevices;
+
+    // Maximal size of a JPEG buffer, in bytes
+    int32_t maxJpegBufSize;
+
+    // Maximum Size that can sustain 30fps streaming
+    Size maxVideoSize;
+
+    // Size of v4l2 buffer queue when streaming <= kMaxVideoSize
+    uint32_t numVideoBuffers;
+
+    // Size of v4l2 buffer queue when streaming > kMaxVideoSize
+    uint32_t numStillBuffers;
+
+    // Indication that the device connected supports depth output
+    bool depthEnabled;
+
+    struct FpsLimitation {
+        Size size;
+        double fpsUpperBound;
+    };
+    std::vector<FpsLimitation> fpsLimits;
+    std::vector<FpsLimitation> depthFpsLimits;
+
+    // Minimum output stream size
+    Size minStreamSize;
+
+    // The value of android.sensor.orientation
+    int32_t orientation;
+
+  private:
+    ExternalCameraConfig();
+    static bool updateFpsList(tinyxml2::XMLElement* fpsList, std::vector<FpsLimitation>& fpsLimits);
+};
+
+}  // namespace common
+}  // namespace external
+
+namespace device {
+namespace implementation {
+
+struct SupportedV4L2Format {
+    int32_t width;
+    int32_t height;
+    uint32_t fourcc;
+    // All supported frame rate for this w/h/fourcc combination
+    struct FrameRate {
+        // Duration (in seconds) of a single frame.
+        // Numerator and denominator of the frame duration are stored separately.
+        // For ex. a frame lasting 1/30 of a second will be stored as {1, 30}
+        uint32_t durationNumerator;         // frame duration numerator.   Ex: 1
+        uint32_t durationDenominator;       // frame duration denominator. Ex: 30
+        double getFramesPerSecond() const;  // FPS as double.        Ex: 30.0
+    };
+    std::vector<FrameRate> frameRates;
+};
+
+// A Base class with basic information about a frame
+struct Frame : public std::enable_shared_from_this<Frame> {
+  public:
+    Frame(uint32_t width, uint32_t height, uint32_t fourcc);
+    virtual ~Frame();
+    const int32_t mWidth;
+    const int32_t mHeight;
+    const uint32_t mFourcc;
+
+    // getData might involve map/allocation
+    virtual int getData(uint8_t** outData, size_t* dataSize) = 0;
+};
+
+// A class provide access to a dequeued V4L2 frame buffer (mostly in MJPG format)
+// Also contains necessary information to enqueue the buffer back to V4L2 buffer queue
+class V4L2Frame : public Frame {
+  public:
+    V4L2Frame(uint32_t w, uint32_t h, uint32_t fourcc, int bufIdx, int fd, uint32_t dataSize,
+              uint64_t offset);
+    virtual ~V4L2Frame();
+
+    virtual int getData(uint8_t** outData, size_t* dataSize) override;
+
+    const int mBufferIndex;  // for later enqueue
+    int map(uint8_t** data, size_t* dataSize);
+    int unmap();
+
+  private:
+    std::mutex mLock;
+    const int mFd;  // used for mmap but doesn't claim ownership
+    const size_t mDataSize;
+    const uint64_t mOffset;  // used for mmap
+    uint8_t* mData = nullptr;
+    bool mMapped = false;
+};
+
+// A RAII class representing a CPU allocated YUV frame used as intermediate buffers
+// when generating output images.
+class AllocatedFrame : public Frame {
+  public:
+    AllocatedFrame(uint32_t w, uint32_t h);  // only support V4L2_PIX_FMT_YUV420 for now
+    ~AllocatedFrame() override;
+
+    virtual int getData(uint8_t** outData, size_t* dataSize) override;
+
+    int allocate(YCbCrLayout* out = nullptr);
+    int getLayout(YCbCrLayout* out);
+    int getCroppedLayout(const IMapper::Rect&, YCbCrLayout* out);  // return non-zero for bad input
+  private:
+    std::mutex mLock;
+    std::vector<uint8_t> mData;
+    size_t mBufferSize;  // size of mData before padding. Actual size of mData might be slightly
+                         // bigger to horizontally pad the frame for jpeglib.
+};
+
+enum CroppingType { HORIZONTAL = 0, VERTICAL = 1 };
+
+// Aspect ratio is defined as width/height here and ExternalCameraDevice
+// will guarantee all supported sizes has width >= height (so aspect ratio >= 1.0)
+#define ASPECT_RATIO(sz) (static_cast<float>((sz).width) / (sz).height)
+const float kMaxAspectRatio = std::numeric_limits<float>::max();
+const float kMinAspectRatio = 1.f;
+
+bool isAspectRatioClose(float ar1, float ar2);
+
+struct HalStreamBuffer {
+    int32_t streamId;
+    int64_t bufferId;
+    int32_t width;
+    int32_t height;
+    ::aidl::android::hardware::graphics::common::PixelFormat format;
+    ::aidl::android::hardware::graphics::common::BufferUsage usage;
+    buffer_handle_t* bufPtr;
+    int acquireFence;
+    bool fenceTimeout;
+};
+
+struct HalRequest {
+    int32_t frameNumber;
+    common::V1_0::helper::CameraMetadata setting;
+    std::shared_ptr<Frame> frameIn;
+    nsecs_t shutterTs;
+    std::vector<HalStreamBuffer> buffers;
+};
+
+static const uint64_t BUFFER_ID_NO_BUFFER = 0;
+
+// buffers currently circulating between HAL and camera service
+// key: bufferId sent via HIDL interface
+// value: imported buffer_handle_t
+// Buffer will be imported during processCaptureRequest (or requestStreamBuffer
+// in the case of HAL buffer manager is enabled) and will be freed
+// when the stream is deleted or camera device session is closed
+typedef std::unordered_map<uint64_t, buffer_handle_t> CirculatingBuffers;
+
+aidl::android::hardware::camera::common::Status importBufferImpl(
+        /*inout*/ std::map<int, CirculatingBuffers>& circulatingBuffers,
+        /*inout*/ HandleImporter& handleImporter, int32_t streamId, uint64_t bufId,
+        buffer_handle_t buf,
+        /*out*/ buffer_handle_t** outBufPtr);
+
+static const uint32_t FLEX_YUV_GENERIC =
+        static_cast<uint32_t>('F') | static_cast<uint32_t>('L') << 8 |
+        static_cast<uint32_t>('E') << 16 | static_cast<uint32_t>('X') << 24;
+
+// returns FLEX_YUV_GENERIC for formats other than YV12/YU12/NV12/NV21
+uint32_t getFourCcFromLayout(const YCbCrLayout&);
+
+using ::android::hardware::camera::external::common::Size;
+int getCropRect(CroppingType ct, const Size& inSize, const Size& outSize, IMapper::Rect* out);
+
+int formatConvert(const YCbCrLayout& in, const YCbCrLayout& out, Size sz, uint32_t format);
+
+int encodeJpegYU12(const Size& inSz, const YCbCrLayout& inLayout, int jpegQuality,
+                   const void* app1Buffer, size_t app1Size, void* out, size_t maxOutSize,
+                   size_t& actualCodeSize);
+
+Size getMaxThumbnailResolution(const common::V1_0::helper::CameraMetadata&);
+
+void freeReleaseFences(std::vector<CaptureResult>&);
+
+status_t fillCaptureResultCommon(common::V1_0::helper::CameraMetadata& md, nsecs_t timestamp,
+                                 camera_metadata_ro_entry& activeArraySize);
+
+// Interface for OutputThread calling back to parent
+struct OutputThreadInterface {
+    virtual ~OutputThreadInterface() {}
+    virtual aidl::android::hardware::camera::common::Status importBuffer(
+            int32_t streamId, uint64_t bufId, buffer_handle_t buf,
+            /*out*/ buffer_handle_t** outBufPtr) = 0;
+
+    virtual void notifyError(int32_t frameNumber, int32_t streamId, ErrorCode ec) = 0;
+
+    // Callbacks are fired within the method if msgs/results are nullptr.
+    // Otherwise the callbacks will be returned and caller is responsible to
+    // fire the callback later
+    virtual aidl::android::hardware::camera::common::Status processCaptureRequestError(
+            const std::shared_ptr<HalRequest>&,
+            /*out*/ std::vector<NotifyMsg>* msgs,
+            /*out*/ std::vector<CaptureResult>* results) = 0;
+
+    virtual aidl::android::hardware::camera::common::Status processCaptureRequestError(
+            const std::shared_ptr<HalRequest>& reqs) final {
+        return processCaptureRequestError(reqs, nullptr, nullptr);
+    }
+
+    virtual aidl::android::hardware::camera::common::Status processCaptureResult(
+            std::shared_ptr<HalRequest>&) = 0;
+
+    virtual ssize_t getJpegBufferSize(int32_t width, int32_t height) const = 0;
+};
+
+// A CPU copy of a mapped V4L2Frame. Will map the input V4L2 frame.
+class AllocatedV4L2Frame : public Frame {
+  public:
+    AllocatedV4L2Frame(std::shared_ptr<V4L2Frame> frameIn);
+    ~AllocatedV4L2Frame() override;
+    virtual int getData(uint8_t** outData, size_t* dataSize) override;
+
+  private:
+    std::vector<uint8_t> mData;
+};
+
+}  // namespace implementation
+}  // namespace device
+}  // namespace camera
+}  // namespace hardware
+}  // namespace android
+
+#endif  // HARDWARE_INTERFACES_CAMERA_DEVICE_DEFAULT_EXTERNALCAMERAUTILS_H_