目录

Video Recording Practices (C/C++)

Before developing a camera application, you must request required permissions.

This example provides an introduction to the complete recording process and the sequence of API calls. For details about individual processes (such as device input, session management, and recording), refer to the corresponding sections.

Development Process

After obtaining the output stream capabilities supported by the camera, create a video stream. The development process is as follows:

Complete Sample Code

  1. Link the dynamic library in the CMake script.

    target_link_libraries(entry PUBLIC
    libace_napi.z.so
    libohcamera.so
    libhilog_ndk.z.so
)

  2. Create the header file ndk_camera.h.

    #include "ohcamera/camera.h"
#include "ohcamera/camera_input.h"
#include "ohcamera/capture_session.h"
#include "ohcamera/photo_output.h"
#include "ohcamera/preview_output.h"
#include "ohcamera/video_output.h"
#include "ohcamera/camera_manager.h"

class NDKCamera {
public:
    ~NDKCamera();
    NDKCamera(char* previewId, char* videoId);
};

  3. Import the NDK APIs on the C++ side, and perform video recording based on the surface ID passed in.

    #include "hilog/log.h"
#include "ndk_camera.h"
#include <cmath>

bool IsAspectRatioEqual(float videoAspectRatio, float previewAspectRatio)
{
    float epsilon = 1e-6f;
    return fabsf(videoAspectRatio - previewAspectRatio) <= epsilon;
}

void OnCameraInputError(const Camera_Input* cameraInput, Camera_ErrorCode errorCode)
{
    OH_LOG_ERROR(LOG_APP, "OnCameraInput errorCode = %{public}d", errorCode);
}

CameraInput_Callbacks* GetCameraInputListener(void)
{
    static CameraInput_Callbacks cameraInputCallbacks = {
        .onError = OnCameraInputError
    };
    return &cameraInputCallbacks;
}

void CaptureSessionOnFocusStateChange(Camera_CaptureSession* session, Camera_FocusState focusState)
{
    OH_LOG_INFO(LOG_APP, "CaptureSessionOnFocusStateChange");
}

void CaptureSessionOnError(Camera_CaptureSession* session, Camera_ErrorCode errorCode)
{
    OH_LOG_ERROR(LOG_APP, "CaptureSessionOnError = %{public}d", errorCode);
}

CaptureSession_Callbacks* GetCaptureSessionRegister(void)
{
    static CaptureSession_Callbacks captureSessionCallbacks = {
        .onFocusStateChange = CaptureSessionOnFocusStateChange,
        .onError = CaptureSessionOnError
    };
    return &captureSessionCallbacks;
}

void VideoOutputOnFrameStart(Camera_VideoOutput* videoOutput)
{
    OH_LOG_INFO(LOG_APP, "VideoOutputOnFrameStart");
}

void VideoOutputOnFrameEnd(Camera_VideoOutput* videoOutput, int32_t frameCount)
{
    OH_LOG_INFO(LOG_APP, "VideoOutput frameCount = %{public}d", frameCount);
}

void VideoOutputOnError(Camera_VideoOutput* videoOutput, Camera_ErrorCode errorCode)
{
    OH_LOG_ERROR(LOG_APP, "VideoOutput errorCode = %{public}d", errorCode);
}

VideoOutput_Callbacks* GetVideoOutputListener(void)
{
    static VideoOutput_Callbacks videoOutputListener = {
        .onFrameStart = VideoOutputOnFrameStart,
        .onFrameEnd = VideoOutputOnFrameEnd,
        .onError = VideoOutputOnError
    };
    return &videoOutputListener;
}

void CameraManagerStatusCallback(Camera_Manager* cameraManager, Camera_StatusInfo* status)
{
    OH_LOG_INFO(LOG_APP, "CameraManagerStatusCallback is called");
}

CameraManager_Callbacks* GetCameraManagerListener()
{
    static CameraManager_Callbacks cameraManagerListener = {
        .onCameraStatus = CameraManagerStatusCallback
    };
    return &cameraManagerListener;
}

NDKCamera::NDKCamera(char* previewId, char* videoId)
{
    Camera_Manager* cameraManager = nullptr;
    Camera_Device* cameras = nullptr;
    Camera_CaptureSession* captureSession = nullptr;
    Camera_OutputCapability* cameraOutputCapability = nullptr;
    Camera_VideoOutput* videoOutput = nullptr;
    const Camera_Profile* previewProfile = nullptr;
    const Camera_Profile* photoProfile = nullptr;
    const Camera_VideoProfile* videoProfile = nullptr;
    Camera_PreviewOutput* previewOutput = nullptr;
    Camera_PhotoOutput* photoOutput = nullptr;
    Camera_Input* cameraInput = nullptr;
    uint32_t size = 0;
    uint32_t cameraDeviceIndex = 0;
    char* videoSurfaceId = videoId;
    char* previewSurfaceId = previewId;
    // Create a CameraManager object.
    Camera_ErrorCode ret = OH_Camera_GetCameraManager(&cameraManager);
    if (cameraManager == nullptr || ret != CAMERA_OK) {
        OH_LOG_ERROR(LOG_APP, "OH_Camera_GetCameraManager failed.");
        return;
    }
    // Listen for camera status changes.
    ret = OH_CameraManager_RegisterCallback(cameraManager, GetCameraManagerListener());
    if (ret != CAMERA_OK) {
        OH_LOG_ERROR(LOG_APP, "OH_CameraManager_RegisterCallback failed.");
        return;
    }

    // Obtain the camera list.
    ret = OH_CameraManager_GetSupportedCameras(cameraManager, &cameras, &size);
    if (cameras == nullptr || size <= 0 || ret != CAMERA_OK) {
        OH_LOG_ERROR(LOG_APP, "OH_CameraManager_GetSupportedCameras failed.");
        return;
    }

    for (int index = 0; index < size; index++) {
        OH_LOG_INFO(LOG_APP, "cameraId  =  %{public}s ", cameras[index].cameraId);              // Obtain the camera ID.
        OH_LOG_INFO(LOG_APP, "cameraPosition  =  %{public}d ", cameras[index].cameraPosition);  // Obtain the camera position.
        OH_LOG_INFO(LOG_APP, "cameraType  =  %{public}d ", cameras[index].cameraType);          // Obtain the camera type.
        OH_LOG_INFO(LOG_APP, "connectionType  =  %{public}d ", cameras[index].connectionType);  // Obtain the camera connection type.
    }

    if (size < cameraDeviceIndex + 1) {
        OH_LOG_ERROR(LOG_APP, "cameraDeviceIndex is invalid.");
        return;
    }

    // Obtain the output stream capability supported by the camera.
    ret = OH_CameraManager_GetSupportedCameraOutputCapability(cameraManager, &cameras[cameraDeviceIndex],
                                                            &cameraOutputCapability);
    if (cameraOutputCapability == nullptr || ret != CAMERA_OK) {
        OH_LOG_ERROR(LOG_APP, "OH_CameraManager_GetSupportedCameraOutputCapability failed.");
        return;
    }

    if (cameraOutputCapability->previewProfiles == nullptr) {
        OH_LOG_ERROR(LOG_APP, "previewProfiles == null");
        return;
    }
    previewProfile = cameraOutputCapability->previewProfiles[0];
    OH_LOG_INFO(LOG_APP, "previewProfile width: %{public}d, height: %{public}d.", previewProfile->size.width,
        previewProfile->size.height);
    if (cameraOutputCapability->photoProfiles == nullptr) {
        OH_LOG_ERROR(LOG_APP, "photoProfiles == null");
        return;
    }
    photoProfile = cameraOutputCapability->photoProfiles[0];

    if (cameraOutputCapability->videoProfiles == nullptr) {
        OH_LOG_ERROR(LOG_APP, "videoProfiles == null");
        return;
    }
    // Ensure that the aspect ratio of the preview stream is the same as that of the video stream. To record HDR videos, choose Camera_VideoProfile that supports HDR.
    Camera_VideoProfile** videoProfiles = cameraOutputCapability->videoProfiles;
    for (int index = 0; index < cameraOutputCapability->videoProfilesSize; index++) {
        bool isEqual = IsAspectRatioEqual((float)videoProfiles[index]->size.width / videoProfiles[index]->size.height,
            (float)previewProfile->size.width / previewProfile->size.height);
        // The profile of CAMERA_FORMAT_YUV_420_SP is used by default.
        if (isEqual && videoProfiles[index]->format == Camera_Format::CAMERA_FORMAT_YUV_420_SP) {
            videoProfile = videoProfiles[index];
            OH_LOG_INFO(LOG_APP, "videoProfile width: %{public}d, height: %{public}d.", videoProfile->size.width,
                videoProfile->size.height);
            break;
        }
    }
    if (videoProfile == nullptr) {
        OH_LOG_ERROR(LOG_APP, "Get videoProfile failed.");
        return;
    }
    // Create a VideoOutput instance.
    ret = OH_CameraManager_CreateVideoOutput(cameraManager, videoProfile, videoSurfaceId, &videoOutput);
    if (videoOutput == nullptr || ret != CAMERA_OK) {
        OH_LOG_ERROR(LOG_APP, "OH_CameraManager_CreateVideoOutput failed.");
        return;
    }

    // Listen for video output errors.
    ret = OH_VideoOutput_RegisterCallback(videoOutput, GetVideoOutputListener());
    if (ret != CAMERA_OK) {
        OH_LOG_ERROR(LOG_APP, "OH_VideoOutput_RegisterCallback failed.");
    }

    // Create a session.
    ret = OH_CameraManager_CreateCaptureSession(cameraManager, &captureSession);
    if (captureSession == nullptr || ret != CAMERA_OK) {
        OH_LOG_ERROR(LOG_APP, "OH_CameraManager_CreateCaptureSession failed.");
        return;
    }
    // Listen for session errors.
    ret = OH_CaptureSession_RegisterCallback(captureSession, GetCaptureSessionRegister());
    if (ret != CAMERA_OK) {
        OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_RegisterCallback failed.");
    }

    // Start configuration for the session.
    ret = OH_CaptureSession_BeginConfig(captureSession);
    if (ret != CAMERA_OK) {
        OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_BeginConfig failed.");
        return;
    }

    // Create a camera input stream.
    ret = OH_CameraManager_CreateCameraInput(cameraManager, &cameras[cameraDeviceIndex], &cameraInput);
    if (cameraInput == nullptr || ret != CAMERA_OK) {
        OH_LOG_ERROR(LOG_APP, "OH_CameraManager_CreateCameraInput failed.");
        return;
    }

    // Listen for camera input errors.
    ret = OH_CameraInput_RegisterCallback(cameraInput, GetCameraInputListener());
    if (ret != CAMERA_OK) {
        OH_LOG_ERROR(LOG_APP, "OH_CameraInput_RegisterCallback failed.");
    }

    // Open the camera.
    ret = OH_CameraInput_Open(cameraInput);
    if (ret != CAMERA_OK) {
        OH_LOG_ERROR(LOG_APP, "OH_CameraInput_Open failed.");
        return;
    }

    // Add the camera input stream to the session.
    ret = OH_CaptureSession_AddInput(captureSession, cameraInput);
    if (ret != CAMERA_OK) {
        OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_AddInput failed.");
        return;
    }

    // Create a preview output stream. The surfaceId parameter is provided by the XComponent component described above. The preview stream uses the surface provided by the XComponent component.
    ret = OH_CameraManager_CreatePreviewOutput(cameraManager, previewProfile, previewSurfaceId, &previewOutput);
    if (previewProfile == nullptr || previewOutput == nullptr || ret != CAMERA_OK) {
        OH_LOG_ERROR(LOG_APP, "OH_CameraManager_CreatePreviewOutput failed.");
        return;
    }

    // Add the preview output stream to the session.
    ret = OH_CaptureSession_AddPreviewOutput(captureSession, previewOutput);
    if (ret != CAMERA_OK) {
        OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_AddPreviewOutput failed.");
        return;
    }

    // Add the video output stream to the session.
    ret = OH_CaptureSession_AddVideoOutput(captureSession, videoOutput);
    if (ret != CAMERA_OK) {
        OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_AddVideoOutput failed.");
        return;
    }

    // Commit the session configuration.
    ret = OH_CaptureSession_CommitConfig(captureSession);
    if (ret != CAMERA_OK) {
        OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_CommitConfig failed.");
        return;
    }

    // Start the session.
    ret = OH_CaptureSession_Start(captureSession);
    if (ret != CAMERA_OK) {
        OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_Start failed.");
        return;
    }

    // Start the video output stream.
    ret = OH_VideoOutput_Start(videoOutput);
    if (ret != CAMERA_OK) {
        OH_LOG_ERROR(LOG_APP, "OH_VideoOutput_Start failed.");
        return;
    }

    // Call avRecorder.start() on the TS side to start video recording.

    // Stop the video output stream.
    ret = OH_VideoOutput_Stop(videoOutput);
    if (ret != CAMERA_OK) {
        OH_LOG_ERROR(LOG_APP, "OH_VideoOutput_Stop failed.");
    }

    // Call avRecorder.stop() on the TS side to stop video recording.

    // Stop the session.
    ret = OH_CaptureSession_Stop(captureSession);
    if (ret == CAMERA_OK) {
        OH_LOG_INFO(LOG_APP, "OH_CaptureSession_Stop success ");
    } else {
        OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_Stop failed. %d ", ret);
    }

    // Release the camera input stream.
    ret = OH_CameraInput_Close(cameraInput);
    if (ret == CAMERA_OK) {
        OH_LOG_INFO(LOG_APP, "OH_CameraInput_Close success ");
    } else {
        OH_LOG_ERROR(LOG_APP, "OH_CameraInput_Close failed. %d ", ret);
    }

    // Release the preview output stream.
    ret = OH_PreviewOutput_Release(previewOutput);
    if (ret == CAMERA_OK) {
        OH_LOG_INFO(LOG_APP, "OH_PreviewOutput_Release success ");
    } else {
        OH_LOG_ERROR(LOG_APP, "OH_PreviewOutput_Release failed. %d ", ret);
    }

    // Release the video output stream.
    ret = OH_VideoOutput_Release(videoOutput);
    if (ret == CAMERA_OK) {
        OH_LOG_INFO(LOG_APP, "OH_VideoOutput_Release success ");
    } else {
        OH_LOG_ERROR(LOG_APP, "OH_VideoOutput_Release failed. %d ", ret);
    }

    // Release the session.
    ret = OH_CaptureSession_Release(captureSession);
    if (ret == CAMERA_OK) {
        OH_LOG_INFO(LOG_APP, "OH_CaptureSession_Release success ");
    } else {
        OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_Release failed. %d ", ret);
    }

    // Release the resources.
    ret = OH_CameraManager_DeleteSupportedCameras(cameraManager, cameras, size);
    if (ret != CAMERA_OK) {
        OH_LOG_ERROR(LOG_APP, "Delete Cameras failed.");
    } else {
        OH_LOG_INFO(LOG_APP, "OH_CameraManager_DeleteSupportedCameras. ok");
    }
    ret = OH_CameraManager_DeleteSupportedCameraOutputCapability(cameraManager, cameraOutputCapability);
    if (ret != CAMERA_OK) {
        OH_LOG_ERROR(LOG_APP, "Delete Cameras failed.");
    } else {
        OH_LOG_INFO(LOG_APP, "OH_CameraManager_DeleteSupportedCameraOutputCapability success");
    }
    ret = OH_Camera_DeleteCameraManager(cameraManager);
    if (ret != CAMERA_OK) {
        OH_LOG_ERROR(LOG_APP, "Delete Cameras failed.");
    } else {
        OH_LOG_INFO(LOG_APP, "OH_Camera_DeleteCameraManager success");
    }
}

Sample Code