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1# Video Recording Practices (C/C++)
2<!--Kit: Camera Kit-->
3<!--Subsystem: Multimedia-->
4<!--Owner: @qano-->
5<!--SE: @leo_ysl-->
6<!--TSE: @xchaosioda-->
7
8Before developing a camera application, request permissions by following the instructions provided in [Requesting Camera Development Permissions](camera-preparation.md).
9
10This topic provides sample code that covers the complete video recording process and the API calling sequence. For details about a single process (such as device input, session management, and video recording), see the corresponding C/C++ development guide links provided in [Requesting Camera Development Permissions](camera-preparation.md).
11
12## Development Process
13
14After obtaining the output stream capabilities supported by the camera, create a video stream. The development process is as follows:
15
16![Recording Development Process](figures/recording-ndk-development-process.png)
17
18## Sample Code
19
201. Link the dynamic library in the CMake script.
21    ```txt
22    target_link_libraries(entry PUBLIC
23        libace_napi.z.so
24        libohcamera.so
25        libhilog_ndk.z.so
26    )
27    ```
28
292. Create the header file **ndk_camera.h**.
30   ```c++
31   #include "ohcamera/camera.h"
32   #include "ohcamera/camera_input.h"
33   #include "ohcamera/capture_session.h"
34   #include "ohcamera/photo_output.h"
35   #include "ohcamera/preview_output.h"
36   #include "ohcamera/video_output.h"
37   #include "ohcamera/camera_manager.h"
38
39   class NDKCamera {
40   public:
41       ~NDKCamera();
42       NDKCamera(char* previewId, char* videoId);
43   };
44   ```
45
463. Import the NDK APIs on the C++ side, and perform video recording based on the surface ID passed in.
47    ```c++
48    #include "hilog/log.h"
49    #include "ndk_camera.h"
50    #include <cmath>
51
52    bool IsAspectRatioEqual(float videoAspectRatio, float previewAspectRatio)
53    {
54        float epsilon = 1e-6f;
55        return fabsf(videoAspectRatio - previewAspectRatio) <= epsilon;
56    }
57
58    void OnCameraInputError(const Camera_Input* cameraInput, Camera_ErrorCode errorCode)
59    {
60        OH_LOG_INFO(LOG_APP, "OnCameraInput errorCode = %{public}d", errorCode);
61    }
62
63    CameraInput_Callbacks* GetCameraInputListener(void)
64    {
65        static CameraInput_Callbacks cameraInputCallbacks = {
66            .onError = OnCameraInputError
67        };
68        return &cameraInputCallbacks;
69    }
70
71    void CaptureSessionOnFocusStateChange(Camera_CaptureSession* session, Camera_FocusState focusState)
72    {
73        OH_LOG_INFO(LOG_APP, "CaptureSessionOnFocusStateChange");
74    }
75
76    void CaptureSessionOnError(Camera_CaptureSession* session, Camera_ErrorCode errorCode)
77    {
78        OH_LOG_INFO(LOG_APP, "CaptureSessionOnError = %{public}d", errorCode);
79    }
80
81    CaptureSession_Callbacks* GetCaptureSessionRegister(void)
82    {
83        static CaptureSession_Callbacks captureSessionCallbacks = {
84            .onFocusStateChange = CaptureSessionOnFocusStateChange,
85            .onError = CaptureSessionOnError
86        };
87        return &captureSessionCallbacks;
88    }
89
90    void VideoOutputOnFrameStart(Camera_VideoOutput* videoOutput)
91    {
92        OH_LOG_INFO(LOG_APP, "VideoOutputOnFrameStart");
93    }
94
95    void VideoOutputOnFrameEnd(Camera_VideoOutput* videoOutput, int32_t frameCount)
96    {
97        OH_LOG_INFO(LOG_APP, "VideoOutput frameCount = %{public}d", frameCount);
98    }
99
100    void VideoOutputOnError(Camera_VideoOutput* videoOutput, Camera_ErrorCode errorCode)
101    {
102        OH_LOG_INFO(LOG_APP, "VideoOutput errorCode = %{public}d", errorCode);
103    }
104
105    VideoOutput_Callbacks* GetVideoOutputListener(void)
106    {
107        static VideoOutput_Callbacks videoOutputListener = {
108            .onFrameStart = VideoOutputOnFrameStart,
109            .onFrameEnd = VideoOutputOnFrameEnd,
110            .onError = VideoOutputOnError
111        };
112        return &videoOutputListener;
113    }
114
115    void CameraManagerStatusCallback(Camera_Manager* cameraManager, Camera_StatusInfo* status)
116    {
117        OH_LOG_INFO(LOG_APP, "CameraManagerStatusCallback is called");
118    }
119
120    CameraManager_Callbacks* GetCameraManagerListener()
121    {
122        static CameraManager_Callbacks cameraManagerListener = {
123            .onCameraStatus = CameraManagerStatusCallback
124        };
125        return &cameraManagerListener;
126    }
127
128    NDKCamera::NDKCamera(char* previewId, char* videoId)
129    {
130        Camera_Manager* cameraManager = nullptr;
131        Camera_Device* cameras = nullptr;
132        Camera_CaptureSession* captureSession = nullptr;
133        Camera_OutputCapability* cameraOutputCapability = nullptr;
134        Camera_VideoOutput* videoOutput = nullptr;
135        const Camera_Profile* previewProfile = nullptr;
136        const Camera_Profile* photoProfile = nullptr;
137        const Camera_VideoProfile* videoProfile = nullptr;
138        Camera_PreviewOutput* previewOutput = nullptr;
139        Camera_PhotoOutput* photoOutput = nullptr;
140        Camera_Input* cameraInput = nullptr;
141        uint32_t size = 0;
142        uint32_t cameraDeviceIndex = 0;
143        char* videoSurfaceId = videoId;
144        char* previewSurfaceId = previewId;
145        // Create a CameraManager object.
146        Camera_ErrorCode ret = OH_Camera_GetCameraManager(&cameraManager);
147        if (cameraManager == nullptr || ret != CAMERA_OK) {
148            OH_LOG_ERROR(LOG_APP, "OH_Camera_GetCameraManager failed.");
149            return;
150        }
151        // Listen for camera status changes.
152        ret = OH_CameraManager_RegisterCallback(cameraManager, GetCameraManagerListener());
153        if (ret != CAMERA_OK) {
154            OH_LOG_ERROR(LOG_APP, "OH_CameraManager_RegisterCallback failed.");
155            return;
156        }
157
158        // Obtain the camera list.
159        ret = OH_CameraManager_GetSupportedCameras(cameraManager, &cameras, &size);
160        if (cameras == nullptr || size <= 0 || ret != CAMERA_OK) {
161            OH_LOG_ERROR(LOG_APP, "OH_CameraManager_GetSupportedCameras failed.");
162            return;
163        }
164
165        for (int index = 0; index < size; index++) {
166            OH_LOG_ERROR(LOG_APP, "cameraId  =  %{public}s ", cameras[index].cameraId);              // Obtain the camera ID.
167            OH_LOG_ERROR(LOG_APP, "cameraPosition  =  %{public}d ", cameras[index].cameraPosition);  // Obtain the camera position.
168            OH_LOG_ERROR(LOG_APP, "cameraType  =  %{public}d ", cameras[index].cameraType);          // Obtain the camera type.
169            OH_LOG_ERROR(LOG_APP, "connectionType  =  %{public}d ", cameras[index].connectionType);  // Obtain the camera connection type.
170        }
171
172        if (size < cameraDeviceIndex + 1) {
173            OH_LOG_ERROR(LOG_APP, "cameraDeviceIndex is invalid.");
174            return;
175        }
176
177        // Obtain the output stream capability supported by the camera.
178        ret = OH_CameraManager_GetSupportedCameraOutputCapability(cameraManager, &cameras[cameraDeviceIndex],
179                                                                &cameraOutputCapability);
180        if (cameraOutputCapability == nullptr || ret != CAMERA_OK) {
181            OH_LOG_ERROR(LOG_APP, "OH_CameraManager_GetSupportedCameraOutputCapability failed.");
182            return;
183        }
184
185        if (cameraOutputCapability->previewProfiles == nullptr) {
186            OH_LOG_ERROR(LOG_APP, "previewProfiles == null");
187            return;
188        }
189        previewProfile = cameraOutputCapability->previewProfiles[0];
190        OH_LOG_INFO(LOG_APP, "previewProfile width: %{public}, height: %{public}.", previewProfile->size.width,
191            previewProfile->size.height);
192        if (cameraOutputCapability->photoProfiles == nullptr) {
193            OH_LOG_ERROR(LOG_APP, "photoProfiles == null");
194            return;
195        }
196        photoProfile = cameraOutputCapability->photoProfiles[0];
197
198        if (cameraOutputCapability->videoProfiles == nullptr) {
199            OH_LOG_ERROR(LOG_APP, "videoProfiles == null");
200            return;
201        }
202        // 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.
203        Camera_VideoProfile** videoProfiles = cameraOutputCapability->videoProfiles;
204        for (int index = 0; index < cameraOutputCapability->videoProfilesSize; index++) {
205            bool isEqual = IsAspectRatioEqual((float)videoProfiles[index]->size.width / videoProfiles[index]->size.height,
206                (float)previewProfile->size.width / previewProfile->size.height);
207            // The profile of CAMERA_FORMAT_YUV_420_SP is used by default.
208            if (isEqual && videoProfiles[index]->format == Camera_Format::CAMERA_FORMAT_YUV_420_SP) {
209                videoProfile = videoProfiles[index];
210                OH_LOG_INFO(LOG_APP, "videoProfile width: %{public}, height: %{public}.", videoProfile->size.width,
211                    videoProfile->size.height);
212                break;
213            }
214        }
215        if (videoProfile == nullptr) {
216            OH_LOG_ERROR(LOG_APP, "Get videoProfile failed.");
217            return;
218        }
219        // Create a VideoOutput instance.
220        ret = OH_CameraManager_CreateVideoOutput(cameraManager, videoProfile, videoSurfaceId, &videoOutput);
221        if (videoOutput == nullptr || ret != CAMERA_OK) {
222            OH_LOG_ERROR(LOG_APP, "OH_CameraManager_CreateVideoOutput failed.");
223            return;
224        }
225
226        // Listen for video output errors.
227        ret = OH_VideoOutput_RegisterCallback(videoOutput, GetVideoOutputListener());
228        if (ret != CAMERA_OK) {
229            OH_LOG_ERROR(LOG_APP, "OH_VideoOutput_RegisterCallback failed.");
230        }
231
232        // Create a session.
233        ret = OH_CameraManager_CreateCaptureSession(cameraManager, &captureSession);
234        if (captureSession == nullptr || ret != CAMERA_OK) {
235            OH_LOG_ERROR(LOG_APP, "OH_CameraManager_CreateCaptureSession failed.");
236            return;
237        }
238        // Listen for session errors.
239        ret = OH_CaptureSession_RegisterCallback(captureSession, GetCaptureSessionRegister());
240        if (ret != CAMERA_OK) {
241            OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_RegisterCallback failed.");
242        }
243
244        // Start configuration for the session.
245        ret = OH_CaptureSession_BeginConfig(captureSession);
246        if (ret != CAMERA_OK) {
247            OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_BeginConfig failed.");
248            return;
249        }
250
251        // Create a camera input stream.
252        ret = OH_CameraManager_CreateCameraInput(cameraManager, &cameras[cameraDeviceIndex], &cameraInput);
253        if (cameraInput == nullptr || ret != CAMERA_OK) {
254            OH_LOG_ERROR(LOG_APP, "OH_CameraManager_CreateCameraInput failed.");
255            return;
256        }
257
258        // Listen for camera input errors.
259        ret = OH_CameraInput_RegisterCallback(cameraInput, GetCameraInputListener());
260        if (ret != CAMERA_OK) {
261            OH_LOG_ERROR(LOG_APP, "OH_CameraInput_RegisterCallback failed.");
262        }
263
264        // Open the camera.
265        ret = OH_CameraInput_Open(cameraInput);
266        if (ret != CAMERA_OK) {
267            OH_LOG_ERROR(LOG_APP, "OH_CameraInput_Open failed.");
268            return;
269        }
270
271        // Add the camera input stream to the session.
272        ret = OH_CaptureSession_AddInput(captureSession, cameraInput);
273        if (ret != CAMERA_OK) {
274            OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_AddInput failed.");
275            return;
276        }
277
278        // Create a preview output stream. For details about the surfaceId parameter, see the XComponent. The preview stream is the surface provided by the XComponent.
279        ret = OH_CameraManager_CreatePreviewOutput(cameraManager, previewProfile, previewSurfaceId, &previewOutput);
280        if (previewProfile == nullptr || previewOutput == nullptr || ret != CAMERA_OK) {
281            OH_LOG_ERROR(LOG_APP, "OH_CameraManager_CreatePreviewOutput failed.");
282            return;
283        }
284
285        // Add the preview output stream to the session.
286        ret = OH_CaptureSession_AddPreviewOutput(captureSession, previewOutput);
287        if (ret != CAMERA_OK) {
288            OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_AddPreviewOutput failed.");
289            return;
290        }
291
292        // Add the video output stream to the session.
293        ret = OH_CaptureSession_AddVideoOutput(captureSession, videoOutput);
294        if (ret != CAMERA_OK) {
295            OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_AddVideoOutput failed.");
296            return;
297        }
298
299        // Commit the session configuration.
300        ret = OH_CaptureSession_CommitConfig(captureSession);
301        if (ret != CAMERA_OK) {
302            OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_CommitConfig failed.");
303            return;
304        }
305
306        // Start the session.
307        ret = OH_CaptureSession_Start(captureSession);
308        if (ret != CAMERA_OK) {
309            OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_Start failed.");
310            return;
311        }
312
313        // Start the video output stream.
314        ret = OH_VideoOutput_Start(videoOutput);
315        if (ret != CAMERA_OK) {
316            OH_LOG_ERROR(LOG_APP, "OH_VideoOutput_Start failed.");
317            return;
318        }
319
320        // Call avRecorder.start() on the TS side to start video recording.
321
322        // Stop the video output stream.
323        ret = OH_VideoOutput_Stop(videoOutput);
324        if (ret != CAMERA_OK) {
325            OH_LOG_ERROR(LOG_APP, "OH_VideoOutput_Stop failed.");
326        }
327
328        // Call avRecorder.stop() on the TS side to stop video recording.
329
330        // Stop the session.
331        ret = OH_CaptureSession_Stop(captureSession);
332        if (ret == CAMERA_OK) {
333            OH_LOG_INFO(LOG_APP, "OH_CaptureSession_Stop success ");
334        } else {
335            OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_Stop failed. %d ", ret);
336        }
337
338        // Release the camera input stream.
339        ret = OH_CameraInput_Close(cameraInput);
340        if (ret == CAMERA_OK) {
341            OH_LOG_INFO(LOG_APP, "OH_CameraInput_Close success ");
342        } else {
343            OH_LOG_ERROR(LOG_APP, "OH_CameraInput_Close failed. %d ", ret);
344        }
345
346        // Release the preview output stream.
347        ret = OH_PreviewOutput_Release(previewOutput);
348        if (ret == CAMERA_OK) {
349            OH_LOG_INFO(LOG_APP, "OH_PreviewOutput_Release success ");
350        } else {
351            OH_LOG_ERROR(LOG_APP, "OH_PreviewOutput_Release failed. %d ", ret);
352        }
353
354        // Release the video output stream.
355        ret = OH_VideoOutput_Release(videoOutput);
356        if (ret == CAMERA_OK) {
357            OH_LOG_INFO(LOG_APP, "OH_VideoOutput_Release success ");
358        } else {
359            OH_LOG_ERROR(LOG_APP, "OH_VideoOutput_Release failed. %d ", ret);
360        }
361
362        // Release the session.
363        ret = OH_CaptureSession_Release(captureSession);
364        if (ret == CAMERA_OK) {
365            OH_LOG_INFO(LOG_APP, "OH_CaptureSession_Release success ");
366        } else {
367            OH_LOG_ERROR(LOG_APP, "OH_CaptureSession_Release failed. %d ", ret);
368        }
369
370        // Release the resources.
371        ret = OH_CameraManager_DeleteSupportedCameras(cameraManager, cameras, size);
372        if (ret != CAMERA_OK) {
373            OH_LOG_ERROR(LOG_APP, "Delete Cameras failed.");
374        } else {
375            OH_LOG_ERROR(LOG_APP, "OH_CameraManager_DeleteSupportedCameras. ok");
376        }
377        ret = OH_CameraManager_DeleteSupportedCameraOutputCapability(cameraManager, cameraOutputCapability);
378        if (ret != CAMERA_OK) {
379            OH_LOG_ERROR(LOG_APP, "Delete Cameras failed.");
380        } else {
381            OH_LOG_ERROR(LOG_APP, "OH_CameraManager_DeleteSupportedCameraOutputCapability success");
382        }
383        ret = OH_Camera_DeleteCameraManager(cameraManager);
384        if (ret != CAMERA_OK) {
385            OH_LOG_ERROR(LOG_APP, "Delete Cameras failed.");
386        } else {
387            OH_LOG_ERROR(LOG_APP, "OH_Camera_DeleteCameraManager success");
388        }
389    }
390    ```
391