updated docs

Signed-off-by: Nwusongqing <wusongqing@huawei.com>

en/application-dev/media/video-recorder.md

@@ -16,21 +16,20 @@ During video recording, audio and video signals are captured, encoded, and saved
 
 ## How to Develop
 
-For details about the APIs used for video recording, see [VideoRecorder in the Media API](../reference/apis/js-apis-media.md).
+For details about the APIs, see [VideoRecorder in the Media API](../reference/apis/js-apis-media.md).
 
 ### Full-Process Scenario
 
-The full video recording process includes creating an instance, setting recording parameters, recording video, pausing, resuming, and stopping recording, and releasing resources.
+The full video recording process includes creating an instance, setting recording parameters, starting, pausing, resuming, and stopping recording, and releasing resources.
 
 ```js
 import media from '@ohos.multimedia.media'
 import mediaLibrary from '@ohos.multimedia.mediaLibrary'
-
-let testFdNumber;
-
-// pathName indicates the passed recording file name, for example, 01.mp4. The generated file address is /storage/media/100/local/files/Movies/01.mp4.
-// To use the media library, declare the following permissions: ohos.permission.MEDIA_LOCATION, ohos.permission.WRITE_MEDIA, and ohos.permission.READ_MEDIA.
-async function getFd(pathName) {
+export class VideoRecorderDemo {
+  private testFdNumber; // Used to save the FD address.
+  // pathName indicates the passed recording file name, for example, 01.mp4. The generated file address is /storage/media/100/local/files/Video/01.mp4.
+  // To use the media library, declare the following permissions: ohos.permission.MEDIA_LOCATION, ohos.permission.WRITE_MEDIA, and ohos.permission.READ_MEDIA.
+  async getFd(pathName) {
     let displayName = pathName;
     const mediaTest = mediaLibrary.getMediaLibrary();
     let fileKeyObj = mediaLibrary.FileKey;
@@ -46,14 +45,31 @@ async function getFd(pathName) {
       let fetchFileResult = await mediaTest.getFileAssets(fetchOp);
       let fileAsset = await fetchFileResult.getAllObject();
       let fdNumber = await fileAsset[0].open('Rw');
-        fdNumber = "fd://" + fdNumber.toString();
-        testFdNumber = fdNumber;
+      this.testFdNumber = "fd://" + fdNumber.toString();
+    }
   }
-}
 
-await getFd('01.mp4');
+  // Error callback triggered in the case of an error
+  failureCallback(error) {
+      console.info('error happened, error name is ' + error.name);
+      console.info('error happened, error code is ' + error.code);
+      console.info('error happened, error message is ' + error.message);
+  }
 
-let videoProfile = {
+  // Error callback triggered in the case of an exception
+  catchCallback(error) {
+      console.info('catch error happened, error name is ' + error.name);
+      console.info('catch error happened, error code is ' + error.code);
+      console.info('catch error happened, error message is ' + error.message);
+  }
+
+  async videoRecorderDemo() {
+    let videoRecorder = null; // videoRecorder is an empty object and assigned with a value after createVideoRecorder is successfully called.
+    let surfaceID = null; // Used to save the surface ID returned by getInputSurface.
+    // Obtain the FD address of the video to be recorded.
+    await this.getFd('01.mp4');
+    // Recording-related parameter settings
+    let videoProfile = {
       audioBitrate : 48000,
       audioChannels : 2,
       audioCodec : 'audio/mp4a-latm',
@@ -64,36 +80,18 @@ let videoProfile = {
       videoFrameWidth : 640,
       videoFrameHeight : 480,
       videoFrameRate : 30
-}
+    }
 
-let videoConfig = {
+    let videoConfig = {
       audioSourceType : 1,
       videoSourceType : 0,
       profile : videoProfile,
-    url: testFdNumber, // testFdNumber is generated by getFd.
+      url : this.testFdNumber, // testFdNumber is generated by getFd.
       orientationHint : 0,
       location : { latitude : 30, longitude : 130 },
-}
-	
-// Error callback triggered in the case of an error
-function failureCallback(error) {
-    console.info('error happened, error name is ' + error.name);
-    console.info('error happened, error code is ' + error.code);
-    console.info('error happened, error message is ' + error.message);
-}
-	
-// Error callback triggered in the case of an exception
-function catchCallback(error) {
-    console.info('catch error happened, error name is ' + error.name);
-    console.info('catch error happened, error code is ' + error.code);
-    console.info('catch error happened, error message is ' + error.message);
-}
-	
-let videoRecorder = null; // videoRecorder is an empty object and assigned with a value after createVideoRecorder is successfully called.
-let surfaceID = null; // Used to save the surface ID returned by getInputSurface.
-
-// Create a VideoRecorder object.
-await media.createVideoRecorder().then((recorder) => {
+    }
+    // Create a VideoRecorder object.
+    await media.createVideoRecorder().then((recorder) => {
       console.info('case createVideoRecorder called');
       if (typeof (recorder) != 'undefined') {
         videoRecorder = recorder;
@@ -101,47 +99,53 @@ await media.createVideoRecorder().then((recorder) => {
       } else {
         console.info('createVideoRecorder failed');
       }
-}, failureCallback).catch(catchCallback);
+    }, this.failureCallback).catch(this.catchCallback);
 
-// Obtain the surface ID, save it, and pass it to camera-related interfaces.
-await videoRecorder.getInputSurface().then((surface) => {
+    // Call the prepare API to prepare for video recording.
+    await videoRecorder.prepare(videoConfig).then(() => {
+      console.info('prepare success');
+    }, this.failureCallback).catch(this.catchCallback);
+
+    // Obtain the surface ID, save it, and pass it to camera-related APIs.
+    await videoRecorder.getInputSurface().then((surface) => {
       console.info('getInputSurface success');
       surfaceID = surface;
-}, failureCallback).catch(catchCallback);
-	
-// Video recording depends on camera-related interfaces. The following operations can be performed only after the video output start interface is invoked.
+    }, this.failureCallback).catch(this.catchCallback);
 
-// Start video recording.
-await videoRecorder.start().then(() => {
+    // Video recording depends on camera-related APIs. The following operations can be performed only after the video output start API is invoked. For details about how to call the camera APIs, see the samples.
+    // Start video recording.
+    await videoRecorder.start().then(() => {
       console.info('start success');
-}, failureCallback).catch(catchCallback);
+    }, this.failureCallback).catch(this.catchCallback);
 
-// Pause video playback before the video output stop interface is invoked.
-await videoRecorder.pause().then(() => {
+    // Pause video recording before the video output stop API of the camera is invoked.
+    await videoRecorder.pause().then(() => {
       console.info('pause success');
-}, failureCallback).catch(catchCallback);
+    }, this.failureCallback).catch(this.catchCallback);
 
-// Resume video playback after the video output start interface is invoked.
-await videoRecorder.resume().then(() => {
+    // Resume video recording after the video output start API of the camera is invoked.
+    await videoRecorder.resume().then(() => {
       console.info('resume success');
-}, failureCallback).catch(catchCallback);
+    }, this.failureCallback).catch(this.catchCallback);
 
-// Stop video recording after the video output stop interface is invoked.
-await videoRecorder.stop().then(() => {
+    // Stop video recording after the video output stop API of the camera is invoked.
+    await videoRecorder.stop().then(() => {
       console.info('stop success');
-}, failureCallback).catch(catchCallback);
+    }, this.failureCallback).catch(this.catchCallback);
 
-// Reset the recording configuration.
-await videoRecorder.reset().then(() => {
+    // Reset the recording configuration.
+    await videoRecorder.reset().then(() => {
       console.info('reset success');
-}, failureCallback).catch(catchCallback);
+    }, this.failureCallback).catch(this.catchCallback);
 
-// Release the video recording resources and camera object resources.
-await videoRecorder.release().then(() => {
+    // Release the video recording resources and camera object resources.
+    await videoRecorder.release().then(() => {
       console.info('release success');
-}, failureCallback).catch(catchCallback);
+    }, this.failureCallback).catch(this.catchCallback);
 
-// Set the related object to null.
-videoRecorder = null;
-surfaceID = null;
+    // Set the related object to null.
+    videoRecorder = undefined;
+    surfaceID = undefined;
+  }
+}
 ```