通过摄像头实时预览拍摄画面，并截取一帧用于识别转换PixelMap时报错？

Question

onImageArrival(receiver: image.ImageReceiver): void {
  receiver.on('imageArrival', () => {
  receiver.readNextImage((err: BusinessError, nextImage: image.Image) => {
  if (err || nextImage === undefined) {
  console.error('readNextImage failed');
  return;
}
nextImage.getComponent(image.ComponentType.JPEG, async (err: BusinessError, imgComponent: image.Component) => {
  if (err || imgComponent === undefined) {
    console.error('getComponent failed');
  }
  if (imgComponent && imgComponent.byteBuffer as ArrayBuffer) {
    let buffer = imgComponent.byteBuffer as ArrayBuffer
    try {
      let pixelMap: image.PixelMap =
        await image.createImageSource(buffer).createPixelMap()
      console.error(`result ${pixelMap.getDensity()}`);
    } catch (e) {
      console.error(JSON.stringify(e))
    }
  } else {
    console.error('byteBuffer is null');
  }
  nextImage.release();
})
})
})
}

详细日志

05-27 16:46:22.152   12178-12424  C02B03/HeifFormatAgent         com.examp...lication  E     [nodict]head type is not ftyp.
05-27 16:46:22.152   12178-12424  C02B05/ImageSource             com.examp...lication  E     [nodict][ImageSource]check mismatched format :image/heif.
05-27 16:46:22.152   12178-12424  C02B05/ImageSource             com.examp...lication  E     [nodict][ImageSource]check mismatched format :image/jpeg.
05-27 16:46:22.152   12178-12424  C02B05/ImageSource             com.examp...lication  E     [nodict][ImageSource]check mismatched format :image/png.
05-27 16:46:22.152   12178-12424  C02B05/ImageSource             com.examp...lication  E     [nodict][ImageSource]check mismatched format :image/svg+xml.
05-27 16:46:22.152   12178-12424  C02B05/ImageSource             com.examp...lication  E     [nodict][ImageSource]check mismatched format :image/vnd.wap.wbmp.
05-27 16:46:22.152   12178-12424  C02B05/ImageSource             com.examp...lication  E     [nodict][ImageSource]check mismatched format :image/webp.
05-27 16:46:22.155   12178-12424  C02B03/RawDecoder              com.examp...lication  E     [nodict]DoDecodeHeader header decode fail, ret=[62980103]
05-27 16:46:22.155   12178-12424  C02B03/RawDecoder              com.examp...lication  E     [nodict][GetImageSize]decode header error on get image size, ret:62980103.
05-27 16:46:22.155   12178-12424  C02B05/ImageSource             com.examp...lication  E     [nodict][ImageSource]decode the image info fail.
05-27 16:46:22.155   12178-12424  C02B05/ImageSource             com.examp...lication  E     [nodict][ImageSource]image info decode fail, ret:62980116.
05-27 16:46:22.155   12178-12424  C02B05/ImageSource             com.examp...lication  E     [nodict][ImageSource]get valid image status fail on create pixel map, ret:62980116.
05-27 16:46:22.155   12178-12424  C02B05/ImageSourceNapi         com.examp...lication  E     [nodict]Create PixelMap error

Answer 1

从代码日志中查看错误码：62980103，可能出现问题的地方是：解码过程中异常退出。图片格式不支持。未读取到图片。参考关于相机能读取到每一帧的demo

import camera from '@ohos.multimedia.camera';
import image from '@ohos.multimedia.image';
import abilityAccessCtrl from '@ohos.abilityAccessCtrl';
import common from '@ohos.app.ability.common';
import fs from '@ohos.file.fs';
import { BusinessError } from '@kit.BasicServicesKit';
import PhotoAccessHelper from '@ohos.file.photoAccessHelper';

@Entry
@Component
struct Scan1 {
  @State message: string = 'Hello World'
  private mXComponentController: XComponentController = new XComponentController;
  private surfaceId: string = '-1';
  @State imgUrl: PixelMap | undefined = undefined;
  private context: ESObject = undefined
  private previewProfilesObj2: camera.Profile | undefined = undefined;
  private receiver: image.ImageReceiver | undefined = undefined;
  @State pixma: PixelMap | undefined = undefined
  @State photoOutput: camera.PhotoOutput | undefined = undefined;
  aboutToAppear() {
    //申请权限
    let context = getContext() as common.UIAbilityContext;
    abilityAccessCtrl.createAtManager().requestPermissionsFromUser(context, ['ohos.permission.CAMERA']).then(() => {

      this.createDualChannelPreview(this.surfaceId);
    });

  }
  onPageShow(): void {
    this.createDualChannelPreview(this.surfaceId);

  }
  async createDualChannelPreview(XComponentSurfaceId: string): Promise<void> {
    let cameraManager = await camera.getCameraManager(getContext() as ESObject);
    let camerasDevices: Array<camera.CameraDevice> = cameraManager.getSupportedCameras(); // 获取支持的相机设备对象
    // 获取profile对象
    let profiles: camera.CameraOutputCapability = cameraManager.getSupportedOutputCapability(camerasDevices[0]); // 获取对应相机设备profiles
    let previewProfiles: Array<camera.Profile> = profiles.previewProfiles;
    // 预览流2
    this.previewProfilesObj2 = previewProfiles[0];
    this.receiver = image.createImageReceiver(this.previewProfilesObj2.size.width, this.previewProfilesObj2.size.height, 2000, 8);
    // 创建 预览流2 输出对象
    let imageReceiverSurfaceId: string = await this.receiver.getReceivingSurfaceId();
    let previewOutput2: camera.PreviewOutput = cameraManager.createPreviewOutput(this.previewProfilesObj2, imageReceiverSurfaceId);
    // 创建拍照输出流
    // let photoOutput: camera.PhotoOutput | undefined = undefined;
    let photoProfilesArray: Array<camera.Profile> = profiles.photoProfiles;
    try {
      this.photoOutput = cameraManager.createPhotoOutput(photoProfilesArray[0]);
    } catch (error) {
      let err = error as BusinessError;
      console.error('Failed to createPhotoOutput errorCode = ' + err.code);
    }
    if (this.photoOutput === undefined) {
      return;
    }
    // 创建cameraInput对象
    let cameraInput: camera.CameraInput = cameraManager.createCameraInput(camerasDevices[0]);
    // 打开相机
    await cameraInput.open();
    // 会话流程
    let captureSession: camera.CaptureSession = cameraManager.createCaptureSession();
    // 开始配置会话
    captureSession.beginConfig();
    // 把CameraInput加入到会话
    captureSession.addInput(cameraInput);
    // 把 预览流2 加入到会话
    captureSession.addOutput(previewOutput2);
    try {
      captureSession.addOutput(this.photoOutput);
    } catch (error) {
      let err = error as BusinessError;
      console.error('Failed to addOutput(photoOutput). errorCode = ' + err.code);
    }
    // 提交配置信息
    await captureSession.commitConfig();
    // 会话开始
    await captureSession.start();
    this.onImageArrival(this.receiver);
    this.setPhotoOutputCb(this.photoOutput)
  }
  async savePicture(buffer: ArrayBuffer, img: image.Image) {
    const context = getContext(this);
    let photoAccessHelper: PhotoAccessHelper.PhotoAccessHelper = PhotoAccessHelper.getPhotoAccessHelper(context);
    let options: PhotoAccessHelper.CreateOptions = {
      title: Date.now().toString()
    };
    let photoUri: string = await photoAccessHelper.createAsset(PhotoAccessHelper.PhotoType.IMAGE, 'jpg', options);
    //createAsset的调用需要ohos.permission.READ_IMAGEVIDEO和ohos.permission.WRITE_IMAGEVIDEO的权限
    let file: fs.File = fs.openSync(photoUri, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
    await fs.write(file.fd, buffer);
    fs.closeSync(file);
    img.release();
  }
  setPhotoOutputCb(photoOutput: camera.PhotoOutput) {
    //设置回调之后，调用photoOutput的capture方法，就会将拍照的buffer回传到回调中
    photoOutput.on('photoAvailable', (errCode: BusinessError, photo: camera.Photo): void => {
      console.info('getPhoto start');
      console.info(`err: ${JSON.stringify(errCode)}`);
      if (errCode || photo === undefined) {
        console.error('getPhoto failed');
        return;
      }
      let imageObj = photo.main;
      imageObj.getComponent(image.ComponentType.JPEG, (errCode: BusinessError, component: image.Component): void => {
        console.info('getComponent start');
        if (errCode || component === undefined) {
          console.error('getComponent failed');
          return;
        }
        let buffer: ArrayBuffer;
        if (component.byteBuffer) {
          buffer = component.byteBuffer;
          if (component.byteBuffer as ArrayBuffer) {
            let sourceOptions: image.SourceOptions = {
              sourceDensity: 120,
              // sourcePixelFormat: 3, // NV21
              sourceSize: {
                height: 240,
                width: 320
              },
            }
            try {
              let imageResource = image.createImageSource(component.byteBuffer);
              imageResource.createPixelMap({}).then((res)=>{
                this.pixma = res;
              });
            }catch (error) {
              let err = error as BusinessError;
              console.error('Failed to addOutput(photoOutput). errorCode = ' + err.code);
            }
          } else {
            return;
          }
        } else {
          console.error('byteBuffer is null');
          return;
        }
        this.savePicture(buffer, imageObj);
      });
    });
  }
  async onImageArrival(receiver: image.ImageReceiver): Promise<void> {
    receiver.on('imageArrival', () => {
      console.error("imageArrival callback");
      receiver.readLatestImage((err, nextImage: image.Image) => {
        if (err || nextImage === undefined) {
          return;
        }
        nextImage.getComponent(image.ComponentType.JPEG, async (err, imgComponent: image.Component) => {
          if (err || imgComponent === undefined) {
            return;
          }
          this.saveImageToFile(imgComponent.byteBuffer);
          if (imgComponent.byteBuffer as ArrayBuffer) {
            let sourceOptions: image.SourceOptions = {
              sourceDensity: 120,
              sourcePixelFormat: 8, // NV21
              sourceSize: {
                height: this.previewProfilesObj2!.size.height,
                width: this.previewProfilesObj2!.size.width
              },
            }
            let imageResource = image.createImageSource(imgComponent.byteBuffer, sourceOptions);
            let decodingOptions : image.DecodingOptions = {
              editable: true,
              desiredPixelFormat: 3,

            }
            imageResource.createPixelMap(decodingOptions).then((res)=>{
              this.imgUrl = res;
            });
          } else {
            return;
          }
          nextImage.release();
        })
      })
    })
  }
  saveImageToFile(data: ArrayBuffer) {
    const context = getContext(this);
    let filePath = context.tempDir + "/test.jpg";
    console.info("path is " + filePath);
    let file = fs.openSync(filePath, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
    fs.write(file.fd, data, (err, writeLen) => {
      if (err) {
        console.info("write failed with error message: " + err.message + ", error code: " + err.code);
      } else {
        console.info("write data to file succeed and size is:" + writeLen);
        fs.closeSync(file);
      }
    });
  }
  build() {
    Column() {
      Row() {
        // 将编辑好的pixelMap传递给状态变量imagePixelMap后，通过Image组件进行渲染
        Image(this.imgUrl).objectFit(ImageFit.None)
      }.width('100%').height('50%').backgroundColor('#F0F0F0')
      Row() {
        Button() {
          Text("拍照")
            .fontColor(Color.Black)
            .alignSelf(ItemAlign.Center)
            .onClick(() => {
              // this.capture(this.photoOutPut, null)
              let settings: camera.PhotoCaptureSetting = {
                quality: camera.QualityLevel.QUALITY_LEVEL_HIGH, // 设置图片质量高
                rotation: camera.ImageRotation.ROTATION_0, // 设置图片旋转角度0
                mirror: false // 设置镜像使能开关(默认关)
              };
              if (this.photoOutput){
                this.photoOutput.capture(settings, (err: BusinessError) => {
                  if (err) {
                    console.error(`Failed to capture the photo. error: ${JSON.stringify(err)}`);
                    return;
                  }
                  console.info('Callback invoked to indicate the photo capture request success.');
                });
              }

            })
        }
        .width(100)
        .height(100)
        Image(this.pixma)
          .width(200)
          .height(200)
      }
    }
  }
}