《鸿蒙开发-答案之书》获取视频第一帧和视频时间

/*** 获取视频信息*```*let result = await MySightUtil.getSightInfo(this.sightUri);*let base64 : string = result[0];*let duration : number = result[1]*```* @param uri 视频地址* @returns 第一个数据是缩略图 base64 字符串，第二个是视频时长（单位秒）*/public static async getSightInfo(uri: string): Promise<[string, number]> {let file = fs.openSync(uri, fs.OpenMode.READ_ONLY);let fdSrc: media.AVFileDescriptor = {fd: file.fd};// 视频第一帧let base64 = '';try {// 获取第一帧let avImageGenerator: media.AVImageGenerator = await media.createAVImageGenerator();// 设置fdSrcavImageGenerator.fdSrc = fdSrc;// 初始化入参let timeUs = 0;let queryOption = media.AVImageQueryOptions.AV_IMAGE_QUERY_NEXT_SYNC;let param: media.PixelMapParams = {};// 获取缩略图（promise模式）let pixelMap = await avImageGenerator.fetchFrameByTime(timeUs, queryOption, param);// 释放资源（promise模式）await avImageGenerator.release();const MAX_SIZE = 240;const MIN_SIZE = 100;await calculateThumbnailScaling(pixelMap, MAX_SIZE, MIN_SIZE);const imagePackerApi: image.ImagePacker = image.createImagePacker();let packOpts: image.PackingOption = { format: 'image/jpeg', quality: 80 };let data: ArrayBuffer = await imagePackerApi.packing(pixelMap, packOpts);let buf: buffer.Buffer = buffer.from(data);base64 = buf.toString('base64', 0, buf.length);} catch (error) {let err = error as BusinessError;hilog.error(0x0000, '', `error code: ${err.code}, error message: ${err.message}`);}// 视频时长let duration: number = 0;try {// 获取视频时长let aVMetadataExtractor: media.AVMetadataExtractor = await media.createAVMetadataExtractor();aVMetadataExtractor.fdSrc = fdSrc;let metadata = await aVMetadataExtractor.fetchMetadata();aVMetadataExtractor.release();// 毫秒duration = new Number(metadata.duration).valueOf();hilog.error(0x0000, 'IM-APP', `metadata: %{public}s`, JSON.stringify(metadata));} catch (error) {let err = error as BusinessError;hilog.error(0x0000, '', `error code: ${err.code}, error message: ${err.message}`);}return [base64, duration / 1000];}