HarmonyOS 如何获得应用沙盒内视频的缩略图

可参考以下官方文档获取图片和视频缩略图：https://developer.huawei.com/consumer/cn/doc/harmonyos-guides-V5/photoaccesshelper-resource-guidelines-V5

@ohos.file.photoAccessHelper (相册管理模块)的getThumbnail方法https://developer.huawei.com/consumer/cn/doc/harmonyos-references-V5/js-apis-medialibrary-V5#getthumbnail8

想要获取相册视频相关信息，推荐使用临时授权方式，https://developer.huawei.com/consumer/cn/doc/harmonyos-guides-V5/user-file-uri-intro-V5

参考以下代码，test1.mp4 在沙箱中

public static writeVideo(ctx: Context) {
  let mgr = ctx.resourceManager
  let buf = mgr.getRawFileContentSync("test1.mp4");
  let file = fileIo.openSync(ctx.cacheDir + "/test1.mp4", fileIo.OpenMode.READ_WRITE | fileIo.OpenMode.CREATE);
  fileIo.writeSync(file.fd, buf.buffer);
}

public static async getVideoPicture(path: string): Promise<PixelMap> {
  let avImageG = await media.createAVImageGenerator();
  let file = fileIo.openSync(path, fileIo.OpenMode.READ_WRITE | fileIo.OpenMode.CREATE);
  avImageG.fdSrc = file;
  let pix = avImageG.fetchFrameByTime(0, media.AVImageQueryOptions.AV_IMAGE_QUERY_NEXT_SYNC, {width: 300, height: 300});
  return pix;
}