10

I can request a video PHAsset using the Photos framework in iOS8. I'd like to know how big the file is on disk. There doesn't seem to be a property of PHAsset to determine that. Does anyone have a solution? (Using Photos framework not required)

4

3 回答 3

30

编辑

至于iOS 9.3，requestImageDataForAsset在视频类型上使用PHAsset会产生一个图像，这是视频的第一帧，所以它不再起作用了。改用下面的方法，对于普通视频，请求选项可以是nil，但对于慢动作视频，PHVideoRequestOptionsVersionOriginal需要设置。

PHVideoRequestOptions *options = [[PHVideoRequestOptions alloc] init];
options.version = PHVideoRequestOptionsVersionOriginal;

[[PHImageManager defaultManager] requestAVAssetForVideo:asset options:options resultHandler:^(AVAsset *asset, AVAudioMix *audioMix, NSDictionary *info) {
    if ([asset isKindOfClass:[AVURLAsset class]]) {
        AVURLAsset* urlAsset = (AVURLAsset*)asset;

        NSNumber *size;

        [urlAsset.URL getResourceValue:&size forKey:NSURLFileSizeKey error:nil];
        NSLog(@"size is %f",[size floatValue]/(1024.0*1024.0)); //size is 43.703005

    }
}];

//原始答案

对于 PHAsset，使用这个：

[[PHImageManager defaultManager] requestImageDataForAsset:asset options:nil resultHandler:^(NSData *imageData, NSString *dataUTI, UIImageOrientation orientation, NSDictionary *info) {
        float imageSize = imageData.length;
        //convert to Megabytes
        imageSize = imageSize/(1024*1024);
        NSLog(@"%f",imageSize);
 }];

对于 ALAsset：

ALAssetRepresentation *rep = [asset defaultRepresentation];
float imageSize = rep.size/(1024.0*1024.0);

我在一个视频资产上进行了测试，PHAsset 显示大小为 43.703125，ALAsset 显示大小为 43.703005。

编辑 PHAsset，另一种获取文件大小的方法。但是正如@Alfie Hanssen 提到的，它适用于普通视频，对于慢动作视频，以下方法将在块中返回一个 AVComposition 资产，因此我添加了对其类型的检查。对于慢动作视频，请使用该requestImageDataForAsset方法。

[[PHImageManager defaultManager] requestAVAssetForVideo:asset options:nil resultHandler:^(AVAsset *asset, AVAudioMix *audioMix, NSDictionary *info) {
    if ([asset isKindOfClass:[AVURLAsset class]]) {
        AVURLAsset* urlAsset = (AVURLAsset*)asset;
        NSNumber *size;

        [urlAsset.URL getResourceValue:&size forKey:NSURLFileSizeKey error:nil];
        NSLog(@"size is %f",[size floatValue]/(1024.0*1024.0)); //size is 43.703005
        NSData *data = [NSData dataWithContentsOfURL:urlAsset.URL];
        NSLog(@"length %f",[data length]/(1024.0*1024.0)); // data size is 43.703005
    }
}];
于 2014-10-24T16:16:24.723 回答
2

带有文件大小格式的 Swift 版本：

    let options = PHVideoRequestOptions()
    options.version = .original

    PHImageManager.default().requestAVAsset(forVideo: asset, options: options) { avAsset, _, _ in
        if let urlAsset = avAsset as? AVURLAsset {  // Could be AVComposition class
            if let resourceValues = try? urlAsset.url.resourceValues(forKeys: [.fileSizeKey]),
                let fileSize = resourceValues.fileSize {

                let formatter = ByteCountFormatter()
                formatter.countStyle = .file
                let string = formatter.string(fromByteCount: Int64(fileSize))

                print(string)
            }
        }
    }
于 2020-07-07T08:36:35.287 回答
0

你很有可能，你想知道的视频的大小不是AVURLAsset. 但是，在引擎盖下有更多的文件是您的视频合成的（例如原始样本、慢动作时间范围、过滤器等），因为您想知道具体可播放文件的大小。我不确定在这种情况下估计的文件大小如何满足现实，但应该这样做：

PHImageManager.defaultManager().requestExportSessionForVideo(asset, options: nil, exportPreset: AVAssetExportPresetHighestQuality, resultHandler: { (assetExportSession, info) -> Void in // Here you set values that specifies your video (original, after edit, slow-mo, ...) and that affects resulting size. 
    assetExportSession.timeRange = CMTimeRangeMake(kCMTimeZero, CMTimeMakeWithSeconds(asset.duration, 30)) // Time interval is default from zero to infinite so it needs to be set prior to file size computations. Time scale is I believe (it is "only" preferred value) not important in this case.
    let HERE_YOU_ARE = assetExportSession.estimatedOutputFileLength
})
于 2015-04-02T17:33:18.453 回答