C＃获取从元数据中的视频文件时长 [英] C# Get video file duration from metadata

问题描述

我想从文件中读取元数据。我只需要视频 - >长度属性，但是我无法找到阅读本信息的简单方法。

I am trying to read metadata from a file. I only need the Video -> Length property, however I am unable to find a simple way of reading this information.

我想这将是相当容易的，因为它是可见默认情况下，在资源管理器，然而，这看起来是比我预期的方式更加复杂。我来用最接近的：

I figured this would be fairly easy since it is visible by default in Explorer, however this looks to be way more complicated than I anticipated. The closest I came was using:

Microsoft.DirectX.AudioVideoPlayback.Video video = new Microsoft.DirectX.AudioVideoPlayback.Video(str);
double duration = video.Duration;

然而，这将引发一个LoaderLock例外，我不知道该如何处理它。

However this throws a LoaderLock exception, and I don't know how to deal with it.

任何想法？

推荐答案

许多这样的细节由shell提供，这样你就可以通过向COM库微软壳牌控制和自动化（SHELL32）的引用，然后使用Folder.GetDetailsOf方法来查询扩展细节做到这一点。

Many of these details are provided by the shell, so you can do this by adding a reference to the COM Library "Microsoft Shell Controls and Automation" (Shell32), and then using the Folder.GetDetailsOf method to query the extended details.

我最近在寻找这一点，碰到的这个非常的MSDN C＃通用论坛质疑。我结束了写这个作为一个扩展的方法对FileInfo：

I was recently looking for this and came across this very question on the MSDN C# General forums. I wound up writing this as an extension method to FileInfo:

    public static Dictionary<string, string> GetDetails(this FileInfo fi)
    {
        Dictionary<string, string> ret = new Dictionary<string, string>();
        Shell shl = new ShellClass();
        Folder folder = shl.NameSpace(fi.DirectoryName);
        FolderItem item = folder.ParseName(fi.Name);

        for (int i = 0; i < 150; i++)
        {
            string dtlDesc = folder.GetDetailsOf(null, i);
            string dtlVal = folder.GetDetailsOf(item, i);

            if (dtlVal == null || dtlVal == "")
                continue;

            ret.Add(dtlDesc, dtlVal);
        }
        return ret;
    }

如果你正在寻找特定的条目，你可以做类似的事情，但它会快得多，找出这些条目是在什么指数（长度为27指数我相信），只是查询这些信息。请注意，我没有做太多研究指数是否可以改变（我对此表示怀疑），这就是为什么我把字典方法。

If you're looking for specific entries, you can do something similar, though it will be far faster to find out what index those entries are at (Length is index 27 I believe) and just query those. Note, I didn't do much research into whether or not the index can change (I doubt it), which is why I took the dictionary approach.

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