从媒体流中读取信息 [英] Reading info from media stream

问题描述

您好， 

我需要从媒体流中获取信息，我发现了类似的主题http://social.msdn.microsoft.com/Forums/en -US / csharpgeneral / thread / 3d2e9e48-8a02-419f-91e1-c61faf28bcf7 /有答案，但FileStream不适用于Windows应用商店应用，我可以使用什么来
从Windows Stor App中的媒体流获取信息？

解决方案

使用帖子中链接的方法，这对我有用：

< pre class ="prettyprint"> private async void Button_Click（object sender，RoutedEventArgs e）
{
FileOpenPicker openPicker = new FileOpenPicker（）;
openPicker.ViewMode = PickerViewMode.Thumbnail;
openPicker.SuggestedStartLocation = PickerLocationId.MusicLibrary;
openPicker.FileTypeFilter.Add（" .mp3"）;

byte [] b =新字节[128];
StorageFile file = await openPicker.PickSingleFileAsync（）;
if（file！= null）
{
var stream = await file.OpenAsync（Windows.Storage.FileAccessMode.Read）;
var size = stream.Size;
using（var inputStream = stream.GetInputStreamAt（stream.Size - 128））
{
DataReader dataReader = new DataReader（inputStream）;
uint numBytesLoaded = await dataReader.LoadAsync（128）;
dataReader.ReadBytes（b）;

String sFlag = System.Text.UTF8Encoding.UTF8.GetString（b，0,3）.TrimEnd（new char [] {'\ 0'}）;
if（sFlag.CompareTo（" TAG"）== 0）
{
MetaData.Text ="找到标签！ " + Environment.NewLine;

//获得歌曲的标题;
var sTitle = System.Text.UTF8Encoding.UTF8.GetString（b，3,30）.TrimEnd（new char [] {'\ 0'}）;
MetaData.Text + =" Title：" + sTitle + Environment.NewLine;
//得到歌手;
var sSinger = System.Text.UTF8Encoding.UTF8.GetString（b，33,30）.TrimEnd（new char [] {'\ 0'}）;
MetaData.Text + ="歌手：" + sSinger + Environment.NewLine;
//获得专辑;
var sAlbum = System.Text.UTF8Encoding.UTF8.GetString（b，63,30）.TrimEnd（new char [] {'\ 0'}）;
MetaData.Text + ="相册：" + sAlbum + Environment.NewLine;
//获得发布年份;
var sYear = System.Text.UTF8Encoding.UTF8.GetString（b，93,4）.TrimEnd（new char [] {'\ 0'}）;
MetaData.Text + =" Year：" + sYear + Environment.NewLine;
//获取评论;
var sComm = System.Text.UTF8Encoding.UTF8.GetString（b，97,30）.TrimEnd（new char [] {'\ 0'}）;
MetaData.Text + ="评论：" + sComm + Environment.NewLine;
}
}
}
其他
{
MetaData.Text ="操作已取消。" ;;
}
}

Hello, 

I need to get info from a media stream, I found similar topic http://social.msdn.microsoft.com/Forums/en-US/csharpgeneral/thread/3d2e9e48-8a02-419f-91e1-c61faf28bcf7/ with answer, but FileStream is not presented for Windows Store Apps, what can I use to get info from media stream in the Windows Stor App?

解决方案

Using the method from the link in your post, here is what works for me:

        private async void Button_Click(object sender, RoutedEventArgs e)
        {
            FileOpenPicker openPicker = new FileOpenPicker();
            openPicker.ViewMode = PickerViewMode.Thumbnail;
            openPicker.SuggestedStartLocation = PickerLocationId.MusicLibrary;
            openPicker.FileTypeFilter.Add(".mp3");

            byte[] b = new byte[128];
            StorageFile file = await openPicker.PickSingleFileAsync();
            if (file != null)
            {
                var stream = await file.OpenAsync(Windows.Storage.FileAccessMode.Read);
                var size = stream.Size;
                using (var inputStream = stream.GetInputStreamAt(stream.Size - 128))
                {
                    DataReader dataReader = new DataReader(inputStream);
                    uint numBytesLoaded = await dataReader.LoadAsync(128);
                    dataReader.ReadBytes(b);

                    String sFlag = System.Text.UTF8Encoding.UTF8.GetString(b, 0, 3).TrimEnd(new char[] { '\0' });
                    if (sFlag.CompareTo("TAG") == 0)
                    {
                        MetaData.Text = "Tag   is   found! " + Environment.NewLine;
                                         
                        //get   title   of   song; 
                        var sTitle = System.Text.UTF8Encoding.UTF8.GetString(b, 3, 30).TrimEnd(new char[] { '\0' });
                        MetaData.Text += "Title: " + sTitle + Environment.NewLine;
                        //get   singer; 
                        var sSinger = System.Text.UTF8Encoding.UTF8.GetString(b, 33, 30).TrimEnd(new char[] { '\0' });
                        MetaData.Text += "Singer: " + sSinger + Environment.NewLine;
                        //get   album; 
                        var sAlbum = System.Text.UTF8Encoding.UTF8.GetString(b, 63, 30).TrimEnd(new char[] { '\0' });
                        MetaData.Text += "Album: " + sAlbum + Environment.NewLine;
                        //get   Year   of   publish; 
                        var sYear = System.Text.UTF8Encoding.UTF8.GetString(b, 93, 4).TrimEnd(new char[] { '\0' });
                        MetaData.Text += "Year: " + sYear + Environment.NewLine;
                        //get   Comment; 
                        var sComm = System.Text.UTF8Encoding.UTF8.GetString(b, 97, 30).TrimEnd(new char[] { '\0' });
                        MetaData.Text += "Comment: " + sComm + Environment.NewLine;
                    }
                }
            }
            else
            {
                MetaData.Text = "Operation cancelled.";
            }
        }

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