上一篇文章介绍了在win8 metro 调用摄像头拍摄照片并将照片保存在相应的位置的功能，那么这一片文章主要介绍了的就是录制视频了，其实这个差不多，所用的思想也是一样的，因为图片和视频都可以转化为流文件，那么它们本质上都是一样的，但是还是有个别地方时不同的，接下来我们就介绍一下这个别地方的不同吧

下面是metro UI的代码：

<Page
    x:Class="Camera1.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:Camera1"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d">

    <Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
        <Button x:Name="btnCamera" Content="打开摄像头" HorizontalAlignment="Left" Margin="67,179,0,0" VerticalAlignment="Top" Click="btnCamera_Click"/>
        <MediaElement x:Name="media" HorizontalAlignment="Left" Height="604" Margin="273,45,0,0" VerticalAlignment="Top" Width="746"/>
        <Button x:Name="btnSave" Content="保存视频" HorizontalAlignment="Left" Margin="67,316,0,0" VerticalAlignment="Top" Click="btnSave_Click"/>
        <TextBox x:Name="txtBox1" HorizontalAlignment="Left" Margin="70,440,0,0" TextWrapping="Wrap" VerticalAlignment="Top"/>

    </Grid>
</Page>

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices.WindowsRuntime;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Navigation;

using Windows.Media.Capture;
using Windows.UI.Xaml.Media.Imaging;
using Windows.Storage;
using Windows.Storage.Streams;
using Windows.Storage.Pickers;

// The Blank Page item template is documented at http://go.microsoft.com/fwlink/?LinkId=234238

namespace Camera1
{
    /// <summary>
    /// An empty page that can be used on its own or navigated to within a Frame.
    /// </summary>
    public sealed partial class MainPage : Page
    {
        private StorageFile file = null;
        public MainPage()
        {
            this.InitializeComponent();
        }

        private async void btnCamera_Click(object sender, RoutedEventArgs e)
        {
            CameraCaptureUI dialog = new CameraCaptureUI();
            dialog.VideoSettings.Format = CameraCaptureUIVideoFormat.Mp4;
            file = await dialog.CaptureFileAsync(CameraCaptureUIMode.Video);
            if (file != null)
            {
                IRandomAccessStream fileStream = await file.OpenAsync(FileAccessMode.Read);
                media.SetSource(fileStream,file.ContentType);
            }
        }

        private async void btnSave_Click(object sender, RoutedEventArgs e)
        {
            
                FileSavePicker picker = new FileSavePicker();
                picker.CommitButtonText = "保存";
                picker.SuggestedFileName = "hello";
                picker.FileTypeChoices.Add("图片",new string[]{".mp4",".avi",".mkv",".mpg",".rmvb"});
                picker.SuggestedStartLocation = PickerLocationId.VideosLibrary;
                StorageFile filePath = await picker.PickSaveFileAsync();
                if (filePath != null)
                {
                    var streamRandom = await file.OpenAsync(FileAccessMode.Read);
                    IBuffer buffer = RandomAccessStreamToBuffer(streamRandom);
                    await FileIO.WriteBufferAsync(filePath, buffer);

                }
            
        }



        //将视频写入到缓冲区
        private IBuffer RandomAccessStreamToBuffer(IRandomAccessStream randomstream)
        {
            Stream stream = WindowsRuntimeStreamExtensions.AsStreamForRead(randomstream.GetInputStreamAt(0));
            MemoryStream memoryStream = new MemoryStream();
            if (stream != null)
            {
                byte[] bytes = ConvertStreamTobyte(stream);
                if (bytes != null)
                {
                    var binaryWriter = new BinaryWriter(memoryStream);
                    binaryWriter.Write(bytes);
                }
            }
            IBuffer buffer = WindowsRuntimeBufferExtensions.GetWindowsRuntimeBuffer(memoryStream, 0, (int)memoryStream.Length);
            return buffer;
        }

        //将流转换成二进制
        public static byte[] ConvertStreamTobyte(Stream input)
        {
            byte[] buffer = new byte[1024 * 1024];
            using (MemoryStream ms = new MemoryStream())
            {
                int read;
                while ((read = input.Read(buffer, 0, buffer.Length)) > 0)
                {
                    ms.Write(buffer, 0, read);
                }
                return ms.ToArray();
            }
        }

    }
}