Question

我正在使用MediaPlayerElement创建Twitch播放器，我想实时更新MediaPlayerElement的缓冲区，但是我不知道如何。

我试图这样做：

public sealed partial class MainPage : Page
{
    MemoryStream stream = new MemoryStream(64 * 1024 * 1024);
    BinaryWriter writer;
    BinaryReader reader;

    Task task;

    public MainPage()
    {
        this.InitializeComponent();

        writer = new BinaryWriter(stream);
    }

    async void ReadTask()
    {
        while (true)
        {
            var bytes = reader.ReadBytes(1024 * 1024);

            if (bytes.Length == 0)
            {
                break;
            }

            writer.Write(bytes);

            // Do some delay to see progress of loading
            await Task.Delay(1000);
        }
    }

    private async void Page_Loaded(object sender, RoutedEventArgs e)
    {
        // I'm using file to speed up tests
        StorageFile file = await StorageFile.GetFileFromApplicationUriAsync(new Uri("ms-appx:///Assets/output.ts"));

        reader = new BinaryReader(await file.OpenStreamForReadAsync());

        // Write few first bytes
        writer.Write(reader.ReadBytes(1024 * 1024));

        // Start task which will write more bytes soon
        task = new Task(ReadTask);
        task.Start();

        StreamMediaPlayer.AreTransportControlsEnabled = true;
        StreamMediaPlayer.AutoPlay = true;
        StreamMediaPlayer.MediaPlayer.Volume = 0;
        StreamMediaPlayer.Source = MediaSource.CreateFromStream(writer.BaseStream.AsRandomAccessStream(), "video/MP2T");
    }
}

此代码有效，但即使TaskRead()在播放视频时写入更多字节，播放器也只会显示我在设置源之前写入的前1 MB。

我还尝试使用方法CreateFromStreamReference代替CreateFromStream，如下所示：

var s = RandomAccessStreamReference.CreateFromStream(writer.BaseStream.AsRandomAccessStream());
StreamMediaPlayer.Source = MediaSource.CreateFromStreamReference(s, "video/MP2T");

但这根本不起作用。

这是一个包含视频的完整项目：https://drive.google.com/open?id=175Z5HzK3MJ-Dm4ZX84r81lWYtZ0ahSSS

Answer 1

我知道了。我必须使用MseStreamSource。

首先，我需要使用以下事件创建MseStreamSource：

streamSource = new MseStreamSource();
streamSource.Opened += (_, __) =>
{
    if (buffer is null)
    {
        // it will create buffer where I can write data
        buffer = streamSource.AddSourceBuffer("video/MP2T");
        buffer.Mode = MseAppendMode.Sequence;
    }
};

然后设置源：

StreamMediaPlayer.Source = MediaSource.CreateFromMseStreamSource(streamSource);

如果我想添加视频，我必须这样做：

buffer.AppendBuffer(reader.ReadBytes(20 * 1024 * 1024).AsBuffer());

我必须确保缓冲区没有更新。此信息提供IsUpdating属性。

如何实时更新MediaPlayerElement的缓冲区？

1 个答案: