IIS在启动时平滑流式传输低质量

Question

我在windows azure上托管一些自适应流媒体视频,我注意到在开始时视频以最低的可用比特率开始.这是一个大问题.

我通过搜索互联网看到一个技巧可以通过挂钩manifestready事件并删除最低比特率然后在一段时间后再添加它们来完成.这很有意义,但我没有看到这样做的示例代码.

我从表达式编码器4获得了播放器代码并看了一眼,但发现无处可去做更改.

有人有更多关于改善平滑流媒体启动的信息吗？

非常感谢你

Answer 1

你好我把这个问题发布到媒体平台播放器论坛,得到了一个有效的答案.

讨论在这里:http://smf.codeplex.com/discussions/271042

这是我使用的代码:

public MainPage() {
        InitializeComponent();
        player.MediaPluginRegistered += new EventHandler<CustomEventArgs<IMediaPlugin>>(player_MediaPluginRegistered);
        player.PlayStateChanged += new EventHandler<CustomEventArgs<MediaPluginState>>(Player_PlayStateChanged);
    }
private IAdaptiveMediaPlugin _adaptivePlugin = null;
private bool isStartupHeuristicsActive = false;

void player_MediaPluginRegistered(object sender, CustomEventArgs<IMediaPlugin> e) {
    var adaptivePlugin = e.Value as IAdaptiveMediaPlugin;
    if (adaptivePlugin == null) return; 
    if (_adaptivePlugin == null) _adaptivePlugin = adaptivePlugin;
    _adaptivePlugin.ManifestReady +=new Action<IAdaptiveMediaPlugin>(_adaptivePlugin_ManifestReady);
}

void  _adaptivePlugin_ManifestReady(IAdaptiveMediaPlugin obj)
{
    if (_adaptivePlugin != null)
    {
        var videoStream = _adaptivePlugin.CurrentSegment.SelectedStreams.Where(i => i.Type == StreamType.Video).FirstOrDefault();

        if (videoStream != null)
        {
            var averageBitrate = videoStream.AvailableTracks.Average(t => t.Bitrate);

            var track = videoStream.AvailableTracks.FirstOrDefault(t => t.Bitrate >= averageBitrate);
            if (track != null)
            {
                isStartupHeuristicsActive = true;
                videoStream.SetSelectedTracks(new[] { track });
            }
        }
    }
}

private void Player_PlayStateChanged(object sender, CustomEventArgs<MediaPluginState> e)
{
    if (isStartupHeuristicsActive && e.Value == MediaPluginState.Playing)
    {
        isStartupHeuristicsActive = false;
        if (_adaptivePlugin != null)
        {
            var videoStream = _adaptivePlugin.CurrentSegment.SelectedStreams.Where(i => i.Type == StreamType.Video).FirstOrDefault();
            if (videoStream != null)
            {
                videoStream.SetSelectedTracks(videoStream.AvailableTracks);
            }
        }
    }
}

谢谢