/// <summary>
/// Returns the best format from the list in this order of availability: WebM, Mp4 or Flash.
/// Mp4 will be chosen if WebM is over 35% smaller.
/// </summary>
/// <param name="list">The list of videos to chose from.</param>
/// <returns>The best format available.</returns>
public static BestFormatInfo SelectBestFormat(MediaStreamInfoSet vstream, DownloadOptions options)
{
var MaxResolutionList = (from v in vstream.Audio.Cast <MediaStreamInfo>().Union(vstream.Video).Union(vstream.Muxed)
where (options.MaxQuality == 0 || GetVideoHeight(v) <= options.MaxQuality)
orderby GetVideoHeight(v) descending
orderby GetVideoFrameRate(v) descending
select v).ToList();
MaxResolutionList = MaxResolutionList.Where(v => GetVideoHeight(v) == GetVideoHeight(MaxResolutionList.First())).ToList();
//double Framerate = GetVideoFrameRate(MaxResolutionList.FirstOrDefault());
//if (Framerate > 0)
// MaxResolutionList = MaxResolutionList.Where(v => GetVideoFrameRate(v) == Framerate).ToList();
MediaStreamInfo BestVideo = (from v in MaxResolutionList
// WebM VP9 encodes ~30% better. non-DASH is VP8 and isn't better than MP4.
let Preference = (int)((GetVideoEncoding(v) == VideoEncoding.Vp9) ? v.Size * 1.3 : v.Size)
where options.PreferredFormat == SelectStreamFormat.Best ||
(options.PreferredFormat == SelectStreamFormat.MP4 && GetVideoEncoding(v) == VideoEncoding.H264) ||
(options.PreferredFormat == SelectStreamFormat.VP9 && GetVideoEncoding(v) == VideoEncoding.Vp9)
orderby Preference descending
select v).FirstOrDefault();
if (BestVideo == null)
{
BestVideo = MaxResolutionList.FirstOrDefault();
}
if (BestVideo != null)
{
BestFormatInfo Result = new BestFormatInfo {
BestVideo = BestVideo,
BestAudio = SelectBestAudio(vstream, options)
};
return(Result);
}
else
{
return(null);
}
}
private async Task StartDownloadAsync(DownloadItem downloadInfo)
{
downloadInfo.Status = DownloadStatus.Initializing;
// Query the download URL for the right file.
string VideoId = null;
Video VInfo = null;
MediaStreamInfoSet VStream = null;
if (YoutubeClient.TryParseVideoId(downloadInfo.Url, out VideoId))
{
try {
var T1 = youtube.GetVideoAsync(VideoId);
var T2 = youtube.GetVideoMediaStreamInfosAsync(VideoId);
await Task.WhenAll(new Task[] { T1, T2 });
VInfo = T1.Result;
VStream = T2.Result;
}
catch {
}
}
if (VStream == null)
{
downloadInfo.Status = DownloadStatus.Failed;
RaiseCallback(downloadInfo);
return;
}
// Get the highest resolution format.
BestFormatInfo BestFile = DownloadManager.SelectBestFormat(VStream, downloadInfo.Options ?? Options);
BestFile.Duration = VInfo.Duration;
if (BestFile.BestVideo != null && (downloadInfo.Action == DownloadAction.Download || downloadInfo.Action == DownloadAction.DownloadVideo))
{
downloadInfo.Files.Add(new FileProgress()
{
Type = StreamType.Video,
Url = BestFile.BestVideo.Url,
Destination = downloadInfo.DestinationNoExt + GetVideoExtension(DownloadManager.GetVideoEncoding(BestFile.BestVideo)),
Stream = BestFile.BestVideo,
BytesTotal = BestFile.BestVideo.Size
});
}
if (BestFile.BestAudio != null && (downloadInfo.Action == DownloadAction.Download || downloadInfo.Action == DownloadAction.DownloadAudio))
{
downloadInfo.Files.Add(new FileProgress()
{
Type = StreamType.Audio,
Url = BestFile.BestAudio.Url,
Destination = downloadInfo.DestinationNoExt + GetAudioExtension(BestFile.BestAudio.AudioEncoding),
Stream = BestFile.BestAudio,
BytesTotal = BestFile.BestAudio.Size
});
}
// Add extension if Destination doesn't already include it.
string Ext = DownloadManager.GetFinalExtension(BestFile.BestVideo, BestFile.BestAudio);
if (!downloadInfo.Destination.ToLower().EndsWith(Ext))
{
downloadInfo.Destination += Ext;
}
await DownloadFilesAsync(downloadInfo).ConfigureAwait(false);
}