/// <summary>
/// Selects formats based on a format specifier from the list of available formats.
/// Note that this only supports single formats, precedence lists ("/") and merges ("+").
/// </summary>
/// <returns>The selected formats or null if none existing.</returns>
public static FormatData[] SelectFormat(this VideoData videoData, string formatSpecifier)
{
// 1. Split by precedence list: "/"
foreach (string group in formatSpecifier.Split('/'))
{
// 2. Split merging group: "+"
string[] splits = group.Split('+');
if (splits.Length == 1)
{
FormatData format = videoData.SelectSingleFormat(splits[0]);
if (format != null)
{
return new[] { format }
}
;
else
{
continue;
}
}
else if (splits.Length == 2)
{
FormatData video = videoData.SelectSingleFormat(splits[0]);
FormatData audio = videoData.SelectSingleFormat(splits[1]);
// continue with next option if one of video or audio is not existing
if (video == null || audio == null)
{
continue;
}
if (video.VideoCodec == "none")
{
throw new ArgumentException("The first format in a merge must contain a video.");
}
if (audio.AudioCodec == "none")
{
throw new ArgumentException("The second format in a merge must contain an audio.");
}
return(new[] { video, audio });
}
else
{
throw new ArgumentException($"Invalid formar specifier {formatSpecifier}");
}
}
// we have found none of the given formats
return(null);
}