public static IMediaMetadata ReadMetadata(this IStorageFile file, string format, out IEnumerable <AttachedPicture> pictures)
{
IMediaEncoder encoder = MediaEncoderExtension.EncoderByMediaType(format);
pictures = null;
if (encoder != null)
{
if (encoder.Init(file, true))
{
pictures = encoder.AttachedPictures;
return(encoder.GetMetadata());
}
}
return(null);
}
/// <summary>
/// Reads media packets passing delegate to read packets using different logic.
/// </summary>
/// <param name="sessionKey">Streaming session key.</param>
/// <param name="mediaId">Media identifier.</param>
/// <param name="funcReadPackets">Delegate function to read packets.</param>
/// <returns></returns>
protected AudioPackets ReadMediaPackets(string sessionKey, string songId, Func <IMediaEncoder, AudioPackets> funcReadPackets)
{
Guid gSongId, sessionId;
if (!Guid.TryParse(songId, out gSongId) || !Guid.TryParse(sessionKey, out sessionId))
{
return(null);
}
var mediaFile = (from s in _mediaDataContext.Get <Song>()
where s.Id == gSongId && s.Media.IsArchived == false
select s.Media).FirstOrDefault();
if (mediaFile == null)
{
return(null);
}
Guid playingMediaId = Guid.Empty;
int playingAtMSec = 0;
if (!_userSession.GetSessionInfo(sessionKey, out playingMediaId, out playingAtMSec))
{
throw new InvalidOperationException("Session not exists !");
}
string encoderStateJson = string.Empty, mediaFileStateJson = string.Empty;
AudioPackets packets = null;
int currentMSec = 0;
// Check media of state json.
if (playingMediaId == gSongId)
{
mediaFileStateJson = _cacheService.ReadFileState <string>(sessionKey);
encoderStateJson = _cacheService.ReadEncoderState <string>(sessionKey);
if (string.IsNullOrEmpty(encoderStateJson))
{
encoderStateJson = ReadMediaFileEncoderStateJson(mediaFile, out mediaFileStateJson);
_cacheService.SaveEncoderState(sessionKey, encoderStateJson);
}
}
else
{
encoderStateJson = ReadMediaFileEncoderStateJson(mediaFile, out mediaFileStateJson);
_cacheService.SaveEncoderState(sessionKey, encoderStateJson);
_cacheService.SaveFileState(sessionKey, mediaFileStateJson);
}
using (var media = string.IsNullOrEmpty(mediaFileStateJson) ?
_storage.Open(mediaFile.Url) :
_storage.OpenAndRestoreState(mediaFile.Url, mediaFileStateJson))
{
IMediaEncoder encoder = MediaEncoderExtension.EncoderByMediaType(mediaFile.Format);
if (encoder == null)
{
throw new InvalidOperationException($"Unable to instantiate encoder by format = '{mediaFile.Format}'!");
}
if (encoder.Init(media, false, encoderStateJson))
{
packets = funcReadPackets.Invoke(encoder);
if (packets != null)
{
// if(encoder.SaveStateIntoJson(out encoderStateJson))
// {
// // Save encoder state in cache.
// SaveEncoderStateInCache(sessionKey, encoderStateJson);
// }
currentMSec = (int)encoder.CurrentMs;
}
}
// Save media file state in cache.
if (string.IsNullOrEmpty(mediaFileStateJson))
{
_cacheService.SaveFileState(sessionKey, media.SaveStateAsJson());
}
// ???
//encoder.Dispose();
}
// Update playing session info.
_userSession.UpdateSessionInfo(sessionKey, gSongId, currentMSec);
return(packets);
}