[5644] [DLNA] [Music] Next track command from any DLNA device does not do anything.

Emby.Dlna/PlayTo/Device.cs

@@ -368,6 +368,42 @@ namespace Emby.Dlna.PlayTo
             RestartTimer(true);
         }
 
+        /*
+         * SetNextAvTransport is used to specify to the DLNA device what is the next track to play.
+         * Without that information, the next track command on the device does not work.
+         */
+        public async Task SetNextAvTransport(string url, string header, string metaData, CancellationToken cancellationToken = default)
+        {
+            var avCommands = await GetAVProtocolAsync(cancellationToken).ConfigureAwait(false);
+
+            url = url.Replace("&", "&", StringComparison.Ordinal);
+
+            _logger.LogDebug("{0} - SetNextAvTransport Uri: {1} DlnaHeaders: {2}", Properties.Name, url, header);
+
+            var command = avCommands.ServiceActions.FirstOrDefault(c => c.Name == "SetNextAVTransportURI");
+            if (command == null)
+            {
+                return;
+            }
+
+            var dictionary = new Dictionary<string, string>
+            {
+                { "NextURI", url },
+                { "NextURIMetaData", CreateDidlMeta(metaData) }
+            };
+
+            var service = GetAvTransportService();
+
+            if (service == null)
+            {
+                throw new InvalidOperationException("Unable to find service");
+            }
+
+            var post = avCommands.BuildPost(command, service.ServiceType, url, dictionary);
+            await new SsdpHttpClient(_httpClientFactory).SendCommandAsync(Properties.BaseUrl, service, command.Name, post, header: header, cancellationToken)
+                .ConfigureAwait(false);
+        }
+
         private static string CreateDidlMeta(string value)
         {
             if (string.IsNullOrEmpty(value))

Emby.Dlna/PlayTo/PlayToController.cs

@@ -102,6 +102,22 @@ namespace Emby.Dlna.PlayTo
             _deviceDiscovery.DeviceLeft += OnDeviceDiscoveryDeviceLeft;
         }
 
+        /*
+         * Send a message to the DLNA device to notify what is the next track in the playlist.
+         */
+        private async void SendNextTrackMessage(int currentPlayListItemIndex, CancellationToken cancellationToken)
+        {
+            if (currentPlayListItemIndex >= 0 && currentPlayListItemIndex < _playlist.Count - 1)
+            {
+                // The current playing item is indeed in the play list and we are not yet at the end of the playlist.
+                var nextItemIndex = currentPlayListItemIndex + 1;
+                var nextItem = _playlist[nextItemIndex];
+
+                // Send the SetNextAvTransport message.
+                await _device.SetNextAvTransport(nextItem.StreamUrl, GetDlnaHeaders(nextItem), nextItem.Didl, cancellationToken).ConfigureAwait(false);
+            }
+        }
+
         private void OnDeviceUnavailable()
         {
             try
@@ -153,6 +169,14 @@ namespace Emby.Dlna.PlayTo
                     return;
                 }
 
+                // Create the new play list item : mainly to have the normalized StreamUrl and find it in the playlist.
+                var user = !_session.UserId.Equals(Guid.Empty) ? _userManager.GetUserById(_session.UserId) : null;
+                var newItem = CreatePlaylistItem(streamInfo.Item, user, 0, streamInfo.MediaSourceId, streamInfo.AudioStreamIndex, streamInfo.SubtitleStreamIndex);
+
+                // Send a message to the DLNA device to notify what is the next track in the playlist.
+                var currentItemIndex = _playlist.FindIndex(item => item.StreamUrl == newItem.StreamUrl);
+                SendNextTrackMessage(currentItemIndex, CancellationToken.None);
+
                 var newItemProgress = GetProgressInfo(streamInfo);
 
                 await _sessionManager.OnPlaybackStart(newItemProgress).ConfigureAwait(false);
@@ -425,6 +449,11 @@ namespace Emby.Dlna.PlayTo
                     var newItem = CreatePlaylistItem(info.Item, user, newPosition, info.MediaSourceId, info.AudioStreamIndex, info.SubtitleStreamIndex);
 
                     await _device.SetAvTransport(newItem.StreamUrl, GetDlnaHeaders(newItem), newItem.Didl, CancellationToken.None).ConfigureAwait(false);
+
+                    // Send a message to the DLNA device to notify what is the next track in the play list.
+                    var newItemIndex = _playlist.FindIndex(item => item.StreamUrl == newItem.StreamUrl);
+                    SendNextTrackMessage(newItemIndex, CancellationToken.None);
+
                     return;
                 }
 
@@ -623,6 +652,9 @@ namespace Emby.Dlna.PlayTo
 
             await _device.SetAvTransport(currentitem.StreamUrl, GetDlnaHeaders(currentitem), currentitem.Didl, cancellationToken).ConfigureAwait(false);
 
+            // Send a message to the DLNA device to notify what is the next track in the play list.
+            SendNextTrackMessage(index, CancellationToken.None);
+
             var streamInfo = currentitem.StreamInfo;
             if (streamInfo.StartPositionTicks > 0 && EnableClientSideSeek(streamInfo))
             {
@@ -736,6 +768,10 @@ namespace Emby.Dlna.PlayTo
 
                     await _device.SetAvTransport(newItem.StreamUrl, GetDlnaHeaders(newItem), newItem.Didl, CancellationToken.None).ConfigureAwait(false);
 
+                    // Send a message to the DLNA device to notify what is the next track in the play list.
+                    var newItemIndex = _playlist.FindIndex(item => item.StreamUrl == newItem.StreamUrl);
+                    SendNextTrackMessage(newItemIndex, CancellationToken.None);
+
                     if (EnableClientSideSeek(newItem.StreamInfo))
                     {
                         await SeekAfterTransportChange(newPosition, CancellationToken.None).ConfigureAwait(false);
@@ -761,6 +797,10 @@ namespace Emby.Dlna.PlayTo
 
                     await _device.SetAvTransport(newItem.StreamUrl, GetDlnaHeaders(newItem), newItem.Didl, CancellationToken.None).ConfigureAwait(false);
 
+                    // Send a message to the DLNA device to notify what is the next track in the play list.
+                    var newItemIndex = _playlist.FindIndex(item => item.StreamUrl == newItem.StreamUrl);
+                    SendNextTrackMessage(newItemIndex, CancellationToken.None);
+
                     if (EnableClientSideSeek(newItem.StreamInfo) && newPosition > 0)
                     {
                         await SeekAfterTransportChange(newPosition, CancellationToken.None).ConfigureAwait(false);