Originally Posted by wmcclain
My album art experiments were long ago and perhaps out of date for the BDP-103, but it seemed to me the player would display images embedded as a tag in the file. This is the same as for local files. I did not see it for any external images, and I didn't think it was common for DLNA servers to support that (but times change).
There are two ways that album art can be transferred:
1) As you mention, the first method is when the actual music file contains meta data tags. This means that as the player downloads the music file from the server, it parses the embedded tags, and displays the respective data on screen. This can work well when the file being played is in the original music format that the user had tagged (e.g. AAC and MP3). However it does not work if the server is transcoding the file to another format (unless the server adds the tags on the fly), and it certainly does not work if the server is streaming lossless LPCM (since PCM is not allowed to contain anything beyond plain music samples).
2) The second method is using the UPnP mechanisms. Actually this splits into two sub- methods depending on whether the player is browsing the server's content directory tree and "pulling" the music ("Play" function) or whether the server or some other Control Point is "pushing" the music to the player ("Play To" function).
2a) UPNP Pull mode: in this mode the player browses the server's content directory tree (using the UPNP Browse action), and for each album or track in the tree the server delivers an xml data packet that contains meta data (title, artists, genre, duration, format, etc.) as well as resource URLs where the player can download (pull) the track from (there may be several URLs coresponding to different transcoded music formats), and also a URL where the player can download the album art from.
2b) UPNP Push mode: in this mode, the server or another Control Point uses the UPNP SetAvTransportUri action to command the player to play a specific track. In this case the server also passes (similar to case 2a above) an xml data packet that contains the track resource URL, the respective meta data and the album art URL.
In my tests, I was running case 2b) above, with music transcoded by the server from M4A format to LPCM, and in this case, the player shows the track meta data but it is not downloading the album art (to be quite precise: I don't know if it is downloading it, but it is certainly not displaying it...)
Originally Posted by wmcclain
How is your album art stored, and what DLNA client displays it?
The question is not really relevant, but just so you know: My source files are a mix of FLAC, M4A, MP3, WAV, and perhaps others. All have meta data within the files (in whatever is the allowed tag format for that file format). My servers all offer the meta data, track resources and art URLs in conformity with the UPNp certification tests. Other clients (such as JRiver, Windows Media Player, Sony Tv, and various mobile phone apps) can display that meta data and art from these servers. However the Oppo does not...