iPhone / iPad Subsonic app that will fade songs into each

[guitargurus]

Hello. I've been using subsonic for many many years and love it. A big thanks to sindre and everyone else that contributes.

I'm looking for an iPhone / iPad app for subsonic, that will allow continuous playback of music, as in songs are faded into each other (end of song fades into the beginning of the next or soft fade out and the next song fades in). I hope i'm explaining this well. This is a standard feature in iTunes, and I'm trying very hard to get the last couple iTunes die-hards in my family to ditch it. They love subsonic, but my mom in particular needs the ability to have songs fade into each other. She is a yoga teacher and the music they use for meditation needs to flow nicely to keep the mood right. I've used iSub on the iphone for many years, but unfortunately it does not support this. It would also be awesome if this could also be done via the web interface/player.

Any help / pointers would be greatly appreciated.

[guitargurus]

I've been doing some research on ffmpeg and ffmpeg does support fading in and out, BUT, all of the examples i've found seem to require the length of the audio file to implement the fade out. Implementing fade in/out on the server side via transcoding would be the best solutions, as it wouldn't require any different/special apps on the phone side. I'm just a bit stuck on how to implement fading via ffmpeg on the subsonic server. Since there is no way to know the length of the audio file/song in advance, and all of them are different, i don't know how i could structure an ffmpeg command to accomplish this.

Any ideas/comments??