m4a issues, uPnP Uniti

Posted by: mdunton on 15 November 2010

I am using Linns Kapinsky Desktop as as control point for my Uniti and encountered issues with .m4a files. Linn have patched Kapinsky desktop for me and it works fine, but point to a potential issue with the Uniti.

David at Linn wrote:
'Thanks for the console output.

The problem is that your AAC files are fundamentally MPEG4 files and can be described by both the audio/x-m4a and the audio/mp4 mime types - as such the Unity should have an entry for both variants (it only has the audio/mp4).

You should contact Naim and ask them to add http-get:*:audio/x-m4a:* to their ProtocolInfo string for the next firmware release. In the mean time I have amended our codebase to alias audio/x-m4a to audio/mp4 and vice versa. This will fix the problem with KinskyDesktop, but Naim will need to do a firmware update to solve this problem on other control points.'

I am bringing this to your attention as suggested.

Thanks!
Posted on: 15 November 2010 by Peter_RN
Have you emailed this directly to Naim HQ? Worth doing I would have thought....Peter
Posted on: 15 November 2010 by 0rangutan
Curious - never had any problems with m4a or mp4 extensions on any files streamed to my Uniti.
Posted on: 15 November 2010 by mdunton
Ok - will send this in.

I think it depends on the control point that you are using and the assumptions that the control point makes about the file formats.

Kapinsky queries what files the media device support and will not queue files that are not of the correct type. It might be that other control points do not do this check. What control point software are you using?
Posted on: 16 November 2010 by Stevesky
Hi Guys,

Thxs for the feedback.

In the current production Uniti/Qute we use the official IANA assigned entries where possible. See: http://www.iana.org/assignments/media-types/audio/

Anything beginning with 'x-' means its a non registered MIME type and naturally can be a bit of a losing battle on manufacturers listing all the 'x-' permutations out there. We'll add that one into the next code release and also do a review of all other permutations we can find at this moment in time to ensure we have them listed.

In regards to ability to play files, it is up to the UPnP Control point to decide if it wants to do sanity check logic on blocking a given format type to a render if it feels it can't play it. Unfortunately it too then has to appreciate all the 'x-' extensions and ideally know that they are equals and can be played. For example: audio/wav and audio/x-wav.

I personally think for compatibility over a wide range of servers and renders, its safer if the control point just attempts to feed the track to the render and if it plays then great, otherwise it will reject the file and go to the stop state.

Regards

Steve H (Naim R&D)
Posted on: 16 November 2010 by Tog
How stable is Kinsky with the Uniti?

Tog
Posted on: 16 November 2010 by David
Tog,

I demoed a Qute at home over the weekend and was impressed enough to place an order today.

I tried controlling it with both Kinsky and Asset Control.

Both found the Qute and were able to control UPnP playback without any issues. No ability to control the volume or other functionality via these apps though.

This could be useful as I did not find a way to add to the playlist directly on the Qute using the remote (but I have to admit I did not read the manual).


David
Posted on: 17 November 2010 by mdunton
Stevesky - thanks for the feedback. I take your point and mostly agree. I think that the only issue with going to the stop state is that if you have a playlist then the playlist stops, where if the control app will not let the file be added to the playlist in the first place then the play list will be continuous (i.e. you hit the issue before it matters).

Tog - Kinsky is reasonably stable, but not bullet proof. The issue that I have with it is that I am running two music libraries, one .flac library for the naim and one compressed library for all other devices. Both are hosted on my NAS, but I don't share the itunes library to avoid confusion and duplication of tracks. I was trying Kinsky out as I wanted an easy way of occasionally playing compressed items to the uniti (this is a much bigger library). This works for wired connections, but as the PC has to shovel the data backwards and forwards for the compressed library it does not work wireless (which was one of the main reasons for wanting to do it, jukebox for parties etc.)

Other than that it seems to be reasonably sound. Personally I think it is good that Linn are developing this software and giving it away for free (hint hint Naim).