Gaplessness....

[MarmiteSandwich]

(21-09-2021 13:26)skeptic Mike Wrote:  Interesting. The nature of lossy compression using mDCT https://en.wikipedia.org/wiki/Modified_d..._transform gives rise to the problem you have found at the beginning of any such compressed audio file - you need something to overlap with.

For aac in m4a files there appear to be 2 solutions: iTunSMPB or a later ISO standard as mentioned in the response you got.

You should be able to figure out whether the ffmpeg code can handle the ISO version of this using qaac, this is a Windows command line program that drives the Apple iTunes encoder software. You can then encode with both versions, see: https://github.com/nu774/qaac/wiki/Encod...figuration

This should enable you to test your mpd installation. If it works with your m4a files that include the ISO gapless information, then you know what to do in future. If it doesn't, then you know what the problem is.

As for converting old files, if ffmpeg doesn't support this, then one other possibility is mp4box from gpac. This project seeks to be standards compliant, so if it doesn't do this, it might accept it as a feature request. see: https://github.com/gpac/gpac

OTOH disk space is cheap, so standardising on flac would also solve your problem. Even though it seems inelegant to use disk space for no audible benefit outside track transition.

Really the problem is tracks. CDs (or even vinyl) don't have tracks, they have cueing points. Most competent PC based music players can read cue sheets, and will handle one audio file and a cue sheet perfectly. Upnp doesn't support this, although playing one file will mean there are no gaps, and you could create separate files where gaps didn't matter

Very useful information, to be followed up in due course, especially if CA don't deliver. Or I might just settle for re-ripping those albums which present problems, using alac. Wherever I mentioned flac previously I meant alac, since iTunes doesn't support flac, obvs.

(21-09-2021 13:26)skeptic Mike Wrote:  PS - should we have a capability matrix for renderers? It's very hard to find out what the limitations are, and as Marmite has shown the manafacturers may not know.

I would be very happy to add my experiences of multiple renderers, both in hardware and software, to such a resource, but I am afraid someone else would need to take the initiative and set it up.
Marmite