Non-playing .m4a files coded from ffmpeg?

[ww1223]

Help sought please, and the standard disclaimers:

- I've spent several hours searching the forums and the Wiki
- apologies in advance for any gross misunderstandings of how things work

I have a Squeezebox Radio (firmware 7.4.1) being fed by Squeezebox Server (also 7.4.1) under Vista, itself sourcing audio from iTunes.

All my iTunes audio files are .m4a AAC. However, some have been ripped using iTunes from CD, others have been recorded from old vinyl using Audacity and ffmpeg.

The problem is that the CD-sourced files play on the Radio, but the Audacity/ffmpeg sourced ones don't ('can't open file' error). In contrast, both sets of files play fine through iTunes/Quicktime.

iTunes 'Info' reports the following for the two types of file:

CD-sourced: AAC audio file,128kpbs, 44100kHz, encoded with Quicktime 6.5.2
Audacity/ffmpeg sourced: AAC audio file, 124kpbs, 44100kHz, encoded with Lavf52.23.1

I understand that the Radio should decode AAC natively. So is there some limitation or bug in the Radio's native decoder that prevents it from decoding certain flavours of .m4a AAC files, amongst them my ffmpeg-coded ones?

I reluctantly decided the answer would have to be transcoding, and reasoned that the best decoder to use would be the same as the encoder, ie ffmpeg. After a lot of blundering about through ignorance I managed to hack convert.conf to pick up ffmpeg.exe and use it to transcode all of the .m4a files to flac. This works fine, but does load my wireless network a lot.

(As an aside, convert.conf is a great idea, but its syntax, particularly around 'Capabilities' and their importance doesn't seem very well documented. Initially, SqueezeServer kept spitting out the ffmpeg command line because 'required capability T' was not supported, and it took ages to work out how to include this correctly in convert.conf)

So, in summary, I would still prefer to send the original .m4a/AAC over the wireless network and get the Radio to do its stuff natively on all my files.

Can anyone shed any light please?

Thanks in anticipation.

[bpa]

Using the original convert.conf file - if you disable both m4a and AAC native in Settings/Advanced/Filetypes and let faad decode - does it work ?

If not what does "faad -i" on your file display ?

[ww1223]

Yes, following this procedure does work - the ffmpeg-coded files play.

Presumably faad is now doing the transcoding job that I managed to get ffmpeg to do? Is there any advantage to this - or does this experiment now give a deeper insight into why the Radio's native decoder won't work?

Please let me know, and many thanks for picking up my query.



PS I don't know if it's still useful, but I also did faad -i on my test file with the following result:

test.m4a file info:

LC AAC 227.032 secs, 2 ch, 44100 Hz

title: You Could've Been a Lady
tool: Lavf52.23.1
track: 8
totaltracks: 16
artist: Hot Chocolate
album: The Very Best of Hot Chocolate
genre: R&B

[andyg]

Please file a bug and attach one of the files.

[bpa]

There have been a few other reports of user who bought iTunes files which play with native disabled but cannot play with Radio's native decoder.

for example:
2 instances noted in this thread : http://forums.slimdevices.com/showthread.php?t=72441

I think this thread may also be the same problem
http://forums.slimdevices.com/showthread.php?t=74128

[florca]

I also had a whole load of issues with ffmpeg-created M4A files which would play on some systems / devices but not others (mainly that although they would work on iTunes and through faad they wouldn't play on an iPod or foobar2000). After trying many ffmpeg options, I ended up "re-packaging" the files by running through MP4Box using:

MP4Box -add <infile> <outfile>

if <outfile> has an .m4a extension then MP4Box will default to a format which seems to work fine on anything I've thrown it at. This doesn't transcode / re-encode the media but seems to sort out the metadata and atom formats to something much more universal. Read more at:

http://gpac.sourceforge.net/doc_mp4box.php

If you want to tag the tracks using the command line then a combination of AtomicParsley and mp4tags (part of the mp4v2 package - http://code.google.com/p/mp4v2/ ) work well, although each only support a subset of tags - the combination seems to do everything I want.

In my case this is all on Linux, but I suspect you can build on Windows / Mac also?

Brgds

Phil

[ww1223]

Thanks for this, I'll take a look at my metadata!

In the meantime, I've filed a bug as recommended (15703, under 'Radio').