AAC decoders different? iTunes-encoded gapless, Nero is not...

[sidewalking]

I was curious.  I enjoy Vorbis on my Rockboxed Sansa e260, but I will be inevitably getting a newer model 120 GB iPod Classic, thus pushing me back to testing AAC.  Nero-encoded stuff isn't gapless (even if encoded with Foobar), but when I pipe it through iTunesEncode.exe, it plays gaplessly on the Sansa.

Are different decoders used (I thought it was FAAD2, maybe)?  If not, does anyone know why the difference?

Thanks!

[Llorean]

This isn't the place for discussing PC-side software. This isn't a general media player forum, it's for questions about Rockbox.

[Lear]

Actually, this is a Rockbox question.

Anyway, for AAC to be gapless, the decoder need to read some extra information, written by the file by the encoder. Currently Rockbox knows where iTunes writes it, but not where Nero writes it.

[Llorean]

He's asking about playing it on an iPod Classic. Those don't even run Rockbox. Our gapless support has nothing to do with what will successfully play on it.

[Chronon]

His current observations regarding gaplessness are apparently made with an e260 (which might be Rockboxed).  So, a connection to Rockbox can be made.  Lear answered the implied Rockbox related question: Why would Rockbox play files produced by one encoder gaplessly, but not files produced by another?

Obviously, advice about what will or won't be gapless on a 120GB iPod Classic has no place here.

[sidewalking]

Actually, this is a Rockbox question.

Anyway, for AAC to be gapless, the decoder need to read some extra information, written by the file by the encoder. Currently Rockbox knows where iTunes writes it, but not where Nero writes it.

Thanks Lear - that answers precisely what I was wondering.  I apologize to the rest for being unclear.  My question was all about AAC playback on the Rockbox firmware. 

To clarify - I do have a Rockboxed Sansa, and I know I won't be able to Rockbox the iPod Classic (well, as things currently stand since Apple locked the new models down).  I was wanting to go with Nero instead of Vorbis for my lower-bitrate encodes (I use LAME for higher bitrate lossy), and Rockbox allows me to listen to AAC on the Sansa.  I know Nero is not the most efficient on Rockbox, but the Vorbis will be of no use to me when I get the iPod Classic later on.  AAC playback is of use to me now because I can play it now on Rockbox and later on the iPod native firmware.

So, I was just wondering why the difference in playback on Rockbox, since I thought there was just the one decoder for AAC streams.