[PATCH] Output AAC as M4A for iTunes with metadata tags (Shevek)

[Jon Davies]

On 28 March 2011 13:59, richard <richard at richsim900.plus.com> wrote:
> I've done some tests with MediaInfo and AtomicParsley to try and find
> why EasyTag makes the m4a file playable on my Marantz cd player.
>...
> 2. Bells_after.m4a :- This is the default file after amending in EasyTag
> (deleting album info and saving file) It plays OK after approx 25 second
> delay.

I have a theory:

As I understand it mpeg-4 files are made of atoms, and each atom can
potentially contain either metadata or stream data.  What if your
marantz cd player doesn't understand the atom that contains the
thumbnail (which is added AtomicParsley in Shevek's patch), and it
spends 25s trying to play this as audio, failing to decode and hence
playing mute instead?

I can think of a couple of tests for this theory:
(a) use AtomicParsley to remove the thumbnail tag, and see if the file
then plays as expected
     (AtomicParsley file.m4a --artwork REMOVE_ALL apparently)
(b) use a metadata editor other than AP to add a thumbnail tag, and
see if the file breaks

Jon