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Topic: Reading Tag data from M4a file (Read 4014 times) previous topic - next topic
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Reading Tag data from M4a file

Hi all,


I want to read Tag data from the M4a file by writing a  C code can somebody provide me direction on this.


Thanks

Reading Tag data from M4a file

Reply #1 –
Quote
I want to read Tag data from the M4a file by writing a  C code can somebody provide me direction on this.


richard123's tg.exe see this thread http://www.hydrogenaudio.org/forums/index....showtopic=12075
mpeg4ip's mp4tags & libmp4v2  http://ww.mpeg4ip.net
bento4    http://www.sourceforge.net/projects/bento4
AtomicParsley  http://www.sourceforge.net/projects/atomicparsley

William Herrera's Audio::M4P  http://search.cpan.org/~billh/ 

You can also look at gpac & ffmpeg for more ideas on how to parse the mpeg4 file. Parsing the file properly is the key to reading the tags - its all about the offset. Writing atoms/boxes out  is inordinately harder than reading them. Writing is all about logic.

See also: geocities.com/xhelmboyx/quicktime/formats/mp4-layout.txt
and a knowledgeable member (mpeg4 guru) "bond" posted a link to the ISO 14496-12 file reference document (somewhere... can't recall where). It's thorough, but doesn't throw much light on the metadata in "moov.udta.meta.ilst".

Reading Tag data from M4a file

Reply #2 –
I wrote some code to this for the Roku PhotoBridge, so you wouldn't be able to compile this code directly, but it should give a good basis/starter.

Tag reading source code

Its using the API of the PhotoBridge so theres some calls you wouldn't be able to use, but they're very simple to understand/port over e.g.

fp->ReadBytes(5, buffer)

just reads five bytes from the fp stream and places the value in the buffer 'buffer'.

Reading Tag data from M4a file

Reply #3 –
Thankyou Friends I'll try it out

Arunkumar

Reading Tag data from M4a file

Reply #4 –
You can also try mt-daapd http://nightlies.mt-daapd.org/ (might only be in nightly snapshots for all I know).

The scan-aac.c file has a rather short parsing method. I love it how every project has the same damn problems: non-standard atoms.