Feature Request: `APPL` chunk support for AIFF/AIFC

[uudd]

I have some `AIFF/AIFC` files that contain custom metadata inside the application specific chunk `APPL`. It would be great if `exiftool` could parse the chunk correctly. The tool currently does recognize the tag but I can't extract anything from it when running `exiftool file.aif -APPL`. I get no output. However, `exiftool file.aif -v` does list the chunk with its correct size at the end, right before the `SSND` chunk (the PCM sound data).

[StarGeek]

Can you provide a sample file?

[uudd]

The files I am trying to work with are from https://op1.fun. Basically everything there has such an APPL tag set.

The attached file is taken from here: https://op1.fun/users/jake/patches/lowcello. It is licensed under the https://creativecommons.org/licenses/by/4.0/, which shouldn't create any problems I think. If it does, I'll remove the upload. Sublicenses aren't possible with CC IIRC, so the file can't be included in test cases (at least that's my interpretation).

[StarGeek]

Yeah, the JSON contents are clearly visible viewing the file through other means.

This is going to require further examination from Phil.

[uudd]

If there is interest/need:
This is the link a specification page I found. Not sure if this is the official one though: http://www-mmsp.ece.mcgill.ca/Documents/AudioFormats/AIFF/AIFF.html
The PDF does list the `APPL` section and gives further details on the implementation (i.e. byte alignment and stuff).

[Phil Harvey]

ExifTool 12.05 will extract this.  I'm thinking about just leaving the application signature ("op-1" in your example file) as the first 4 bytes of the data, ie.

Code Select Expand

> exiftool lowcello.aif -applicationdata
Application Data                : op-1{"adsr":[512,10746,32767,10000,4000,64,4000,4000],"base_freq":174.6139984130859,"fx_active":false,"fx_params":[5376,14729,9610,16456,0,0,0,0],"fx_type":"delay","knobs":[0,13829,18185,23253,12000,8192,0,11583],"lfo_active":true,"lfo_params":[23168,948,270,11772,0,0,0,0],"lfo_type":"tremolo","name":"user","octave":-1,"synth_version":2,"type":"sampler"}.

- Phil

[uudd]

Awesome! Thank you very much!