IFF format, how does it work?

20 January 2012, 08:47

How does the EA-85 IFF format work, really?

I want to create a new file format, but get some structure, so I wanted to use the EA-85 IFF format. But I don't understand from the standards document exactly how it works. Especially the difference between FORM CAT and LIST is very unclear. (To me.) So I wanted to used iffw.c from EA to help me write correctly and not miss anything. But it does not work...

I posted on StackOverflow, but no answer so far. Then I thought here is where all the experts are...

http://stackoverflow.com/questions/8...to-write-chunk

References:
http://netghost.narod.ru/gff/vendspec/iff/iff.txt
http://www.fileformat.info/format/iff/egff.htm
And links in the StackOverflow question.

thomas · 20 January 2012, 10:55

LIST and CAT are only needed if you want to combine multiple documents in one file. Usually, for example for a picture file, you only need FORM.

Amiga1992 · 20 January 2012, 13:04

I love the definition of this format. It's the way media files of today are dealt with. A container like Quicktime surely owes a lot of inspiration to IFF!

Photon · 20 January 2012, 13:15

Knowing only the IFF format as described in the thick blue Amiga books (online docs here), I'm not sure I can help you. I guess you've googled already. If you describe why the new format and what the files will be for, maybe more people can help you here.

20 January 2012, 16:25

Thanks!

It's for a flash file for the Natami. The first version will contain only one flash file for a FPGA, but later versions will contain three flash files. So maybe the first version will be a FORM, and later versions a LIST or CAT with three FORMs in them?

thomas · 20 January 2012, 17:45

You shouldn't make it more complicated than it needs to be. A normal FORM file can have multiple chunks of the same type. For example if you check the WBPattern prefs file, you will see that it looks like this:

FORM....PREF
PRHD
PTRN
PTRN
PTRN

Each of the three PTRN chunks stands for one of the three patterns (screen, workbench, window).

21 January 2012, 01:15

Thanks, I will try this.

Photon · 22 January 2012, 21:40

Yeah, a FORM and a chunk for each 'entry' is good. But if it's 3 separate files of the same type it could be better to make them 3 files and just zip them if you need to distribute as a single file.

Any which way is good really, if it's to be supported in future by the community it would be nice with a few lines in a doc that makes it to the web.

01 February 2012, 11:18

Thank you! The official ROM file format for Natami (.nff) is now based on IFF-85 thanks to answers here. The legacy lives. :-)

20 January 2012, 08:47	#1
jakov Posts: n/a	IFF format, how does it work? How does the EA-85 IFF format work, really? I want to create a new file format, but get some structure, so I wanted to use the EA-85 IFF format. But I don't understand from the standards document exactly how it works. Especially the difference between FORM CAT and LIST is very unclear. (To me.) So I wanted to used iffw.c from EA to help me write correctly and not miss anything. But it does not work... I posted on StackOverflow, but no answer so far. Then I thought here is where all the experts are... http://stackoverflow.com/questions/8...to-write-chunk References: http://netghost.narod.ru/gff/vendspec/iff/iff.txt http://www.fileformat.info/format/iff/egff.htm And links in the StackOverflow question.

21 January 2012, 01:15	#7
jakov Posts: n/a	Thanks Thanks, I will try this.

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20 January 2012, 10:55	#2
thomas Registered User Join Date: Jan 2002 Location: Germany Posts: 6,985	LIST and CAT are only needed if you want to combine multiple documents in one file. Usually, for example for a picture file, you only need FORM.

20 January 2012, 13:04	#3
Amiga1992 Registered User Join Date: May 2001 Location: ? Posts: 19,645	I love the definition of this format. It's the way media files of today are dealt with. A container like Quicktime surely owes a lot of inspiration to IFF!

20 January 2012, 13:15	#4
Photon Moderator Join Date: Nov 2004 Location: Eksjö / Sweden Posts: 5,602	Knowing only the IFF format as described in the thick blue Amiga books (online docs here), I'm not sure I can help you. I guess you've googled already. If you describe why the new format and what the files will be for, maybe more people can help you here.

20 January 2012, 16:25	#5
jakov Posts: n/a	Thanks! It's for a flash file for the Natami. The first version will contain only one flash file for a FPGA, but later versions will contain three flash files. So maybe the first version will be a FORM, and later versions a LIST or CAT with three FORMs in them?

20 January 2012, 17:45	#6
thomas Registered User Join Date: Jan 2002 Location: Germany Posts: 6,985	You shouldn't make it more complicated than it needs to be. A normal FORM file can have multiple chunks of the same type. For example if you check the WBPattern prefs file, you will see that it looks like this: FORM....PREF PRHD PTRN PTRN PTRN Each of the three PTRN chunks stands for one of the three patterns (screen, workbench, window).

22 January 2012, 21:40	#8
Photon Moderator Join Date: Nov 2004 Location: Eksjö / Sweden Posts: 5,602	Yeah, a FORM and a chunk for each 'entry' is good. But if it's 3 separate files of the same type it could be better to make them 3 files and just zip them if you need to distribute as a single file. Any which way is good really, if it's to be supported in future by the community it would be nice with a few lines in a doc that makes it to the web.

01 February 2012, 11:18	#9
jakov Posts: n/a	Thank you! The official ROM file format for Natami (.nff) is now based on IFF-85 thanks to answers here. The legacy lives. :-)

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