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December 20th, 2007, 11:13 AM
#1
Good website for file specifications?
Does anyone know of any good websites that list several different file specifications? (ex. .txt, .jpg, .xxx)
I am wanting to read files using binaryreader and want to know which parts of the file contain what information (like file header contents).
Thanks
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December 20th, 2007, 11:25 AM
#2
Re: Good website for file specifications?
 Originally Posted by Tineras
Does anyone know of any good websites that list several different file specifications? (ex. .txt, .jpg, .xxx)
You mean file extensions? Here, for example: http://filext.com/
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December 20th, 2007, 11:34 AM
#3
Re: Good website for file specifications?
I'm actually wanting to read and edit the Hex data in the file headers of various file types. For example, if I want to find out the image width of a .jpg file, my program would use BinaryReader to get the Hex info from the file header that tell me that.
Last edited by Tineras; December 20th, 2007 at 11:36 AM.
Reason: Spelling Error
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December 20th, 2007, 11:43 AM
#4
Re: Good website for file specifications?
 Originally Posted by Tineras
I'm actually wanting to read and edit the Hex data in the file headers of various file types. For example, if I want to find out the image width of a .jpg file, my program would use BinaryReader to get the Hex info from the file header that tell me that.
Sure. But in this case, you need not only know which type of file is behind an extension, but also a the file format (and the site I showed you usually has links to the format descriptions of the various file types). However - there a thousands of different file types - I wonder how you would want to deal with all of them?
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December 20th, 2007, 11:47 AM
#5
Re: Good website for file specifications?
http://www.w3.org/ seems to cover a wide range of file format specifications related to the web. For .jpg files you'd want to look up the JFIF specification.
Anyway, google is your friend, and so are 3rd-party libraries.
- Alon
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December 20th, 2007, 12:00 PM
#6
Re: Good website for file specifications?
Another good resource I use a lot is Wotsit.
Hope it helps.
Be sure to rate those who help!
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December 20th, 2007, 12:00 PM
#7
Re: Good website for file specifications?
I tried to find such sites without too much success. Here is the best I found, but only has a handful of file formats:
http://www.daubnet.com/formats/
If you find a better one post it here, I'm curious too.
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December 20th, 2007, 01:35 PM
#8
Re: Good website for file specifications?
 Originally Posted by gstercken
Sure. But in this case, you need not only know which type of file is behind an extension, but also a the file format (and the site I showed you usually has links to the format descriptions of the various file types). However - there a thousands of different file types - I wonder how you would want to deal with all of them? 
I'm sorry, I didn't know that it had detailed information. I guess I just wasn't paying close attention.
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December 20th, 2007, 01:39 PM
#9
Re: Good website for file specifications?
I surprised there are more databases with this information.
I found some info on http://www.wotsit.org
This is the kind of information I was looking for:
Code:
X'FF', SOI
X'FF', APP0, length, identifier, version, units, Xdensity, Ydensity, Xthumbnail,
Ythumbnail, (RGB)n
length (2 bytes) Total APP0 field byte count, including the byte
count value (2 bytes), but excluding the APP0
marker itself
identifier (5 bytes) = X'4A', X'46', X'49', X'46', X'00'
This zero terminated string ("JFIF") uniquely
identifies this APP0 marker. This string shall
have zero parity (bit 7=0).
version (2 bytes) = X'0102'
The most significant byte is used for major
revisions, the least significant byte for minor
revisions. Version 1.02 is the current released
revision.
units (1 byte) Units for the X and Y densities.
units = 0: no units, X and Y specify the pixel
aspect ratio
units = 1: X and Y are dots per inch
units = 2: X and Y are dots per cm
Xdensity (2 bytes) Horizontal pixel density
Ydensity (2 bytes) Vertical pixel density
Xthumbnail (1 byte) Thumbnail horizontal pixel count
Ythumbnail (1 byte) Thumbnail vertical pixel count
(RGB)n (3n bytes) Packed (24-bit) RGB values for the thumbnail
pixels, n = Xthumbnail * Ythumbnail
Thank you all. I will keep searching too.
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