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dosin



Joined: 24 Aug 2007
Posts: 337
dosin
Does anyone know of any good links on the specs.. of a jpeg file -decoding it..
I have been looking for it and am getting a lot of differnet info..

If anyone here that has been down this road and has any info on this like docs/sites.. ?

Thanks in advance! Very Happy
Post 27 Jan 2008, 05:49
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f0dder



Joined: 19 Feb 2004
Posts: 3170
Location: Denmark
f0dder
Post 27 Jan 2008, 09:26
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Octavio



Joined: 21 Jun 2003
Posts: 366
Location: Spain
Octavio
Post 27 Jan 2008, 21:11
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Dex4u



Joined: 08 Feb 2005
Posts: 1601
Location: web
Dex4u
If it's for the FBrowser project, i already have a bmp, gif, and jpeg decoder coded Smile.
Post 27 Jan 2008, 21:14
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edfed



Joined: 20 Feb 2006
Posts: 4242
Location: 2018
edfed
do you know what google do with your datas?

each time you google, big brother is watchin you.

now, google=big brother.
Post 27 Jan 2008, 21:45
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drhowarddrfine



Joined: 10 Jul 2007
Posts: 535
drhowarddrfine
And he's watching you and you alone! He's sitting right outside your door, right now, because YOU have something he wants. It is YOU and only you that he needs. And he's going to get it from you. And your little dog, too.
Post 28 Jan 2008, 00:15
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f0dder



Joined: 19 Feb 2004
Posts: 3170
Location: Denmark
f0dder
<3 obsessive compulsive paranoia.
Post 28 Jan 2008, 00:21
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edfed



Joined: 20 Feb 2006
Posts: 4242
Location: 2018
edfed
Post 28 Jan 2008, 00:56
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dosin



Joined: 24 Aug 2007
Posts: 337
dosin
lol Very Happy -To the above google ref....s


I was not asking for people to search google for me.. just asking if anyone here had some docs..on this or a good website.. Sometimes if you ask.. Someone may have just programmed one and share sites they used/docs..

If I find any thing worth reading I hang on to it!
There is a lot of junk out there to sort through!




But yes I was going to try and decode a jpeg.. later on.. and i wanted to begin reading on it..and in the future I want to try to decode mpeg..
I read has simular compresion.

Thanks again!
Post 28 Jan 2008, 02:19
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rugxulo



Joined: 09 Aug 2005
Posts: 2341
Location: Usono (aka, USA)
rugxulo
Look at Octavio's OctaOS for JPEG decoding srcs (and there's also a small 320x200-only DOS version he wrote, but you'll have to PM him or me for it, it's no longer attached on this forum).

EDIT: Well, it's small enough (the DOS version), so I may as well just attach it here (assuming Tomasz and Octavio don't mind, heh).


Description: 320x200 JPEG viewer for DOS (by Octavio)
Download
Filename: JPEG.ZIP
Filesize: 10.79 KB
Downloaded: 235 Time(s)

Post 28 Jan 2008, 20:07
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dosin



Joined: 24 Aug 2007
Posts: 337
dosin
Thanks,
I will take a look..
Post 29 Jan 2008, 02:18
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edfed



Joined: 20 Feb 2006
Posts: 4242
Location: 2018
edfed
*2 Very Happy

project is running.........yeah!!!
Post 29 Jan 2008, 02:21
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dosin



Joined: 24 Aug 2007
Posts: 337
dosin
edfed:
I have been working on finding out why the irq1 was having problems with the keyboard code you added.. I added a little to the rest of the ints.. and fixed that fault from happening.. but the int you coded is not working.. not sure why seams to be getting stuck? or something? not sure what it is...Confused
and then again I could be over looking something...

But like I said.. I don't think this is needed just yet.. or the IDT.. really I just wanted to try something different..try with it with the vesa text in the ints..

I am going to keep working on a parser/driver for the project.. but for right now I am done with the keyboard for now - later I may try some of my keyboard code... to double check it..
Post 29 Jan 2008, 07:50
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Octavio



Joined: 21 Jun 2003
Posts: 366
Location: Spain
Octavio
rugxulo wrote:

(and there's also a small 320x200-only DOS version he wrote, but you'll have to PM him or me for it, it's no longer attached on this forum).

jpeg.com is here:
http://www.programmersheaven.com/zone10/cat453/index.htm
but this program has a bug (some colors are not correct),the bug is corrected in the menuetos version of the program.
To write this program i used documents found at
http://www.wotsit.org/
and also looked at sources of some jpeg programs written in C.
Post 29 Jan 2008, 08:22
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edfed



Joined: 20 Feb 2006
Posts: 4242
Location: 2018
edfed
dosin:
i think the main problem is in the interrupt handler, as it send me an invalid opcode if i replace
Code:
include 'vesaconstant.inc'
    

by a
Code:
...
include 'vesaconstant.inc'
...
call vesaconstant..
...
    

that's why vesaconstant.inc is directlly in the sequential source.


about farpointers & fasm...
Code:
..
...
far_pointer df 0:0 
...
...
far_pointer:
dw 0
dd 0
...
..
    


octavio:
jpg source code is like soup.... Very Happy.
i am litterally impressed by the lengh of the source needed to decode jpg...
i prefer bmp.
Post 29 Jan 2008, 12:41
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Dex4u



Joined: 08 Feb 2005
Posts: 1601
Location: web
Dex4u
But there's a big difference between 64k for jpeg and 900k or so for a 640x480 24bpp bmp Wink. It took me 3 months of work to code a jpeg decoder for DexOS, but it was well worthit.
Post 29 Jan 2008, 15:13
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Octavio



Joined: 21 Jun 2003
Posts: 366
Location: Spain
Octavio
edfed wrote:

octavio:
jpg source code is like soup.... Very Happy.

Thats because is written in Fasm ,look at Octasm sources they are like
a cake Smile

Dex wrote:
But there's a big difference between 64k for jpeg and 900k

what do you mean?
Post 29 Jan 2008, 15:53
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edfed



Joined: 20 Feb 2006
Posts: 4242
Location: 2018
edfed
640*480 24bpp
bmp = 900 kbytes
jpg = 64 kbytes
Post 29 Jan 2008, 16:04
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Dex4u



Joined: 08 Feb 2005
Posts: 1601
Location: web
Dex4u
Dex wrote:
But there's a big difference between 64k for jpeg and 900k
Octavio wrote:
what do you mean?

I mean it may look alot of code (the jpeg decoder), but once its coded it save you alot of space, as jpegs are much small in size than bmp, so its worthit.
Post 30 Jan 2008, 15:46
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rugxulo



Joined: 09 Aug 2005
Posts: 2341
Location: Usono (aka, USA)
rugxulo
Dex4u wrote:

I mean it may look alot of code (the jpeg decoder), but once its coded it save you alot of space, as jpegs are much small in size than bmp, so its worthit.


Yes, although there are various amounts of compression JPEG can use (even none, but I truly haven't seen such an example). Oh, and I'm sure you know that BMP can be compressed too (just not as well).

P.S. Just for more dopey useless information (for trivia buffs like me), you can indeed (re)compress JPEG images (as something else entirely, not transparently). See Matt Mahoney's PAQ8o8.
Post 31 Jan 2008, 03:23
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