Anyone up for a programming challenge?

**DimPrawn** · 29 May 2008, 19:11

Originally posted by gadgetman View Post

I have an Archos 605 media player which apparently uses a proprietary format for the graphics files used as wallpaper.

I and other users would like to be able to convert to and from this format to something more useful, like a simple BMP format.

Someone on an Archos forum has already done a basic analysis of one of the files and it looks like it may be a fairly simple 1k header followed by an uncompressed bitmap, see below:

Code:

well, looking at the files, they are quite large, so I guess uncompressed.

One file I have starts like this:

Code:
       [ 0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15  0123456789012345]
000000: 12 46 54 41 00 EE 02 00 00 00 01 EE 04 00 00 00 |.FTA............|
000016: 00 00 02 EE 04 00 00 00 00 00 03 EE 02 00 20 03 |.............. .|
000032: 04 EE 02 00 E0 01 08 EE 80 00 02 00 00 00 00 00 |................|
000048: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
000064: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|


FTA = ATF backwards and lots of 00 and EE, but also 0x0320 and 0x01E which is 800 and 480.
now 800 x 480 x 2 = 768000 and the file size is 769028 = 768000 + 1028

So, look like uncompressed 16bit per sample, most likely YUV and a small header at the start.

Anyone here willing to take a crack at this?

www.rentacoder.com

Some guy in Russia or similar with a PhD will do it for a few quid I'm sure.

Everyone here will want £600/day and then they'll just spend the time posting here.

**VectraMan** · 29 May 2008, 19:16

I'll do it for £600 per day.

I wonder what all the EEs are for.

**Jaws** · 29 May 2008, 23:03

Originally posted by VectraMan View Post

I wonder what all the EEs are for.

238

HTH

**NickFitz** · 30 May 2008, 00:45

Originally posted by gadgetman View Post

I have an Archos 605 media player which apparently uses a proprietary format for the graphics files used as wallpaper.

<snip>

One file I have starts like this:

Code:
[ 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0123456789012345]
000000: 12 46 54 41 00 EE 02 00 00 00 01 EE 04 00 00 00 |.FTA............|
000016: 00 00 02 EE 04 00 00 00 00 00 03 EE 02 00 20 03 |.............. .|
000032: 04 EE 02 00 E0 01 08 EE 80 00 02 00 00 00 00 00 |................|
000048: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
000064: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|

FTA = ATF backwards and lots of 00 and EE, but also 0x0320 and 0x01E which is 800 and 480.
now 800 x 480 x 2 = 768000 and the file size is 769028 = 768000 + 1028

So, look like uncompressed 16bit per sample, most likely YUV and a small header at the start. [/CODE]

Anyone here willing to take a crack at this?

Got a link to the forum & thread with that post in, and maybe two or three sample files? Digging through hex dumps reverse engineering file formats is something I quite enjoy doing on a quiet afternoon (it reminds me of the Eighties, when I actually got paid for doing stuff like that) so I'd be willing to have a go at deciphering the file format, at least

As for creating an app to do the conversion: it would have to be Java (cross-platform), or I could look into creating a web app and do the heavy lifting on the server with something like Python or Java or even PHP (yes, really, it's possible) - but I'm not learning Win32 API programming just for fun

PM me if you don't want to post the links here, although I'm not promising anything, and I'm at conferences until Monday, when I settle back on to the bench

**NickFitz** · 30 May 2008, 00:49

Oh BTW, I assume this is just as it was in the original thread, but you should let that poster know that the row of labels at the top of a hex dump should be "0 1 2 3 4 5 6 7 8 9 A B C D E F", not "0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15" - one can safely assume that if the reader can make any sense of a hex dump, they must know that "C" means "12"

**gadgetman** · 30 May 2008, 08:23

Thanks for the reply Nick, I have sent you a PM.

Yeah, I don't know what he's used to dump the file, seems a little odd. However the info appears to be correct as I've tried manually decoding the height and width values on a couple of different sizes of wallpaper file myself today.

Originally posted by NickFitz View Post

Oh BTW, I assume this is just as it was in the original thread, but you should let that poster know that the row of labels at the top of a hex dump should be "0 1 2 3 4 5 6 7 8 9 A B C D E F", not "0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15" - one can safely assume that if the reader can make any sense of a hex dump, they must know that "C" means "12"

**VectraMan** · 30 May 2008, 09:19

Originally posted by NickFitz View Post

Oh BTW, I assume this is just as it was in the original thread, but you should let that poster know that the row of labels at the top of a hex dump should be "0 1 2 3 4 5 6 7 8 9 A B C D E F", not "0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15" - one can safely assume that if the reader can make any sense of a hex dump, they must know that "C" means "12"

All this talk of bytes and hex is a bit advanced for a Java programmer isn't it?

If C is 12, what is C++?

**luke warm** · 30 May 2008, 09:24

Originally posted by VectraMan View Post

All this talk of bytes and hex is a bit advanced for a Java programmer isn't it?

If C is 12, what is C++?

--BCPL

**gadgetman** · 2 June 2008, 08:08

I eventually decided to have a go myself, so armed with a dusty copy of K&R, a download of Tiny C and some web searches on bitmap formats I managed to knock up a command line app over the weekend.

Its not pretty but it does the job.

If anyone wants to make a nice Java GUI version I'm open to offers

Anyone up for a programming challenge?