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Dark frame control

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Offline ewavr

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Re: Dark frame control
« Reply #10 on: 25 / July / 2008, 16:58:12 »
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Hehe. Aside from capture twice, was it moved to solve some other problem ?

Yes, "old" RAW  on some cameras caused E16 (capture timeout?) error.

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Offline reyalp

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Re: Dark frame control
« Reply #11 on: 25 / July / 2008, 17:12:39 »
Yes, "old" RAW  on some cameras caused E16 (capture timeout?) error.
Yeah, I actually expected my change to do something like that (or just crash). I was quite surprised that it worked at all. Do you have a link or svn rev for the old code ? I'd be interested to see where it is in relation to what I've done.
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Offline ewavr

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Re: Dark frame control
« Reply #12 on: 25 / July / 2008, 17:27:19 »
Do you have a link or svn rev for the old code ?

??? As usually, http://tools.assembla.com/chdk - trunk before rev.167 or Grand's branch before rev.191 (without capt_seq.c files)
« Last Edit: 25 / July / 2008, 17:30:15 by ewavr »

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Offline LjL

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Re: Dark frame control
« Reply #13 on: 26 / July / 2008, 08:30:41 »
Quote from: reyalp
Disabling jpeg should be fairly easy... we ought to be able to just jump past it after writing the raw. If you are lucky, you can just jump to the end of one of those functions that we've hooked, but there might be some essential housekeeping that has to happen after you take an image. Try it and see...

I'd gladly try, but I think I need some kind of jump start...
I don't have IDA and I'd rather work on Linux, and right now I really just have no clue how the firmware is structured.

It would be nice if someone already into this things would spend some time improving the wiki's developers' documentation... I'm sure it's time well spent: people, like me, often just don't do things because they 1) see that few other people are doing them, so assume they're beyond themselves 2) don't quite know where to start.

Just see the topic about temperature sensors: the functions to use those have been there since forever, I think, for some models. And only those models. Now that someone suggested that they may be there in all cameras, everyone is jumping at IDA and actually finding them.

I don't think I personally need a step-by-step tutorial, as in "press this and then that", but I'd benefit from a technical explanation of how the firmware is layed out (and there is something like that, it's not bad but very limited), the difference between adding our own routines and modifying existing Canon routines (how do we actually do that, since we aren't modifying the firmware?), what I can expect to find in plain text in the firmware code, and what I should plan to reverse-engineer manually; and generally speaking, what sort of things I can expect to be able to change, and which others are set in stone (because they're not done in the ARM processor, or whatever reason).

Now I'll go back in a corner and stop hijacking this thread, but I thought I'd just throw a rock and see where it lands.


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Offline reyalp

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Re: Dark frame control
« Reply #14 on: 26 / July / 2008, 17:01:35 »
Quote from: reyalp
Disabling jpeg should be fairly easy... we ought to be able to just jump past it after writing the raw. If you are lucky, you can just jump to the end of one of those functions that we've hooked, but there might be some essential housekeeping that has to happen after you take an image. Try it and see...

I'd gladly try, but I think I need some kind of jump start...
I don't have IDA and I'd rather work on Linux, and right now I really just have no clue how the firmware is structured.
If you look at capt_seq_task, it has a bunch of asm copied from ROM. When it's done doing it's special magic, it just jumps back into the ROM. It calls several functions made in the same way.

Somewhere in those routines is the part that saves the jpeg, and that will be somewhere after the raw hook is called.
Don't forget what the H stands for.

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Offline RaduP

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Re: Dark frame control
« Reply #15 on: 27 / July / 2008, 10:43:24 »
Being able to modify the ROM is great, one use I thought of is to put a RET (or whatever it is called in ARM assembly) in the error functions, to be able to take pictures with the lens removed.
And I second the request for someone to document the ROM structure better, because I'd also like to contribute, but I don't know where to begin.

 

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