Camera as multimedia player - it IS possible! - General Discussion and Assistance - CHDK Forum  

Camera as multimedia player - it IS possible!

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Offline shali

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Camera as multimedia player - it IS possible!
« on: 25 / March / 2008, 15:35:49 »
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I was trying to convert my camera (A570IS) to kind of portable movie player, and for this I need both A/V out and LCD enabled (to insert headphones), which is normally imposible, BUT with CHDK nothing is impossible. This is result of my search through memory and firmware is shown on this movie:

http://www.volny.cz/shali/DSCF3468.AVI
(sorry about quality, I must use my extremely old FinePix camera to shot this, and it even don't record sound)

On this movie, you can see what is happening - I'm playing video on TV using A/V out, then press ALT and +/- button to start my function, TV goes blank, LCD turns white and after a second video is playing on LCD (sound is still going to TV).

What did I do:
* write 0x00209CC0 at addr. 0xc0220214 - I found this out by comparing special memory dumps when A/V connected and not-connected.
* write 0x0000F8F0 at addr. 0xc0910080 - described somewhere else on the forum, control LCD backlight
* wait one second - smaller time is probably needed, meanwhile TV goes off, LCD goes on and show white
* call function at 0xFFDDA430 with parameter 0 - this enables showing screen on LCD. Sorry but this function doesn't have name in IDA (its called sub_FFDDA430), at least when using current signature file.

MAJOR DRAWBACKS:
* You can see some white and black strips on left of the LCD (better on this photo: http://www.volny.cz/shali/DSCF3470.JPG) and the picture is slightly stretched so its height is bigger.
* You can only view videos - attemp to show photo of any size is shown at the end of the movie - the camera shuts itself down.
* I tested it only on A570IS - memory locations probably vary on other models.

So conclusion - it IS POSSIBLE to watch movie on camera with amplified headphones on, but it will need someone who know ARM / IDA / everything better than I to make this a real part of CHDK.
« Last Edit: 25 / March / 2008, 17:03:32 by shali »

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Offline PhyrePhoX

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Re: Camera as multimedia player - it IS possible!
« Reply #1 on: 25 / March / 2008, 16:16:43 »
 :o nice find!

Re: Camera as multimedia player - it IS possible!
« Reply #2 on: 25 / March / 2008, 17:20:29 »
Is it possible to save videostream on memory card?
« Last Edit: 25 / March / 2008, 17:23:45 by yolk »

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Offline GrAnd

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Re: Camera as multimedia player - it IS possible!
« Reply #3 on: 26 / March / 2008, 05:39:01 »
@yolk
Which videostream? It's already on the card. Because the camera is a player and does not have TV-in.
CHDK Developer.


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Offline a710is

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Re: Camera as multimedia player - it IS possible!
« Reply #4 on: 26 / March / 2008, 06:13:34 »
for starters the ability to watch video on the lcd while using headphones without buzz in one headphone would be great  :)
if sound could be sent thru the video channel as well instead of video, that would be even better :) .

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Offline jetzt

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Re: Camera as multimedia player - it IS possible!
« Reply #5 on: 26 / March / 2008, 06:20:41 »
Ah the old stereo sound dream.
Shall I repeat Barney's answer? I think I don't have to. But equal. :D

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Offline a710is

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Re: Camera as multimedia player - it IS possible!
« Reply #6 on: 26 / March / 2008, 06:26:35 »
I'm not talking about stereo sound, there aren't 2 mics, I'm just talking about mono sound sent to both headphones

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Offline shali

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Re: Camera as multimedia player - it IS possible!
« Reply #7 on: 26 / March / 2008, 06:41:13 »
I'm not talking about stereo sound, there aren't 2 mics, I'm just talking about mono sound sent to both headphones

Well, I don't think that is possible, but since you need to use an amplifier for headphones, you can use one which will produce mono sound by mixing the two channel from camera (one with sound and one blank) together.


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Offline a710is

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Re: Camera as multimedia player - it IS possible!
« Reply #8 on: 26 / March / 2008, 06:56:15 »
I don't really need an amplifier. sound plays decently loud in my Sennheiser 212Pro and these are big headphones. if not possible to use both channels then having video on the lcd and audio in the AV on one channel will do.
« Last Edit: 26 / March / 2008, 07:00:21 by a710is »

Re: Camera as multimedia player - it IS possible!
« Reply #9 on: 26 / March / 2008, 17:44:49 »
Deleted
« Last Edit: 22 / April / 2008, 15:00:29 by Barney Fife »
[acseven/admin commented out: please refrain from more direct offensive language to any user. FW complaints to me] I felt it imperative to withdraw my TOTAL participation. Nobody has my permission, nor the right, to reinstate MY posts. Make-do with my quoted text in others' replies only. Bye

 

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