PowerShot SX230 HS - Porting Thread - page 58 - General Discussion and Assistance - CHDK Forum

PowerShot SX230 HS - Porting Thread

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Offline reyalp

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Re: PowerShot SX230 HS - Porting Thread
« Reply #570 on: 23 / October / 2012, 22:12:31 »
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Is anyone having an issue with chdk and the hand held night shot mode?

When I use it with chdk, the images come out completely distorted, but with CHDK not in use, it works just fine.
Sounds like there is then. If you can post an example of how it comes out distorted, that might be helpful. Also, just to clarify, when you use this mode, you are saying that just having CHDK running at all makes the jpeg come out distorted?

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Also is there an option to adjust the video bitrate. the current method of control is quality control and it only seems to reduce video quality. If you increase it too high, then the video randomly stops recording.
This most likely means the camera is already operating very close to it's maximum processing capability.
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With other versions of CHDK for other camera models, you could simply adjust the bitrate by power, eg 1.5X bitrate would basically tell the device to just use 50% higher bit rate compared to what it would otherwise use which allowed the bitrate to scale in a much more manageable manner
We only know how to control bitrate on cameras that use MJPEG for video, if it's possible on H264 cams, no one has figured it out.
Don't forget what the H stands for.

Re: PowerShot SX230 HS - Porting Thread
« Reply #571 on: 25 / October / 2012, 04:58:47 »
Here is a picture of what happens when the night shot is used (it quickly takes 3 images at a higher shutter speed to get better low light images)

http://i.imgur.com/VDPRd.jpg


I also uploaded the original jpeg file as well as the RAW file.

jpeg file: http://www.mediafire.com/view/?n35pr36k67tkkex

RAW file: http://www.mediafire.com/?n6dkj0d5f0k12h3

If there is almost no light in the scene (low light enough to not get a usable image), then the night shot works fine without the distortion

Here is an example of CHDK enabled and there being very little light


jpeg image: http://www.mediafire.com/view/?a7eh17b5b4v02f2

RAW image: http://www.mediafire.com/?undefined

The jpeg image in this case comes out fine but the RAW file is still distorted (though once in a while I will get a image where both the jpeg and the raw image is fine (and in those cases, a scene that would seem too dark for the jpeg, can be recovered quite extensively with the RAW file).



And with CHDK not set to boot The night shot feature works in any lighting level (even if the scene is outdoors with direct sun light )


night shot option with CHDK not set to boot

http://i.imgur.com/oUkTA.jpg


image from camera: http://www.mediafire.com/view/?6c7zevmis2ndw7q

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Offline reyalp

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Re: PowerShot SX230 HS - Porting Thread
« Reply #572 on: 25 / October / 2012, 15:58:02 »
Is the jpeg ever affected if you don't have raw enabled ?

From the description, I'm not at all surprised that raw breaks this mode.
Don't forget what the H stands for.

Re: PowerShot SX230 HS - Porting Thread
« Reply #573 on: 25 / October / 2012, 21:50:03 »
The issue goes away if raw is disabled but there is no way to add a raw exception for a specific option in scene mode


Re: PowerShot SX230 HS - Porting Thread
« Reply #574 on: 25 / October / 2012, 22:56:23 »
The issue goes away if raw is disabled but there is no way to add a raw exception for a specific option in scene mode
Well,  there is no way to add a raw exception unless you change the CHDK code.  One dirty little CHDK secret is that RAW can be disabled for the S3IS camera when the camera is in SPORTS mode.  But only for that camera.  I assume its a legacy thing.   So adding another scene specific disable is possible - you just have to figure out exactly when it will apply.

Ported :   A1200    SD940   G10    Powershot N    G16

Re: PowerShot SX230 HS - Porting Thread
« Reply #575 on: 25 / October / 2012, 23:48:08 »
it's not too big of a deal, I don't really see my self suing this feature much as it is only useful for still objects, and in that case why not just do a long exposure?

While it does get good low light results, the 3 exposures have enough delay to cause ghosting. It's just a weird issue.

If it worked reliably with raw enabled, then it would be more useful since the raw images have a lot of latitude in how far you can recover them.

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Offline reyalp

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Re: PowerShot SX230 HS - Porting Thread
« Reply #576 on: 26 / October / 2012, 00:09:16 »
There appears to already be an ifdef to hardcode raw disabled for this mode: CAM_DISABLE_RAW_IN_HANDHELD_NIGHT_SCN, looks like philmoz ran into the same issue on sx40. See conf.c is_raw_enabled()
Don't forget what the H stands for.

Re: PowerShot SX230 HS - Porting Thread
« Reply #577 on: 28 / October / 2012, 23:02:24 »
Sorry to bump this thread yet again, I have been having a little bit of trouble with one specific aspect of color correcting raw images.
 Compared to the raw image, the jpeg images generated by the camera represent the color orange better than I am able to get out of the RAW image.

I tried using the dual-illuminant profile from this link http://chdk.wikia.com/wiki/Calibrating_colors_for_DNG_processing

and from my test it way overrepresented the color blue.

So overall, the RAW images offer more detail and color quality on just about all colors except orange, the orange I see in real like is more closely portrayed in the jpeg image than in the RAW and with camera raw in photoshop, I cant seem to match the jpeg result orange.


Re: PowerShot SX230 HS - Porting Thread
« Reply #578 on: 30 / October / 2012, 00:07:20 »
<i>We only know how to control bitrate on cameras that use MJPEG for video, if it's possible on H264 cams, no one has figured it out.</i>

The varying bitrate with a given quality setting does make it hard to know whether I'm going to go over the 4 GB limit with a video of a certain time length (public meetings that start and end at time X and Y). The "Video without time limit" feature is great, but is it also theoretically possible to bypass the 4GB limit? If so, that would be wonderful.

Re: PowerShot SX230 HS - Porting Thread
« Reply #579 on: 30 / October / 2012, 09:53:28 »
.... it is it also theoretically possible to bypass the 4GB limit?
I think that being able to bypass the built-in hard coded video time limits opens some new possibilities.   The next limit  (4G file size) is a result of using FAT32 - it's the maximum file size supported by that format.

However, newer cameras will format very large (16G,  32G...?) cards using exFAT, which does allow for larger file sizes.   So far,  I don't know if anyone has looked into whether the cameras enforce the 4G limit in the video_rec.c task or if they stop when some file system function tells them the file is full (as opposed to the card being full).  If its the later, then using the "firmware update" booting method and an exFAT formatted card might allow larger video file sizes right now !  I guess someone with a large card formatted exFAT would need to test that ?

Then, if simply using exFAT gets around the 4G video limit,  the next step might be to add "dual partition" booting back into new cameras to allow booting from a small FAT16 partitions before switching to the large exFAT partition (as none of the cameras so far will autoboot from a pure exFAT card).

Finally,  if all that fails then its a questions of looking into the code again to determine why the camera will not write a file larger than 4G to an exFAT format card.

Somehow,  compared to the old 10 minute time limit,  this seems a little greedy. But its really just a question of someone with the right camera, large card and time going through this step by step.   Perhaps you could start with the easy one first - exFAT format with a "firmware update" boot ?

tl;dr > Yes,  its theoretically possible.
« Last Edit: 30 / October / 2012, 10:10:21 by waterwingz »
Ported :   A1200    SD940   G10    Powershot N    G16

 

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