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Overwriting HQ Burst mode on G15 - best practice

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Offline yesbird

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Overwriting HQ Burst mode on G15 - best practice
« on: 09 / April / 2019, 05:58:23 »
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Few days ago I installed CHDK on my G15 and was very impressed by power and flexibility of my renewed camera. Mostly interesting in macro, Focus bracketing in continues mode and exposure/JPEG quality overwriting in HQ Burst mode (HQBM) is mine main points of focus.

Grepping the forum and doing a lot of experiments I found that HQBM works fine, but with following limits:

    1. Can not set write balance manually.
    2. 10 fps is absolutely limit independent of JPEG quality
    3. Writing RAW slows down process reducing it to ordinary continues shooting mode - suppose that more fast flash card can help here.

The question is: how to improve using of HQBM ?

I suppose that some scripting tricks can do that, but at the same time forum experts confirms that calling Lua is slow process and I am in doubt will scripting help in this case. At the same time being software developer I thing that implementing some extension on C can speed-up things a lot and I am ready to start writing it.

So the second question: Is it possible to improve HQBM by Lua scripting / C extension ?

Thanks in advance.



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Offline reyalp

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Re: Overwriting HQ Burst mode on G15 - best practice
« Reply #1 on: 09 / April / 2019, 13:31:06 »
Quote from: yesbird on 09 / April / 2019, 05:58:23
    1. Can not set write balance manually.
It's possible you could override the WB mode propcase to set it to custom in a mode that does not allow it through the UI. You would have to test to see if this has the desired effect.

Note the CHDK cannot currently set custom WB values, but changing the mode generally works.
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    2. 10 fps is absolutely limit independent of JPEG quality
    3. Writing RAW slows down process reducing it to ordinary continues shooting mode - suppose that more fast flash card can help here.
Cameras with digic 6 and lower processors (and a few early digic 6 models) do not have UHS support, meaning the absolute maximum write speed is around 20-25 MB/s. Faster cards beyond that will not help significantly. Digic 6 cameras with UHS support appear to top out around 40 MB/s. Some discussion can be found in https://chdk.setepontos.com/index.php?topic=13089.50

It's possible you could overclock the SD interface.
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I suppose that some scripting tricks can do that, but at the same time forum experts confirms that calling Lua is slow process and I am in doubt will scripting help in this case.
Lua is quite fast for general scripting (see https://chdk.setepontos.com/index.php?topic=12451.0 for some discussion), but it's not clear anything you can do in Lua would be applicable to your goals.

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At the same time being software developer I thing that implementing some extension on C can speed-up things a lot and I am ready to start writing it.
Again, it's not clear to specifically you expect to improve. It's quite unlikely that you can make fundamental operations like processing a jpeg or writing a file faster than Canon did.
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Offline yesbird

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Re: Overwriting HQ Burst mode on G15 - best practice
« Reply #2 on: 09 / April / 2019, 14:34:07 »
Thank you for your answer and links, could you please provide more details about WB overwrite ? I did not found anything similar in menus - may be I was not attentive enough.

The thing that I would like improve are following:

1. Burst speed (with RAW and JPEG only) - according to your answer this is hardly possible.
2. To have Av priority mode while bursting, leaving Tv to authomation (after couple of experiments I found it is not possible now).
3. WB control in burst mode, hope I will find it.
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Offline srsa_4c

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Re: Overwriting HQ Burst mode on G15 - best practice
« Reply #3 on: 09 / April / 2019, 15:35:16 »
Some propcase and scripting related links (WB mode propcase is called PROPCASE_WB_MODE):
https://chdk.fandom.com/wiki/PropertyCase
https://chdk.fandom.com/wiki/CHDK_Scripting_Cross_Reference_Page
propsetN.h headers in https://app.assembla.com/spaces/chdk/subversion/source/HEAD/trunk/include

About setting and restoring custom WB (no-one has picked up this, unfortunately):
https://chdk.setepontos.com/index.php?topic=12208.0
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Offline yesbird

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Re: Overwriting HQ Burst mode on G15 - best practice
« Reply #4 on: 09 / April / 2019, 15:43:57 »
Thank you very much ! Will try to implement it.
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Offline reyalp

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Re: Overwriting HQ Burst mode on G15 - best practice
« Reply #5 on: 10 / April / 2019, 00:10:20 »
Quote from: yesbird on 09 / April / 2019, 14:34:07
Thank you for your answer and links, could you please provide more details about WB overwrite ? I did not found anything similar in menus - may be I was not attentive enough.
See srsa_4c's links

In lua, you can do something like
Code: [Select]
props=require'propcase'
set_prop(props.WB_MODE, 7)
If you are using a shooting mode where the camera doesn't normally allow manual WB, you'd probably have to do this after setting the shooting mode.

I generally use chdkptp for this kind of thing, calling functions interactively is a lot more convenient than uploading code.

Note that the value for custom WB changed in propsets after 7.
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