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CHDK RAW Video?

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CHDK RAW Video?
« on: 26 / November / 2013, 12:43:54 »
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After recently seeing the quality of Magic Lantern Canon 5D III RAW video am wondering if there is a CHDK RAW video for Canon P&S?

While I have not seen any recent postings concerning this, decided to do a forum search and found
"RAW video (was: Difference between Canon CRW and CHDK CRW?)"
http://chdk.setepontos.com/index.php?topic=5585.msg105915#msg105915  which mentions not possible with the DIGIC 4 image processor and slow SD cards.

Since there are now DIGIC 6 image processors and faster SD cards am wondering if it is now possible?

If not, would be interested to know what is now preventing it from happening?

Thanks

Gene

Re: CHDK RAW Video?
« Reply #1 on: 26 / November / 2013, 12:49:09 »
At the risk of someone once again proving me wrong,   :haha  I think its safe to day that CHDK does not currently support this,  nobody is working on it,  and there are several issues that will make this difficult.   

Not the least of which is that CHDK has not been converted to run on DIGIC6 based cameras.

Having said that,  several of the devs have discussed the desirability of such a feature.

Update : this also brings up the conversation about the value of RAW on P&S cameras - unlike DSLR's the RAW's from P&S cameras need a lot of post processing to compete with quality of the camera's built-in jpeg conversion.  I have no idea if there is additional value that having RAW in video would actually bring?
« Last Edit: 26 / November / 2013, 13:01:34 by waterwingz »
Ported :   A1200    SD940   G10    Powershot N    G16

Re: CHDK RAW Video?
« Reply #2 on: 26 / November / 2013, 13:33:47 »
this also brings up the conversation about the value of RAW on P&S cameras

:)

That said, I am about to batch-correct about eighty raw images for the really bad vignetting on the SX50hs (and SX40hs).
The very effective method supported by RawTherapee is done on raw images even before demosaicing.

There is no effective method for JPG's and the vignetting completely ruins stitched panoramas.


Re: CHDK RAW Video?
« Reply #3 on: 26 / November / 2013, 13:40:48 »
That said, I am about to batch-correct about eighty raw images for the really bad vignetting on the SX50hs (and SX40hs). The very effective method supported by RawTherapee is done on raw images even before demosaicing.
There is no effective method for JPG's and the vignetting completely ruins stitched panoramas.
Now that's interesting to know.  Maybe there are also reason to want to post-process RAW for video too?  I imagine you'd want a really fast PC with lots of memory if you get into that game.

I realize this is a bit off-topic, but does is also make you the winner of your own challenge ?
http://chdk.setepontos.com/index.php?topic=10159.msg101665#msg101665

Ported :   A1200    SD940   G10    Powershot N    G16


Re: CHDK RAW Video?
« Reply #4 on: 26 / November / 2013, 13:56:17 »
does is also make you the winner of your own challenge ?

That is what the smiley was referring to.

Yes, absolutely.
I have no problem admitting that in this special situation it is the ONLY solution.
You can read endless tutorials about using free or expensive editing software to correct vignetting.
In this situation they are simply too crude, leaving easily discerned concentric rings of varying brightness.

This topic will resurface in Paco's 'Smoothing timelapse videos' thread.

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Offline reyalp

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Re: CHDK RAW Video?
« Reply #5 on: 26 / November / 2013, 17:38:36 »
http://chdk.setepontos.com/index.php?topic=5585.msg105915#msg105915  which mentions not possible with the DIGIC 4 image processor and slow SD cards.
I think you are misunderstanding srsa's post. The point is that the interface to the SD card is slow, which is not necessarily a characteristic of the CPU or the SD card.
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Since there are now DIGIC 6 image processors and faster SD cards am wondering if it is now possible?
CHDK doesn't run on Digic 6 yet so any hypothetical speed improvement is currently irrelevant.

But as I said above, the issue is the SD controller speed (and associated DMA, buses etc.) not CPU speed. While the limits of the P&S aren't really clear to me, it is clear that Canon's P&S have less IO throughput than DSLRs using the "same" Digic version.

For example, according to http://www.dpreview.com/reviews/canon-eos-700d-rebel-t5i/14 the Digic 5 based 700D has a "buffer full" continuous shooting rate for 1.4 FPS shooting 18 MP 14 bit raw.

The SX50 is also Digic 5, but according to http://www.dpreview.com/reviews/canon-powershot-sx50-hs/6 only manages 1.1 FPS, shooting 12 MP, 12 bit raw.
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If not, would be interested to know what is now preventing it from happening?
The main obstacle is unchanged: To even find out whether it is possible, you need a programmer who has sufficient skill, time and interest to do the actual work.
Don't forget what the H stands for.

Re: CHDK RAW Video?
« Reply #6 on: 04 / December / 2013, 15:03:11 »
Everyone,

Thanks for all your comments.

reyalp,

"...issue is the SD controller speed (and associated DMA, buses etc.) not CPU speed. While the limits of the P&S aren't really clear to me, it is clear that Canon's P&S have less IO throughput than DSLRs using the "same" Digic version."

Thanks for your detailed analysis.

I did some checking on Canon's website for P&S but did not find any cameras (even the latest N
http://shop.usa.canon.com/shop/en/catalog/cameras/powershot-n-series-digital-cameras/powershot-n-black) that are using USB 3.

Since it is now USB 3.1 and there is a new plug in the works. http://www.usb.org/developers/USB-Futures.pdf  seems best to wait until these features are incorporated in the P&S cameras.

Also checked the standard camera review sites but did not find any mention of slow "SD controller speed (and associated DMA, buses etc.)".

Has anyone found reviews mentioning this?

Gene
« Last Edit: 04 / December / 2013, 15:06:44 by genosmm »

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Offline reyalp

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Re: CHDK RAW Video?
« Reply #7 on: 04 / December / 2013, 15:54:05 »
I did some checking on Canon's website for P&S but did not find any cameras (even the latest N
http://shop.usa.canon.com/shop/en/catalog/cameras/powershot-n-series-digital-cameras/powershot-n-black) that are using USB 3.
USB 3 is not necessarily relevant, the USB interface used to connect to the PC isn't used to talk to the SD controller. The SD controller is probably directly connected to the camera system bus, not on USB, but even if it was USB, it would need to be a host controller where the PC connection is a device.

The thing to watch for would be cameras that support UHS SD speeds http://en.wikipedia.org/wiki/Secure_Digital#Ultra-High_Speed_bus

Note UHS is backwards compatible, so just listing UHS support does not mean that the camera actually has a UHS controller.
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Also checked the standard camera review sites but did not find any mention of slow "SD controller speed (and associated DMA, buses etc.)".
The camera manufacturers do not publish this kind of low level spec. Taking continuous raw shooting speed and converting it to mb/sec should be a reasonable proxy. This won't give you an absolute measure, but it should be a fairly decent relative measure: If camera X can do say 30 MB/s and camera Y can do 60 MB/s you can bet that camera Y has faster hardware.

edit: the above refers to raw in the stock firmware, which is presumably well optimized and close to the limits of the hardware. I wouldn't assume that comparing CHDK raw speed to factory raw is valid.

Of course, when making this kind of comparison you'd have check the "buffer full" speed, not some buffered burst rate.

On cameras with hacks like CHDK or ML, one could arrange more objective benchmarks.
« Last Edit: 04 / December / 2013, 15:58:22 by reyalp »
Don't forget what the H stands for.


Re: CHDK RAW Video?
« Reply #8 on: 26 / December / 2013, 09:18:20 »
I'd just like to add some thoughts of how it might be done.
-Use (lossless) compression before writing
-Write only some subset of the sensor data
-Preprocess the effect you're looking for before writing 8bit/compressed

The benefits could be:
-Less compression artefacts
-Slightly better quality (some tone adjustments would have less banding)

I just noticed something the other day with a low-light video test.  There was a definite pattern visible, it could be fixed with raw.

I should also mention you can capture uncompressed video through HDMI with live view.
You can also stream video through USB.
« Last Edit: 26 / December / 2013, 11:02:34 by jmac698 »

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Offline reyalp

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Re: CHDK RAW Video?
« Reply #9 on: 26 / December / 2013, 15:54:14 »
I'd just like to add some thoughts of how it might be done.
-Use (lossless) compression before writing
Normal video compression is done by the very fast dedicated video processing hardware in Digic. The main ARM CPU is not nearly fast enough. It's not clear whether Digic could be programmed to do this, and even if it could, it's not clear it would have enough bandwidth.
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-Preprocess the effect you're looking for before writing 8bit/compressed
Again, unless you can figure out how to do it in the image processor, modifying the video stream on the fly is out of the question.
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I should also mention you can capture uncompressed video through HDMI with live view.
Most HDMI capable cameras only enable it on playback, not live view. It's also not guaranteed that the HDMI is actually very high quality.

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You can also stream video through USB.
Not with high quality uncompressed video. The 720x240 live view already saturates the USB interface at < 30 FPS on many cameras.
Don't forget what the H stands for.

 

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