Limitation of movie modes - General Help and Assistance on using CHDK stable releases - CHDK Forum

Limitation of movie modes

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Limitation of movie modes
« on: 03 / May / 2012, 10:48:58 »
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Hi.

I've got interested in CHDK and tomorrow I'll get my SX40 camera.

I want to play around with movie modes. These modes are available for SX40:
1) 320x240 at 240fps
2) 640x480 at 120fps
3) 1280x720 at 30fps
4) 1920x1080 at 27fps

I'm really confused, why is there no "1280x720 at 120 fps" or "1280x720 at 60 fps" available?
As far as I know SX40 have the DIGIC5 processor, which is approximately 5 times faster, than DIGIC4 processor. "1280x720 at 30fps" was available to DIGIC4 cameras. So by a common sense SX40 should be able to record at least at "1280x720 at 60 fps".

So is it a firmware limitation, or a problem with something else(e.g. memory consumption)?
What I've read on this forum so far made me think, that camera requires memory for number of uncompressed frames of 1 sec. of movie while recording. Am I correct at that?

Re: Limitation of movie modes
« Reply #1 on: 03 / May / 2012, 16:28:39 »
As far as I know SX40 have the DIGIC5 processor, which is approximately 5 times faster, than DIGIC4 processor. "1280x720 at 30fps" was available to DIGIC4 cameras. So by a common sense SX40 should be able to record at least at "1280x720 at 60 fps".
Canon P&S cameras also have a DSP processor that does most of the heavy image processing work.  So a faster DIGIC processor might look good on the product brochures but does not count for much if the DSP cannot process images any faster ....

Quote
So is it a firmware limitation, or a problem with something else(e.g. memory consumption)?
What I've read on this forum so far made me think, that camera requires memory for number of uncompressed frames of 1 sec. of movie while recording. Am I correct at that?
Does it matter ?   You buy a camera based on the specs.  Probably not a good idea to assume they can be exceeded (by CHDK or anything else) otherwise Canon probably would have done so in the first place to enhance the competitive position of the camera.  Sometimes with CHDK you get lucky but you mostly get what you pay for and pretty much never get anything more.
Ported :   A1200    SD940   G10    Powershot N    G16

 

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