[libcamera-devel] Camera mode selection

[Kieran Bingham]

Hi David,

On 22/01/2021 14:29, David Plowman wrote:
> Hi everyone
> 
> I was wondering if I might return to the topic of camera mode
> selection. (Apologies if this might turn into another long
> meta-discussion!)
> 
> We already know that there are questions as to how and when you might
> trade off things like better resolution versus higher framerates, and
> it's not clear how an application might signal what it wants.
> 
> Another case I've found myself faced with recently is how to select
> camera modes jointly, such as when doing preview and then capture.
> Typically the preview will ask for a smaller resolution, and capture a
> larger one. You might adjust the preview to have the same aspect ratio
> as the capture. But so far as I understand it, it's difficult to
> guarantee that the preview mode will have the same field of view as
> the capture.

Are you considering this use case as configuring one stream as preview,
running, and then reconfiguring for capture? or as two stream
configurations?


> Do others see this as a problem, and if so how might one fix it? Have
> more in the way of flags that "hint" at what the application wants?
> Perhaps pass in a second resolution with the rule that the mode
> selected for the first resolution must have the save FoV as the
> second?

Is this where the 'Raw' stream would be configured, but without
providing buffers to control what the FoV defined at the sensor actually
is ?

> I often find myself coming back to the idea of selecting modes
> explicitly - applications frequently know what sensor they're dealing
> with, and probably know exactly which modes they want too.

To clarify, for a 'mode' do you mean a fixed setting of (Sensor)
width/height/framerate? or something more?
--
Kieran



> 
> Anyway, I'd be interested to hear people's thoughts on this one!
> 
> Thanks and best regards
> David
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> 

-- 
Regards
--
Kieran