[libcamera-devel] [PATCH 0/2] raspberrypi: FPS control

[Naushir Patuck]

Hi Laurent,

On Tue, 12 May 2020 at 01:28, Laurent Pinchart
<laurent.pinchart at ideasonboard.com> wrote:
>
> Hi Naush,
>
> Thank you for the patches.
>
> On Mon, May 11, 2020 at 11:01:48AM +0100, Naushir Patuck wrote:
> > Hi,
> >
> > The following two patches add variable framerate control to a sensor
> > subdevice.  This will allow shutter speeds below 33ms during
> > viewfinder (for example).
> >
> > I've currently hardcoded the maximum limit at 30.0fps, but we ought to
> > have a discussion on how a user can request fps limits - perhaps
> > though a Request, or stream configuration parameters?
>
> That's an API we need indeed. I think the frame rate would need to be
> modifiable at runtime, so that would require a control. Should we go for
> a frame duration, using the same units as the exposure time ?

I can prepare an array control to provide min/max framerate and send
out a v2 patch with this.  Normally I prefer representing framerate as
1/t, e.g. 30 fps.  No objections to using the same form (t) and units
as exposure - it's your call.

Thanks,
Naush


>
> > Naushir Patuck (2):
> >   libcamera: raspberrypi: Add control of sensor vblanking
> >   libcamera: raspberrypi: Limit the maximum framerate to 30.0fps
> >
> >  src/ipa/raspberrypi/cam_helper.hpp            |  1 +
> >  src/ipa/raspberrypi/cam_helper_imx219.cpp     | 23 +++++++++++++++++++
> >  src/ipa/raspberrypi/cam_helper_imx477.cpp     | 23 +++++++++++++++++++
> >  src/ipa/raspberrypi/cam_helper_ov5647.cpp     | 23 +++++++++++++++++++
> >  src/ipa/raspberrypi/raspberrypi.cpp           | 14 ++++++++++-
> >  .../pipeline/raspberrypi/raspberrypi.cpp      |  2 ++
> >  6 files changed, 85 insertions(+), 1 deletion(-)
>
> --
> Regards,
>
> Laurent Pinchart