[libcamera-devel] [PATCH v12 1/3] libcamera: controls: Add frame duration control

[Laurent Pinchart]

Hi Naush,

On Wed, Jan 20, 2021 at 11:54:38AM +0000, Naushir Patuck wrote:
> On Wed, 20 Jan 2021 at 11:50, Laurent Pinchart wrote:
> > On Tue, Jan 19, 2021 at 03:30:45PM +0000, Naushir Patuck wrote:
> > > Add an int64_t array control (controls::FrameDurations) to specify the
> > > minimum and maximum (in that order) frame duration to be used by the
> > > camera sensor.
> > >
> > > Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
> > > Reviewed-by: David Plowman <david.plowman at raspberrypi.com>
> > > Tested-by: David Plowman <david.plowman at raspberrypi.com>
> > > Reviewed-by: Jacopo Mondi <jacopo at jmondi.org>
> > > ---
> > >  src/libcamera/control_ids.yaml | 36 ++++++++++++++++++++++++++++++++++
> > >  1 file changed, 36 insertions(+)
> > >
> > > diff --git a/src/libcamera/control_ids.yaml b/src/libcamera/control_ids.yaml
> > > index 6d6f0fee508b..36c37161a3d5 100644
> > > --- a/src/libcamera/control_ids.yaml
> > > +++ b/src/libcamera/control_ids.yaml
> > > @@ -306,6 +306,42 @@ controls:
> > >          maximum valid value is given by the properties::ScalerCropMaximum
> > >          property, and the two can be used to implement digital zoom.
> > >
> > > +  - FrameDurations:
> > > +      type: int64_t
> > > +      description: |
> > > +          The minimum and maximum (in that order) frame duration,
> > > +          expressed in micro-seconds.
> >
> > s/micro-seconds/microseconds/
> >
> > (The indentation should be 2 spaces btw)
> >
> > I'll handle this when applying.
> 
> Thank you!  Apologies that I missed fixing those typos you pointed out
> earlier.

No worries at all. I've now pushed the series.

> > Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> >
> > > +
> > > +          When provided by applications, the control specifies the sensor frame
> > > +          duration interval the pipeline has to use. This limits the largest
> > > +          exposure time the sensor can use. For example, if a maximum frame
> > > +          duration of 33ms is requested (corresponding to 30 frames per second),
> > > +          the sensor will not be able to raise the exposure time above 33ms.
> > > +          A fixed frame duration is achieved by setting the minimum and maximum
> > > +          values to be the same. Setting both values to 0 reverts to using the
> > > +          IPA provided defaults.
> > > +
> > > +          The maximum frame duration provides the absolute limit to the shutter
> > > +          speed computed by the AE algorithm and it overrides any exposure mode
> > > +          setting specified with controls::AeExposureMode. Similarly, when a
> > > +          manual exposure time is set through controls::ExposureTime, it also
> > > +          gets clipped to the limits set by this control. When reported in
> > > +          metadata, the control expresses the minimum and maximum frame
> > > +          durations used after being clipped to the sensor provided frame
> > > +          duration limits.
> > > +
> > > +          \sa AeExposureMode
> > > +          \sa ExposureTime
> > > +
> > > +          \todo Define how to calculate the capture frame rate by
> > > +          defining controls to report additional delays introduced by
> > > +          the capture pipeline or post-processing stages (ie JPEG
> > > +          conversion, frame scaling).
> > > +
> > > +          \todo Provide an explicit definition of default control values, for
> > > +          this and all other controls.
> > > +      size: [2]
> > > +
> > >    # ----------------------------------------------------------------------------
> > >    # Draft controls section
> > >

-- 
Regards,

Laurent Pinchart