[libcamera-devel] [PATCH 1/1] libcamera: controls: Add controls for HDR

[Naushir Patuck]

Hi David,

Thank you for your patch.

On Fri, 28 Jul 2023 at 13:28, David Plowman via libcamera-devel
<libcamera-devel at lists.libcamera.org> wrote:
>
> We add an HdrMode control (to enable and disable HDR processing)
> and an HdrChannel, which indicates what kind of HDR frame (short, long
> medium) has just arrived.
>
> Currently the HdrMode supports three values:
>
> * Off - no HDR processing at all.
> * MultiExposure - frames at multiple different exposures are combined
>   to create HDR images.
> * SingleExposure - multiple frames all at the same exposure are
>   combined to create HDR images.
>
> Signed-off-by: David Plowman <david.plowman at raspberrypi.com>
> ---
>  src/libcamera/control_ids.yaml | 47 ++++++++++++++++++++++++++++++++++
>  1 file changed, 47 insertions(+)
>
> diff --git a/src/libcamera/control_ids.yaml b/src/libcamera/control_ids.yaml
> index 056886e6..34df7adb 100644
> --- a/src/libcamera/control_ids.yaml
> +++ b/src/libcamera/control_ids.yaml
> @@ -701,6 +701,53 @@ controls:
>              Continuous AF is paused. No further state changes or lens movements
>              will occur until the AfPauseResume control is sent.
>
> +  - HdrMode:
> +      type: int32_t
> +      description: |
> +        Control to set the mode to be used for High Dynamic Range (HDR)
> +        imaging.
> +
> +      enum:
> +        - name: HdrModeOff
> +          value: 0
> +          description: |
> +            HDR is not enabled.
> +        - name: HdrModeMultiExposure
> +          value: 1
> +          description: |
> +            Multiple exposures will be used to create HDR images.
> +        - name: HdrModeSingleExposure
> +          value: 2
> +          description: |
> +            Multiple frames all at a single exposure will be used to create HDR
> +            images.
> +
> +  - HdrChannel:
> +      type: int32_t
> +      description: |
> +        This value is reported back to the application so that it can discover
> +        whether this capture corresponds to the short or long exposure image (or
> +        any other image used by the HDR procedure).

Only a minor comment about this control.  Instead of an enum, should we use an
explicit integer to determine channel number?  Then we are not limited to only
short/medium/long channels as below?

I'm not too bothered either way so,

Reviewed-by: Naushir Patuck <naush at raspberrypi.com>

> +      enum:
> +        - name: HdrChannelNone
> +          value: 0
> +          description: |
> +            This image does not correspond to any of the captures used to create
> +            an HDR image.
> +        - name: HdrChannelShort
> +          value: 1
> +          description: |
> +            This is a short exposure image.
> +        - name: HdrChannelMedium
> +          value: 2
> +          description: |
> +            This is a medium exposure image.
> +        - name: HdrChannelLong
> +          value: 3
> +          description: |
> +            This is a long exposure image.
> +
>    # ----------------------------------------------------------------------------
>    # Draft controls section
>
> --
> 2.30.2
>