[libcamera-devel] [PATCH] android: camera_device: Fix exposure time tag in exif and android

[Jacopo Mondi]

Hi Paul,

On Thu, Jan 28, 2021 at 07:22:14PM +0900, Paul Elder wrote:
> The exposure time libcamera control is in microseconds while android and
> our exif component use nanoseconds. Convert it appropriately.

My bad! Sorry about overlooking this
(you can write ExposureTime as it's the actual control name)

>
> CTS also expects the exposure time exif tag to match the exposure time
> set in the android result metadata. Fix it.

Correct, looks like a separate patch though, but ok...

>
> Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
> ---
>  src/android/camera_device.cpp            | 2 +-
>  src/android/jpeg/post_processor_jpeg.cpp | 3 ++-
>  2 files changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/src/android/camera_device.cpp b/src/android/camera_device.cpp
> index f5066709..36382941 100644
> --- a/src/android/camera_device.cpp
> +++ b/src/android/camera_device.cpp
> @@ -2058,7 +2058,7 @@ CameraDevice::getResultMetadata(Camera3RequestDescriptor *descriptor,
>  	}
>
>  	if (metadata.contains(controls::ExposureTime)) {
> -		int32_t exposure = metadata.get(controls::ExposureTime);
> +		int64_t exposure = metadata.get(controls::ExposureTime) * 1000;
>  		resultMetadata->addEntry(ANDROID_SENSOR_EXPOSURE_TIME,
>  	}
> diff --git a/src/android/jpeg/post_processor_jpeg.cpp b/src/android/jpeg/post_processor_jpeg.cpp
> index cac0087b..6250b050 100644
> --- a/src/android/jpeg/post_processor_jpeg.cpp
> +++ b/src/android/jpeg/post_processor_jpeg.cpp
> @@ -113,7 +113,8 @@ int PostProcessorJpeg::process(const FrameBuffer &source,
>  	exif.setTimestamp(std::time(nullptr), 0ms);
>
>  	/* \todo Get this information from libcamera::Request::metadata */
> -	exif.setExposureTime(0);
> +	ret = resultMetadata->getEntry(ANDROID_SENSOR_EXPOSURE_TIME, &entry);
> +	exif.setExposureTime(ret ? *entry.data.i64 : 0);

If I'm not mistaken, this is the first getEntry() we call on the
result metadata, that has to be populated already by out
getResultMetadata().

If think it's fine, we need a single pass to convert libcamera
controls to Android format, and indeed the EXIF tags should reflect
the Android expected format.

Could you remove the \todo then ?

The patch content looks good
Reviewed-by: Jacopo Mondi <jacopo at jmondi.org>

Thanks
  j

>  	ret = requestMetadata.getEntry(ANDROID_LENS_APERTURE, &entry);
>  	if (ret)
>  		exif.setAperture(*entry.data.f);
> --
> 2.27.0
>
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