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authorNaushir Patuck <naush@raspberrypi.com>2021-01-19 15:30:46 +0000
committerLaurent Pinchart <laurent.pinchart@ideasonboard.com>2021-01-20 14:13:50 +0200
commit92b8ccc42a0f3ad323c79bde3c132d6956011239 (patch)
treec0e5beff20fd126387ba78d26977bdc37b2c61cf /src/ipa/raspberrypi/cam_helper.cpp
parent6232ec3c164102eb59c2deec9facb6552b55cca0 (diff)
libcamera: raspberrypi: Add control of sensor vblanking
Add support for setting V4L2_CID_VBLANK appropriately when setting V4L2_CID_EXPOSURE. This will allow adaptive framerates during viewfinder use cases (e.g. when the exposure time goes above 33ms, we can reduce the framerate to lower than 30fps). The minimum and maximum frame durations are provided via libcamera controls, and will prioritise exposure time limits over any AGC request. V4L2_CID_VBLANK is controlled through the staggered writer, just like the exposure and gain controls. Signed-off-by: Naushir Patuck <naush@raspberrypi.com> Reviewed-by: David Plowman <david.plowman@raspberrypi.com> Tested-by: David Plowman <david.plowman@raspberrypi.com> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Diffstat (limited to 'src/ipa/raspberrypi/cam_helper.cpp')
-rw-r--r--src/ipa/raspberrypi/cam_helper.cpp35
1 files changed, 33 insertions, 2 deletions
diff --git a/src/ipa/raspberrypi/cam_helper.cpp b/src/ipa/raspberrypi/cam_helper.cpp
index 6efa0d7f..b7b8faf0 100644
--- a/src/ipa/raspberrypi/cam_helper.cpp
+++ b/src/ipa/raspberrypi/cam_helper.cpp
@@ -34,8 +34,10 @@ CamHelper *CamHelper::Create(std::string const &cam_name)
return nullptr;
}
-CamHelper::CamHelper(MdParser *parser)
- : parser_(parser), initialized_(false)
+CamHelper::CamHelper(MdParser *parser, unsigned int maxFrameLength,
+ unsigned int frameIntegrationDiff)
+ : parser_(parser), initialized_(false), maxFrameLength_(maxFrameLength),
+ frameIntegrationDiff_(frameIntegrationDiff)
{
}
@@ -56,6 +58,35 @@ double CamHelper::Exposure(uint32_t exposure_lines) const
return exposure_lines * mode_.line_length / 1000.0;
}
+uint32_t CamHelper::GetVBlanking(double &exposure, double minFrameDuration,
+ double maxFrameDuration) const
+{
+ uint32_t frameLengthMin, frameLengthMax, vblank;
+ uint32_t exposureLines = ExposureLines(exposure);
+
+ assert(initialized_);
+
+ /*
+ * Clamp frame length by the frame duration range and the maximum allowable
+ * value in the sensor, given by maxFrameLength_.
+ */
+ frameLengthMin = std::clamp<uint32_t>(1e3 * minFrameDuration / mode_.line_length,
+ mode_.height, maxFrameLength_);
+ frameLengthMax = std::clamp<uint32_t>(1e3 * maxFrameDuration / mode_.line_length,
+ mode_.height, maxFrameLength_);
+ /*
+ * Limit the exposure to the maximum frame duration requested, and
+ * re-calculate if it has been clipped.
+ */
+ exposureLines = std::min(frameLengthMax - frameIntegrationDiff_, exposureLines);
+ exposure = Exposure(exposureLines);
+
+ /* Limit the vblank to the range allowed by the frame length limits. */
+ vblank = std::clamp(exposureLines + frameIntegrationDiff_,
+ frameLengthMin, frameLengthMax) - mode_.height;
+ return vblank;
+}
+
void CamHelper::SetCameraMode(const CameraMode &mode)
{
mode_ = mode;