[{"id":38126,"web_url":"https://patchwork.libcamera.org/comment/38126/","msgid":"<177039188540.607498.2136232235053485447@neptunite.rasen.tech>","date":"2026-02-06T15:31:25","subject":"Re: [PATCH v3 12/19] ipa: libipa: agc: Compute max shutter time with\n\tframe duration","submitter":{"id":17,"url":"https://patchwork.libcamera.org/api/people/17/","name":"Paul Elder","email":"paul.elder@ideasonboard.com"},"content":"Quoting Jacopo Mondi (2025-11-14 23:17:07)\n> The maximum shutter time the AGC algorithm can achieve is, by definition,\n> limited by the maximum programmed frame duration.\n> \n> When configuring the AGC algorithm, use the frame duration to calculate\n> the maximum shutter time by using the CameraSensorHelper::maxShutterTime()\n> function, unless the IPA has asked for a fixed exposure by setting min ==\n\ns/exposure/frame duration/ ?\n\n> max.\n> \n> Signed-off-by: Jacopo Mondi \n\nReviewed-by: Paul Elder \n\n> ---\n> src/ipa/libipa/exposure_mode_helper.cpp | 20 ++++++++++++++++++--\n> 1 file changed, 18 insertions(+), 2 deletions(-)\n> \n> diff --git a/src/ipa/libipa/exposure_mode_helper.cpp b/src/ipa/libipa/exposure_mode_helper.cpp\n> index f771b10a28eead2976c0000cf099ba5cfbe78e0f..45f51f9088170c983bb0de2c18714627514c5641 100644\n> --- a/src/ipa/libipa/exposure_mode_helper.cpp\n> +++ b/src/ipa/libipa/exposure_mode_helper.cpp\n> @@ -127,14 +127,30 @@ ExposureModeHelper::ExposureModeHelper(const Span void ExposureModeHelper::configure(const SensorConfiguration &sensorConfig,\n> const CameraSensorHelper *sensorHelper)\n> {\n> + ASSERT(sensorHelper);\n> +\n> sensor_ = sensorConfig;\n> sensorHelper_ = sensorHelper;\n> \n> /* Initialize run-time limits with sensor's default. */\n> - minExposureTime_ = sensor_.minExposureTime_;\n> - maxExposureTime_ = sensor_.maxExposureTime_;\n> minGain_ = sensor_.minGain_;\n> maxGain_ = sensor_.maxGain_;\n> +\n> + minExposureTime_ = sensor_.minExposureTime_;\n> +\n> + /*\n> + * Compute the maximum shutter time.\n> + *\n> + * If maxExposureTime is equal to minExposureTime then we use them\n> + * to fix the exposure time.\n> + *\n> + * Otherwise, if the exposure can range between a min and max delegate\n> + * the maximum shutter time calculation to the sensor helper.\n> + */\n> + maxExposureTime_ = minExposureTime_ != sensorConfig.maxExposureTime_\n> + ? sensorHelper_->maxShutterTime(sensorConfig.maxFrameDuration_,\n> + sensorConfig.lineDuration_)\n> + : minExposureTime_;\n> }\n> \n> /**\n> \n> -- \n> 2.51.1\n>","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id E0D79C32E7\n\tfor ;\n\tFri, 6 Feb 2026 15:31:32 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 6FFA16209B;\n\tFri, 6 Feb 2026 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+0900","Message-ID":"<177039188540.607498.2136232235053485447@neptunite.rasen.tech>","User-Agent":"alot/0.0.0","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}},{"id":38131,"web_url":"https://patchwork.libcamera.org/comment/38131/","msgid":"<177039220647.607498.2480897708229257814@neptunite.rasen.tech>","date":"2026-02-06T15:36:46","subject":"Re: [PATCH v3 12/19] ipa: libipa: agc: Compute max shutter time with\n\tframe duration","submitter":{"id":17,"url":"https://patchwork.libcamera.org/api/people/17/","name":"Paul Elder","email":"paul.elder@ideasonboard.com"},"content":"Quoting Paul Elder (2026-02-07 00:31:25)\n> Quoting Jacopo Mondi (2025-11-14 23:17:07)\n> > The maximum shutter time the AGC algorithm can achieve is, by definition,\n> > limited by the maximum programmed frame duration.\n> > \n> > When configuring the AGC algorithm, use the frame duration to calculate\n> > the maximum shutter time by using the CameraSensorHelper::maxShutterTime()\n> > function, unless the IPA has asked for a fixed exposure by setting min ==\n> \n> s/exposure/frame duration/ ?\n\noic it's from the IPA not the application, lgtm.\n\n\nPaul\n\n> \n> > max.\n> > \n> > Signed-off-by: Jacopo Mondi \n> \n> Reviewed-by: Paul Elder \n> \n> > ---\n> > src/ipa/libipa/exposure_mode_helper.cpp | 20 ++++++++++++++++++--\n> > 1 file changed, 18 insertions(+), 2 deletions(-)\n> > \n> > diff --git a/src/ipa/libipa/exposure_mode_helper.cpp b/src/ipa/libipa/exposure_mode_helper.cpp\n> > index f771b10a28eead2976c0000cf099ba5cfbe78e0f..45f51f9088170c983bb0de2c18714627514c5641 100644\n> > --- a/src/ipa/libipa/exposure_mode_helper.cpp\n> > +++ b/src/ipa/libipa/exposure_mode_helper.cpp\n> > @@ -127,14 +127,30 @@ ExposureModeHelper::ExposureModeHelper(const Span > void ExposureModeHelper::configure(const SensorConfiguration &sensorConfig,\n> > const CameraSensorHelper *sensorHelper)\n> > {\n> > + ASSERT(sensorHelper);\n> > +\n> > sensor_ = sensorConfig;\n> > sensorHelper_ = sensorHelper;\n> > \n> > /* Initialize run-time limits with sensor's default. */\n> > - minExposureTime_ = sensor_.minExposureTime_;\n> > - maxExposureTime_ = sensor_.maxExposureTime_;\n> > minGain_ = sensor_.minGain_;\n> > maxGain_ = sensor_.maxGain_;\n> > +\n> > + minExposureTime_ = sensor_.minExposureTime_;\n> > +\n> > + /*\n> > + * Compute the maximum shutter time.\n> > + *\n> > + * If maxExposureTime is equal to minExposureTime then we use them\n> > + * to fix the exposure time.\n> > + *\n> > + * Otherwise, if the exposure can range between a min and max delegate\n> > + * the maximum shutter time calculation to the sensor helper.\n> > + */\n> > + maxExposureTime_ = minExposureTime_ != sensorConfig.maxExposureTime_\n> > + ? sensorHelper_->maxShutterTime(sensorConfig.maxFrameDuration_,\n> > + sensorConfig.lineDuration_)\n> > + : minExposureTime_;\n> > }\n> > \n> > /**\n> > \n> > -- \n> > 2.51.1\n> >","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 85AACBD78E\n\tfor ;\n\tFri, 6 Feb 2026 15:36:54 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 34B8E620BE;\n\tFri, 6 Feb 2026 16:36:54 +0100 (CET)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 15117620AE\n\tfor ;\n\tFri, 6 Feb 2026 16:36:52 +0100 (CET)","from neptunite.rasen.tech (unknown\n\t[IPv6:2404:7a81:160:2100:5247:7b72:2b7:10da])\n\tby perceval.ideasonboard.com 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