{"id":27482,"url":"https://patchwork.libcamera.org/api/patches/27482/?format=json","web_url":"https://patchwork.libcamera.org/patch/27482/","project":{"id":1,"url":"https://patchwork.libcamera.org/api/projects/1/?format=json","name":"libcamera","link_name":"libcamera","list_id":"libcamera_core","list_email":"libcamera-devel@lists.libcamera.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20260723154327.1357866-34-barnabas.pocze@ideasonboard.com>","date":"2026-07-23T15:43:16","name":"[RFC,v2,33/43] ipa: simple: agc: Separate MSV calculation","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"b75ad0e58f581454e9100ff5f5766b9eebc0a8a2","submitter":{"id":216,"url":"https://patchwork.libcamera.org/api/people/216/?format=json","name":"Barnabás Pőcze","email":"barnabas.pocze@ideasonboard.com"},"delegate":null,"mbox":"https://patchwork.libcamera.org/patch/27482/mbox/","series":[{"id":6075,"url":"https://patchwork.libcamera.org/api/series/6075/?format=json","web_url":"https://patchwork.libcamera.org/project/libcamera/list/?series=6075","date":"2026-07-23T15:42:43","name":"ipa: libipa: agc rework","version":2,"mbox":"https://patchwork.libcamera.org/series/6075/mbox/"}],"comments":"https://patchwork.libcamera.org/api/patches/27482/comments/","check":"pending","checks":"https://patchwork.libcamera.org/api/patches/27482/checks/","tags":{},"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 7A3AFC32CE\n\tfor ;\n\tThu, 23 Jul 2026 15:44:19 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 0455767F52;\n\tThu, 23 Jul 2026 17:44:19 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id F1AA667EFB\n\tfor ;\n\tThu, 23 Jul 2026 17:43:38 +0200 (CEST)","from pb-laptop.local (185.182.215.156.nat.pool.zt.hu\n\t[185.182.215.156])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 1FA7D23B9\n\tfor ;\n\tThu, 23 Jul 2026 17:42:38 +0200 (CEST)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"oGKB23Ux\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1784821358;\n\tbh=JnG6U3ReObdvdyhBhEGao+Rl2y+v4KH1tXn9bxTK8yA=;\n\th=From:To:Subject:Date:In-Reply-To:References:From;\n\tb=oGKB23Uxq3lpJ3g8BobRu7vuXdJI3urZO0s72+3+QygrniQPidkgV3O1MRjHFYbNx\n\ti41OrtWNwYlf2M7l2GsReTa16lMeyNh7GFhz3tlF7jKFKM1TkGdeZVXlHqVCEvhULc\n\thdiUIsq8pgyxJ8gGa/JdFofbyETwJ9APSGqzA2vI=","From":"=?utf-8?q?Barnab=C3=A1s_P=C5=91cze?= ","To":"libcamera-devel@lists.libcamera.org","Subject":"[RFC PATCH v2 33/43] ipa: simple: agc: Separate MSV calculation","Date":"Thu, 23 Jul 2026 17:43:16 +0200","Message-ID":"<20260723154327.1357866-34-barnabas.pocze@ideasonboard.com>","X-Mailer":"git-send-email 2.55.0","In-Reply-To":"<20260723154327.1357866-1-barnabas.pocze@ideasonboard.com>","References":"<20260723154327.1357866-1-barnabas.pocze@ideasonboard.com>","MIME-Version":"1.0","Content-Type":"text/plain; charset=UTF-8","Content-Transfer-Encoding":"8bit","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\" "},"content":"Add a separate function that does the MSV calculation.\n\nSigned-off-by: Barnabás Pőcze \n---\n src/ipa/simple/algorithms/agc.cpp | 72 ++++++++++++++++++-------------\n 1 file changed, 42 insertions(+), 30 deletions(-)","diff":"diff --git a/src/ipa/simple/algorithms/agc.cpp b/src/ipa/simple/algorithms/agc.cpp\nindex 93505f7665..f959abeba5 100644\n--- a/src/ipa/simple/algorithms/agc.cpp\n+++ b/src/ipa/simple/algorithms/agc.cpp\n@@ -9,6 +9,7 @@\n \n #include \n #include \n+#include \n #include \n \n #include \n@@ -61,6 +62,44 @@ static constexpr float kExpProportionalGain = 0.04;\n */\n static constexpr float kExpMaxStep = 0.15;\n \n+namespace {\n+\n+std::optional calculateMSV(const SwIspStats::Histogram &histogram, uint8_t blackLevel)\n+{\n+\t/*\n+\t * Calculate Mean Sample Value (MSV) according to formula from:\n+\t * https://www.araa.asn.au/acra/acra2007/papers/paper84final.pdf\n+\t */\n+\tconst unsigned int blackLevelHistIdx =\n+\t\tblackLevel / (256 / SwIspStats::kYHistogramSize);\n+\tconst unsigned int histogramSize =\n+\t\tSwIspStats::kYHistogramSize - blackLevelHistIdx;\n+\tconst unsigned int yHistValsPerBin = histogramSize / kExposureBinsCount;\n+\tconst unsigned int yHistValsPerBinMod =\n+\t\thistogramSize / (histogramSize % kExposureBinsCount + 1);\n+\tint exposureBins[kExposureBinsCount] = {};\n+\tunsigned int denom = 0;\n+\tunsigned int num = 0;\n+\n+\tif (yHistValsPerBin == 0)\n+\t\treturn {};\n+\n+\tfor (unsigned int i = 0; i < histogramSize; i++) {\n+\t\tunsigned int idx = (i - (i / yHistValsPerBinMod)) / yHistValsPerBin;\n+\t\texposureBins[idx] += histogram[blackLevelHistIdx + i];\n+\t}\n+\n+\tfor (unsigned int i = 0; i < kExposureBinsCount; i++) {\n+\t\tLOG(IPASoftExposure, Debug) << i << \": \" << exposureBins[i];\n+\t\tdenom += exposureBins[i];\n+\t\tnum += exposureBins[i] * (i + 1);\n+\t}\n+\n+\treturn (denom == 0 ? 0 : static_cast(num) / denom);\n+}\n+\n+} /* namespace */\n+\n Agc::Agc()\n {\n }\n@@ -158,41 +197,14 @@ void Agc::process(IPAContext &context,\n \t\treturn;\n \t}\n \n-\t/*\n-\t * Calculate Mean Sample Value (MSV) according to formula from:\n-\t * https://www.araa.asn.au/acra/acra2007/papers/paper84final.pdf\n-\t */\n-\tconst auto &histogram = stats->yHistogram;\n-\tconst unsigned int blackLevelHistIdx =\n-\t\tcontext.activeState.blc.level / (256 / SwIspStats::kYHistogramSize);\n-\tconst unsigned int histogramSize =\n-\t\tSwIspStats::kYHistogramSize - blackLevelHistIdx;\n-\tconst unsigned int yHistValsPerBin = histogramSize / kExposureBinsCount;\n-\tconst unsigned int yHistValsPerBinMod =\n-\t\thistogramSize / (histogramSize % kExposureBinsCount + 1);\n-\tint exposureBins[kExposureBinsCount] = {};\n-\tunsigned int denom = 0;\n-\tunsigned int num = 0;\n-\n-\tif (yHistValsPerBin == 0) {\n+\tauto exposureMSV = calculateMSV(stats->yHistogram, context.activeState.blc.level);\n+\tif (!exposureMSV) {\n \t\tLOG(IPASoftExposure, Debug)\n \t\t\t<< \"Not adjusting exposure due to insufficient histogram data\";\n \t\treturn;\n \t}\n \n-\tfor (unsigned int i = 0; i < histogramSize; i++) {\n-\t\tunsigned int idx = (i - (i / yHistValsPerBinMod)) / yHistValsPerBin;\n-\t\texposureBins[idx] += histogram[blackLevelHistIdx + i];\n-\t}\n-\n-\tfor (unsigned int i = 0; i < kExposureBinsCount; i++) {\n-\t\tLOG(IPASoftExposure, Debug) << i << \": \" << exposureBins[i];\n-\t\tdenom += exposureBins[i];\n-\t\tnum += exposureBins[i] * (i + 1);\n-\t}\n-\n-\tfloat exposureMSV = (denom == 0 ? 0 : static_cast(num) / denom);\n-\tupdateExposure(context, frameContext, exposureMSV);\n+\tupdateExposure(context, frameContext, *exposureMSV);\n }\n \n REGISTER_IPA_ALGORITHM(Agc, \"Agc\")\n","prefixes":["RFC","v2","33/43"]}