{"id":24174,"url":"https://patchwork.libcamera.org/api/patches/24174/?format=json","web_url":"https://patchwork.libcamera.org/patch/24174/","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":"<20250821134141.83236-6-mzamazal@redhat.com>","date":"2025-08-21T13:41:41","name":"[5/5] libcamera: simple: Prevent division by zero in BLC","commit_ref":null,"pull_url":null,"state":"superseded","archived":false,"hash":"c7e9010e27bee29f34793d2121e33912a5284933","submitter":{"id":177,"url":"https://patchwork.libcamera.org/api/people/177/?format=json","name":"Milan Zamazal","email":"mzamazal@redhat.com"},"delegate":null,"mbox":"https://patchwork.libcamera.org/patch/24174/mbox/","series":[{"id":5397,"url":"https://patchwork.libcamera.org/api/series/5397/?format=json","web_url":"https://patchwork.libcamera.org/project/libcamera/list/?series=5397","date":"2025-08-21T13:41:36","name":"Fix stats related problems in software ISP","version":1,"mbox":"https://patchwork.libcamera.org/series/5397/mbox/"}],"comments":"https://patchwork.libcamera.org/api/patches/24174/comments/","check":"pending","checks":"https://patchwork.libcamera.org/api/patches/24174/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 9A231BEFBE\n\tfor ;\n\tThu, 21 Aug 2025 13:42:10 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 5A698692ED;\n\tThu, 21 Aug 2025 15:42:10 +0200 (CEST)","from us-smtp-delivery-124.mimecast.com\n\t(us-smtp-delivery-124.mimecast.com [170.10.129.124])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 5C76669257\n\tfor ;\n\tThu, 21 Aug 2025 15:42:09 +0200 (CEST)","from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com\n\t(ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63])\n\tby relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3,\n\tcipher=TLS_AES_256_GCM_SHA384) id us-mta-375-mta7ESvZNnSo9hdAa00arA-1;\n\tThu, 21 Aug 2025 09:42:02 -0400","from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com\n\t(mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com\n\t[10.30.177.111])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\tkey-exchange X25519 server-signature RSA-PSS (2048 bits)\n\tserver-digest SHA256) (No client certificate requested)\n\tby mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix)\n\twith ESMTPS id 9B362195608A; Thu, 21 Aug 2025 13:42:01 +0000 (UTC)","from mzamazal-thinkpadp1gen7.tpbc.com (unknown [10.45.224.162])\n\tby mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix)\n\twith ESMTP id BF20A180029B; Thu, 21 Aug 2025 13:41:59 +0000 (UTC)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=redhat.com header.i=@redhat.com\n\theader.b=\"LJqq8SIO\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com;\n\ts=mimecast20190719; t=1755783728;\n\th=from:from:reply-to:subject:subject:date:date:message-id:message-id:\n\tto:to:cc:cc:mime-version:mime-version:content-type:content-type:\n\tcontent-transfer-encoding:content-transfer-encoding:\n\tin-reply-to:in-reply-to:references:references;\n\tbh=KMRZfXmG+aUPlclYMk6hPyaAt+ixcRkQlW0Jn7FZTro=;\n\tb=LJqq8SIO3G8Sm8OLXpoD+82uAMsG2frNj0F1v1+a+H3hwAxXskIbeD26zAt2WuN9zpj54F\n\tf002UCV5R4DRKCzdnq3wP0pVZiXhgEAHzQnfQUz0ANzahqq2h0avo09R58lG+/M3iXKZlO\n\t50BHMYRMD0ARjJbxyMlzf9MNY9wxou8=","X-MC-Unique":"mta7ESvZNnSo9hdAa00arA-1","X-Mimecast-MFC-AGG-ID":"mta7ESvZNnSo9hdAa00arA_1755783721","From":"Milan Zamazal ","To":"libcamera-devel@lists.libcamera.org","Cc":"Milan Zamazal , pobrn@protonmail.com,\n\tmail@maciej.szmigiero.name","Subject":"[PATCH 5/5] libcamera: simple: Prevent division by zero in BLC","Date":"Thu, 21 Aug 2025 15:41:41 +0200","Message-ID":"<20250821134141.83236-6-mzamazal@redhat.com>","In-Reply-To":"<20250821134141.83236-1-mzamazal@redhat.com>","References":"<20250821134141.83236-1-mzamazal@redhat.com>","MIME-Version":"1.0","X-Scanned-By":"MIMEDefang 3.4.1 on 10.30.177.111","X-Mimecast-Spam-Score":"0","X-Mimecast-MFC-PROC-ID":"1cZxlQJAJ0U8ypNAe53BvVcnbiOY7qaNjm85xmmK0LQ_1755783721","X-Mimecast-Originator":"redhat.com","Content-Transfer-Encoding":"8bit","content-type":"text/plain; charset=\"US-ASCII\"; x-default=true","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":"When there are no values in the histogram, BLC simple IPA can crash on\ndivision by zero. We cannot get anything meaningful in such a case\nanyway, let's simply return from `process()' then.\n\nSigned-off-by: Milan Zamazal \n---\n src/ipa/simple/algorithms/blc.cpp | 5 +++++\n 1 file changed, 5 insertions(+)","diff":"diff --git a/src/ipa/simple/algorithms/blc.cpp b/src/ipa/simple/algorithms/blc.cpp\nindex 8c1e9ed08..71731c6f6 100644\n--- a/src/ipa/simple/algorithms/blc.cpp\n+++ b/src/ipa/simple/algorithms/blc.cpp\n@@ -77,6 +77,11 @@ void BlackLevel::process(IPAContext &context,\n \tconstexpr float ignoredPercentage = 0.02;\n \tconst unsigned int total =\n \t\tstd::accumulate(begin(histogram), end(histogram), 0);\n+\tif (total == 0) {\n+\t\tLOG(IPASoftBL, Debug) << \"Not guessing black level, histogram is empty\";\n+\t\treturn;\n+\t};\n+\n \tconst unsigned int pixelThreshold = ignoredPercentage * total;\n \tconst unsigned int histogramRatio = 256 / SwIspStats::kYHistogramSize;\n \tconst unsigned int currentBlackIdx =\n","prefixes":["5/5"]}