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{
    "id": 27487,
    "url": "https://patchwork.libcamera.org/api/patches/27487/?format=api",
    "web_url": "https://patchwork.libcamera.org/patch/27487/",
    "project": {
        "id": 1,
        "url": "https://patchwork.libcamera.org/api/projects/1/?format=api",
        "name": "libcamera",
        "link_name": "libcamera",
        "list_id": "libcamera_core",
        "list_email": "libcamera-devel@lists.libcamera.org",
        "web_url": "",
        "scm_url": "",
        "webscm_url": ""
    },
    "msgid": "<20260723154327.1357866-39-barnabas.pocze@ideasonboard.com>",
    "date": "2026-07-23T15:43:21",
    "name": "[RFC,v2,38/43] ipa: libipa: agc_msv: Ensure limits are always respected",
    "commit_ref": null,
    "pull_url": null,
    "state": "new",
    "archived": false,
    "hash": "1ddd19ac00602e268257ae9374f4c2381e7a67fa",
    "submitter": {
        "id": 216,
        "url": "https://patchwork.libcamera.org/api/people/216/?format=api",
        "name": "Barnabás Pőcze",
        "email": "barnabas.pocze@ideasonboard.com"
    },
    "delegate": null,
    "mbox": "https://patchwork.libcamera.org/patch/27487/mbox/",
    "series": [
        {
            "id": 6075,
            "url": "https://patchwork.libcamera.org/api/series/6075/?format=api",
            "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/27487/comments/",
    "check": "pending",
    "checks": "https://patchwork.libcamera.org/api/patches/27487/checks/",
    "tags": {},
    "headers": {
        "Return-Path": "<libcamera-devel-bounces@lists.libcamera.org>",
        "X-Original-To": "parsemail@patchwork.libcamera.org",
        "Delivered-To": "parsemail@patchwork.libcamera.org",
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        ],
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        "From": "=?utf-8?q?Barnab=C3=A1s_P=C5=91cze?= <barnabas.pocze@ideasonboard.com>",
        "To": "libcamera-devel@lists.libcamera.org",
        "Subject": "[RFC PATCH v2 38/43] ipa: libipa: agc_msv: Ensure limits are always\n\trespected",
        "Date": "Thu, 23 Jul 2026 17:43:21 +0200",
        "Message-ID": "<20260723154327.1357866-39-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>",
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        "Content-Type": "text/plain; charset=UTF-8",
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        "X-BeenThere": "libcamera-devel@lists.libcamera.org",
        "X-Mailman-Version": "2.1.29",
        "Precedence": "list",
        "List-Id": "<libcamera-devel.lists.libcamera.org>",
        "List-Unsubscribe": "<https://lists.libcamera.org/options/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=unsubscribe>",
        "List-Archive": "<https://lists.libcamera.org/pipermail/libcamera-devel/>",
        "List-Post": "<mailto:libcamera-devel@lists.libcamera.org>",
        "List-Help": "<mailto:libcamera-devel-request@lists.libcamera.org?subject=help>",
        "List-Subscribe": "<https://lists.libcamera.org/listinfo/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=subscribe>",
        "Errors-To": "libcamera-devel-bounces@lists.libcamera.org",
        "Sender": "\"libcamera-devel\" <libcamera-devel-bounces@lists.libcamera.org>"
    },
    "content": "Make sure that even in the presence of continous limit changes, the\nreturned exposure and gain values are always within bounds. This is\nneeded for integration into `AgcAlgorithm`, which might vary the limits\nfor every invocation.\n\nSigned-off-by: Barnabás Pőcze <barnabas.pocze@ideasonboard.com>\n---\n src/ipa/libipa/agc_msv.cpp | 84 ++++++++++++++++++++------------------\n 1 file changed, 45 insertions(+), 39 deletions(-)",
    "diff": "diff --git a/src/ipa/libipa/agc_msv.cpp b/src/ipa/libipa/agc_msv.cpp\nindex 63580a0055..956551685c 100644\n--- a/src/ipa/libipa/agc_msv.cpp\n+++ b/src/ipa/libipa/agc_msv.cpp\n@@ -157,59 +157,65 @@ void AgcMSV::setLimits(const Limits &limits)\n  */\n AgcMSV::Result AgcMSV::calculateNewEv(const Params &params)\n {\n-\tauto exposureMSV = calculateMSV(params.yHist);\n-\tif (!exposureMSV) {\n+\tAgcMSV::Result result = { params.exposure, params.gain };\n+\n+\tif (auto exposureMSV = calculateMSV(params.yHist)) {\n+\t\tresult = updateExposure(params.exposure, params.gain, *exposureMSV);\n+\t} else {\n \t\tLOG(AgcMSV, Debug)\n \t\t\t<< \"Not adjusting exposure due to insufficient histogram data\";\n-\t\treturn { params.exposure, params.gain };\n \t}\n \n-\treturn updateExposure(params.exposure, params.gain, *exposureMSV);\n+\tresult.exposure = std::clamp(result.exposure, limits_.exposure[0], limits_.exposure[1]);\n+\tresult.analogueGain = std::clamp(result.analogueGain, limits_.gain[0], limits_.gain[1]);\n+\n+\tLOG(AgcMSV, Debug)\n+\t\t<< \"exposure:\" << result.exposure\n+\t\t<< \" analogue-gain:\" << result.analogueGain;\n+\n+\treturn result;\n }\n \n AgcMSV::Result AgcMSV::updateExposure(uint32_t exposure, double again, float exposureMSV)\n {\n \tfloat error = kExposureOptimal - exposureMSV;\n-\tif (std::abs(error) <= kExposureSatisfactory)\n-\t\treturn { exposure, again };\n \n-\t/*\n-\t * Compute a proportional correction factor. The sign of the error\n-\t * determines the direction: positive error means too dark (increase),\n-\t * negative means too bright (decrease).\n-\t */\n-\tfloat step = std::clamp(error * kExpProportionalGain,\n-\t\t\t\t-kExpMaxStep, kExpMaxStep);\n-\tfloat factor = 1.0f + step;\n-\n-\tif (factor > 1.0f) {\n-\t\t/* Scene too dark: increase exposure first, then gain. */\n-\t\tif (exposure < limits_.exposure[1]) {\n-\t\t\tuint32_t next = exposure * factor;\n-\t\t\texposure = std::max(next, exposure + 1);\n-\t\t} else {\n-\t\t\tdouble next = again * factor;\n-\t\t\tagain = std::max(next, again + limits_.gainMinStep);\n-\t\t}\n-\t} else {\n-\t\t/* Scene too bright: decrease gain first, then exposure. */\n-\t\tif (again > limits_.gain1) {\n-\t\t\tdouble next = again * factor;\n-\t\t\tagain = std::min(next, again - limits_.gainMinStep);\n+\tLOG(AgcMSV, Debug)\n+\t\t<< \"exposureMSV:\" << exposureMSV << \" error:\" << error;\n+\n+\tif (std::abs(error) > kExposureSatisfactory) {\n+\t\t/*\n+\t\t * Compute a proportional correction factor. The sign of the error\n+\t\t * determines the direction: positive error means too dark (increase),\n+\t\t * negative means too bright (decrease).\n+\t\t */\n+\t\tfloat step = std::clamp(error * kExpProportionalGain,\n+\t\t\t\t\t-kExpMaxStep, kExpMaxStep);\n+\t\tfloat factor = 1.0f + step;\n+\n+\t\tLOG(AgcMSV, Debug) << \"factor:\" << factor;\n+\n+\t\tif (factor > 1.0f) {\n+\t\t\t/* Scene too dark: increase exposure first, then gain. */\n+\t\t\tif (exposure < limits_.exposure[1]) {\n+\t\t\t\tuint32_t next = exposure * factor;\n+\t\t\t\texposure = std::max(next, exposure + 1);\n+\t\t\t} else {\n+\t\t\t\tdouble next = again * factor;\n+\t\t\t\tagain = std::max(next, again + limits_.gainMinStep);\n+\t\t\t}\n \t\t} else {\n-\t\t\tuint32_t next = exposure * factor;\n-\t\t\texposure = std::min(next, exposure - 1);\n+\t\t\t/* Scene too bright: decrease gain first, then exposure. */\n+\t\t\tif (again > limits_.gain1) {\n+\t\t\t\tdouble next = again * factor;\n+\t\t\t\tagain = std::min(next, again - limits_.gainMinStep);\n+\t\t\t} else {\n+\t\t\t\tuint32_t next = exposure * factor;\n+\t\t\t\texposure = std::min(next, exposure - 1);\n+\t\t\t}\n \t\t}\n \t}\n \n-\texposure = std::clamp(exposure, limits_.exposure[0], limits_.exposure[1]);\n-\tagain = std::clamp(again, limits_.gain[0], limits_.gain[1]);\n-\n-\tLOG(AgcMSV, Debug)\n-\t\t<< \"exposureMSV:\" << exposureMSV\n-\t\t<< \" error:\" << error << \" factor:\" << factor\n-\t\t<< \" exposure:\" << exposure << \" analogue-gain:\" << again;\n-\n \treturn { exposure, again };\n }\n \n",
    "prefixes": [
        "RFC",
        "v2",
        "38/43"
    ]
}