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{
    "id": 26360,
    "url": "https://patchwork.libcamera.org/api/patches/26360/?format=api",
    "web_url": "https://patchwork.libcamera.org/patch/26360/",
    "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": "<20260325151416.2114564-19-stefan.klug@ideasonboard.com>",
    "date": "2026-03-25T15:13:50",
    "name": "[v2,18/32] libipa: algorithm: Update docs",
    "commit_ref": null,
    "pull_url": null,
    "state": "new",
    "archived": false,
    "hash": "cbc0c18808a44ae619316db0f077cc7f4cf3d07e",
    "submitter": {
        "id": 184,
        "url": "https://patchwork.libcamera.org/api/people/184/?format=api",
        "name": "Stefan Klug",
        "email": "stefan.klug@ideasonboard.com"
    },
    "delegate": null,
    "mbox": "https://patchwork.libcamera.org/patch/26360/mbox/",
    "series": [
        {
            "id": 5849,
            "url": "https://patchwork.libcamera.org/api/series/5849/?format=api",
            "web_url": "https://patchwork.libcamera.org/project/libcamera/list/?series=5849",
            "date": "2026-03-25T15:13:32",
            "name": "rkisp1: pipeline rework for PFC",
            "version": 2,
            "mbox": "https://patchwork.libcamera.org/series/5849/mbox/"
        }
    ],
    "comments": "https://patchwork.libcamera.org/api/patches/26360/comments/",
    "check": "pending",
    "checks": "https://patchwork.libcamera.org/api/patches/26360/checks/",
    "tags": {},
    "headers": {
        "Return-Path": "<libcamera-devel-bounces@lists.libcamera.org>",
        "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 20BCCC3302\n\tfor <parsemail@patchwork.libcamera.org>;\n\tWed, 25 Mar 2026 15:15:34 +0000 (UTC)",
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        ],
        "Authentication-Results": "lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"BBL8VjlX\"; dkim-atps=neutral",
        "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1774451653;\n\tbh=EFewKCAt/7JAXms7yDaFl2tWUeG+Y0w4vVz6NT4aA/A=;\n\th=From:To:Cc:Subject:Date:In-Reply-To:References:From;\n\tb=BBL8VjlX4prXE/fovZXaBsjasQ5dAc3cLXxHFW9twH6NxvdVg9umPPJCY/Rnsn48Y\n\thrpP7CwfXNmSf711na/4v7uZCHDEp5yt9dPfU6c7NQEDTS96G6I6s8uLzmBjJYxS7O\n\t3u/ga9VpvSB/xNhinNIr0LjJcH/y2xu5nLXQXGWM=",
        "From": "Stefan Klug <stefan.klug@ideasonboard.com>",
        "To": "libcamera-devel@lists.libcamera.org",
        "Cc": "Stefan Klug <stefan.klug@ideasonboard.com>",
        "Subject": "[PATCH v2 18/32] libipa: algorithm: Update docs",
        "Date": "Wed, 25 Mar 2026 16:13:50 +0100",
        "Message-ID": "<20260325151416.2114564-19-stefan.klug@ideasonboard.com>",
        "X-Mailer": "git-send-email 2.51.0",
        "In-Reply-To": "<20260325151416.2114564-1-stefan.klug@ideasonboard.com>",
        "References": "<20260325151416.2114564-1-stefan.klug@ideasonboard.com>",
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        "Content-Transfer-Encoding": "8bit",
        "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": "Update the algorithm documentation to reflect the changed timing model.\n\nSigned-off-by: Stefan Klug <stefan.klug@ideasonboard.com>\n\n---\n\nChanges in v2:\n- Added more documentation\n---\n src/ipa/libipa/algorithm.cpp | 41 ++++++++++++++++++++++--------------\n 1 file changed, 25 insertions(+), 16 deletions(-)",
    "diff": "diff --git a/src/ipa/libipa/algorithm.cpp b/src/ipa/libipa/algorithm.cpp\nindex 201efdfdba25..e491cb241442 100644\n--- a/src/ipa/libipa/algorithm.cpp\n+++ b/src/ipa/libipa/algorithm.cpp\n@@ -76,11 +76,13 @@ namespace ipa {\n  *\n  * This function is called for each request queued to the camera. It provides\n  * the controls stored in the request to the algorithm. The \\a frame number\n- * is the Request sequence number and identifies the desired corresponding\n+ * is the sensor sequence number and identifies the desired corresponding\n  * frame to target for the controls to take effect.\n  *\n  * Algorithms shall read the applicable controls and store their value for later\n- * use during frame processing.\n+ * use during frame processing. All values that are already known (like exposure\n+ * time/gain in manual mode) shall be updated in \\a frameContext to support\n+ * cases where prepare() is never called (like in raw mode).\n  */\n \n /**\n@@ -92,20 +94,29 @@ namespace ipa {\n  * \\param[out] params The ISP specific parameters\n  *\n  * This function is called for every frame when the camera is running before it\n- * is processed by the ISP to prepare the ISP processing parameters for that\n- * frame.\n+ * is processed by the ISP to prepare the ISP processing parameters and the\n+ * sensor parameters for that frame.\n  *\n  * Algorithms shall fill in the parameter structure fields appropriately to\n  * configure the ISP processing blocks that they are responsible for. This\n  * includes setting fields and flags that enable those processing blocks.\n+ *\n+ * Additionally \\a frameContext shall be updated with the most up to date values\n+ * necessary to configure the sensor. After prepare() the \\a frameContext for\n+ * this frame shall be treated read only.\n+ *\n+ * \\todo: For offline ISPs there might be use cases where it is beneficial to\n+ * separate the calculation of sensor parameters from the calculation of ISP\n+ * paremeters. This is currently not supported.\n  */\n \n /**\n  * \\fn Algorithm::process()\n  * \\brief Process ISP statistics, and run algorithm operations\n  * \\param[in] context The shared IPA context\n- * \\param[in] frame The frame context sequence number\n- * \\param[in] frameContext The current frame's context\n+ * \\param[in] frame The frame sequence number that produces the stats\n+ * \\param[in] frameContext The frame context for the frame that produced the\n+ * stats\n  * \\param[in] stats The IPA statistics and ISP results\n  * \\param[out] metadata Metadata for the frame, to be filled by the algorithm\n  *\n@@ -118,19 +129,17 @@ namespace ipa {\n  * computationally expensive calculations or operations must be handled\n  * asynchronously in a separate thread.\n  *\n- * Algorithms can store state in their respective IPAFrameContext structures,\n- * and reference state from the IPAFrameContext of other algorithms.\n- *\n- * \\todo Historical data may be required as part of the processing.\n- * Either the previous frame, or the IPAFrameContext state of the frame\n- * that generated the statistics for this operation may be required for\n- * some advanced algorithms to prevent oscillations or support control\n- * loops correctly. Only a single IPAFrameContext is available currently,\n- * and so any data stored may represent the results of the previously\n- * completed operations.\n+ * Care must be taken to ensure that the frameContext is only updated in cases\n+ * where the frame was not processed yet. This usually differs between offline\n+ * and inline ISPs. In an inline ISP the stats are received after processing the\n+ * frame. In this case the frame context *must not* be updated. Algorithms\n+ * typically update the active state which is then picked up in prepare().\n  *\n  * Care shall be taken to ensure the ordering of access to the information\n  * such that the algorithms use up to date state as required.\n+ *\n+ * The \\a stats parameter can be null in which case only the frame metadata\n+ * shall be filled with the data from frameContext.\n  */\n \n /**\n",
    "prefixes": [
        "v2",
        "18/32"
    ]
}