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{
    "id": 21977,
    "url": "https://patchwork.libcamera.org/api/1.1/patches/21977/?format=api",
    "web_url": "https://patchwork.libcamera.org/patch/21977/",
    "project": {
        "id": 1,
        "url": "https://patchwork.libcamera.org/api/1.1/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": "<20241118221618.13953-18-laurent.pinchart@ideasonboard.com>",
    "date": "2024-11-18T22:16:18",
    "name": "[v3,17/17] ipa: rkisp1: awb: Expand comment",
    "commit_ref": null,
    "pull_url": null,
    "state": "superseded",
    "archived": false,
    "hash": "2583a7b1628b1af4a12359990ebe7918ac3fe13d",
    "submitter": {
        "id": 2,
        "url": "https://patchwork.libcamera.org/api/1.1/people/2/?format=api",
        "name": "Laurent Pinchart",
        "email": "laurent.pinchart@ideasonboard.com"
    },
    "delegate": null,
    "mbox": "https://patchwork.libcamera.org/patch/21977/mbox/",
    "series": [
        {
            "id": 4798,
            "url": "https://patchwork.libcamera.org/api/1.1/series/4798/?format=api",
            "web_url": "https://patchwork.libcamera.org/project/libcamera/list/?series=4798",
            "date": "2024-11-18T22:16:01",
            "name": "Improve linear algebra helpers in libipa",
            "version": 3,
            "mbox": "https://patchwork.libcamera.org/series/4798/mbox/"
        }
    ],
    "comments": "https://patchwork.libcamera.org/api/patches/21977/comments/",
    "check": "pending",
    "checks": "https://patchwork.libcamera.org/api/patches/21977/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 92873C32F0\n\tfor <parsemail@patchwork.libcamera.org>;\n\tMon, 18 Nov 2024 22:17:06 +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=\"HTdlQL5s\"; dkim-atps=neutral",
        "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1731968194;\n\tbh=/XTcCf7GgzVrQeALl6c200OUkd+x2DRlPNXv8XuCRrw=;\n\th=From:To:Subject:Date:In-Reply-To:References:From;\n\tb=HTdlQL5sw3lPK6h3QECNUM7ucWDkJzfhcDmZ6/RgdZymg6RZtnZPtJk0tGUO/HHsc\n\tLOjDN4NUvNlOph/fcTbzRgLaLiMRPUwUAw8booGKmLrvpSfkiFhBJqQRJta0OkfyoI\n\tb764ccTh+1CY8UE6wbx4HUBUUghh0sIEhWMW2SlQ=",
        "From": "Laurent Pinchart <laurent.pinchart@ideasonboard.com>",
        "To": "libcamera-devel@lists.libcamera.org",
        "Subject": "[PATCH v3 17/17] ipa: rkisp1: awb: Expand comment",
        "Date": "Tue, 19 Nov 2024 00:16:18 +0200",
        "Message-ID": "<20241118221618.13953-18-laurent.pinchart@ideasonboard.com>",
        "X-Mailer": "git-send-email 2.45.2",
        "In-Reply-To": "<20241118221618.13953-1-laurent.pinchart@ideasonboard.com>",
        "References": "<20241118221618.13953-1-laurent.pinchart@ideasonboard.com>",
        "MIME-Version": "1.0",
        "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": "The RGB to YCbCr conversion matrix mentioned in a comment, coming from\nthe hardware documentation, does not match any of the canonical matrices\nspecified by any standard. While researching where the values came from,\nit became apparent they are likely Bt.601 limited range coefficients\nrounded to 6 bits of decimal precision. Record this in comments.\n\nSigned-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>\n---\n src/ipa/rkisp1/algorithms/awb.cpp | 13 +++++++++----\n 1 file changed, 9 insertions(+), 4 deletions(-)",
    "diff": "diff --git a/src/ipa/rkisp1/algorithms/awb.cpp b/src/ipa/rkisp1/algorithms/awb.cpp\nindex 26d7b8138f17..4bb4f5b88375 100644\n--- a/src/ipa/rkisp1/algorithms/awb.cpp\n+++ b/src/ipa/rkisp1/algorithms/awb.cpp\n@@ -210,13 +210,18 @@ void Awb::process(IPAContext &context,\n \t\t});\n \n \t\t/*\n-\t\t * Convert from YCbCr to RGB.\n-\t\t * The hardware uses the following formulas:\n-\t\t * Y = 16 + 0.2500 R + 0.5000 G + 0.1094 B\n+\t\t * Convert from YCbCr to RGB. The hardware uses the following\n+\t\t * formulas:\n+\t\t *\n+\t\t * Y  =  16 + 0.2500 R + 0.5000 G + 0.1094 B\n \t\t * Cb = 128 - 0.1406 R - 0.2969 G + 0.4375 B\n \t\t * Cr = 128 + 0.4375 R - 0.3750 G - 0.0625 B\n \t\t *\n-\t\t * The inverse matrix is thus:\n+\t\t * This seems to be based on limited range BT.601 with Q1.6\n+\t\t * precision.\n+\t\t *\n+\t\t * The inverse matrix is:\n+\t\t *\n \t\t * [[1,1636, -0,0623,  1,6008]\n \t\t *  [1,1636, -0,4045, -0,7949]\n \t\t *  [1,1636,  1,9912, -0,0250]]\n",
    "prefixes": [
        "v3",
        "17/17"
    ]
}