[{"id":36613,"web_url":"https://patchwork.libcamera.org/comment/36613/","msgid":"<176209706034.2973778.2247697030014694063@ping.linuxembedded.co.uk>","date":"2025-11-02T15:24:20","subject":"Re: [RFC PATCH v3 15/22] guides: application: Document\n\tCamera::metadataAvailable","submitter":{"id":4,"url":"https://patchwork.libcamera.org/api/people/4/","name":"Kieran Bingham","email":"kieran.bingham@ideasonboard.com"},"content":"Quoting Barnabás Pőcze (2025-10-30 16:58:09)\n> From: Jacopo Mondi \n> \n> Document the Camera::metadataAvailable signal in the application\n> developer guide as an opt-in feature to receive early metadata\n> notifications.\n> \n> Signed-off-by: Jacopo Mondi \n> Signed-off-by: Barnabás Pőcze \n> ---\n> Original: https://patchwork.libcamera.org/patch/22228/\n> \n> changes in v3:\n> * adjust previous paragraph about signals\n> ---\n> Documentation/guides/application-developer.rst | 13 +++++++++++--\n> 1 file changed, 11 insertions(+), 2 deletions(-)\n> \n> diff --git a/Documentation/guides/application-developer.rst b/Documentation/guides/application-developer.rst\n> index 06c07d1e94..166919cf62 100644\n> --- a/Documentation/guides/application-developer.rst\n> +++ b/Documentation/guides/application-developer.rst\n> @@ -350,8 +350,17 @@ them.\n> \n> .. _Qt Signals and Slots: https://doc.qt.io/qt-6/signalsandslots.html\n> \n> -The ``Camera`` device emits two signals that applications can connect to in\n> -order to execute callbacks on frame completion events.\n> +During request processing, the ``Camera`` device emits certain signals\n> +to notify the application about events regarding each and every request.\n> +These signals are described below.\n> +\n> +The ``Camera::metadataAvailable`` signal notifies applications of the\n> +availability of metadata results before a request completes. Receiving\n> +notification about metadata availability allows application to fast-track\n\neither \"an application\" or \"applications\"\n\n> +handling of metadata results before all the image buffers in a request are\n> +ready. The full list of metadata results associated with a Request is also\n> +available at request complete time, and receiving notifications for early\n> +metadata availability is an optional feature for applications.\n\nReviewed-by: Kieran Bingham \n\n> The ``Camera::bufferCompleted`` signal notifies applications that a buffer with\n> image data is available. Receiving notifications about the single buffer\n> -- \n> 2.51.1\n>","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 55DCBC3241\n\tfor ;\n\tSun, 2 Nov 2025 15:24:25 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id C5AB0606E6;\n\tSun, 2 Nov 2025 16:24:24 +0100 (CET)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 761B1606E6\n\tfor ;\n\tSun, 2 Nov 2025 16:24:23 +0100 (CET)","from pendragon.ideasonboard.com\n\t(cpc89244-aztw30-2-0-cust6594.18-1.cable.virginm.net [86.31.185.195])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 1A06310D4;\n\tSun, 2 Nov 2025 16:22:31 +0100 (CET)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"pJu9ZpgW\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1762096951;\n\tbh=7yX+jlbaaX5bxnHFMh0vrP5rqgnZYLhQDnlvNO0BT6k=;\n\th=In-Reply-To:References:Subject:From:Cc:To:Date:From;\n\tb=pJu9ZpgWLA+dHErG39yLwfsEU0e8cl4OVdZOFst9qZZLKP9PmTPD5IaC6015njmJX\n\tly1ekwM9lHCpNzIE+EFtPOejoRiLpPvrm7W9vd0xRkHTWhyWn+dyEDOSTdFmE5sK5O\n\tWJm+HwoOISAQ0dTsyTk7kUpKQnKPfeBFXPadTgD0=","Content-Type":"text/plain; charset=\"utf-8\"","MIME-Version":"1.0","Content-Transfer-Encoding":"quoted-printable","In-Reply-To":"<20251030165816.1095180-16-barnabas.pocze@ideasonboard.com>","References":"<20251030165816.1095180-1-barnabas.pocze@ideasonboard.com>\n\t<20251030165816.1095180-16-barnabas.pocze@ideasonboard.com>","Subject":"Re: [RFC PATCH v3 15/22] guides: application: Document\n\tCamera::metadataAvailable","From":"Kieran Bingham ","Cc":"Jacopo Mondi ","To":"=?utf-8?q?Barnab=C3=A1s_P=C5=91cze?= ,\n\tlibcamera-devel@lists.libcamera.org","Date":"Sun, 02 Nov 2025 15:24:20 +0000","Message-ID":"<176209706034.2973778.2247697030014694063@ping.linuxembedded.co.uk>","User-Agent":"alot/0.9.1","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\" "}}]