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{ "id": 25454, "url": "https://patchwork.libcamera.org/api/covers/25454/?format=api", "web_url": "https://patchwork.libcamera.org/cover/25454/", "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": "<20251210133704.2711629-1-barnabas.pocze@ideasonboard.com>", "date": "2025-12-10T13:37:02", "name": "[RFC,v1,0/2] libcamera: pipeline: uvcvideo: FrameDurationLimits", "submitter": { "id": 216, "url": "https://patchwork.libcamera.org/api/people/216/?format=api", "name": "Barnabás Pőcze", "email": "barnabas.pocze@ideasonboard.com" }, "mbox": "https://patchwork.libcamera.org/cover/25454/mbox/", "series": [ { "id": 5648, "url": "https://patchwork.libcamera.org/api/series/5648/?format=api", "web_url": "https://patchwork.libcamera.org/project/libcamera/list/?series=5648", "date": "2025-12-10T13:37:02", "name": "libcamera: pipeline: uvcvideo: FrameDurationLimits", "version": 1, "mbox": "https://patchwork.libcamera.org/series/5648/mbox/" } ], "comments": "https://patchwork.libcamera.org/api/covers/25454/comments/", "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 CD778C3257\n\tfor <parsemail@patchwork.libcamera.org>;\n\tWed, 10 Dec 2025 13:37:11 +0000 (UTC)", "from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id F2BBF61475;\n\tWed, 10 Dec 2025 14:37:10 +0100 (CET)", "from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id A8E08613CB\n\tfor <libcamera-devel@lists.libcamera.org>;\n\tWed, 10 Dec 2025 14:37:09 +0100 (CET)", "from pb-laptop.local (185.221.143.114.nat.pool.zt.hu\n\t[185.221.143.114])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 021D66DC\n\tfor <libcamera-devel@lists.libcamera.org>;\n\tWed, 10 Dec 2025 14:37:06 +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=\"mQBCUMAJ\"; dkim-atps=neutral", "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1765373827;\n\tbh=PaHng9z1B9Te7XfEl6Nk0sA+FRDToKieTnpdYZGMxUw=;\n\th=From:To:Subject:Date:From;\n\tb=mQBCUMAJBx2IOOA3Ezs5HB8+hvdHwB+XrnfPczBJg3rz/FyhPyIwm6oifR6JzlNOh\n\tRVTIIIhoOeIr997GlQOlOmzqXeBd1RYKVgtVfnz2aZsKIWqKA0RPmizYjE1GgPgQdR\n\tltumQiyh8dUhFbVPcqt97eisydUmlq6x1F7htfyc=", "From": "=?utf-8?q?Barnab=C3=A1s_P=C5=91cze?= <barnabas.pocze@ideasonboard.com>", "To": "libcamera-devel@lists.libcamera.org", "Subject": "[RFC PATCH v1 0/2] libcamera: pipeline: uvcvideo:\n\tFrameDurationLimits", "Date": "Wed, 10 Dec 2025 14:37:02 +0100", "Message-ID": "<20251210133704.2711629-1-barnabas.pocze@ideasonboard.com>", "X-Mailer": "git-send-email 2.52.0", "MIME-Version": "1.0", "Content-Type": "text/plain; charset=UTF-8", "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": "This patch set tries to add at least some kind of support for setting a frame\nduration on uvc camera to address https://gitlab.freedesktop.org/camera/libcamera/-/issues/296\n\nThe mismatches in the kernel and libcamera interfaces are elaborated in the last patch.\n\nA couple points remain:\n\n(a) Since the frame interval cannot be set during streaming, could this indicate that a\n \"startup control\" concept would be useful in libcamera, where cameras could mark\n certain controls in their `ControlInfoMap` to indicate that they can only be set\n when passed to `Camera::start()`?\n\n(B) I originally intended to advertise all available discrete options in the `ControlInfo`.\n For example:\n\n $ v4l2-ctl --list-formats-ext\n ioctl: VIDIOC_ENUM_FMT\n \tType: Video Capture\n\n \t[0]: 'YUYV' (YUYV 4:2:2)\n \t\tSize: Discrete 640x480\n \t\t\tInterval: Discrete 0.033s (30.000 fps)\n \t\t\tInterval: Discrete 0.040s (25.000 fps)\n \t\t\tInterval: Discrete 0.050s (20.000 fps)\n \t\t\tInterval: Discrete 0.067s (15.000 fps)\n \t\t\tInterval: Discrete 0.100s (10.000 fps)\n \t\t\tInterval: Discrete 0.200s (5.000 fps)\n\n would produce:\n\n ControlInfo {\n .min = { 0.033s },\n .max = { 0.200s },\n .values = {\n { 0.033s, 0.033s },\n { 0.040s, 0.040s },\n { 0.050s, 0.050s },\n { 0.067s, 0.067s },\n { 0.100s, 0.100s },\n { 0.200s, 0.200s },\n },\n }\n\n This would be done in order to satisfy two requirements:\n * every item in `ControlInfo::values()` should be of the proper shape and type\n to be directly applicable as the value of the control;\n * the min/max for array like controls (except strings) should denote the min/max\n for any single element in the array.\n\n Unfortunately, there is no constructor of `ControlInfo` that achieves this.\n Would it be useful to add one?\n\n\nBarnabás Pőcze (2):\n libcamera: pipeline: uvcvideo: Report `FrameDuration`\n libcamera: pipeline: uvcvideo: Handle `FrameDurationLimits`\n\n include/libcamera/internal/v4l2_videodevice.h | 5 +\n src/libcamera/pipeline/uvcvideo/uvcvideo.cpp | 72 ++++++++\n src/libcamera/v4l2_videodevice.cpp | 171 ++++++++++++++++++\n 3 files changed, 248 insertions(+)\n\n--\n2.52.0" }