From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 178F32F4A; Fri, 14 Mar 2025 06:35:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741934102; cv=none; b=WGJxt6OQhn13I5L2zZdXb4EnfCMmZxiF/OSWNTsuAk3JIxWGoSF2XV545kcVSoVpLuExcrO9MgK2X3RYvVTHNWG7/y4to7sHJfwbkqVjUDGrwKZqLz1Mzroul4MaJh0ZSqnESLxqqM10KtKBMMoGrynW+vxvOV7KoSHFaZjKDXc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741934102; c=relaxed/simple; bh=zHa1YR43gS+g+8/IcC54v4zmSih9SACYwhm1yGincVg=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=KI30O9AYlItROcpxeWJalgJgEcaRH/xTVs8tK5InL/N99Y10pTKxPFYNrvO9hx6sBxQbikYa5AZl1ECrwA9yEfJmJ2ZrvoqYBX1KKwFcKdsU8mDJxb4bRGWQj+DGxWflUij+tb+ZDOLO7Xm1dZSAZ42mCtbTZdB2tRaaNxluiUQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=qfVqAqKi; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="qfVqAqKi" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E28F1C4CEE3; Fri, 14 Mar 2025 06:34:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1741934101; bh=zHa1YR43gS+g+8/IcC54v4zmSih9SACYwhm1yGincVg=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=qfVqAqKiSFbgrzaWubxdV5cdnie0qi43IqStGiLj/XlAXiThAl8eGS0iZqLBULNWb dRKLQUKZmIkaP4BIdBgEwis/gz0yvUQQzYrdkLyQmdNK3a95ztTYw2SpNjVhLdeAzT zPP+o9s5Q6kVgNE+uVo9duQlOe8omR/wekTow6g5ayRFEnORMt/C2ZTt9MuvT0CCNa ACTeB54QLLlV6NpLWcBb1XuPOzKmvD7KshNrMQ0wrnJ5cwBpiJHdcG+xF80Wg1SGZ6 ygZ39b3IwDWUuxoU5jKAJK6szOUEqzdR9UmCQRmB+PwAGIF/unxxmE9pukXV9wNuQb qNTINQdTAPeTg== Date: Fri, 14 Mar 2025 07:34:56 +0100 From: Mauro Carvalho Chehab To: Ricardo Ribalda Cc: Mauro Carvalho Chehab , Laurent Pinchart , Hans de Goede , Guennadi Liakhovetski , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 3/3] media: uvcvideo: Introduce V4L2_META_FMT_UVC_CUSTOM Message-ID: <20250314073456.25817a3d@foz.lan> In-Reply-To: <20250313-uvc-metadata-v3-3-c467af869c60@chromium.org> References: <20250313-uvc-metadata-v3-0-c467af869c60@chromium.org> <20250313-uvc-metadata-v3-3-c467af869c60@chromium.org> X-Mailer: Claws Mail 4.3.0 (GTK 3.24.43; x86_64-redhat-linux-gnu) Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Em Thu, 13 Mar 2025 12:06:27 +0000 Ricardo Ribalda escreveu: > The UVC driver provides two metadata types V4L2_META_FMT_UVC, and > V4L2_META_FMT_D4XX. The only difference between the two of them is that > V4L2_META_FMT_UVC only copies PTS, SCR, size and flags, and > V4L2_META_FMT_D4XX copies the whole metadata section. > > Now we only enable V4L2_META_FMT_D4XX for the Intel D4xx family of > devices, but it is useful to have the whole metadata section for any > device where vendors include other metadata, such as the one described by > Microsoft: > https://learn.microsoft.com/en-us/windows-hardware/drivers/stream/mf-capture-metadata > > This patch introduces a new format V4L2_META_FMT_UVC_CUSTOM, that is > identical to V4L2_META_FMT_D4XX but it is available to all the UVC > devices. > > Suggested-by: Hans de Goede > Signed-off-by: Ricardo Ribalda > --- > .../userspace-api/media/v4l/meta-formats.rst | 1 + > .../userspace-api/media/v4l/metafmt-uvc-custom.rst | 31 +++++++++++++++++ > MAINTAINERS | 1 + > drivers/media/usb/uvc/uvc_metadata.c | 40 ++++++++++++++++++---- > drivers/media/v4l2-core/v4l2-ioctl.c | 1 + > include/uapi/linux/videodev2.h | 1 + > 6 files changed, 69 insertions(+), 6 deletions(-) > > diff --git a/Documentation/userspace-api/media/v4l/meta-formats.rst b/Documentation/userspace-api/media/v4l/meta-formats.rst > index 86ffb3bc8ade2e0c563dd84441572ecea1a571a6..9fd83f4a3cc8509702a2a9f032fdc04bf6c6d1bc 100644 > --- a/Documentation/userspace-api/media/v4l/meta-formats.rst > +++ b/Documentation/userspace-api/media/v4l/meta-formats.rst > @@ -19,6 +19,7 @@ These formats are used for the :ref:`metadata` interface only. > metafmt-pisp-fe > metafmt-rkisp1 > metafmt-uvc > + metafmt-uvc-custom > metafmt-vivid > metafmt-vsp1-hgo > metafmt-vsp1-hgt > diff --git a/Documentation/userspace-api/media/v4l/metafmt-uvc-custom.rst b/Documentation/userspace-api/media/v4l/metafmt-uvc-custom.rst > new file mode 100644 > index 0000000000000000000000000000000000000000..9f150fc2b6f379cc4707ff45041dd014956ae11a > --- /dev/null > +++ b/Documentation/userspace-api/media/v4l/metafmt-uvc-custom.rst > @@ -0,0 +1,31 @@ > +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later > + > +.. _v4l2-meta-fmt-uvc-custom: > + > +********************************* > +V4L2_META_FMT_UVC_CUSTOM ('UVCC') > +********************************* > + > +UVC Custom Payload Metadata. > + > + > +Description > +=========== > + > +V4L2_META_FMT_UVC_CUSTOM buffers follow the metadata buffer layout of > +V4L2_META_FMT_UVC with the only difference that it includes all the UVC > +metadata, not just the first 2-12 bytes. > + > +The most common metadata format is the one proposed by Microsoft(R)'s UVC > +extension [1_], but other vendors might have different formats. > + > +Applications might use information from the Hardware Database (hwdb)[2_] to > +process the camera's metadata accordingly. Having something like that at the userspace API shouldn't be handled lightly. This sounds to me that passing a blank check for vendors to stream whatever they want without any requirements to provide and sort of documentation for the usersace to decode it. Also, it would be hard for userspace to distinguish what metatata is contained for a random UVC camera. Please let's not do that. As the specific issue here is to support an already known extension, which is already documented, Just add an specific format for it, e.g. you could add something like that at the documentation: V4L2_META_FMT_MSXU_UVC_1_5 Microsoft extensions to USB Video Class 1.5 specification. For more details, see: https://learn.microsoft.com/en-us/windows-hardware/drivers/stream/uvc-extensions-1-5 And then add the corresponding format to V4L2 API. Regards, Mauro