[{"id":28848,"web_url":"https://patchwork.libcamera.org/comment/28848/","msgid":"","date":"2024-03-05T08:21:25","subject":"Re: [PATCH/RFC 03/32] libcamera: v4l2_subdevice: Expose media bus\n\tformat info as internal API","submitter":{"id":143,"url":"https://patchwork.libcamera.org/api/people/143/","name":"Jacopo Mondi","email":"jacopo.mondi@ideasonboard.com"},"content":"Hi Laurent\n\nOn Fri, Mar 01, 2024 at 11:20:52PM +0200, Laurent Pinchart wrote:\n> The V4L2SubdeviceFormatInfo structure, internal to the\n> v4l2_subdevice.cpp compilation unit, contains information about media\n> bus formats that will be useful in other parts of libcamera. To prepare\n> for this, expose the structure in the v4l2_subdevice.h header and turn\n> it into a class with a similar design as PixelFormatInfo.\n>\n> Signed-off-by: Laurent Pinchart \n\nReviewed-by: Jacopo Mondi \n\n> ---\n> Changes since v1:\n>\n> - Improve MediaBusFormatInfo::code documentation\n> ---\n> include/libcamera/internal/v4l2_subdevice.h | 13 +++\n> src/libcamera/v4l2_subdevice.cpp | 94 ++++++++++++++-------\n> 2 files changed, 76 insertions(+), 31 deletions(-)\n>\n> diff --git a/include/libcamera/internal/v4l2_subdevice.h b/include/libcamera/internal/v4l2_subdevice.h\n> index 17db311bcfb3..a4df9ddfd322 100644\n> --- a/include/libcamera/internal/v4l2_subdevice.h\n> +++ b/include/libcamera/internal/v4l2_subdevice.h\n> @@ -29,6 +29,19 @@ namespace libcamera {\n>\n> class MediaDevice;\n>\n> +class MediaBusFormatInfo\n> +{\n> +public:\n> +\tbool isValid() const { return code != 0; }\n> +\n> +\tstatic const MediaBusFormatInfo &info(uint32_t code);\n> +\n> +\tconst char *name;\n> +\tuint32_t code;\n> +\tunsigned int bitsPerPixel;\n> +\tPixelFormatInfo::ColourEncoding colourEncoding;\n> +};\n> +\n> struct V4L2SubdeviceCapability final : v4l2_subdev_capability {\n> \tbool isReadOnly() const\n> \t{\n> diff --git a/src/libcamera/v4l2_subdevice.cpp b/src/libcamera/v4l2_subdevice.cpp\n> index a74b8362b6d1..6a491088161b 100644\n> --- a/src/libcamera/v4l2_subdevice.cpp\n> +++ b/src/libcamera/v4l2_subdevice.cpp\n> @@ -36,28 +36,40 @@ namespace libcamera {\n>\n> LOG_DECLARE_CATEGORY(V4L2)\n>\n> +/**\n> + * \\class MediaBusFormatInfo\n> + * \\brief Information about media bus formats\n> + *\n> + * The MediaBusFormatInfo class groups together information describing a media\n> + * bus format. It facilitates handling of media bus formats by providing data\n> + * commonly used in pipeline handlers.\n> + *\n> + * \\var MediaBusFormatInfo::name\n> + * \\brief The format name as a human-readable string, used as the text\n> + * representation of the format\n> + *\n> + * \\var MediaBusFormatInfo::code\n> + * \\brief The media bus format code described by this instance (MEDIA_BUS_FMT_*)\n> + *\n> + * \\var MediaBusFormatInfo::bitsPerPixel\n> + * \\brief The average number of bits per pixel\n> + *\n> + * The number of bits per pixel averages the total number of bits for all\n> + * colour components over the whole image, excluding any padding bits or\n> + * padding pixels.\n> + *\n> + * For formats that transmit multiple or fractional pixels per sample, the\n> + * value will differ from the bus width.\n> + *\n> + * Formats that don't have a fixed number of bits per pixel, such as compressed\n> + * formats, report 0 in this field.\n> + *\n> + * \\var MediaBusFormatInfo::colourEncoding\n> + * \\brief The colour encoding type\n> + */\n> +\n> namespace {\n>\n> -/*\n> - * \\struct MediaBusFormatInfo\n> - * \\brief Information about media bus formats\n> - * \\param name Name of MBUS format\n> - * \\param code The media bus format code\n> - * \\param bitsPerPixel Bits per pixel\n> - * \\param colourEncoding Type of colour encoding\n> - */\n> -struct MediaBusFormatInfo {\n> -\tconst char *name;\n> -\tuint32_t code;\n> -\tunsigned int bitsPerPixel;\n> -\tPixelFormatInfo::ColourEncoding colourEncoding;\n> -};\n> -\n> -/*\n> - * \\var mediaBusFormatInfo\n> - * \\brief A map that associates MediaBusFormatInfo struct to V4L2 media\n> - * bus codes\n> - */\n> const std::map mediaBusFormatInfo{\n> \t/* This table is sorted to match the order in linux/media-bus-format.h */\n> \t{ MEDIA_BUS_FMT_RGB444_2X8_PADHI_BE, {\n> @@ -533,6 +545,33 @@ const std::map mediaBusFormatInfo{\n>\n> } /* namespace */\n>\n> +/**\n> + * \\fn bool MediaBusFormatInfo::isValid() const\n> + * \\brief Check if the media bus format info is valid\n> + * \\return True if the media bus format info is valid, false otherwise\n> + */\n> +\n> +/**\n> + * \\brief Retrieve information about a media bus format\n> + * \\param[in] code The media bus format code\n> + * \\return The MediaBusFormatInfo describing the \\a code if known, or an invalid\n> + * MediaBusFormatInfo otherwise\n> + */\n> +const MediaBusFormatInfo &MediaBusFormatInfo::info(uint32_t code)\n> +{\n> +\tstatic const MediaBusFormatInfo invalid{};\n> +\n> +\tconst auto it = mediaBusFormatInfo.find(code);\n> +\tif (it == mediaBusFormatInfo.end()) {\n> +\t\tLOG(V4L2, Warning)\n> +\t\t\t<< \"Unsupported media bus format \"\n> +\t\t\t<< utils::hex(code, 4);\n> +\t\treturn invalid;\n> +\t}\n> +\n> +\treturn it->second;\n> +}\n> +\n> /**\n> * \\struct V4L2SubdeviceCapability\n> * \\brief struct v4l2_subdev_capability object wrapper and helpers\n> @@ -629,14 +668,7 @@ const std::string V4L2SubdeviceFormat::toString() const\n> */\n> uint8_t V4L2SubdeviceFormat::bitsPerPixel() const\n> {\n> -\tconst auto it = mediaBusFormatInfo.find(mbus_code);\n> -\tif (it == mediaBusFormatInfo.end()) {\n> -\t\tLOG(V4L2, Error) << \"No information available for format '\"\n> -\t\t\t\t << *this << \"'\";\n> -\t\treturn 0;\n> -\t}\n> -\n> -\treturn it->second.bitsPerPixel;\n> +\treturn MediaBusFormatInfo::info(mbus_code).bitsPerPixel;\n> }\n>\n> /**\n> @@ -903,9 +935,9 @@ std::optional V4L2Subdevice::toColorSpace(const v4l2_mbus_framefmt &\n> \t\treturn std::nullopt;\n>\n> \tPixelFormatInfo::ColourEncoding colourEncoding;\n> -\tauto iter = mediaBusFormatInfo.find(format.code);\n> -\tif (iter != mediaBusFormatInfo.end()) {\n> -\t\tcolourEncoding = iter->second.colourEncoding;\n> +\tconst MediaBusFormatInfo &info = MediaBusFormatInfo::info(format.code);\n> +\tif (info.isValid()) {\n> +\t\tcolourEncoding = info.colourEncoding;\n> \t} else {\n> \t\tLOG(V4L2, Warning)\n> \t\t\t<< \"Unknown subdev format \"\n> --\n> Regards,\n>\n> Laurent Pinchart\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 67A13C326B\n\tfor ;\n\tTue, 5 Mar 2024 08:21:31 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id CBED162873;\n\tTue, 5 Mar 2024 09:21:30 +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 C1FB962868\n\tfor ;\n\tTue, 5 Mar 2024 09:21:29 +0100 (CET)","from ideasonboard.com (unknown\n\t[IPv6:2001:b07:5d2e:52c9:cc1e:e404:491f:e6ea])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id B7EB9CC8;\n\tTue, 5 Mar 2024 09:21:12 +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=\"V7c08Pfb\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1709626872;\n\tbh=ICFJ+HmjFE3p/9Df9fFHQM/aKS6OI0e5TM1YSIkqcIA=;\n\th=Date:From:To:Cc:Subject:References:In-Reply-To:From;\n\tb=V7c08PfbNwdjf8/xGpH8RJoqYuAZlloWdwh68ZjzY1RtBtYo43MhM8r/sJucIWfjM\n\txNxieOOGyq2bopdAAXSxNUlaGEbm3i90i3Std96bzd7XyfBmKyhRLWfaK1eMq5/9s2\n\tvgu46oDnWLkE4si0B1oCC5AWTNvZ6V1oscb8PmXA=","Date":"Tue, 5 Mar 2024 09:21:25 +0100","From":"Jacopo Mondi ","To":"Laurent Pinchart ","Subject":"Re: [PATCH/RFC 03/32] libcamera: v4l2_subdevice: Expose media bus\n\tformat info as internal API","Message-ID":"","References":"<20240301212121.9072-1-laurent.pinchart@ideasonboard.com>\n\t<20240301212121.9072-4-laurent.pinchart@ideasonboard.com>","MIME-Version":"1.0","Content-Type":"text/plain; charset=utf-8","Content-Disposition":"inline","In-Reply-To":"<20240301212121.9072-4-laurent.pinchart@ideasonboard.com>","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","Cc":"libcamera-devel@lists.libcamera.org, Sakari Ailus ","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}}]