{"id":20937,"url":"https://patchwork.libcamera.org/api/1.1/patches/20937/?format=json","web_url":"https://patchwork.libcamera.org/patch/20937/","project":{"id":1,"url":"https://patchwork.libcamera.org/api/1.1/projects/1/?format=json","name":"libcamera","link_name":"libcamera","list_id":"libcamera_core","list_email":"libcamera-devel@lists.libcamera.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20240815082944.170109-6-dan.scally@ideasonboard.com>","date":"2024-08-15T08:29:42","name":"[v2,5/7] Documentation: Remove camera stack from introduction.rst","commit_ref":null,"pull_url":null,"state":"superseded","archived":false,"hash":"655de3bcb951020c98818f81bdfbc82baadd20e0","submitter":{"id":156,"url":"https://patchwork.libcamera.org/api/1.1/people/156/?format=json","name":"Dan Scally","email":"dan.scally@ideasonboard.com"},"delegate":null,"mbox":"https://patchwork.libcamera.org/patch/20937/mbox/","series":[{"id":4521,"url":"https://patchwork.libcamera.org/api/1.1/series/4521/?format=json","web_url":"https://patchwork.libcamera.org/project/libcamera/list/?series=4521","date":"2024-08-15T08:29:37","name":"Documentation improvements","version":2,"mbox":"https://patchwork.libcamera.org/series/4521/mbox/"}],"comments":"https://patchwork.libcamera.org/api/patches/20937/comments/","check":"pending","checks":"https://patchwork.libcamera.org/api/patches/20937/checks/","tags":{},"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 73658C32A9\n\tfor ;\n\tThu, 15 Aug 2024 08:30:16 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 4EFD4633C9;\n\tThu, 15 Aug 2024 10:30:15 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id C684C633C0\n\tfor ;\n\tThu, 15 Aug 2024 10:30:04 +0200 (CEST)","from mail.ideasonboard.com\n\t(cpc141996-chfd3-2-0-cust928.12-3.cable.virginm.net [86.13.91.161])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 78EC1AD8;\n\tThu, 15 Aug 2024 10:29:06 +0200 (CEST)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"WKZvUHD/\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1723710546;\n\tbh=zciuuDUELT9FEPe1x2lbqBc4TiibKBUSbZq882OyAlE=;\n\th=From:To:Cc:Subject:Date:In-Reply-To:References:From;\n\tb=WKZvUHD/MPn0aCLxJ5OuzkU+UBxsBUtY02ji6zJKnXOP/aIwXX0lAxySnAh5A5fE5\n\t6VksIu2NUhTMnjNyEIUAXXmQu0+8uJ9shgwzTNsvWUC/wYhp+NZni5cKOEPpPjEbUU\n\t8jdjSncLQmjsIHcvZXtLXXWwGcn2U+Z3STj6qboQ=","From":"Daniel Scally ","To":"libcamera-devel@lists.libcamera.org","Cc":"Daniel Scally ","Subject":"[PATCH v2 5/7] Documentation: Remove camera stack from\n\tintroduction.rst","Date":"Thu, 15 Aug 2024 09:29:42 +0100","Message-Id":"<20240815082944.170109-6-dan.scally@ideasonboard.com>","X-Mailer":"git-send-email 2.34.1","In-Reply-To":"<20240815082944.170109-1-dan.scally@ideasonboard.com>","References":"<20240815082944.170109-1-dan.scally@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":"","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\" "},"content":"The Camera Stack section of the introduction is largely a duplicate\nof the section broken out from docs.rst. Remove it from the\nintroduction.rst file and consolidate anything that wasn't duplicated\ninto camera_stack.rst.\n\nSigned-off-by: Daniel Scally \n---\nChanges since v1:\n\n\t- None\n\n Documentation/camera_stack.rst | 31 +++++++\n Documentation/guides/introduction.rst | 112 +-------------------------\n 2 files changed, 33 insertions(+), 110 deletions(-)","diff":"diff --git a/Documentation/camera_stack.rst b/Documentation/camera_stack.rst\nindex 381385cb..6045ed91 100644\n--- a/Documentation/camera_stack.rst\n+++ b/Documentation/camera_stack.rst\n@@ -76,3 +76,34 @@ The camera stack comprises four software layers. From bottom to top:\n * The applications and upper level frameworks are based on the\n libcamera framework or libcamera adaptation, and are outside of\n the scope of the libcamera project.\n+\n+V4L2 Compatibility Layer\n+ V4L2 compatibility is achieved through a shared library that traps all\n+ accesses to camera devices and routes them to libcamera to emulate high-level\n+ V4L2 camera devices. It is injected in a process address space through\n+ ``LD_PRELOAD`` and is completely transparent for applications.\n+\n+ The compatibility layer exposes camera device features on a best-effort basis,\n+ and aims for the level of features traditionally available from a UVC camera\n+ designed for video conferencing.\n+\n+Android Camera HAL\n+ Camera support for Android is achieved through a generic Android camera HAL\n+ implementation on top of libcamera. The HAL implements features required by\n+ Android and out of scope from libcamera, such as JPEG encoding support.\n+\n+ This component is used to provide support for ChromeOS platforms\n+\n+GStreamer element (gstlibcamerasrc)\n+ A `GStreamer element`_ is provided to allow capture from libcamera supported\n+ devices through GStreamer pipelines, and connect to other elements for further\n+ processing.\n+\n+ Development of this element is ongoing and is limited to a single stream.\n+\n+Native libcamera API\n+ Applications can make use of the libcamera API directly using the C++\n+ API. An example application and walkthrough using the libcamera API can be\n+ followed in the :doc:`Application writer's guide `\n+\n+.. _GStreamer element: https://gstreamer.freedesktop.org/documentation/application-development/basics/elements.html\ndiff --git a/Documentation/guides/introduction.rst b/Documentation/guides/introduction.rst\nindex 1898d5fe..e419eb9d 100644\n--- a/Documentation/guides/introduction.rst\n+++ b/Documentation/guides/introduction.rst\n@@ -26,10 +26,8 @@ desirable results from the camera.\n .. _Media Controller: https://www.linuxtv.org/downloads/v4l-dvb-apis-new/userspace-api/mediactl/media-controller.html\n \n \n-In this developers guide, we will explore the `Camera Stack`_ and how it is\n-can be visualised at a high level. The current `Platform Support`_ is\n-detailed, as well as an overview of the `Licensing`_ requirements of the\n-project.\n+In this developers guide the current `Platform Support`_ is detailed, as well as\n+an overview of the `Licensing`_ requirements of the project.\n \n This introduction is followed by a walkthrough tutorial to newcomers wishing to\n support a new platform with the `Pipeline Handler Writers Guide`_ and for those\n@@ -41,112 +39,6 @@ provides a tutorial of the key APIs exposed by libcamera.\n \n .. TODO: Correctly link to the other articles of the guide\n \n-Camera Stack\n-------------\n-\n-The libcamera library is implemented in userspace, and makes use of underlying\n-kernel drivers that directly interact with hardware.\n-\n-Applications can make use of libcamera through the native `libcamera API`_'s or\n-through an adaptation layer integrating libcamera into a larger framework.\n-\n-.. _libcamera API: https://www.libcamera.org/api-html/index.html\n-\n-::\n-\n- Application Layer\n- / +--------------+ +--------------+ +--------------+ +--------------+\n- | | Native | | Framework | | Native | | Android |\n- | | V4L2 | | Application | | libcamera | | Camera |\n- | | Application | | (gstreamer) | | Application | | Framework |\n- \\ +--------------+ +--------------+ +--------------+ +--------------+\n-\n- ^ ^ ^ ^\n- | | | |\n- | | | |\n- v v | v\n- Adaptation Layer |\n- / +--------------+ +--------------+ | +--------------+\n- | | V4L2 | | gstreamer | | | Android |\n- | | Compatibility| | element | | | Camera |\n- | | (preload) | |(libcamerasrc)| | | HAL |\n- \\ +--------------+ +--------------+ | +--------------+\n- |\n- ^ ^ | ^\n- | | | |\n- | | | |\n- v v v v\n- libcamera Framework\n- / +--------------------------------------------------------------------+\n- | | |\n- | | libcamera |\n- | | |\n- \\ +--------------------------------------------------------------------+\n-\n- ^ ^ ^\n- Userspace | | |\n- --------------------- | ---------------- | ---------------- | ---------------\n- Kernel | | |\n- v v v\n-\n- +-----------+ +-----------+ +-----------+\n- | Media | <--> | Video | <--> | V4L2 |\n- | Device | | Device | | Subdev |\n- +-----------+ +-----------+ +-----------+\n-\n-The camera stack comprises of four software layers. From bottom to top:\n-\n-* The kernel drivers control the camera hardware and expose a low-level\n- interface to userspace through the Linux kernel V4L2 family of APIs\n- (Media Controller API, V4L2 Video Device API and V4L2 Subdev API).\n-\n-* The libcamera framework is the core part of the stack. It handles all control\n- of the camera devices in its core component, libcamera, and exposes a native\n- C++ API to upper layers.\n-\n-* The libcamera adaptation layer is an umbrella term designating the components\n- that interface to libcamera in other frameworks. Notable examples are the V4L2\n- compatibility layer, the gstreamer libcamera element, and the Android camera\n- HAL implementation based on libcamera which are provided as a part of the\n- libcamera project.\n-\n-* The applications and upper level frameworks are based on the libcamera\n- framework or libcamera adaptation, and are outside of the scope of the\n- libcamera project, however example native applications (cam, qcam) are\n- provided for testing.\n-\n-\n-V4L2 Compatibility Layer\n- V4L2 compatibility is achieved through a shared library that traps all\n- accesses to camera devices and routes them to libcamera to emulate high-level\n- V4L2 camera devices. It is injected in a process address space through\n- ``LD_PRELOAD`` and is completely transparent for applications.\n-\n- The compatibility layer exposes camera device features on a best-effort basis,\n- and aims for the level of features traditionally available from a UVC camera\n- designed for video conferencing.\n-\n-Android Camera HAL\n- Camera support for Android is achieved through a generic Android camera HAL\n- implementation on top of libcamera. The HAL implements features required by\n- Android and out of scope from libcamera, such as JPEG encoding support.\n-\n- This component is used to provide support for ChromeOS platforms\n-\n-GStreamer element (gstlibcamerasrc)\n- A `GStreamer element`_ is provided to allow capture from libcamera supported\n- devices through GStreamer pipelines, and connect to other elements for further\n- processing.\n-\n- Development of this element is ongoing and is limited to a single stream.\n-\n-Native libcamera API\n- Applications can make use of the libcamera API directly using the C++\n- API. An example application and walkthrough using the libcamera API can be\n- followed in the `Application Writers Guide`_\n-\n-.. _GStreamer element: https://gstreamer.freedesktop.org/documentation/application-development/basics/elements.html\n-\n Platform Support\n ----------------\n \n","prefixes":["v2","5/7"]}