[libcamera-devel] README.rst: Add FAQ section.

3679 diff mbox series

Provide an initial set of Questions and Answers.

Hopefully these will provide quick insights to the project from the
README, and can be incorporated into the website.

Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
---
 README.rst | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 65 insertions(+)

Hi Kieran,

Thanks for your work on this.

Just a few comments already, I'll provide more tomorrow.

On Sun, May 03, 2020 at 02:17:20AM +0100, Kieran Bingham wrote:
> Provide an initial set of Questions and Answers.
> 
> Hopefully these will provide quick insights to the project from the
> README, and can be incorporated into the website.
> 
> Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
> ---
>  README.rst | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 65 insertions(+)
> 
> diff --git a/README.rst b/README.rst
> index 40d45196c7d6..af44686b969c 100644
> --- a/README.rst
> +++ b/README.rst
> @@ -89,3 +89,68 @@ default video display element on your system.
>    gst-launch-1.0 libcamerasrc camera-name="Camera 1" ! videoconvert ! autovideosink
>  
>  .. section-end-getting-started
> +.. section-begin-faq
> +
> +Frequently Asked Questions
> +--------------------------
> +
> +What is libcamera?
> +  libcamera is an open source camera stack implemented entirely in user space.
> +  It aims to encourage the development of new embedded camera applications by
> +  limiting the complexity that developers have to deal with.  The interface is

s/  The/ The/

> +  designed around the way that modern embedded camera hardware works.
> +
> +What is the correct way to display the name 'libcamera'

s/$/?/

> +  libcamera, is always in lowercase; in titles, or at the beginning of
> +  sentences.
> +
> +How is libcamera different from V4L2?
> +  We see libcamera as a continuation of V4L2. One that can more easily handle
> +  the recent advances in hardware design. As embedded cameras have developed,
> +  all of the complexity has been pushed on to the developers. With libcamera,
> +  all of that complexity is simplified and a single model is presented to
> +  application developers.
> +
> +Does this mean the camera stack is completely open?
> +  libcamera is open-source friendly which means all of libcamera itself is open
> +  source. Because vendors are reluctant to open-source their Image Processing
> +  Algorithms, libcamera can support closed-source Image Processing Algorithm
> +  modules (IPAs) which will be sandboxed to minimise the exposure of binary
> +  blobs.
> +
> +libcamera has been described as “the MESA of the camera stack”. What does that mean?
> +  Mesa provides powerful high-level APIs to applications and implements
> +  device-specific code in userspace to support the implementation. libcamera
> +  provides high-level APIs that handle device-specific code in userspace to
> +  simplify development for application developers.
> +
> +Which cameras SoCs (pipelines) are supported?
> +  Currently supported pipelines include the Intel IPU3, RockChip RK3399, UVC,
> +  and VIMC/VIVID test drivers
> +
> +Which camera protocols are supported?
> +  libcamera supports cameras that use MIPI/CSI2 protocols.

s/MIPI\/CSI2/MIPI CSI-2/

> +
> +Can I use libcamera to access photos on digital cameras?
> +  No, libcamera is a library for controlling embedded camera hardware, it’s not
> +  an application for accessing photos and has no relationship to gphoto2.
> +  libcamera supports internal cameras designed for point-and-shoot still image
> +  and video capture and external UVC cameras designed for video conferencing.
> +
> +Can libcamera handle multiple cameras simultaneously?
> +  libcamera can support multiple cameras within a system, and allows only a
> +  single application to consume each stream. An application must ‘acquire’ a

We lock at the camera level, not at the stream level, don't we ?

> +  Camera to start operations on it, and should release it when finished.
> +  Logical cameras where multiple cameras are treated as a single camera is a
> +  pipeline and hardware specific extension that will be supported in the
> +  future.
> +
> +Does libcamera do format conversion and debayering?
> +  Format conversion and debayering operations are dependent upon the Image
> +  Signal Processor (ISP) and hardware available. Our demonstration application,
> +  QCam, does basic software format conversions to handle display but we aim to
> +  move to using OpenGL to improve real time conversion performance. Where
> +  possible, QCam will request formats that can be displayed natively without
> +  requiring software conversions.
> +
> +.. section-end-faq