Editing Webcam (section)

== Technology ==

=== Image sensor ===
{{Main|Image sensor}}
[[File:Webcam CCD closeup.jpg|thumb|[[Charge-coupled device]] (CCD) image sensor of a webcam]]
Image sensors can be [[CMOS]] or [[Charge-coupled device|CCD]], the former being dominant for low-cost cameras, but CCD cameras do not necessarily outperform CMOS-based cameras in the low-price range. Most consumer webcams are capable of providing [[Video Graphics Array|VGA]]-resolution video at a [[frame rate]] of 30 frames per second. Many newer devices can produce video in multi-[[megapixel]] resolutions, and a few can run at high frame rates such as the [[PlayStation Eye]], which can produce [[Quarter VGA|320×240]] video at 120 frames per second.<ref>{{Cite web |url=https://www.cnet.com/reviews/samsung-700g7c-review/ |title=Cnet |access-date=2021-07-19 |archive-date=2021-07-14 |archive-url=https://web.archive.org/web/20210714184641/https://www.cnet.com/reviews/samsung-700g7c-review/ |url-status=live }}</ref> Most image sensors are sourced from [[Omnivision]] or [[Sony]].

As webcams evolved simultaneously with display technologies, USB interface speeds and broadband internet speeds, the resolution went up from gradually from 320×240, to 640×480, and some now even offer 1280×720 (aka [[720p]]) or 1920×1080 (aka [[1080p]]) resolution.<ref>{{cite web |title=How Much Resolution is Enough? Picking a Webcam |url=http://www.ebay.com/gds/How-Much-Resolution-is-Enough-Picking-a-Webcam-/10000000177742678/g.html |url-status=live |archive-url=https://web.archive.org/web/20150704045758/http://www.ebay.com/gds/How-Much-Resolution-is-Enough-Picking-a-Webcam-/10000000177742678/g.html |archive-date=4 July 2015 |access-date=29 July 2015 |work=eBay}}</ref><ref>{{cite web |author=Jonathan Knoder |date=9 May 2013 |title=1080p, 2.0 Mega Pixels? Understanding Webcam Technical Terms |url=http://webcam-review.toptenreviews.com/1080p-2.0-mega-pixels-understanding-webcam-technical-terms.html |url-status=live |archive-url=https://web.archive.org/web/20150810121755/http://webcam-review.toptenreviews.com/1080p-2.0-mega-pixels-understanding-webcam-technical-terms.html |archive-date=10 August 2015 |access-date=29 July 2015 |work=Top Ten Reviews}}</ref><ref>{{cite web |author=Alan Henry |date=18 November 2012 |title=Five Best Webcams |url=http://lifehacker.com/5961369/five-best-webcams |url-status=live |archive-url=https://web.archive.org/web/20150729132917/http://lifehacker.com/5961369/five-best-webcams |archive-date=29 July 2015 |access-date=29 July 2015 |work=Lifehacker |publisher=Gawker Media}}</ref> Despite the low cost, the [[Image resolution|resolution]] offered as of 2019 is impressive, with now the low-end webcams offering resolutions of [[720p]], mid-range webcams offering [[1080p]] resolution, and high-end webcams offering 4K resolution at 60 fps.

=== Optics ===
[[File:Board Lens.jpg|left|thumb|[[S-mount (CCTV lens)|S-mount]] lens, designed to attach to the webcam's [[Printed circuit board|PCB]]]]
Various lenses are available, the most common in consumer-grade webcams being a plastic [[Lens (optics)|lens]] that can be manually moved in and out to focus the camera. [[Fixed-focus lens]]es, which have no provision for adjustment, are also available. As a camera system's [[depth of field]] is greater for small image formats and is greater for lenses with a large [[f-number]] (small aperture), the systems used in webcams have a sufficiently large depth of field that the use of a fixed-focus lens does not impact image sharpness to a great extent.

Most models use simple, focal-free optics (fixed focus, factory-set for the usual distance from the monitor to which it is fastened to the user) or manual focus.

Webcams can come with different presets and [[Field of view|fields of view]]. Individual users can make use of less than 90° horizontal FOV for home offices and live streaming. Webcams with as much as 360° horizontal FOV can be used for small- to medium-sized rooms (sometimes even large rooms). Depending on the users' purposes, webcams in the market can display the whole room or just the general vicinity.

=== Internal software ===
As the [[bayer filter]] is proprietary, any webcam contains some built-in [[image processing]], separate from compression. Digital video streams are represented by huge amounts of data, burdening its transmission (from the image sensor, where the data is continuously created) and storage alike. Most if not all cheap webcams come with built-in [[Application-specific integrated circuit|ASIC]] to do [[video compression]] in real-time.

Support electronics read the image from the sensor and transmit it to the host computer. Most webcams come with a controller that translates video over [[Universal Serial Bus|USB]] from Sonix, Suyin, [[Ricoh]], [[Realtek]] or others. Typically, each frame is transmitted uncompressed in [[RGB]] or [[YUV]] or compressed as [[JPEG]]. Some cameras, such as [[camera phone|mobile-phone cameras]], use a CMOS sensor with supporting electronics "on die", i.e. the sensor and the support electronics are built on a single [[Integrated circuit|silicon chip]] to save space and manufacturing costs. Most webcams feature built-in [[microphone]]s to make [[videotelephone|video calling]] and [[videoconferencing]] more convenient.

=== Interface and external software ===
[[File:1975 Alvarez guitar (2010-10-18 03.14.15 by fenderfish).jpg|alt=Very noisy image, filled with color specks|thumb|A picture taken by a webcam in 2010, showing a large amount of noise]]Typical [[Interface (computing)|interfaces]] used by articles marketed as a "webcam" are [[USB]], [[Ethernet]] and [[IEEE 802.11]] (denominated as [[IP camera]]). Further interfaces such as e.g. [[Composite video]], [[S-Video]] or [[FireWire]] were also available. The [[USB video device class]] (UVC) specification allows inter-connectivity of webcams to computers without the need for proprietary device drivers.

Various proprietary as well as free and open-source software is available to handle the UVC stream. One could use [[Guvcview]] or [[GStreamer]] and GStreamer-based software to handle the UVC stream. Another could use multiple USB cameras attached to the host computer the software resides on, and broadcast multiple streams at once over (Wireless) Ethernet, such as MotionEye. MotionEye can either be installed onto a Raspberry Pi as MotionEyeOs, or afterwards on Raspbian as well. MotionEye can also be set up on Debian, Raspbian is a variant of Debian. MotionEye V4.1.1 ( Aug '21 ) can only run on Debian 10 Buster ( oldstable ) and Python 2.7. Newer versions such as 3.X are not supported at this point of time according to Ccrisan, foundator and author of MotionEye.

Various software tools in wide use can be employed to take video and pictures, such as [[PicMaster]] and Microsoft's Camera app (for use with [[Windows]] operating systems), [[Photo Booth]] ([[Mac (computer)|Mac]]), or [[Cheese (software)|Cheese]] (with [[Unix]] systems). For a more complete list see [[Comparison of webcam software]].