Audio and video interfaces and connectors: Difference between revisions

Revision as of 21:14, 6 August 2021

Revision as of 15:30, 3 September 2021

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{{Refimprove|date=February 2009}}

'''Audio connectors''' and '''video connectors''' are [[electrical connector|electrical]] or [[optical fiber connector|optical connectors]] for carrying [[audio signal|audio]] andor [[video signal]]s. '''Audio interfaces''' andor '''video interfaces''' define physical parameters and interpretation of signals. For [[digital audio]] and [[digital video]], this can be thought of as defining the [[physical layer]], [[data link layer]], and most or all of the [[application layer]]. For [[analog audio]] and [[analog video]] these functions are all represented in a single signal specification like [[NTSC]] or the direct [[Loudspeaker|speaker]]-driving signal of analog audio. Physical characteristics of the electrical or optical equipment includes the types and numbers of wires required, voltages, frequencies, optical intensity, and the physical design of the connectors. Any data link layer details define how application data is encapsulated (for example for synchronization or error-correction). Application layer details define the actual audio or video format being transmitted, often incorporating a [[codec]]s not specific to the interface, such as [[PCM]], [[MPEG-2]], or the [[DTS Coherent Acoustics codec]]. In some cases, the application layer is left open; for example, [[HDMI]] contains an [[Ethernet]] channel for general data transmission.

Physical characteristics of the electrical or optical equipment include the types and numbers of wires required, voltages, frequencies, optical intensity, and the physical design of the connectors. Any data link layer details define how application data is encapsulated (for example for [[synchronization]] or [[error-correction]]). Application layer details define the actual audio or video format being transmitted, often incorporating [[codec]]s not specific to the interface, such as [[PCM]], [[MPEG-2]], or the [[DTS Coherent Acoustics codec]]. In some cases, the application layer is left open; for example, [[HDMI]] contains an [[Ethernet]] channel for general data transmission.

Some types of connectors are used by multiple hardware interfaces; for example, [[RCA connector]]s are defined both by the [[composite video]] and [[component video]] interfaces, but [[Digital Visual Interface|DVI]] is the only interface that uses the DVI connector. This means that in some cases not all components with physically compatible connectors will actually work together.

Some types of connectors are used by multiple hardware interfaces; for example, [[RCA connector]]s are definedused both by the [[composite video]] and [[component video]] interfaces, but [[Digital Visual Interface|DVI]] is the only interface that uses the DVI connector. This means that in some cases not all components with physically compatible connectors will actually work together.

Some of these connectors, and other types of connectors, are also used at [[radio frequency]] (RF) to connect a radio or television receiver to an antenna or to a cable system; RF connector applications are not further described here. Analog A/V connectors often use [[shielded cable]]s to inhibit [[RF interference|radio frequency interference]] (RFI) and [[noise]].

Analog A/V connectors often use [[shielded cable]]s to inhibit [[RF interference|radio frequency interference]] (RFI) and [[noise]].

For efficiency and simplicity, the same codec or signal convention is used by the storage medium. For example, [[VHS]] tapes can store a magnetic representation of an NTSC signal, and the specification for [[Blu-ray Disc]]s incorporates PCM, MPEG-2, and DTS. Some playback devices can re-encode audio or video so that the format used for storage does not have to be the same as the format transmitted over the A/V interface (which is helpful if a projector or monitor cannot handle a newer codec).

== Interfaces and their connectors ==

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| rowspan=2 |'''Analog'''

| Often unmarked on consumer audio equipment since it is so common, or labelled with [[headphones]] symbol or as "line out". Computers and other equipment sometimes use [[PC_System_Design_Guide#Color-coding_scheme_for_connectors_and_ports|Microsoft-Intel color coding scheme]], especially when there are multiple input/output plugs.

| [[Phone connector (audio)|3.5 mm TRS minijack]], [[RCA connector]]

|-

| [[Balanced audio]]

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Newer connectors are identified by their shape and not their colour.

==Storage==

For efficiency and simplicity, the same codec or signal convention is used by the storage medium. For example, [[VHS]] tapes can store a magnetic representation of an NTSC signal, and the specification for [[Blu-ray Disc]]s incorporates PCM, MPEG-2, and DTS. Some playback devices can re-encode audio or video so that the format used for storage does not have to be the same as the format transmitted over the A/V interface (which is helpful if a projector or monitor cannot handle a newer codec).

==See also==