AV motherboard Prototype PCB Assembly

      AV format is also called AV interface, short for audio and video. The original text of the AV port is Composite video connector, which is a common port used by household audio-visual appliances to transmit analog video such as NTSC, PAL, and SECAM. The AV port is usually a yellow RCA port, and two red and white RCA ports are used to transmit audio. European TV sets usually use SCART ports instead of RCA ports, but SCART is designed to carry RGB signals with better picture quality than YUV, so it is also used to connect monitors, video games or DVD players.

Introduction to Composite Video

     Composite video (composite video): Chinese explanation: Composite video broadcast signal or composite video blanking and synchronization Full name: Composite Video Broadcast Signal or Composite Video Blanking and Sync It is an analog TV program (picture) signal combined with a sound signal, and A format prior to modulation onto a radio frequency carrier. Among them, the V interface is connected to the mixed video signal and is a yellow socket; the L interface is connected to the left channel sound signal and is a white socket; the R interface is connected to the right channel sound signal and is a red socket. The composite video interface has two types of terminals: RCA terminal and BNC terminal. The RCA terminal is the so-called lotus head and lotus seat, and the BNC terminal is the BNC head and BNC seat. RCA terminals can be used in both composite video interface and audio interface. If used in audio interface, it is usually called 3.5 lotus head (seat). Composite video, also known as baseband video or RCA video, is the traditional method of transmitting image data for National Television Standards Committee (NTSC) television signals, which transmits data in an analog waveform.

Composite video interface

     Composite Video Interface: Composite Video (Composite Video) signal is defined as a single-channel analog signal including luminance and chrominance, that is, the video signal after the audio is separated from the full TV signal. At this time, the chrominance signal is still interleaved with the luminance the high end of the signal. Since the luminance and chrominance of composite video are interleaved, it is difficult to restore completely consistent colors when the signal is replayed. This signal can generally be input or output to a home video recorder through a cable, and its signal bandwidth is relatively narrow, generally only having a resolution rate of about 240 horizontal lines. Early TVs only had antenna input ports, and newer TVs are equipped with composite video input and output ports (VideoIn, Video Out), that is, they can directly input and output demodulated video signals. The video signal does not contain high-frequency components, and it is relatively simple to process, so the video card of the computer generally uses the video input terminal to obtain the video signal.

Composite video interface and CVBS interface

      Abbreviation for "Color, Video, Blank and Sync", "CompositeVideoBasebandSignal", "CompositeVideoBurstSignal", or "CompositeVideowithBurstandSync". CVBS is a widely used standard, also known as baseband video or RCA video, is a traditional image data transmission method for National Television System Committee (NTSC) television signals, which transmits data in analog waveforms. It is a format in which an analog TV program (picture) signal is combined with a sound signal and modulated onto a radio frequency carrier. AV=AUDIO+VIDEO, in fact, VIDEO is CVBS

CVBS connection and RCA interface

     Composite video signal (CVBS) interface, also known as RCA interface. RCA is an acronym for Radio Corporation of America, because the RCA connector was invented by this company. RCA is commonly known as lotus socket, also known as AV terminal, also known as AV interface. It is usually a pair of white audio interface and yellow video interface. It is usually connected by RCA (commonly known as lotus head). Connect the standard AV cable of the head to the corresponding interface. RCA connector is by far the most common type of audio/video terminal. RCA audio terminals are generally marked in pairs with different colors: the right channel is red, and the left channel is black or white. Generally speaking, the RCA stereo audio cable is a group of left and right channels, and each channel is a line in appearance. Usually paired audio interface right channel (red) left channel (white) and video interface (yellow) composite video (Composite) usually uses yellow RCA (lotus socket) connectors. "Composite" means an analog signal that transmits luminance and chrominance signals in the same channel, but if the TV cannot separate the two signals well, ghosting will appear. The audio interface and the video interface are used in pairs, usually a white audio interface and a yellow video interface, using RCA (lotus head) for connection, you only need to connect the standard AV cable with the lotus head to the corresponding interface when using it. Can.

Composite video connection and AV interface

     Composite video interface, also called AV interface or Video interface, is the most common video interface at present, and almost all TVs and DVD players have this interface. AV Composite (Composite) video interface, which is an analog interface, is a video interface that separates audio and video. It is generally composed of three independent RCA plugs (also called plum blossom interface, RCA interface) in yellow, white, and red. Among them, V The interface is connected to the mixed video signal, which is a yellow socket; the L interface is connected to the left channel sound signal, which is a white socket; the R interface is connected to the right channel sound signal, which is a red socket. The output port is also equipped with audio input and output ports (AudioIn, AudioOut) for synchronous transmission of audio. Therefore, sometimes the composite video interface is also called AV (AudioVideo) port. The AV interface realizes the separate transmission of audio and video, which avoids the degradation of image quality caused by the interference of audio/video mixing, but because the AV interface still transmits a luminance/chroma (Y/C) mixed video The signal needs to be separated by brightness/color and decoded by chroma before it can be imaged. In the process of mixing first and then separating, the signal will inevitably be lost or distorted, and the chroma signal and the luminance signal will also have a great chance to interfere with each other. . Due to the inherent technical defects of the brightness/chroma (Y/C) mixed video signal processing method, the application of the AV video interface has great restrictions and usage restrictions.

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