A One-Minute Guide to HDMI
Release time:
2023-08-28
Source:
Internet
High Definition Multimedia Interface (HDMI) is a fully digital interface for transmitting video and audio signals, capable of sending uncompressed audio and video. HDMI is used in devices such as set-top boxes, DVD players, personal computers, televisions, game consoles, AV receivers, digital audio systems, and TVs. It can transmit both audio and video simultaneously, and because both types of signals share the same cable, it significantly simplifies the installation of system cabling.
HDMI was designed to replace older analog audio‑video interfaces such as SCART or RCA connectors. It supports a wide range of TV and computer video formats, including SDTV and HDTV, along with multi‑channel digital audio. Both HDMI and UDI— which omits audio transmission—inherit DVI’s core technology, Transition‑Minimized Differential Signaling (TMDS), and are essentially extensions of DVI. Video data in DVI, HDMI, and UDI is transmitted over dedicated, low‑latency links, ensuring that heavy video traffic does not cause congestion. Each pixel is represented by 24 bits, and the signal timing closely resembles that of VGA. Images are sent progressively, with specific blanking intervals inserted after each line and each frame; the data is not packetized using a micro‑packet architecture, nor is only the changed portion of successive frames updated. Instead, each complete frame is retransmitted whenever an update occurs. Initially, the standard specified a maximum pixel‑transfer rate of 165 Mpx/s, sufficient to support 1080p at 60 frames per second or UXGA resolution (1600×1200). Later, in the HDMI 1.3 specification, this rate was increased to 340 Mpx/s to accommodate future requirements.
Meanwhile, DisplayPort was initially developed for LCD monitors and employs a “Micro-Packet Architecture” for data transmission, with video content conveyed in the form of data packets—this sets it apart from video‑transmission technologies such as DVI and HDMI. In other words, HDMI supplanted analog video signals, whereas DisplayPort succeeded the DVI and VGA interfaces.
HDMI also supports the transmission of uncompressed 8‑channel digital audio (at a sampling rate of 192 kHz and a bit depth of 24 bits per sample), as well as any compressed audio stream such as Dolby Digital or DTS, and it further accommodates the 8‑channel 1‑bit DSD signal used by SACD. In the HDMI 1.3 specification, support was added for ultra‑high‑bitrate uncompressed audio streams like Dolby TrueHD and DTS‑HD.
The standard Type A HDMI connector has 19 pins, and a Type B connector supporting higher resolutions has also been defined; however, no manufacturers currently use the Type B connector. The Type B connector features 29 pins, enabling it to transmit additional video channels to meet future high‑resolution requirements, such as WQSXGA (3200×2048).
Type A HDMI is backward compatible with the Single-link DVI‑D or DVI‑I interfaces commonly used on today’s monitors and graphics cards (though it does not support DVI‑A). This means that a signal source equipped with a DVI‑D connector can drive an HDMI display via an adapter cable; however, this type of conversion does not support audio transmission or remote‑control functionality. Furthermore, DVI displays that lack HDCP certification will be unable to decode video streams protected by HDCP when output via HDMI (all HDMI displays support HDCP, but most DVI‑based monitors do not). The Type B HDMI connector is also backward compatible with Dual‑link DVI interfaces.
RELATED INFORMATION
Copyright©Dongguan Houpu Electronics Co., Ltd. All rights reserved
Powerby:www.300.cn | SEO