HD is the term used to differentiate the systems that generate, transmit or support HD content (High Definition) with those of standard definition or low definition (SD).

HD resolutions are usually at least 1280 x 720 pixels by taking the ratio "width x height". Being the height, 720 pixels, which make high resolution.

The English acronym "HDMi" refers to "High Definition Multimedia Interface", that is, it corresponds to the initials of high definition multimedia interface.

The HDMi interface allows the transmission of video and audio between different devices, supporting the video resolutions 480i, 480p, 576i, 576p, 720p, 1080i, 1080p, 1440p, 1600p.

Different versions of HDMi

HDMi 1.0
- December 2002.
- Maximum transfer of 4.9 Gbit / s.
- Support up to 165 Mpixels / s in video mode (1080p 60Hz or UXGA) and 8 channels / 192 kHz / 24-bit in audio mode.

HDMi 1.2
- August 2005.
- Added support for One Bit Audio, used in Super Audio CD, up to 8 channels.
- HDMi Type A availability for PC connectors.

HDMi 1.3
- June 2006
- Bandwidth at 340 MHz.
- 10.2 Gbit / s data rate.
- Dolby TrueHD and DTS-HD,

HDMi 1.4
- Send high definition video and audio,
- 3D data and video.
- FullHD to XHD (eXtended High Definition) up to 4096 × 2160 pixels (24 frames per second) or 3840 × 2160 to (30 frames per second).
- Audio return channel that will require fewer cables to have a surround sound system connected to the television.
- Ethernet connection built into the cable itself with speeds of up to 100 Mbit / s.

HDMi 2.0
- September of 2013
- Bandwidth up to 18 Gbit / s
- 4K @ 50/60 (2160p) video
- Up to 32 audio channels for a multi-dimensional immersive experience
- Up to 1536kHz audio frequency for maximum sound fidelity
- Simultaneous delivery of 2 streaming video for multiple users on the same screen
- Audio streaming up to 4 users
- Support Theater Angle 21: 9 radio
- Dynamic synchronization of video and audio in streaming
- CEC command extensions to control multiple devices from a single point.


Types of HDMi

Type A (in image 1): It is the most standard connector used in almost all devices.
Type B (in image 2): It is a very little used connector.
Type C (in image 3): It is a connector widely used in tablets, smartphones and other devices.
Type D (in image 4): It is a connector used in smartphones.
Type E (in image 5): It is a connector used in vehicle connectivity.

1080p is an alternative name for the maximum resolution used in high definition television (HDTV). The number 1080 represents 1080 lines of vertical display resolution, while the letter p stands for progressive scan and non-interlaced.