Bluetooth is a technology used to connect various devices wirelessly directly. In media centers and TV receivers, it can be used to broadcast sound to wireless headphones and acoustics, to work with wireless mice and keyboards, to use a smartphone / tablet as a remote control, etc.; specific functionality should be specified separately. Also note that the supported version of Bluetooth can be specified here. The newest and most advanced is
Bluetooth 5.0, but here is a more detailed description of the different versions:
- Bluetooth v4.0. The version in which the "Bluetooth Low Energy" (LE) format was first introduced — in addition to regular Bluetooth (version 2.1 functionality) and the high-speed HE standard for transferring large amounts of information (introduced in version 3.0). Bluetooth LE allows you to significantly reduce power consumption when transmitting small data packets, such as request-responses about connection activity in idle mode. For the media centers and TV receivers themselves, this is not particularly important, but for portable equipment (especially miniature ones, where battery capacity is very limited), such functionality will be useful.
- Bluetooth v 4.1. Development and improvement of Bluetooth 4.0. One of the key improvements was the optimization of collaboration with 4G LTE communication modules so that Bluetooth and LTE do not interfere with each other. In addition, this ve...rsion has the ability to simultaneously use a Bluetooth device in several roles — for example, to remotely control an external device while simultaneously streaming music to headphones.
- Bluetooth v4.2. Further, after 4.1, the development of the Bluetooth standard. It did not introduce fundamental updates, but received a number of improvements regarding reliability and noise immunity, as well as improved compatibility with the Internet of Things.
- Bluetooth v5.0. Version introduced in 2016. One of the most notable updates was the introduction of two new modes of operation for Bluetooth LE — with an increase in speed by reducing the range and with an increase in range by reducing the speed. In addition, a number of improvements have been introduced regarding simultaneous work with numerous connected devices, as well as work with the components of the Internet of Things.
HDMI is the most common modern interface for working with HD content and multi-channel audio. Video and audio signals with this connection are transmitted over a single cable, and the bandwidth in the latest versions (
HDMI 2.0 and
HDMI 2.1) is enough to work with UltraHD resolution and even higher. Almost any modern screen (TV, monitor, etc.) with HD support has at least one HDMI input, which is why most media players and TV receivers have outputs of this type. However, there are also models without HDMI — these are mostly outdated or the most inexpensive solutions that use only analogue video interfaces. There are also models for several HDMI and in most cases one of these ports is for the incoming signal, while the HDMI ports differ in versions.
— v 1.4. The version presented back in 2009, however, does not lose popularity to this day. Supports 4K (4096x2160) video at 24 fps and Full HD at 120 fps; the latter, among other things, allows you to transfer 3D video over this interface. In addition to the original v 1.4, there are also improved versions v 1.4a and v 1.4b, where the possibilities for working with 3D have been further expanded.
-v 2.0. Version released in 2013. Among other things, it introduced the ability to work with 4K video at speeds up to 60 fps, compatibility with ultra-wide format 21: 9, as well as support for up to 32 channels and 4
...audio streams simultaneously. HDR support was not originally included in this release, but was introduced in v 2.0a and further enhanced in v 2.0b; media players from this category can support both the original version 2.0 and one of the improved ones.
— v 2.1. 2017 version, also known as HDMI Ultra High Speed. Indeed, it provides a very solid bandwidth, allowing you to work even with 10K video at a speed of 120 fps; in addition, a number of improvements have been made to HDR support. Note that the full use of HDMI v 2.1 is possible only with a special cable, but the functions of earlier versions remain available when using conventional wires. 
