Bluetooth
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
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. AV output
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AV output. Analogue output for video and audio transferring. Previously, due to the large size of the equipment, it consisted of 3 RCA jacks and was connected to the TV accordingly. Now the devices have become more compact and don't have free space on the case. Therefore, the AV output is a single headphone jack, to which a tee cable is already connected (check availability in the package). Since all components of the video signal are on the same cable, the picture quality and immunity to interference are low.
Optical output
A variation of the SP/DIF audio interface that uses a TOSLINK fibre optic cable. Like the coaxial connector,
the optical output uses a digital data transfer format and can work with multi-channel audio. At the same time, optical fibre requires rather delicate handling, but it is absolutely insensitive to electrical interference.
Audio output (3.5 mm)
The presence of an audio output in most cases implies
a 3.5 mm mini-Jack connector for headphones. This connector does not transmit high power, which can fully supply the TV with an audio signal, but for compact devices, which include headphones, it will come in handy, since most household wired headphones are produced with a 3.5 mm plug. Headphones can be useful in noisy environments, or vice versa, when loud sound is undesirable, as well as in situations where sound must be listened to attentively (for example, when listening to radio broadcasts to learn a foreign language).
CPU
The model of the CPU installed in the media player.
This information is mainly of reference value: the processor is selected in such a way as to provide certain practical characteristics (maximum resolution, support for certain standards, embedded applications, etc.). So when choosing, you should focus primarily on these specifications. However, if you wish, knowing the processor model, you can find detailed data on it and evaluate the capabilities of the media centre to work with resource-consuming applications. This can be useful, in particular, if you choose an Android model (see above) and plan to use additional software intensively — the set of applications for this OS is very extensive, and some of them are quite demanding on system resources.
Also note that CPU data is often specified for advertising purposes — to emphasize that the device has a fairly advanced chip from a well-known brand. Among the most common brands of such processors are
Allwinner,
Amlogic,
Rockchip,
Realtek.
CPU frequency
The clock speed of the CPU installed in the media centre.
On the technical side, the higher this indicator, the faster the processor works and the higher, accordingly, the overall system performance. At the same time, the CPU performance depends, in addition to the frequency itself, on a number of factors — architecture, number of cores, special design features, etc.; and the actual speed of the entire system is affected by performance of components other than the processor. In addition, manufacturers usually select processors in such a way that their computing power is guaranteed to be enough for all the features claimed for a media centre. Therefore, in this case, the CPU frequency is more of a reference parameter (and partly an advertising indicator that demonstrates the advanced specifications of the device), rather than practically significant for buyer.
HDR support
HDR standard supported by the media player.
For more details about HDR in general, see above, while the standard defines some features of the implementation of this feature. Today, the following HDR formats are relevant:
— HDR10. Historically the first of the consumer HDR formats, less advanced than the options described below, but extremely widespread. In particular, HDR10 is supported by almost all streaming services that provide HDR content at all, and it is also common for Blu-ray discs. Allows to work with a colour depth of 10 bits (hence the name). At the same time, devices of this format are also compatible with content in HDR10 +, although its quality will be limited by the capabilities of the original HDR10.
— HDR10+. An improved version of HDR10. With the same colour depth (10 bits), it uses the so-called dynamic metadata, which allows transmitting information about the colour depth not only for groups of several frames, but also for individual frames. This results in an additional improvement in colour reproduction.
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Dolby Vision. An advanced standard used particularly in professional cinematography. Allows to achieve a colour depth of 12 bits, uses the dynamic metadata described above, and also makes it possible to transmit two image options at once in one video stream — HDR and standard (SDR). At the same time, Dolby Vision is based on the same tec
...hnology as HDR10, so in modern video technology this format is usually combined with HDR10 or HDR10 +. Audio decoders
The set of audio codecs supported by the device
Codec — from the phrase "Encoder-DEcoder" — in this case, the format used for encoding and compressing sound in digital form during storage/transmission and decoding — during playback (digital sound is basically impossible without encoding, and compression allows to reduce the amount of data). Information about supported codecs is relevant primarily for assessing whether the player will be able to work with sound in a particular video file. The fact is that even in video files of the same format (see below), sound can be compressed by different codecs; and if the player supports the file format, but does not support the codec, sound playback will become impossible.
Theoretically, these rules are also relevant for audio files and online broadcasts (all formats — TV, video, audio). However, in fact, when working with such content, you can ignore codec data. So, for each audio file format, usually, its own standard codec is used, and file type support automatically means codec support. Broadcasts usually use generally accepted audio decoders like MPEG-1 or MPEG-2, which are practically guaranteed to be supported by any modern player designed for such broadcasts.
As for specific codecs, detailed information on them can be found in special sources, however, with the standard use of devices, such details are usually not needed.