Comparison World Vision T645D5 FM vs World Vision T644A FM

— Proprietary system. The operating system of the device is represented by the proprietary software shell of the manufacturer. Usually, such operating systems have an attractive and convenient menu. A proprietary operating system is developed directly by the manufacturer for the hardware resources of a particular model or a whole line, but has limited capabilities.

— Android (AOSP). This type of operating system is a modification of the popular Android OS, mainly notable for being open source. It is a versatile operating system that gives the user much more freedom to create changes and customizations within the system itself. At the same time, the installation and stability of certain applications on this platform are not guaranteed, and the overall system management was not specially “tailored” for large screens, which may cause some inconvenience. First of all, such solutions will interest users who understand the features of the Android OS, like to customize and control everything for themselves, and have time for this.

— Android TV. Devices of this type have full-fledged Android TV software, specially adapted to work on large screens. In accordance with the name, it is a type of Android OS, specially designed for such equipment. In addition to the common features of all Androids (such as the ability to install additional applications,...including even games), it has a number of special features: an optimized interface, integration with smartphones (including the ability to use them as a remote control), voice search, etc. Thanks to this, TVs with this feature are significantly superior in functionality to models with a “regular” Smart TV. Of course, a dedicated processor, graphics subsystem and memory are provided for the operation of a multifunctional OS, and the presence of such hardware resources is reflected in the overall cost.

— Google TV. Rebranding of the Android TV platform for TVs and smart consoles, or rather, a new shell on top of the operating system under the sign of the “green droid”, introduced since 2021. Among the innovations, it has a redesigned user interface, an improved knowledge base that more efficiently distributes content by genre and collects search information from the entire list of installed applications and subscriptions. The voice assistant now understands the needs of the audience better and provides a detailed list of what was found. A separate tab in the interface contains live broadcasts of current events, whether it be sports events or a rocket launch to Mars. Among other things, the aspects that involve the use of TV as a command post for managing a single ecosystem of a “smart” home have been improved in the system.

Wi-Fi is a technology used for wireless connection to computer networks and for direct connection between devices. In media players, tuners and video capture devices, it can be used both to access the Internet or "local area" through a wireless router, and to communicate with a smartphone, tablet, etc. The AirPlay, Chromecast and Miracast functions are also based on this technology. The specific set of Wi-Fi features should be clarified separately; here we note that in this paragraph the specific supported version of such a connection can also be specified. Here are the main current options:

• Wi-Fi 5(802.11ac). One of the newest (for 2020) standards. Uses the 5 GHz band (less crowded than used in earlier 2.4 GHz versions) for improved reliability and lower latency; and speeds can reach 6.77 Gbps with multiple antennas and 1.69 Gbps with a single antenna.
• Wi-Fi 4 (802.11n). The predecessor of the above Wi-Fi 5, the first standard in which the 5 GHz band was introduced — here it is used along with the traditional 2.4 GHz and is not supported by some devices with Wi-Fi 4. Data transfer rate — up to 600 Mbps.

Note that, in addition to the directly claimed Wi-Fi standard, the media centre, digital receivers and video capture devices usually provide support for earlier versions — for maximum compatibility with different devices.

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.

Codec — from the phrase "Encoder-DECoder" — in this case is the format used for encoding digital video during storage/transmission and decoding during playback (without encoding, video data would take up an unjustifiably large amount of space). Do not confuse this parameter with the format of video files: different files of the same format can be encoded with different codecs, and if the corresponding codec is not supported by the player, video playback will be impossible, even if the file format itself corresponds to the capabilities of the device. And in models with online TV support (see "Features") this nuance also determines compatibility with a specific broadcast: the general format of the broadcast is indicated by the codec used for this.

In general, modern devices usually have quite extensive sets of codecs (one of the most advanced is H.265, AV1 codecis also popular), and there are usually no problems with video playback; in extreme cases, you can use special programs for transcoding files. As for specific codecs, detailed data on them can be found in special sources, but with standard use of media players, such details are not needed.