Features of the Android TV box with multicast broadcasting

Once I wanted to find among inexpensive 2-core Android TV set-top boxes such that it would just work with HD TV channels broadcast by providers in my city. It turned out that out of 4 purchased consoles with RK3066, Allwinner A20, Amlogic 8726-MX chips, only one correctly and without hangs the video plays HD channels received in multicast mode. At the same time, watching movies with a resolution of 1080p from the internal memory or “flash drive” occurred qualitatively on all consoles. So, IPTV set-top box CA9-DA (see. Fig. 1).

Fig. 1. Appearance of IPTV set-top box CA9-DA.

- Dual-core video accelerator Mali 400;
- Dual-core Amlogic 8726-MX processor with Cortex A9 architecture;
- 1 GB of RAM;
- 4GB user memory + slot for SD / MMC memory cards;
- Communication: Wi-Fi 802.11 b / g / n 2.4 GHz, Fast Ethernet.

Options (see Fig. 2):

Fig. 2. Options CA9-DA.

- HDMI cable;
- Remote Control;
- 5V / 2A power adapter.

Fig. 3. Remote for CA9-DA.

Among other consoles CA9-DA stands out support for hardware video decoding in MX-Player. At the moment, MX-Player is most adapted for playing video on Android devices, so it was he who, after a short practical selection, was chosen to play TV. Installing all additional codecs for MX-Player hosted on Google Play is required. In the descriptions on the consoles, support for hardware decoding is not mentioned anywhere, and until you try in real work, you won’t be able to find out. While the other devices were working, video decoding could only be set to software, and despite the fact that the processor at the same time was loaded by no more than 50%, the image on the screen partially decayed into squares. It was this nuance that allowed us to discard the rest of the consoles and continue to study only CA9-DA. I clarify.

The remote control in the kit is simple (see Fig. 3). The cursor is moved by pressing the control buttons. There is no gyroscope inside. For convenience, it is better to connect a wireless mouse and keyboard. Or use the gyroscopic mouse keyboard AirMouse. In my subjective opinion, there is nothing better than a wireless mouse. The cursor control is not convenient, an external keyboard is superfluous in the presence of a virtual one, AirMouse requires getting used to. The mouse remains.

The connectors are located on the back side (see Fig. 4):
- Ethernet port (10/100 Mbps);
- USB-HOST 2 pcs;
- HDMI 1.4;
- input for power supply.

Fig. 4. Rear Panel CA9-DA.

On the right side there was a receiver for SD memory cards (see. Fig. 5).

Fig. 5. Right side panel CA9-DA.

On the front panel there is an IR radiation sensor and an on / off button (see. Fig. 6).

Fig. 6. Front panel CA9-DA.

Wi-Fi antenna built-in.
The case is made of glossy black plastic on top / bottom and matte light gray plastic from the ends. No manufacturer logo.
The internal view is shown in Figures 7 and 8.

Fig. 7. The top of the CA9-DA board.

Fig. 8. The bottom of the CA9-DA board.

From above, a radiator is pressed to the AML8726-MX chip through a heat-conducting paste. Wi-Fi operation is provided by the Realtek RTL8188ETV chip. During operation, the CA9-DA practically does not heat up.

In the prefix, Android 4.2.2 is preinstalled (see. Fig. 9).

Fig. 9. Information about CA9-DA.

Initially, the “Auto” screen resolution setting is used (see. Fig. 10).

Fig. 10. Screen settings CA9-DA.

Interestingly, the very presence of this setting turned out to be critical for broadcasting. In the "auto" mode, 720p resolution is turned on (it is with this resolution that HD channels are broadcast), if at the same time the set-top box is forced to enter the resolution mode of 1080p, sometimes the video slows down. So, specifically for the experiment, I found a cheap 4-core MINIX X7 prefix also on Adroid 4.2.2 and also supporting hardware video decoding in MX-Player and found that it had no “auto” mode! Watch a movie 1080p - manually set the resolution of the screen to 1080p in the Android settings. If you forgot to set 720p when switching to watching multicast TV, you will have a video slowdown. 4-core and high clock frequency of the chip does not save from this. Expensive is not always the best.

One of the annoying factors when watching TV channels was that switching from channel to channel is carried out in a few mouse clicks or in a few keystrokes on the remote control. Tested applications taken from Google Play. IPTV Alexander Sofronov did not experience any failures, but the channels are switched in three clicks - exit the channel being watched, move the cursor to the next channel, click OK. At IP-TV Qsmart, switching channels is already in two clicks - once at the beginning of viewing: you call up the channel list (on the left side of the screen is a horizontal bar with the list), then move the cursor and press OK. True, if you collapse the list of channels (sometimes you want to remove the excess from the screen), and then call it again - the application freezes. The “IPTV set-top box emulator” has one-click switching, moreover, the interface is copied from the most famous MAG 250/254 TV set-top box, which is very pleased. But the application does not support playlists in m3u format. The only way to play them in the application is to use a portal that supports such playlists. Not every provider organizes such a portal on their server, so the versatility of the application is lost. As a result, when choosing an application for watching TV channels, you need to find a compromise with yourself.

On Wi-Fi as a client, the console works flawlessly. The problem arises when routing Internet traffic wired to the console via a LAN port and then distributing it to Wi-Fi to two or more devices - AP mode. Internal traffic between clients passes “with a bang” (testing was carried out using the Iperf program), and when accessing the Internet at the same time all clients (running at each speedtest.net) CA9-DA “hung”. Immediately before the hang-up, the console noticeably starts to slow down the interface - the behavior of the mouse with jerks, the suspension of window switching, etc. It seems that this drawback is connected with the hardware, because on the 4-core console the same problem was not observed with the three clients, and with one client, CA9-DA also manages.

And finally, the Miracast mode was tested - wireless “mirroring” the screen of an Android device, for example, a tablet on a TV screen with an Android set-top box connected. Simply put, this standard solves problems very similar to Apple's AirPlay, Intel's WiDi, or the good old DLNA. Miracast works via Wi-Fi, and the first logical step when turning on Miracast was asking for itself - to turn on Wi-Fi in the console and on the tablet and establish a connection between them. There it was. After a series of attempts, the following sequence of correct actions was revealed. On the set-top box and tablet \ phone, turn on Wi-Fi without pairing (!!!) the device in Wi-Fi Direct. On the console, start the Miracast program, and on the tablet \ phone go to the Screen-> Wireless screen (Miracast) section and wait (!!!) for the link to the console in this menu. After the link appears, pairing occurs on tap and the image appears on the TV. The initial connection may be thrown out with an error, but repeated waiting for the icon and connecting with a tap brings a positive result. After asking about the reasons for such a complex algorithm, the manufacturer of the console recognized the flaws in the work of miracast. In his defense, he said that he had been negotiating with the chip manufacturer Amlogic 8726-MX for some time to improve the performance of Miracast.

In the end, I want to say that when choosing the Android TV box, reading the descriptions provided by the manufacturer does not give an understanding of the behavior of the consoles in various modes. Therefore, at this stage, the most compromise and most importantly studied option is the console with the Amlogic 8726-MX chip.

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