OSD-weergavefunctie op COFDM-ontvanger
key1: turn on/off the status of the OSD displaying, druk er lang op om te schakelen(meer dan 1s). the status will be kept after reboot. Wanneer de OSD-status is ingeschakeld zonder enige OSD-gegevensinvoer van de data uart, het apparaat geeft informatie op het videoscherm weer als:
RF：338.0MHz BW：4.0MHz; RF, werkfrequentie; BW, bandbreedte
QPSK CR：2/3 GI:1/16; Sterrenbeeld, FEC, Guard interval.
LUCHT：3.90Mbps; LUCHT, draadloze transmissiebitrates
VBR：3.05Mbps AES OFF; VBR, video-bitrates; AES OFF, AES-codering uitgeschakeld.
SIG1：27 SIG2：22; SIG1, signal intensity of ant 1; SIG2, signal intensity of ant 2
ber1:0.14% ber2:100.00%; ber1, bit error rate of ant 1; ber2, bit error rate of ant 2
REC OFF Geen Storage; video-opnamestatus
What is VBR? VBR is the video encoding bit rate at the transmitter. Since the video picture changes dynamically, VBR is of course variable, but it fluctuates around the encoding bit rate set by the transmission system: 7.81*0.8=6.248Mbps
How to use OSD API in Our COFDM systems?
Steps description:
1) The customer’s module sends the digital data to our COFDM transmitter via UART;
2) Our transmitter will send the digital data with video data together to our COFDM receiver via the wireless link;
3) Our receiver will send out the digital data to the customer’s module via UART;
4) The customer’s module should transfer the digital data into the characters string they want to show on the video screen in OSD mode. Then the customer’s module sends the characters string to our receiver via the same UART.
5) Our receiver will display the character’s string on the HDMI display screen with the video together in OSD mode.
API of Our COFDM receiver:
| command | ATOSD$(font), $(X),$(y),$(str) _example：ATOSD1,40,20,height: 100m_ |
| parameters | font: 0: 8×16, pixels; 1: 16×24, pixels; X: 0 tot 1919, horizontal axis; en: 0 tot 1079, vertical axis; Str: characters string start to show on the HDMI screen from (X,y) point; space characters used for a clean screen at that point. Since ’_’ is the command end flag, No ’_’ can be used in these parameters. |
| functie | To display the characters string on the HDMI screen with the video in OSD mode |
| return | Null |
| Omschrijving | 1) This command is used for the customer’s MCU module to our Receiver via data UART; 2) You can use ATST command(described in other documents) to define our Receiver UART; 3) You should draw the HDMI screen following 1920*1080 pixels via (X,y) axis. Our receiver firmware will adjust it automatically according to the real screen systems. |