singmai DB11 Video Character Overlay Module User Manual
- June 4, 2024
- singmai
Table of Contents
singmai DB11 Video Character Overlay Module
Revisions
| Date | Revisions | Version |
|---|---|---|
| 09-10-2023 | First draft | 0.1 |
Introduction
DB11 is a character/text overlay module for digital video sources. DB11 is
ideal for inserting text, channel IDs, menus, status and titles on video
sources.
DB11 accepts serial digital inputs (SDI, HD-SDI or 3G-SDI), which it can
overlay with text, before outputting as a re-clocked serial digital output.
DB11 auto-detects the input standard and supports 525i, 625i,
720p-25/30/50/59.94/60Hz; 1080p-24/25/29.97/30/50/59.94/60Hz and
1080i-50/59.94/60Hz standards. Text is written via an RS232 interface.
DB11 offers 112 pre-programmed characters: each character is 12×16 pixels but
a x2 (24×32 pixels) and x4 (48×64 pixels) magnify function is available. The
colour of the character and the background is programmable.
DB11 requires 12VDC which is provided via the supplied AC-DC converter.
Quick start guide
Connect the DB11 to the supplied AC/DC adaptor. Fit the appropriate blades to the adaptor for your country. Blades are supplied for North America, Europe, UK, China and Australia. The adaptor accepts AC between 90 and 264VAC – the full specification is provided in Appendix A.
The connections to the DB11 are shown in Figure 1.
Connect the 12VDC jack from the adaptor to the +12VDC ‘Power in’ socket on the
DB11. The ‘Power On’ LED should light up blue.
Connect a valid serial digital video source to the SDI input BNC socket: the
SDI Lock should light.
Connect the SDI output to a monitor or other SDI compatible device – the SDI
output is a reclocked copy of the input. By default, the input standard is
automatically detected but the standard can be manually preset via the RS232
interface if required. The standards accepted are shown in Table 1.
| RS232 Setting | Video standard | Character display | Comments |
|---|---|---|---|
| $00 | 720p25 | 106 x 45 | |
| $01 | 720p30 | 106 x 45 | |
| $02 | 720p50 | 106 x 45 | |
| $03 | 720p59 | 106 x 45 | |
| $04 | 720p60 | 106 x 45 | |
| $05 | 1080p24 | 128 x 64 | The 128 characters are limited by the DB11 memory. For |
1080p standards 1920/12 =
160 characters could be displayed. The horizontal position command may be used to move the 128-character display as required.
$06| 1080p25| 128 x 64
$07| 1080p29| 128 x 64
$08| 1080p30| 128 x 64
$09| 1080i50| 128 x 64
$0A| 1080i59| 128 x 64
$0B| 1080i60| 128 x 64
$0C| 1080p50| 128 x 64
$0D| 1080p59| 128 x 64
$0E| 1080p60| 128 x 64
$10| 525i| 60 x 30|
$11| 625i| 60 x 32|
Table 1 DB11 video standards.
If no valid SDI input is detected the output will not be valid.
The RS232 interface is used to write text to the display. The connections to
the RS232 9 pin D-type connector are as follows:
- Pin 2 RS232 output (from DB11 to PC).
- Pin 3 RS232 input (to DB11 from PC).
- Pin 5 Ground.
- Pin 7 Connected to Pin 8.
- Pin 8 Connected to Pin 7.
- Pin 1,4,6,9 Not connected.
The RS232 interface is described in Chapter 4
DB11 Technical Details
A simplified block diagram of the DB11 is shown in Figure 3.
The +12VDC from the AC/DC power adaptor is filtered and protected from over-
range or reverse polarity inputs. The 12VDC input is then regulated to provide
clean power supplies for the module.
The SDI input is equalized and de-serialised. An FPGA overlays the required
characters on the SDI input video before outputting the video to an SDI
serialiser and driver.
Each character is 12 pixels wide and 16 lines high, regardless of the video
standard. There is an option to enlarge the character by a factor of 2 (24 x
32) or 4 (48 x 64). The enlarged character pixel replicates the original 12×16
character.
Figure 4 shows the character layout for 720p resolution. 720p has an active
display of 1280 pixels x 720 lines. Therefore, we have 1280/12 = 106
characters (RS232 command $86 – value between $00 [010] and $69 [10510]).
Vertically we have 720/16 = 45 characters (RS232 command $87 – value between
$00 [010] and $2C [4410]).
If the Size of the character is set to x2 (24×32 pixels) the display will be 53 x 22 characters. Characters written outside of this range will be stored but not displayed.
If the Size of the character is set to x2 (24×32 pixels) the display will be 30 x 15 (525i) or 30 x 18 (625i) characters. Characters written outside of this range will be stored but not displayed.
RS232 control
The format of the RS232 interface is 8-bit data, 1 start, 1 stop bit and no
parity. The communication speed is 9600 baud.
The command interface has the following structure:
Command word : Command data (optional) : Command data (optional) : Command
termination ($FD). The commands are shown in Table 1.
| Command | Data | Command description | Comments |
|---|---|---|---|
| $80 | NA. | Clear display. | Erases all the stored characters. |
| $81 | NA. | Set auto standard. | Video standard is automatically determined. |
| $82 | See Table 1. | Set manual standard. | Video standard is manually set. If |
the SDI input does not match this setting the output if forced to colour bars
at the manually set standard.
$83| MSB, LSB| Horizontal position.|
$84| MSB, LSB| Vertical position.|
$85| Auto/manual| Address increment.| If the data is set to $00, the
horizontal character address automatically increments when each character is
written.
If the data is set to $01, the horizontal character address does not increment and the existing character is overwritten.
$86| Address| Set horizontal character address.| Address value between 010 and
12710.
$87| Address| Set vertical character address.| Address value between 010 and
6310.
$88| Size| Character size.| If Size is set to $00 the character size is 12×16
pixels.
If Size is set to $01 the character size is 24×32 pixels.
If Size is set to $02 the character size is 48×64 pixels.
The larger character sizes use pixel
replication.
$90| Y Value| Sets the character Y value.| See Table 4.
$91| Cb Value| Sets the character Cb value.| See Table 4.
$92| Cr Value| Sets the character Cr value.| See Table 4.
$93| NA| Turns on colour background.| If set the background behind each
character is turned on, else only the character is displayed.
$94| NA| Turns on video background.| If set the video ‘behind’ the character
is dimmed and made monochrome,
else only the character is displayed.
$95| Y Value| Sets the background Y value.| See Table 4.
$96| Cb Value| Sets the background Cb value.| See Table 4.
$97| Cr Value| Sets the background Cr value.| See Table 4.
Table 2 DB11 RS232 commands.
Example commands are:
- $82, $04, $FD – Set manual standard to 720p/60Hz.
- $83, $00, $64, $FD – Shift the character display right by 100 pixels.
The output of the character RAM selects one of 112 characters; the characters
available are shown in Table 3.
To write a character it is only necessary to send the character value via the
RS232 interface (no termination character). The character will be written at
the address set by commands $86 and $87. If the address auto-increment is
enabled the next character will be written at the next horizontal position.
For example, to write ‘SingMai’ at the starting address previously set, the
sequence $1D, $2D, $32, $2B, $17, $25, $2D would be sent.
Table 3 Pre-programmed Characters
The colour of each character and the background is programmable. Example values are shown in Table 4.
Specification
- Power: +9-14V (+12VDC nominal) @ ~350mA.
- Dimensions: 120mm x 78mm x 27mm.
- Video input: SDI (SMPTE-259M), HD-SDI (SMPTE-292M), 3G-SDI (SMPTE-425M). >15dB return loss.
- Video output: SDI/HD-SDI/3G-SDI. >15dB return loss.
- Characters: 112 characters. 12 pixels x 16 lines.
- Maximum display size: 128 x 64 characters.
- Operating temperature: -10 – +40 degC.
Appendix A: AC-DC adaptor
The specification for the supplied AC-DC adaptor is shown in Figures 7 and 8.
Figure 8 Power supply specification: mechanical.
Documents / Resources
|
singmai DB11 Video Character Overlay
Module
[pdf] User Manual
DB11 Video Character Overlay Module, DB11, Video Character Overlay Module,
Character Overlay Module, Overlay Module, Module
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