The MontiVision Text Overlay filter overlays user specific text onto the output video stream.
The new IMVTextOverlay2 interface extends the filter for use with up to ten different text overlays. The new text input pin may be used to set the text to be overlayed. If multiple strings are send to the text input pin, they are separated using the separator configured via COM interface or property page. If e.g. '#' is chosen as separator, the input text could look like: 'This#shows#four#overlays'. Format and positions of the strings have to be configured before receiving text through the I/O text pin.
If you want to create a ticker like overlay, you should use MV Ticker Overlay instead. In case you want to be free to draw onto the live stream using any available Windows GDI command, you can use MV GDI Overlay.
This MontiVision DirectShow Filter is used in combination with the MontiVision Smart Control in the 24Videorecorder and TextOverlay SampleApplications.
| File: | textoverlay.ax |
| CLSID: | CLSID_MVTextOverlay |
Interface
Supported COM Events
The filter supports following events through the IMVFilterEvents interface. Look at the filter events page for more information.
| Event |
Value |
Description |
| MV_ALGORITHM_START_EVENT |
0 |
A filter starts processing a video frame or sample. |
| MV_ALGORITHM_END_EVENT |
1 |
A filter finishes processing a video frame or sample. |
Supported I/O Pins
| I/O Pin | Corresponding method | Discription |
|
Text In |
IMVTextOverlay::put_Text | Sets the text that is to be drawn onto the video stream. |
Attention:
I/O Pins are dominant, that means that they have a
higher priority than the corresponding method of the filters
interface!
MV Text Overlay Proeprty Page
Uses the IMVTextOverlay configuration interface.
| Enable Overlay | Enables or disables the text overlay. |
| Number of overlays | The number of different text overlays you want to use. |
| Selected overlay | Select the index of an overlay in order to adjust its format and position. |
| Date/Time | The current date and time is overlaid onto the video stream. |
| Text | The user specified text is overlaid onto the video stream. |
| Font properties | Size, typeface and properties of the font that is used to draw the text. |
| Colours | Text, shadow and background colours. |
| Margins | Horizontal and vertical margins for the drawn text. |
| Relative Position | Places the text within the selected corner. |
| Absolute Position | Places the text exactly at the defined position relative to the lower left corner of the video stream. |
| I/O Pin Separator | The separator used to split up the text received on the I/O Text Input Pin into substrings. |
Example Configuration
The following setup shows how to receive text strings from MV I/O Text File Source in order to overlay two different texts at two different positions. '#' was used as separator between the two text strings.
The following text file was used with MV I/O Text File Source:
