Class VideoStreamOverlay

VideoStreamOverlay Class

Description

VideoStreamOverlay also known as On-Screen Display (OSD) that allows contents such as texts and shapes to be displayed on video streams. VideoStreamOverlay class is used to draw on video streams.

Syntax

class VideoStreamOverlay

Members

Public Constructors
VideoStreamOverlay::VideoStreamOverlay	Constructs a VideoStreamOverlay object.
Public Methods
VideoStreamOverlay::configVideo	Configure input video stream parameters.
VideoStreamOverlay:: configTextSize	Configure text width and height shown on OSD.
VideoStreamOverlay:: createBitmap	Create bitmap on video streams.
VideoStreamOverlay::begin	Enable OSD and start drawing on top of video streams.
VideoStreamOverlay::end	Stop OSD drawing on all video streams.
VideoStreamOverlay::endChannel	Stop OSD drawing on specified video stream.
VideoStreamOverlay::getTextHeight	Get current configuration of OSD text height.
VideoStreamOverlay::getTextWidth	Get current configuration of OSD text width.
VideoStreamOverlay::color	Convert ARGB color values into a format compatible for OSD use.
VideoStreamOverlay::drawLine	Draw a line in OSD frame buffer.
VideoStreamOverlay::drawPoint	Draw a point in OSD frame buffer.
VideoStreamOverlay::drawRect	Draw a rectangle on OSD frame buffer.
VideoStreamOverlay::drawText	Draw text on OSD frame buffer.
VideoStreamOverlay::update	Update OSD and display drawings on video streams.

VideoStreamOverlay::configVideo

Description

Configure input video stream parameters.

Syntax

void configVideo(int ch, VideoSetting& config);

Parameters

ch: Channel to configure.

0
1
2

config: VideoSetting object.

Returns

NA

Example Code

Example: MotionDetection/LoopPostProcessing

Note

OSD only supports channel 0, 1 and 2. “VideoStreamOverlay.h” must be included to use the class function.

VideoStreamOverlay::configTextSize

Description

Configure text width and height shown on OSD.

Syntax

void configTextSize(int ch, int text_width, int text_height);

Parameters

ch: Channel to configure.

0
1
2

text_width: Text width in pixels. (Default value is 16)

text_height: Text height in pixels (Default value is 32)

Returns

NA

Example Code

NA

Note

“VideoStreamOverlay.h” must be included to use the class function. Text size should be configured before OSD is started using begin().

VideoStreamOverlay::createBitmap

Description

Create bitmap on video streams.

Syntax

void createBitmap (int ch, int idx = 0);

Parameters

ch: Channel to configure.

0
1
2

idx: Layer index of OSD.

0 to 5 (Default value is 0)

Returns

NA

Example Code

Example: MotionDetection/LoopPostProcessing

Note

“VideoStreamOverlay.h” must be included to use the class function.

VideoStreamOverlay::begin

Description

Enable OSD and start drawing on top of video streams.

Syntax

void begin(void);

Parameters

NA

Returns

NA

Example Code

Example: MotionDetection/LoopPostProcessing

Note

“VideoStreamOverlay.h” must be included to use the class function.

VideoStreamOverlay::end

Description

Stop OSD drawing on all video streams.

Syntax

void end(void);

Parameters

NA

Returns

NA

Example Code

NA

Note

“VideoStreamOverlay.h” must be included to use the class function.

VideoStreamOverlay::endChannel

Description

Stop OSD drawing on specified video stream.

Syntax

void endChannel(int ch);

Parameters

ch: Channel to stop.

0
1
2

Returns

NA

Example Code

NA

Note

“VideoStreamOverlay.h” must be included to use the class function.

VideoStreamOverlay::getTextHeight

Description

Get current configuration of OSD text height.

Syntax

int getTextHeight(int ch);

Parameters

ch: Channel to get the OSD text’s height.

0
1
2

Returns

This function returns the OSD text’s height on selected channel.

Example Code

Example: RTSPFaceDetection

Note

“VideoStreamOverlay.h” must be included to use the class function.

VideoStreamOverlay::getTextWidth

Description

Get current configuration of OSD text width.

Syntax

int getTextWidth(int ch);

Parameters

ch: Channel to get the OSD text’s width.

0
1
2

Returns

This function returns the OSD text’s width on the selected channel.

Example Code

NA

Note

“VideoStreamOverlay.h” must be included to use the class function.

VideoStreamOverlay::color

Description

Convert ARGB color values into a format compatible for OSD use.

Syntax

uint32_t color(uint8_t red, uint8_t green, uint8_t blue, uint8_t alpha = 0xff);

Parameters

red: Intensity level of red color expressed as an 8-bit unsigned integer.

0 to 255

green: Intensity level of green color expressed as an 8-bit unsigned integer. - 0 to 255

blue: Intensity level of blue color expressed as an 8-bit unsigned integer. - 0 to 255

alpha: Transparency of color expressed as an 8-bit unsigned integer. - 0 to 255 (Default value is 255. This value is optional)

Returns 

This function returns the ARGB value in a format compatible for OSD use.

Example Code

NA

Note

“VideoStreamOverlay.h” must be included to use the class function.

VideoStreamOverlay::drawLine

Description

Draw a line in OSD frame buffer.

Syntax

void drawLine(int ch, int xmin, int ymin, int xmax, int ymax, int line_width, uint32_t color, int idx = 0);

Parameters

ch: Channel to draw on.

0
1
2

xmin: x coordinate of the top left corner.

ymin: y coordinate of the top left corner.

xmax: x coordinate of the bottom right corner.

ymax: y coordinate of bottom right corner.

line_width: Width of a line.

color: Color of the line.

idx: Layer index of OSD.

0 to 5 (Default value is 0)

Returns

NA

Example Code

NA

Note

VideoStreamOverlay::update() needs to be called for drawings to be shown on the video streams. “VideoStreamOverlay.h” must be included to use the class function.

VideoStreamOverlay::drawPoint

Description

Draw a point in OSD frame buffer.

Syntax

void VideoStreamOverlay::drawPoint(int ch, int xmin, int ymin, int point_width, uint32_t color, int idx = 0);

Parameters

ch: Channel to draw on.

0
1
2

xmin: x coordinate of the point

ymin: y coordinate of the point

point_width: size of the point.

color: Color of the point.

idx: Layer index of OSD.

0 to 5 (Default value is 0)

Returns

NA

Example Code

Example: RTSPFaceDetection

Note

VideoStreamOverlay::update() needs to be called for drawings to be shown on the video streams. “VideoStreamOverlay.h” must be included to use the class function.

VideoStreamOverlay::drawRect

Description

Draw a rectangle on OSD frame buffer.

Syntax

void drawRect(int ch, int xmin, int ymin, int xmax, int ymax, int line_width, uint32_t color, int idx = 0);

Parameters

ch: Channel to draw rectangle on.

0
1
2

xmin: x coordinate of the top left corner.

ymin: y coordinate of the top left corner.

xmax: x coordinate of the bottom right corner.

ymax: y coordinate of bottom right corner.

line_width: Width of a rectangle’s border.

color: Color of the rectangle.

idx: Layer index of OSD.

0 to 5 (Default value is 0)

Returns

NA

Example Code

Example: MotionDetection/LoopPostProcessing

Note

VideoStreamOverlay::update() needs to be called for drawings to be shown on the video streams. “VideoStreamOverlay.h” must be included to use the class function.

void drawText(int ch, int xmin, int ymin, const char *text_string, uint32_t color, int idx = 0);

Parameters

ch: Channel to draw text on.

0
1
2

xmin: x coordinate of top left corner of text box.

ymin: y coordinate of top left corner of text box.

text_string: pointer to a character array containing the text to be displayed.

color: Color of the text.

idx: Layer index of OSD.

0 to 5 (Default value is 0)

Returns

NA

Example Code

Example: MotionDetection/LoopPostProcessing

Note

VideoStreamOverlay::update() needs to be called for drawings to be shown on the video streams. “VideoStreamOverlay.h” must be included to use the class function.