simplevideomarkdetect: GStreamer Bad Plugins 1.0 Plugins Reference Manual

simplevideomarkdetect

Properties

gint	bottom-offset	Read / Write / Construct
gint	left-offset	Read / Write / Construct
gboolean	message	Read / Write / Construct
gdouble	pattern-center	Read / Write / Construct
gint	pattern-count	Read / Write / Construct
gint	pattern-data-count	Read / Write / Construct
gint	pattern-height	Read / Write / Construct
gdouble	pattern-sensitivity	Read / Write / Construct
gint	pattern-width	Read / Write / Construct

Types and Values

struct

GstSimpleVideoMarkDetect

Object Hierarchy

    GObject
    ╰── GInitiallyUnowned
        ╰── GstObject
            ╰── GstElement
                ╰── GstBaseTransform
                    ╰── GstVideoFilter
                        ╰── GstSimpleVideoMarkDetect

Description

This plugin detects “pattern-count” squares in the bottom left corner of the video frames. The squares have a width and height of respectively “pattern-width” and “pattern-height”. Even squares must be black and odd squares must be white.

When the pattern has been found, “pattern-data-count” squares after the pattern squares are read as a bitarray. White squares represent a 1 bit and black squares a 0 bit. The bitarray will will included in the element message that is posted (see below).

After the pattern has been found and the data pattern has been read, an element message called GstSimpleVideoMarkDetect will be posted on the bus. If the pattern is no longer found in the frame, the same element message is posted with the have-pattern field set to FALSE. The message is only posted if the “message” property is TRUE.

The message's structure contains these fields:

gbooleanhave-pattern: if the pattern was found. This field will be set to TRUE for as long as the pattern was found in the frame and set to FALSE for the first frame that does not contain the pattern anymore.
GstClockTime timestamp: the timestamp of the buffer that triggered the message.
GstClockTime stream-time: the stream time of the buffer.
GstClockTime running-time: the running_time of the buffer.
GstClockTime duration: the duration of the buffer.
guint64 data: the data-pattern found after the pattern or 0 when have-signal is FALSE.

Example launch line

1	gst-launch-1.0 videotestsrc ! simplevideomarkdetect ! videoconvert ! ximagesink

Synopsis

Element Information

plugin	videosignal
author	Wim Taymans <wim@fluendo.com>
class	Filter/Effect/Video

Element Pads

name	sink
direction	sink
presence	always
details	video/x-raw, format=(string){ I420, YV12, Y41B, Y42B, Y444, YUY2, UYVY, AYUV, YVYU }, width=(int)[ 1, 2147483647 ], height=(int)[ 1, 2147483647 ], framerate=(fraction)[ 0/1, 2147483647/1 ]

name	src
direction	source
presence	always
details	video/x-raw, format=(string){ I420, YV12, Y41B, Y42B, Y444, YUY2, UYVY, AYUV, YVYU }, width=(int)[ 1, 2147483647 ], height=(int)[ 1, 2147483647 ], framerate=(fraction)[ 0/1, 2147483647/1 ]

Functions

Types and Values

struct GstSimpleVideoMarkDetect

struct GstSimpleVideoMarkDetect;