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gboolean | message | 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 |
gint | bottom-offset | Read / Write / Construct |
gint | left-offset | Read / Write / Construct |
gdouble | pattern-center | Read / Write / Construct |
GObject ╰── GstObject ╰── GstElement ╰── GstBaseTransform ╰── GstVideoFilter ╰── GstVideoDetect
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 "GstVideoDetect"
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:
gboolean
"have-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-uint64"
:
the data-pattern found after the pattern or 0 when have-signal is FALSE.
guint
"data"
:
the data-pattern found after the pattern or 0 when have-signal is FALSE.
Last reviewed on 2007-05-30 (0.10.5)
“message”
property“message” gboolean
Post statics messages.
Flags: Read / Write / Construct
Default value: TRUE
“pattern-count”
property“pattern-count” gint
The number of pattern markers.
Flags: Read / Write / Construct
Allowed values: >= 0
Default value: 4
“pattern-data-count”
property“pattern-data-count” gint
The number of extra data pattern markers.
Flags: Read / Write / Construct
Allowed values: >= 0
Default value: 5
“pattern-height”
property“pattern-height” gint
The height of the pattern markers.
Flags: Read / Write / Construct
Allowed values: >= 1
Default value: 16
“pattern-sensitivity”
property“pattern-sensitivity” gdouble
The sensitivity around the center for detecting the markers (0.0 = lowest, 1.0 highest).
Flags: Read / Write / Construct
Allowed values: [0,1]
Default value: 0.3
“pattern-width”
property“pattern-width” gint
The width of the pattern markers.
Flags: Read / Write / Construct
Allowed values: >= 1
Default value: 4
“bottom-offset”
property“bottom-offset” gint
The offset from the bottom border where the pattern starts.
Flags: Read / Write / Construct
Allowed values: >= 0
Default value: 0
“left-offset”
property“left-offset” gint
The offset from the left border where the pattern starts.
Flags: Read / Write / Construct
Allowed values: >= 0
Default value: 0
“pattern-center”
property“pattern-center” gdouble
The center of the black/white separation (0.0 = lowest, 1.0 highest).
Flags: Read / Write / Construct
Allowed values: [0,1]
Default value: 0.5