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 ::patern-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:

Example launch line

gst-launch videotestsrc ! videodetect ! ffmpegcolorspace ! ximagesink

Element Information

GstVideoDetect

typedef struct {
  GstVideoFilter videofilter;
  
  gint width, height;
  guint32 format;

  gboolean message;
  gint pattern_width;
  gint pattern_height;
  gint pattern_count;
  gint pattern_data_count;
  gdouble pattern_sensitivity;

  gboolean in_pattern;
} GstVideoDetect;

Opaque datastructure.