gstreamer/gst/videosignal/gstvideodetect.c

/* GStreamer
 * Copyright (C) <2007> Wim Taymans <wim@fluendo.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

/**
 * SECTION:element-videodetect
 * @short_description: Detect a pattern in a video signal
 *
 * <refsect2>
 * <para>
 * 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.
 * </para>
 * <para>
 * 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).
 * </para>
 * <para>
 * After the pattern has been found and the data pattern has been read, an
 * element message called <classname>&quot;GstVideoDetect&quot;</classname> 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 <link linkend="GstVideoDetect--message">message
 * property</link> is #TRUE.
 * </para>
 * <para>
 * The message's structure contains these fields:
 * <itemizedlist>
 * <listitem>
 *   <para>
 *   #gboolean
 *   <classname>&quot;have-pattern&quot;</classname>:
 *   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.
 *   </para>
 * </listitem>
 * <listitem>
 *   <para>
 *   #GstClockTime
 *   <classname>&quot;timestamp&quot;</classname>:
 *   the timestamp of the buffer that triggered the message.
 *   </para>
 * </listitem>
 * <listitem>
 *   <para>
 *   #GstClockTime
 *   <classname>&quot;stream-time&quot;</classname>:
 *   the stream time of the buffer.
 *   </para>
 * </listitem>
 * <listitem>
 *   <para>
 *   #GstClockTime
 *   <classname>&quot;running-time&quot;</classname>:
 *   the running_time of the buffer.
 *   </para>
 * </listitem>
 * <listitem>
 *   <para>
 *   #GstClockTime
 *   <classname>&quot;duration&quot;</classname>:
 *   the duration of the buffer.
 *   </para>
 * </listitem>
 * <listitem>
 *   <para>
 *   #guint
 *   <classname>&quot;data&quot;</classname>:
 *   the data-pattern found after the pattern or 0 when have-signal is #FALSE.
 *   </para>
 * </listitem>
 * </itemizedlist>
 * </para>
 * <title>Example launch line</title>
 * <para>
 * <programlisting>
 * gst-launch videotestsrc ! videodetect ! ffmpegcolorspace ! ximagesink
 * </programlisting>
 * </para>
 * </refsect2>
 *
 * Last reviewed on 2007-05-30 (0.10.5)
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "gstvideodetect.h"

#include <string.h>
#include <math.h>

#include <gst/video/video.h>

/* GstVideoDetect signals and args */

#define DEFAULT_MESSAGE              TRUE
#define DEFAULT_PATTERN_WIDTH        4
#define DEFAULT_PATTERN_HEIGHT       16
#define DEFAULT_PATTERN_COUNT        4
#define DEFAULT_PATTERN_DATA_COUNT   5
#define DEFAULT_PATTERN_SENSITIVITY  0.2

enum
{
  PROP_0,
  PROP_MESSAGE,
  PROP_PATTERN_WIDTH,
  PROP_PATTERN_HEIGHT,
  PROP_PATTERN_COUNT,
  PROP_PATTERN_DATA_COUNT,
  PROP_PATTERN_SENSITIVITY
};

GST_DEBUG_CATEGORY_STATIC (video_detect_debug);
#define GST_CAT_DEFAULT video_detect_debug

static const GstElementDetails video_detect_details =
GST_ELEMENT_DETAILS ("Video detecter",
    "Filter/Effect/Video",
    "Detect patterns in a video signal",
    "Wim Taymans <wim@fluendo.com>");

static GstStaticPadTemplate gst_video_detect_src_template =
GST_STATIC_PAD_TEMPLATE ("src",
    GST_PAD_SRC,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS (GST_VIDEO_CAPS_YUV ("{ I420, YV12 }"))
    );

static GstStaticPadTemplate gst_video_detect_sink_template =
GST_STATIC_PAD_TEMPLATE ("sink",
    GST_PAD_SINK,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS (GST_VIDEO_CAPS_YUV ("{ I420, YV12 }"))
    );

static GstVideoFilterClass *parent_class = NULL;

static gboolean
gst_video_detect_set_caps (GstBaseTransform * btrans, GstCaps * incaps,
    GstCaps * outcaps)
{
  GstVideoDetect *vf;
  GstStructure *in_s;
  gboolean ret;

  vf = GST_VIDEO_DETECT (btrans);

  in_s = gst_caps_get_structure (incaps, 0);

  ret = gst_structure_get_int (in_s, "width", &vf->width);
  ret &= gst_structure_get_int (in_s, "height", &vf->height);
  ret &= gst_structure_get_fourcc (in_s, "format", &vf->format);

  return ret;
}

/* Useful macros */
#define GST_VIDEO_I420_Y_ROWSTRIDE(width) (GST_ROUND_UP_4(width))
#define GST_VIDEO_I420_U_ROWSTRIDE(width) (GST_ROUND_UP_8(width)/2)
#define GST_VIDEO_I420_V_ROWSTRIDE(width) ((GST_ROUND_UP_8(GST_VIDEO_I420_Y_ROWSTRIDE(width)))/2)

#define GST_VIDEO_I420_Y_OFFSET(w,h) (0)
#define GST_VIDEO_I420_U_OFFSET(w,h) (GST_VIDEO_I420_Y_OFFSET(w,h)+(GST_VIDEO_I420_Y_ROWSTRIDE(w)*GST_ROUND_UP_2(h)))
#define GST_VIDEO_I420_V_OFFSET(w,h) (GST_VIDEO_I420_U_OFFSET(w,h)+(GST_VIDEO_I420_U_ROWSTRIDE(w)*GST_ROUND_UP_2(h)/2))

#define GST_VIDEO_I420_SIZE(w,h)     (GST_VIDEO_I420_V_OFFSET(w,h)+(GST_VIDEO_I420_V_ROWSTRIDE(w)*GST_ROUND_UP_2(h)/2))

static void
gst_video_detect_post_message (GstVideoDetect * videodetect, GstBuffer * buffer,
    guint data)
{
  GstBaseTransform *trans;
  GstMessage *m;
  guint64 duration, timestamp, running_time, stream_time;

  trans = GST_BASE_TRANSFORM_CAST (videodetect);

  /* get timestamps */
  timestamp = GST_BUFFER_TIMESTAMP (buffer);
  duration = GST_BUFFER_DURATION (buffer);
  running_time = gst_segment_to_running_time (&trans->segment, GST_FORMAT_TIME,
      timestamp);
  stream_time = gst_segment_to_stream_time (&trans->segment, GST_FORMAT_TIME,
      timestamp);

  /* post message */
  m = gst_message_new_element (GST_OBJECT_CAST (videodetect),
      gst_structure_new ("GstVideoDetect",
          "have-pattern", G_TYPE_BOOLEAN, videodetect->in_pattern,
          "timestamp", G_TYPE_UINT64, timestamp,
          "stream-time", G_TYPE_UINT64, stream_time,
          "running-time", G_TYPE_UINT64, running_time,
          "duration", G_TYPE_UINT64, duration,
          "data", G_TYPE_UINT, data, NULL));
  gst_element_post_message (GST_ELEMENT_CAST (videodetect), m);
}

static gdouble
gst_video_detect_calc_brightness (GstVideoDetect * videodetect, guint8 * data,
    gint width, gint height, gint stride)
{
  gint i, j;
  guint64 sum;

  sum = 0;
  for (i = 0; i < height; i++) {
    for (j = 0; j < width; j++) {
      sum += data[j];
    }
    /* move to next line */
    data += stride;
  }
  return sum / (255.0 * width * height);
}

static void
gst_video_detect_420 (GstVideoDetect * videodetect, GstBuffer * buffer)
{
  gdouble brightness;
  gint i, pw, ph, stride, width, height;
  guint8 *d, *data;
  guint pattern_data;

  data = GST_BUFFER_DATA (buffer);

  width = videodetect->width;
  height = videodetect->height;

  pw = videodetect->pattern_width;
  ph = videodetect->pattern_height;
  stride = GST_VIDEO_I420_Y_ROWSTRIDE (width);

  /* analyse the bottom left pixels */
  for (i = 0; i < videodetect->pattern_count; i++) {
    d = data;
    /* move to start of bottom left */
    d += stride * (height - ph);
    /* move to i-th pattern */
    d += pw * i;

    /* calc brightness of width * height box */
    brightness =
        gst_video_detect_calc_brightness (videodetect, d, pw, ph, stride);

    GST_DEBUG_OBJECT (videodetect, "brightness %f", brightness);

    if (i & 1) {
      /* odd pixels must be white */
      if (brightness < (1.0 - videodetect->pattern_sensitivity))
        goto no_pattern;
    } else {
      /* even pixels must be black */
      if (brightness > videodetect->pattern_sensitivity)
        goto no_pattern;
    }
  }
  GST_DEBUG_OBJECT (videodetect, "found pattern");

  pattern_data = 0;

  /* get the data of the pattern */
  for (i = 0; i < videodetect->pattern_data_count; i++) {
    d = data;
    /* move to start of bottom left, after the pattern */
    d += stride * (height - ph) + (videodetect->pattern_count * pw);
    /* move to i-th pattern data */
    d += pw * i;

    /* calc brightness of width * height box */
    brightness =
        gst_video_detect_calc_brightness (videodetect, d, pw, ph, stride);
    /* update pattern */
    pattern_data <<= 1;
    if (brightness > 0.5)
      pattern_data |= 1;
  }

  GST_DEBUG_OBJECT (videodetect, "have data %u", pattern_data);

  videodetect->in_pattern = TRUE;
  gst_video_detect_post_message (videodetect, buffer, pattern_data);

  return;

no_pattern:
  {
    GST_DEBUG_OBJECT (videodetect, "no pattern found");
    if (videodetect->in_pattern) {
      videodetect->in_pattern = FALSE;
      gst_video_detect_post_message (videodetect, buffer, 0);
    }
    return;
  }
}

static GstFlowReturn
gst_video_detect_transform_ip (GstBaseTransform * trans, GstBuffer * buf)
{
  GstVideoDetect *videodetect;
  GstFlowReturn ret = GST_FLOW_OK;

  videodetect = GST_VIDEO_DETECT (trans);

  gst_video_detect_420 (videodetect, buf);

  return ret;
}

static void
gst_video_detect_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec)
{
  GstVideoDetect *videodetect;

  videodetect = GST_VIDEO_DETECT (object);

  switch (prop_id) {
    case PROP_MESSAGE:
      videodetect->message = g_value_get_boolean (value);
      break;
    case PROP_PATTERN_WIDTH:
      videodetect->pattern_width = g_value_get_int (value);
      break;
    case PROP_PATTERN_HEIGHT:
      videodetect->pattern_height = g_value_get_int (value);
      break;
    case PROP_PATTERN_COUNT:
      videodetect->pattern_count = g_value_get_int (value);
      break;
    case PROP_PATTERN_DATA_COUNT:
      videodetect->pattern_data_count = g_value_get_int (value);
      break;
    case PROP_PATTERN_SENSITIVITY:
      videodetect->pattern_sensitivity = g_value_get_double (value);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static void
gst_video_detect_get_property (GObject * object, guint prop_id, GValue * value,
    GParamSpec * pspec)
{
  GstVideoDetect *videodetect;

  videodetect = GST_VIDEO_DETECT (object);

  switch (prop_id) {
    case PROP_MESSAGE:
      g_value_set_boolean (value, videodetect->message);
      break;
    case PROP_PATTERN_WIDTH:
      g_value_set_int (value, videodetect->pattern_width);
      break;
    case PROP_PATTERN_HEIGHT:
      g_value_set_int (value, videodetect->pattern_height);
      break;
    case PROP_PATTERN_COUNT:
      g_value_set_int (value, videodetect->pattern_count);
      break;
    case PROP_PATTERN_DATA_COUNT:
      g_value_set_int (value, videodetect->pattern_data_count);
      break;
    case PROP_PATTERN_SENSITIVITY:
      g_value_set_double (value, videodetect->pattern_sensitivity);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static void
gst_video_detect_base_init (gpointer g_class)
{
  GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);

  gst_element_class_set_details (element_class, &video_detect_details);

  gst_element_class_add_pad_template (element_class,
      gst_static_pad_template_get (&gst_video_detect_sink_template));
  gst_element_class_add_pad_template (element_class,
      gst_static_pad_template_get (&gst_video_detect_src_template));
}

static void
gst_video_detect_class_init (gpointer klass, gpointer class_data)
{
  GObjectClass *gobject_class;
  GstBaseTransformClass *trans_class;

  gobject_class = (GObjectClass *) klass;
  trans_class = (GstBaseTransformClass *) klass;

  parent_class = g_type_class_peek_parent (klass);

  gobject_class->set_property = gst_video_detect_set_property;
  gobject_class->get_property = gst_video_detect_get_property;

  g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_MESSAGE,
      g_param_spec_boolean ("message", "Message",
          "Post statics messages",
          DEFAULT_MESSAGE, G_PARAM_READWRITE | G_PARAM_CONSTRUCT));
  g_object_class_install_property (gobject_class, PROP_PATTERN_WIDTH,
      g_param_spec_int ("pattern-width", "Pattern width",
          "The width of the pattern markers", 1, G_MAXINT,
          DEFAULT_PATTERN_WIDTH, G_PARAM_READWRITE | G_PARAM_CONSTRUCT));
  g_object_class_install_property (gobject_class, PROP_PATTERN_HEIGHT,
      g_param_spec_int ("pattern-height", "Pattern height",
          "The height of the pattern markers", 1, G_MAXINT,
          DEFAULT_PATTERN_HEIGHT, G_PARAM_READWRITE | G_PARAM_CONSTRUCT));
  g_object_class_install_property (gobject_class, PROP_PATTERN_COUNT,
      g_param_spec_int ("pattern-count", "Pattern count",
          "The number of pattern markers", 1, G_MAXINT,
          DEFAULT_PATTERN_COUNT, G_PARAM_READWRITE | G_PARAM_CONSTRUCT));
  g_object_class_install_property (gobject_class, PROP_PATTERN_DATA_COUNT,
      g_param_spec_int ("pattern-data-count", "Pattern data count",
          "The number of extra data pattern markers", 0, G_MAXINT,
          DEFAULT_PATTERN_DATA_COUNT, G_PARAM_READWRITE | G_PARAM_CONSTRUCT));
  g_object_class_install_property (gobject_class, PROP_PATTERN_SENSITIVITY,
      g_param_spec_double ("pattern-sensitivity", "Pattern sensitivity",
          "The sensitivity for detecting the markers (0.0 = highest, 0.5 lowest)",
          0.0, 0.5, DEFAULT_PATTERN_SENSITIVITY,
          G_PARAM_READWRITE | G_PARAM_CONSTRUCT));

  trans_class->set_caps = GST_DEBUG_FUNCPTR (gst_video_detect_set_caps);
  trans_class->transform_ip = GST_DEBUG_FUNCPTR (gst_video_detect_transform_ip);
  trans_class->passthrough_on_same_caps = TRUE;

  GST_DEBUG_CATEGORY_INIT (video_detect_debug, "videodetect", 0,
      "Video detect");
}

static void
gst_video_detect_init (GTypeInstance * instance, gpointer g_class)
{
  GstVideoDetect *videodetect;

  videodetect = GST_VIDEO_DETECT (instance);

  GST_DEBUG_OBJECT (videodetect, "gst_video_detect_init");

  videodetect->in_pattern = FALSE;
}

GType
gst_video_detect_get_type (void)
{
  static GType video_detect_type = 0;

  if (!video_detect_type) {
    static const GTypeInfo video_detect_info = {
      sizeof (GstVideoDetectClass),
      gst_video_detect_base_init,
      NULL,
      gst_video_detect_class_init,
      NULL,
      NULL,
      sizeof (GstVideoDetect),
      0,
      gst_video_detect_init,
    };

    video_detect_type = g_type_register_static (GST_TYPE_VIDEO_FILTER,
        "GstVideoDetect", &video_detect_info, 0);
  }
  return video_detect_type;
}