gstreamer/libs/gst/controller/gst-interpolation.c

/*
 * gst-interpolation.h
 * 
 * Interpolation methodws for dynamic properties
 */

#include "config.h"
#include "gst-controller.h"

#define GST_CAT_DEFAULT gst_controller_debug
GST_DEBUG_CATEGORY_EXTERN (GST_CAT_DEFAULT);

// common helper

/*
 * gst_controlled_property_find_timed_value_node:
 * @prop: the controlled property to search in
 * @timestamp: the search key
 *
 * Find last value before given timestamp in timed value list.
 *
 * Returns: the found #GList node or %NULL
 */
GList *
gst_controlled_property_find_timed_value_node (GstControlledProperty * prop,
    GstClockTime timestamp)
{
  //GList *prev_node = NULL;
  GList *prev_node = g_list_last (prop->values);
  GList *node;
  GstTimedValue *tv;

  /*
     if((prop->last_value) &&
     (timestamp>((GstTimedValue *)(prop->last_value->data))->timestamp)) {
     node=prop->last_value;
     }
     else {
     node=prop->values;
     }
   */

  /* iterate over timed value list */
  for (node = prop->values; node; node = g_list_next (node)) {
    tv = node->data;
    /* this timestamp is newer that the one we look for */
    if (timestamp < tv->timestamp) {
      /* get previous one again */
      prev_node = g_list_previous (node);
      break;
    }
  }
  /*
     if(node) {
     prop->last_value=prev_node;
     }
   */
  return (prev_node);
}

// steps-like (no-)interpolation, default
// just returns the value for the most recent key-frame

static GValue *
interpolate_none_get (GstControlledProperty * prop, GstClockTime timestamp)
{
  GList *node;

  if ((node = gst_controlled_property_find_timed_value_node (prop, timestamp))) {
    GstTimedValue *tv = node->data;

    return (&tv->value);
  }
  return (&prop->default_value);
}

#define DEFINE_NONE_GET(type) \
static gboolean \
interpolate_none_get_##type##_value_array (GstControlledProperty * prop, \
    GstClockTime timestamp, GstValueArray * value_array) \
{ \
  gint i; \
  GstClockTime ts=timestamp; \
  g##type *values=(g##type *)value_array->values; \
  \
  for(i=0;i<value_array->nbsamples;i++) { \
    *values=g_value_get_##type (interpolate_none_get (prop,ts)); \
    ts+=value_array->sample_interval; \
    values++; \
  } \
  return (TRUE); \
}

DEFINE_NONE_GET (int)
    DEFINE_NONE_GET (long)
DEFINE_NONE_GET (float)
DEFINE_NONE_GET (double)

     static GstInterpolateMethod interpolate_none = {
       interpolate_none_get,
       interpolate_none_get_int_value_array,
       interpolate_none_get,
       interpolate_none_get_long_value_array,
       interpolate_none_get,
       interpolate_none_get_float_value_array,
       interpolate_none_get,
       interpolate_none_get_double_value_array
     };

// returns the default value of the property, except for times with specific values
// needed for one-shot events, such as notes and triggers

static GValue *
interpolate_trigger_get (GstControlledProperty * prop, GstClockTime timestamp)
{
  GList *node;
  GstTimedValue *tv;

  /* check if there is a value at the registered timestamp */
  for (node = prop->values; node; node = g_list_next (node)) {
    tv = node->data;
    if (timestamp == tv->timestamp) {
      return (&tv->value);
    }
  }

  return (&prop->default_value);
}

static gboolean
interpolate_trigger_get_value_array (GstControlledProperty * prop,
    GstClockTime timestamp, GstValueArray * value_array)
{
  return (FALSE);
}

static GstInterpolateMethod interpolate_trigger = {
  interpolate_trigger_get,
  interpolate_trigger_get_value_array,
  interpolate_trigger_get,
  NULL,
  interpolate_trigger_get,
  NULL,
  interpolate_trigger_get,
  NULL
};

// linear interpolation
// smoothes inbetween values

#define DEFINE_LINEAR_GET(type) \
static g##type \
_interpolate_linear_get_##type (GstControlledProperty * prop, GstClockTime timestamp) \
{ \
  GList *node; \
  \
  if ((node = gst_controlled_property_find_timed_value_node (prop, timestamp))) { \
    GstTimedValue *tv1, *tv2; \
    \
    tv1 = node->data; \
    if ((node = g_list_next (node))) { \
      gdouble timediff,valuediff; \
      g##type value1,value2; \
      \
      tv2 = node->data; \
      \
      timediff = (gdouble)(tv2->timestamp - tv1->timestamp); \
      value1 = g_value_get_##type (&tv1->value); \
      value2 = g_value_get_##type (&tv2->value); \
      valuediff = (gdouble)(value2-value1); \
      \
      return((g##type)(value1+valuediff*((timestamp-tv1->timestamp)/timediff))); \
    } \
    else { \
      return (g_value_get_##type (&tv1->value)); \
    } \
  } \
  return (g_value_get_##type (&prop->default_value)); \
} \
\
static GValue * \
interpolate_linear_get_##type (GstControlledProperty * prop, GstClockTime timestamp) \
{ \
  g_value_set_##type (&prop->result_value,_interpolate_linear_get_##type (prop,timestamp)); \
  return (&prop->result_value); \
} \
\
static gboolean \
interpolate_linear_get_##type##_value_array (GstControlledProperty * prop, \
    GstClockTime timestamp, GstValueArray * value_array) \
{ \
  gint i; \
  GstClockTime ts=timestamp; \
  gint *values=(gint *)value_array->values; \
  \
  for(i=0;i<value_array->nbsamples;i++) { \
    *values=_interpolate_linear_get_##type (prop,ts); \
    ts+=value_array->sample_interval; \
    values++; \
  } \
  return (TRUE); \
}

DEFINE_LINEAR_GET (int)
DEFINE_LINEAR_GET (long)
DEFINE_LINEAR_GET (float)
DEFINE_LINEAR_GET (double)

     static GstInterpolateMethod interpolate_linear = {
       interpolate_linear_get_int,
       interpolate_linear_get_int_value_array,
       interpolate_linear_get_long,
       interpolate_linear_get_long_value_array,
       interpolate_linear_get_float,
       interpolate_linear_get_float_value_array,
       interpolate_linear_get_double,
       interpolate_linear_get_double_value_array,
     };

// square interpolation

// cubic interpolation

// register all interpolation methods
GstInterpolateMethod *interpolation_methods[] = {
  &interpolate_none,
  &interpolate_trigger,
  &interpolate_linear,
  NULL,
  NULL
};