gstreamer/ext/pango/gstclockoverlay.c
Chris Shoemaker 6bd90dc0cc clockoverlay: only rerender text if time string has changed
The textoverlay element will rerender the text string whenever
overlay sets the 'need_render' flag to TRUE.  Previously, we
lazily set the flag to TRUE every time the time string was requested.
Now, we save a copy of the previously given string, and only set
'need_render' to TRUE if the string has changed.

In my tests with a 30fps video stream, and a time string including
a seconds field, this change reduced the CPU usage of the clockoverlay
element from 60% to 5%.

Fixes bug #627780.
2010-08-24 09:29:33 +02:00

246 lines
7.3 KiB
C

/* GStreamer
* Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
* Copyright (C) <2005> Tim-Philipp Müller <tim@centricular.net>
*
* 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-clockoverlay
* @see_also: #GstTextOverlay, #GstTimeOverlay
*
* This element overlays the current clock time on top of a video
* stream. You can position the text and configure the font details
* using the properties of the #GstTextOverlay class. By default, the
* time is displayed in the top left corner of the picture, with some
* padding to the left and to the top.
*
* <refsect2>
* <title>Example launch lines</title>
* |[
* gst-launch -v videotestsrc ! clockoverlay ! xvimagesink
* ]| Display the current time in the top left corner of the video picture
* |[
* gst-launch -v videotestsrc ! clockoverlay halign=right valign=bottom text="Edge City" shaded-background=true ! ffmpegcolorspace ! ximagesink
* ]| Another pipeline that displays the current time with some leading
* text in the bottom right corner of the video picture, with the background
* of the text being shaded in order to make it more legible on top of a
* bright video background.
* </refsect2>
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <gstclockoverlay.h>
#include <gst/video/video.h>
#include <time.h>
#define DEFAULT_PROP_TIMEFORMAT "%H:%M:%S"
enum
{
PROP_0,
PROP_TIMEFORMAT,
PROP_LAST
};
GST_BOILERPLATE (GstClockOverlay, gst_clock_overlay, GstTextOverlay,
GST_TYPE_TEXT_OVERLAY);
static void
gst_clock_overlay_base_init (gpointer g_class)
{
GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
gst_element_class_set_details_simple (element_class, "Clock overlay",
"Filter/Editor/Video",
"Overlays the current clock time on a video stream",
"Tim-Philipp Müller <tim@centricular.net>");
}
static void gst_clock_overlay_finalize (GObject * object);
static void gst_clock_overlay_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec);
static void gst_clock_overlay_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec);
static gchar *
gst_clock_overlay_render_time (GstClockOverlay * overlay)
{
struct tm *t;
time_t now;
gchar buf[256];
#ifdef HAVE_LOCALTIME_R
struct tm dummy;
#endif
now = time (NULL);
#ifdef HAVE_LOCALTIME_R
/* Need to call tzset explicitly when calling localtime_r for changes
to the timezone between calls to be visible. */
tzset ();
t = localtime_r (&now, &dummy);
#else
/* on win32 this apparently returns a per-thread struct which would be fine */
t = localtime (&now);
#endif
if (t == NULL)
return g_strdup ("--:--:--");
if (strftime (buf, sizeof (buf), overlay->format, t) == 0)
return g_strdup ("");
return g_strdup (buf);
}
/* Called with lock held */
static gchar *
gst_clock_overlay_get_text (GstTextOverlay * overlay, GstBuffer * video_frame)
{
gchar *time_str, *txt, *ret;
GstClockOverlay *clock_overlay = GST_CLOCK_OVERLAY (overlay);
txt = g_strdup (overlay->default_text);
time_str = gst_clock_overlay_render_time (clock_overlay);
if (txt != NULL && *txt != '\0') {
ret = g_strdup_printf ("%s %s", txt, time_str);
} else {
ret = time_str;
time_str = NULL;
}
if (g_strcmp0 (ret, clock_overlay->text)) {
overlay->need_render = TRUE;
g_free (clock_overlay->text);
clock_overlay->text = g_strdup (ret);
}
g_free (txt);
g_free (time_str);
return ret;
}
static void
gst_clock_overlay_class_init (GstClockOverlayClass * klass)
{
GObjectClass *gobject_class;
GstTextOverlayClass *gsttextoverlay_class;
gobject_class = (GObjectClass *) klass;
gsttextoverlay_class = (GstTextOverlayClass *) klass;
gobject_class->finalize = gst_clock_overlay_finalize;
gobject_class->set_property = gst_clock_overlay_set_property;
gobject_class->get_property = gst_clock_overlay_get_property;
gsttextoverlay_class->get_text = gst_clock_overlay_get_text;
g_object_class_install_property (gobject_class, PROP_TIMEFORMAT,
g_param_spec_string ("time-format", "Date/Time Format",
"Format to use for time and date value, as in strftime.",
DEFAULT_PROP_TIMEFORMAT, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
}
static void
gst_clock_overlay_finalize (GObject * object)
{
GstClockOverlay *overlay = GST_CLOCK_OVERLAY (object);
g_free (overlay->format);
g_free (overlay->text);
overlay->format = NULL;
G_OBJECT_CLASS (parent_class)->finalize (object);
}
static void
gst_clock_overlay_init (GstClockOverlay * overlay, GstClockOverlayClass * klass)
{
PangoFontDescription *font_description;
GstTextOverlay *textoverlay;
PangoContext *context;
textoverlay = GST_TEXT_OVERLAY (overlay);
context = GST_TEXT_OVERLAY_CLASS (klass)->pango_context;
pango_context_set_language (context, pango_language_from_string ("en_US"));
pango_context_set_base_dir (context, PANGO_DIRECTION_LTR);
font_description = pango_font_description_new ();
pango_font_description_set_family_static (font_description, "Monospace");
pango_font_description_set_style (font_description, PANGO_STYLE_NORMAL);
pango_font_description_set_variant (font_description, PANGO_VARIANT_NORMAL);
pango_font_description_set_weight (font_description, PANGO_WEIGHT_NORMAL);
pango_font_description_set_stretch (font_description, PANGO_STRETCH_NORMAL);
pango_font_description_set_size (font_description, 18 * PANGO_SCALE);
pango_context_set_font_description (context, font_description);
pango_font_description_free (font_description);
textoverlay->valign = GST_TEXT_OVERLAY_VALIGN_TOP;
textoverlay->halign = GST_TEXT_OVERLAY_HALIGN_LEFT;
overlay->format = g_strdup (DEFAULT_PROP_TIMEFORMAT);
}
static void
gst_clock_overlay_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec)
{
GstClockOverlay *overlay = GST_CLOCK_OVERLAY (object);
GST_OBJECT_LOCK (overlay);
switch (prop_id) {
case PROP_TIMEFORMAT:
g_free (overlay->format);
overlay->format = g_value_dup_string (value);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
GST_OBJECT_UNLOCK (overlay);
}
static void
gst_clock_overlay_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec)
{
GstClockOverlay *overlay = GST_CLOCK_OVERLAY (object);
GST_OBJECT_LOCK (overlay);
switch (prop_id) {
case PROP_TIMEFORMAT:
g_value_set_string (value, overlay->format);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
GST_OBJECT_UNLOCK (overlay);
}