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1 /* GStreamer |
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2 * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu> |
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3 * Copyright (C) <2005> Tim-Philipp Müller <tim@centricular.net> |
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4 * |
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5 * This library is free software; you can redistribute it and/or |
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6 * modify it under the terms of the GNU Library General Public |
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7 * License as published by the Free Software Foundation; either |
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8 * version 2 of the License, or (at your option) any later version. |
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9 * |
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10 * This library is distributed in the hope that it will be useful, |
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11 * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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13 * Library General Public License for more details. |
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14 * |
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15 * You should have received a copy of the GNU Library General Public |
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16 * License along with this library; if not, write to the |
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17 * Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
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18 * Boston, MA 02111-1307, USA. |
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19 */ |
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20 |
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21 /** |
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22 * SECTION:element-timeoverlay |
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23 * @see_also: #GstTextOverlay, #GstClockOverlay |
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24 * |
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25 * <refsect2> |
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26 * <para> |
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27 * This element overlays the buffer time stamps of a video stream on |
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28 * top of itself. You can position the text and configure the font details |
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29 * using the properties of the #GstTextOverlay class. By default, the |
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30 * time stamp is displayed in the top left corner of the picture, with some |
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31 * padding to the left and to the top. |
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32 * </para> |
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33 * <para> |
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34 * Here is a simple pipeline that displays the time stamps in the top left |
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35 * corner of the video picture: |
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36 * <programlisting> |
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37 * gst-launch -v videotestsrc ! timeoverlay ! xvimagesink |
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38 * </programlisting> |
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39 * </para> |
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40 * <para> |
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41 * Here is another pipeline that displays the time stamps with some leading |
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42 * text in the bottom right corner of the video picture, with the background |
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43 * of the text being shaded in order to make it more legible on top of a |
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44 * bright video background: |
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45 * <programlisting> |
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46 * gst-launch -v videotestsrc ! timeoverlay halign=right valign=bottom text="Stream time:" shaded-background=true ! xvimagesink |
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47 * </programlisting> |
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48 * </para> |
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49 * </refsect2> |
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50 */ |
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51 |
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52 #ifdef HAVE_CONFIG_H |
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53 #include "config.h" |
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54 #endif |
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55 |
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56 #include <gst/video/video.h> |
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57 |
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58 #include <gsttimeoverlay.h> |
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59 |
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60 static const GstElementDetails time_overlay_details = |
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61 GST_ELEMENT_DETAILS ("Time overlay", |
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62 "Filter/Editor/Video", |
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63 "Overlays buffer time stamps on a video stream", |
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64 "Tim-Philipp Müller <tim@centricular.net>"); |
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65 |
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66 GST_BOILERPLATE (GstTimeOverlay, gst_time_overlay, GstTextOverlay, |
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67 GST_TYPE_TEXT_OVERLAY) |
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68 |
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69 static void gst_time_overlay_base_init (gpointer g_class) |
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70 { |
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71 GstElementClass *element_class = GST_ELEMENT_CLASS (g_class); |
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72 |
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73 gst_element_class_set_details (element_class, &time_overlay_details); |
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74 } |
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75 |
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76 static gchar * |
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77 gst_time_overlay_render_time (GstTimeOverlay * overlay, GstClockTime time) |
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78 { |
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79 guint hours, mins, secs, msecs; |
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80 |
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81 if (!GST_CLOCK_TIME_IS_VALID (time)) |
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82 return g_strdup (""); |
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83 |
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84 hours = (guint) (time / (GST_SECOND * 60 * 60)); |
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85 mins = (guint) ((time / (GST_SECOND * 60)) % 60); |
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86 secs = (guint) ((time / GST_SECOND) % 60); |
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87 msecs = (guint) ((time % GST_SECOND) / (1000 * 1000)); |
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88 |
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89 return g_strdup_printf ("%u:%02u:%02u.%03u", hours, mins, secs, msecs); |
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90 } |
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91 |
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92 /* Called with lock held */ |
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93 static gchar * |
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94 gst_time_overlay_get_text (GstTextOverlay * overlay, GstBuffer * video_frame) |
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95 { |
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96 GstClockTime time = GST_BUFFER_TIMESTAMP (video_frame); |
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97 gchar *time_str, *txt, *ret; |
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98 |
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99 overlay->need_render = TRUE; |
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100 |
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101 if (!GST_CLOCK_TIME_IS_VALID (time)) { |
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102 GST_DEBUG ("buffer without valid timestamp"); |
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103 return g_strdup (""); |
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104 } |
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105 |
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106 GST_DEBUG ("buffer with timestamp %" GST_TIME_FORMAT, GST_TIME_ARGS (time)); |
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107 |
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108 txt = g_strdup (overlay->default_text); |
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109 |
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110 time_str = gst_time_overlay_render_time (GST_TIME_OVERLAY (overlay), time); |
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111 if (txt != NULL && *txt != '\0') { |
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112 ret = g_strdup_printf ("%s %s", txt, time_str); |
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113 } else { |
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114 ret = time_str; |
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115 time_str = NULL; |
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116 } |
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117 |
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118 g_free (txt); |
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119 g_free (time_str); |
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120 |
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121 return ret; |
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122 } |
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123 |
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124 static void |
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125 gst_time_overlay_class_init (GstTimeOverlayClass * klass) |
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126 { |
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127 GstTextOverlayClass *gsttextoverlay_class; |
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128 |
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129 gsttextoverlay_class = (GstTextOverlayClass *) klass; |
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130 |
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131 gsttextoverlay_class->get_text = gst_time_overlay_get_text; |
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132 } |
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133 |
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134 static void |
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135 gst_time_overlay_init (GstTimeOverlay * overlay, GstTimeOverlayClass * klass) |
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136 { |
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137 PangoFontDescription *font_description; |
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138 GstTextOverlay *textoverlay; |
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139 PangoContext *context; |
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140 |
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141 textoverlay = GST_TEXT_OVERLAY (overlay); |
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142 |
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143 context = GST_TEXT_OVERLAY_CLASS (klass)->pango_context; |
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144 |
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145 pango_context_set_language (context, pango_language_from_string ("en_US")); |
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146 pango_context_set_base_dir (context, PANGO_DIRECTION_LTR); |
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147 |
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148 font_description = pango_font_description_new (); |
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149 pango_font_description_set_family_static (font_description, "Monospace"); |
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150 pango_font_description_set_style (font_description, PANGO_STYLE_NORMAL); |
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151 pango_font_description_set_variant (font_description, PANGO_VARIANT_NORMAL); |
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152 pango_font_description_set_weight (font_description, PANGO_WEIGHT_NORMAL); |
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153 pango_font_description_set_stretch (font_description, PANGO_STRETCH_NORMAL); |
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154 pango_font_description_set_size (font_description, 18 * PANGO_SCALE); |
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155 pango_context_set_font_description (context, font_description); |
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156 pango_font_description_free (font_description); |
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157 |
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158 textoverlay->valign = GST_TEXT_OVERLAY_VALIGN_TOP; |
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159 textoverlay->halign = GST_TEXT_OVERLAY_HALIGN_LEFT; |
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160 } |