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1 /* GStreamer snapshot example |
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2 * Copyright (C) <2007> Wim Taymans <wim.taymans@gmail.com> |
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3 * |
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4 * This library is free software; you can redistribute it and/or |
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5 * modify it under the terms of the GNU Library General Public |
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6 * License as published by the Free Software Foundation; either |
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7 * version 2 of the License, or (at your option) any later version. |
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8 * |
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9 * This library is distributed in the hope that it will be useful, |
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10 * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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12 * Library General Public License for more details. |
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13 * |
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14 * You should have received a copy of the GNU Library General Public |
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15 * License along with this library; if not, write to the |
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16 * Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
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17 * Boston, MA 02111-1307, USA. |
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18 */ |
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19 |
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20 #include <gst/gst.h> |
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21 #include <gtk/gtk.h> |
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22 |
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23 #include <stdlib.h> |
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24 |
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25 #define CAPS "video/x-raw-rgb,width=160,pixel-aspect-ratio=1/1,bpp=(int)24,depth=(int)24,endianness=(int)4321,red_mask=(int)0xff0000, green_mask=(int)0x00ff00, blue_mask=(int)0x0000ff" |
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26 |
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27 int |
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28 main (int argc, char *argv[]) |
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29 { |
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30 GstElement *pipeline, *sink; |
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31 gint width, height; |
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32 GstBuffer *buffer; |
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33 gchar *descr; |
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34 GError *error = NULL; |
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35 GdkPixbuf *pixbuf; |
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36 gint64 duration, position; |
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37 GstFormat format; |
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38 GstStateChangeReturn ret; |
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39 gboolean res; |
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40 |
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41 gst_init (&argc, &argv); |
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42 |
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43 if (argc != 2) { |
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44 g_print ("usage: %s <uri>\n Writes snapshot.png in the current directory", |
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45 argv[0]); |
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46 exit (-1); |
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47 } |
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48 |
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49 /* create a new pipeline */ |
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50 descr = |
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51 g_strdup_printf ("uridecodebin uri=%s ! ffmpegcolorspace ! videoscale ! " |
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52 " appsink name=sink caps=\"" CAPS "\"", argv[1]); |
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53 pipeline = gst_parse_launch (descr, &error); |
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54 |
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55 if (error != NULL) { |
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56 g_print ("could not construct pipeline: %s", error->message); |
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57 g_error_free (error); |
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58 exit (-1); |
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59 } |
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60 |
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61 /* get sink */ |
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62 sink = gst_bin_get_by_name (GST_BIN (pipeline), "sink"); |
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63 |
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64 /* set to PAUSED to make the first frame arrive in the sink */ |
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65 ret = gst_element_set_state (pipeline, GST_STATE_PAUSED); |
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66 switch (ret) { |
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67 case GST_STATE_CHANGE_FAILURE: |
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68 g_print ("failed to play the file\n"); |
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69 exit (-1); |
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70 case GST_STATE_CHANGE_NO_PREROLL: |
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71 /* for live sources, we need to set the pipeline to PLAYING before we can |
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72 * receive a buffer. We don't do that yet */ |
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73 g_print ("live sources not supported yet\n"); |
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74 exit (-1); |
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75 default: |
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76 break; |
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77 } |
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78 /* This can block for up to 5 seconds. If your machine is really overloaded, |
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79 * it might time out before the pipeline prerolled and we generate an error. A |
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80 * better way is to run a mainloop and catch errors there. */ |
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81 ret = gst_element_get_state (pipeline, NULL, NULL, 5 * GST_SECOND); |
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82 if (ret == GST_STATE_CHANGE_FAILURE) { |
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83 g_print ("failed to play the file\n"); |
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84 exit (-1); |
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85 } |
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86 |
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87 /* get the duration */ |
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88 format = GST_FORMAT_TIME; |
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89 gst_element_query_duration (pipeline, &format, &duration); |
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90 |
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91 if (duration != -1) |
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92 /* we have a duration, seek to 5% */ |
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93 position = duration * 5 / 100; |
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94 else |
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95 /* no duration, seek to 1 second, this could EOS */ |
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96 position = 1 * GST_SECOND; |
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97 |
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98 /* seek to the a position in the file. Most files have a black first frame so |
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99 * by seeking to somewhere else we have a bigger chance of getting something |
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100 * more interesting. An optimisation would be to detect black images and then |
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101 * seek a little more */ |
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102 gst_element_seek_simple (pipeline, GST_FORMAT_TIME, GST_SEEK_FLAG_FLUSH, |
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103 position); |
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104 |
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105 /* get the preroll buffer from appsink, this block untils appsink really |
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106 * prerolls */ |
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107 g_signal_emit_by_name (sink, "pull-preroll", &buffer, NULL); |
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108 |
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109 /* if we have a buffer now, convert it to a pixbuf. It's possible that we |
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110 * don't have a buffer because we went EOS right away or had an error. */ |
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111 if (buffer) { |
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112 GstCaps *caps; |
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113 GstStructure *s; |
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114 |
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115 /* get the snapshot buffer format now. We set the caps on the appsink so |
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116 * that it can only be an rgb buffer. The only thing we have not specified |
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117 * on the caps is the height, which is dependant on the pixel-aspect-ratio |
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118 * of the source material */ |
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119 caps = GST_BUFFER_CAPS (buffer); |
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120 if (!caps) { |
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121 g_print ("could not get snapshot format\n"); |
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122 exit (-1); |
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123 } |
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124 s = gst_caps_get_structure (caps, 0); |
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125 |
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126 /* we need to get the final caps on the buffer to get the size */ |
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127 res = gst_structure_get_int (s, "width", &width); |
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128 res |= gst_structure_get_int (s, "height", &height); |
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129 if (!res) { |
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130 g_print ("could not get snapshot dimension\n"); |
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131 exit (-1); |
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132 } |
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133 |
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134 /* create pixmap from buffer and save, gstreamer video buffers have a stride |
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135 * that is rounded up to the nearest multiple of 4 */ |
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136 pixbuf = gdk_pixbuf_new_from_data (GST_BUFFER_DATA (buffer), |
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137 GDK_COLORSPACE_RGB, FALSE, 8, width, height, |
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138 GST_ROUND_UP_4 (width * 3), NULL, NULL); |
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139 |
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140 /* save the pixbuf */ |
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141 gdk_pixbuf_save (pixbuf, "snapshot.png", "png", &error, NULL); |
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142 } else { |
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143 g_print ("could not make snapshot\n"); |
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144 } |
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145 |
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146 /* cleanup and exit */ |
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147 gst_element_set_state (pipeline, GST_STATE_NULL); |
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148 gst_object_unref (pipeline); |
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149 |
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150 exit (0); |
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151 } |