mirror of
https://gitlab.freedesktop.org/gstreamer/gstreamer.git
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updates
Original commit message from CVS: updates
This commit is contained in:
Thomas Vander Stichele
parent
a70416bcd8
commit
9150369f92
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@ -242,12 +242,14 @@ main (int argc, char *argv[])
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-o helloworld
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</programlisting>
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<para>
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We use pkg-config to get the compiler flags needed to compile this application.
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make sure to have your PKG_CONFIG_PATH environment variable set to the correct
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location if you are building this application against the uninstalled location.
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We use pkg-config to get the compiler flags needed to compile
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this application. Make sure to have your PKG_CONFIG_PATH environment
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variable set to the correct location if you are building this
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application against the uninstalled location.
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</para>
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<para>
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You can run the example with (substitute helloworld.mp3 with you favorite MP3 file):
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You can run the example with
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(substitute helloworld.mp3 with you favorite MP3 file):
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</para>
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<programlisting>
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./helloworld helloworld.mp3
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@ -41,7 +41,7 @@ void
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new_pad_created (GstElement *parse, GstPad *pad, GstElement *pipeline)
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{
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GstElement *decode_video = NULL;
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GstElement *decode_audio, *play, *show;
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GstElement *decode_audio, *play, *color, *show;
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GstElement *audio_queue, *video_queue;
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GstElement *audio_thread, *video_thread;
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@ -66,7 +66,8 @@ new_pad_created (GstElement *parse, GstPad *pad, GstElement *pipeline)
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audio_queue = gst_element_factory_make ("queue", "audio_queue");
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g_return_if_fail (audio_queue != NULL);
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gst_bin_add_many (GST_BIN (audio_thread), audio_queue, decode_audio, play, NULL);
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gst_bin_add_many (GST_BIN (audio_thread),
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audio_queue, decode_audio, play, NULL);
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/* set up pad connections */
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gst_element_add_ghost_pad (audio_thread,
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@ -90,6 +91,10 @@ new_pad_created (GstElement *parse, GstPad *pad, GstElement *pipeline)
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decode_video = gst_element_factory_make ("mpeg2dec", "decode_video");
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g_return_if_fail (decode_video != NULL);
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color = gst_element_factory_make ("colorspace", "color");
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g_return_if_fail (color != NULL);
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show = gst_element_factory_make ("xvideosink", "show");
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g_return_if_fail (show != NULL);
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@ -100,14 +105,15 @@ new_pad_created (GstElement *parse, GstPad *pad, GstElement *pipeline)
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/* create the thread and pack stuff into it */
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video_thread = gst_thread_new ("video_thread");
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g_return_if_fail (video_thread != NULL);
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gst_bin_add_many (GST_BIN (video_thread), video_queue, decode_video, show, NULL);
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gst_bin_add_many (GST_BIN (video_thread), video_queue,
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decode_video, color, show, NULL);
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/* set up pad connections */
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gst_element_add_ghost_pad (video_thread,
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gst_element_get_pad (video_queue, "sink"),
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"sink");
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gst_element_connect (video_queue, decode_video);
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gst_element_connect (decode_video, show);
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gst_element_connect_many (decode_video, color, show, NULL);
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gst_bin_add (GST_BIN (pipeline), video_thread);
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@ -242,12 +242,14 @@ main (int argc, char *argv[])
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-o helloworld
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</programlisting>
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<para>
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We use pkg-config to get the compiler flags needed to compile this application.
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make sure to have your PKG_CONFIG_PATH environment variable set to the correct
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location if you are building this application against the uninstalled location.
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We use pkg-config to get the compiler flags needed to compile
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this application. Make sure to have your PKG_CONFIG_PATH environment
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variable set to the correct location if you are building this
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application against the uninstalled location.
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</para>
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<para>
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You can run the example with (substitute helloworld.mp3 with you favorite MP3 file):
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You can run the example with
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(substitute helloworld.mp3 with you favorite MP3 file):
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</para>
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<programlisting>
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./helloworld helloworld.mp3
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@ -11,19 +11,95 @@
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<para>
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We will create a second version of the helloworld application using
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autoplugging. Its source code is a bit more complicated but
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it can handle many more data types.
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it can handle many more data types. It can even play the audio track
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of a video file.
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</para>
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<para>
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We start by creating the main() of our program:
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Here is the full program listing. Start by looking at the main ()
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function.
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</para>
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<programlisting>
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/* example-begin helloworld.c */
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/* example-begin helloworld2.c */
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#include <gst/gst.h>
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static void gst_play_have_type (GstElement *typefind, GstCaps *caps, GstElement *pipeline);
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static void gst_play_cache_empty (GstElement *element, GstElement *pipeline);
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static void
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gst_play_have_type (GstElement *typefind, GstCaps *caps, GstElement *pipeline)
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{
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GstElement *osssink;
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GstElement *new_element;
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GstAutoplug *autoplug;
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GstElement *autobin;
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GstElement *filesrc;
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GstElement *cache;
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GST_DEBUG (0,"GstPipeline: play have type");
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gst_element_set_state (pipeline, GST_STATE_PAUSED);
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filesrc = gst_bin_get_by_name (GST_BIN (pipeline), "disk_source");
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autobin = gst_bin_get_by_name (GST_BIN (pipeline), "autobin");
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cache = gst_bin_get_by_name (GST_BIN (autobin), "cache");
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// disconnect the typefind from the pipeline and remove it
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gst_element_disconnect (cache, typefind);
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gst_bin_remove (GST_BIN (autobin), typefind);
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/* and an audio sink */
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osssink = gst_element_factory_make ("osssink", "play_audio");
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g_assert(osssink != NULL);
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autoplug = gst_autoplug_factory_make ("staticrender");
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g_assert (autoplug != NULL);
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new_element = gst_autoplug_to_renderers (autoplug, caps, osssink, NULL);
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if (!new_element) {
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g_print ("could not autoplug, no suitable codecs found...\n");
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exit (-1);
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}
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gst_element_set_name (new_element, "new_element");
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gst_bin_add (GST_BIN (autobin), new_element);
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g_object_set (G_OBJECT (cache), "reset", TRUE, NULL);
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gst_element_connect (cache, new_element);
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gst_element_set_state (pipeline, GST_STATE_PLAYING);
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}
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static void
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gst_play_cache_empty (GstElement *element, GstElement *pipeline)
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{
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GstElement *autobin;
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GstElement *filesrc;
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GstElement *cache;
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GstElement *new_element;
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fprintf (stderr, "have cache empty\n");
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gst_element_set_state (pipeline, GST_STATE_PAUSED);
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filesrc = gst_bin_get_by_name (GST_BIN (pipeline), "disk_source");
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autobin = gst_bin_get_by_name (GST_BIN (pipeline), "autobin");
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cache = gst_bin_get_by_name (GST_BIN (autobin), "cache");
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new_element = gst_bin_get_by_name (GST_BIN (autobin), "new_element");
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gst_element_disconnect (filesrc, cache);
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gst_element_disconnect (cache, new_element);
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gst_bin_remove (GST_BIN (autobin), cache);
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gst_element_connect (filesrc, new_element);
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gst_element_set_state (pipeline, GST_STATE_PLAYING);
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fprintf (stderr, "done with cache_empty\n");
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}
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int
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main (int argc, char *argv[])
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{
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@ -61,11 +137,12 @@ main (int argc, char *argv[])
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gst_bin_add (GST_BIN (autobin), cache);
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gst_bin_add (GST_BIN (autobin), typefind);
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gst_element_connect (cache, "src", typefind, "sink");
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gst_element_add_ghost_pad (autobin, gst_element_get_pad (cache, "sink"), "sink");
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gst_element_connect (cache, typefind);
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gst_element_add_ghost_pad (autobin,
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gst_element_get_pad (cache, "sink"), "sink");
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gst_bin_add (GST_BIN( pipeline), autobin);
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gst_element_connect (filesrc, "src", autobin, "sink");
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gst_element_connect (filesrc, autobin);
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/* start playing */
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gst_element_set_state( GST_ELEMENT (pipeline), GST_STATE_PLAYING);
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@ -79,7 +156,7 @@ main (int argc, char *argv[])
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exit(0);
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}
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/* example-end helloworld.c */
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/* example-end helloworld2.c */
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</programlisting>
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<para>
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We start by constructing a 'filesrc' element and an 'autobin' element that
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@ -87,64 +164,13 @@ main (int argc, char *argv[])
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</para>
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<para>
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We attach the "cache_empty" signal to gst_play_cache_empty and the
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"have_type" to our gst_play_have_type function (defined below).
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"have_type" to our gst_play_have_type function.
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</para>
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<programlisting>
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static void
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gst_play_have_type (GstElement *typefind, GstCaps *caps, GstElement *pipeline)
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{
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GstElement *osssink;
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GstElement *new_element;
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GstAutoplug *autoplug;
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GstElement *autobin;
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GstElement *filesrc;
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GstElement *cache;
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GST_DEBUG (0,"GstPipeline: play have type");
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gst_element_set_state (pipeline, GST_STATE_PAUSED);
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filesrc = gst_bin_get_by_name (GST_BIN (pipeline), "disk_source");
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autobin = gst_bin_get_by_name (GST_BIN (pipeline), "autobin");
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cache = gst_bin_get_by_name (GST_BIN (autobin), "cache");
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// disconnect the typefind from the pipeline and remove it
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gst_element_disconnect (cache, "src", typefind, "sink");
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gst_bin_remove (GST_BIN (autobin), typefind);
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/* and an audio sink */
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osssink = gst_element_factory_make("osssink", "play_audio");
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g_assert(osssink != NULL);
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autoplug = gst_autoplug_factory_make ("staticrender");
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g_assert (autoplug != NULL);
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new_element = gst_autoplug_to_renderers (autoplug,
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caps,
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osssink,
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NULL);
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if (!new_element) {
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g_print ("could not autoplug, no suitable codecs found...\n");
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exit (-1);
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}
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gst_element_set_name (new_element, "new_element");
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gst_bin_add (GST_BIN (autobin), new_element);
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g_object_set (G_OBJECT (cache), "reset", TRUE, NULL);
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gst_element_connect (cache, "src", new_element, "sink");
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gst_element_set_state (pipeline, GST_STATE_PLAYING);
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}
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</programlisting>
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<para>
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The _have_type function first sets the pipeline to the PAUSED state so that
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it can safely modify the pipeline. It then finds the elements it is going to
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manipulate in the pipeline with:
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The _have_type function first sets the pipeline to the PAUSED state
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so that it can safely modify the pipeline. It then finds the elements
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it is going to manipulate in the pipeline with:
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</para>
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<programlisting>
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filesrc = gst_bin_get_by_name (GST_BIN (pipeline), "disk_source");
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@ -157,10 +183,11 @@ gst_play_have_type (GstElement *typefind, GstCaps *caps, GstElement *pipeline)
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the next step.
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</para>
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<para>
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We don't need the typefind element anymore so we remove it from the pipeline:
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We don't need the typefind element anymore so we remove it from
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the pipeline:
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</para>
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<programlisting>
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// disconnect the typefind from the pipeline and remove it
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/* disconnect the typefind from the pipeline and remove it */
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gst_element_disconnect (cache, "src", typefind, "sink");
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gst_bin_remove (GST_BIN (autobin), typefind);
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</programlisting>
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@ -208,38 +235,9 @@ gst_play_have_type (GstElement *typefind, GstCaps *caps, GstElement *pipeline)
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<para>
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Finally we set the pipeline back to the playing state. At this point the
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cache will replay the buffers. We will be notified when the cache is empty
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with the gst_play_cache_empty callback function:
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by the gst_play_cache_empty callback function.
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</para>
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<programlisting>
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static void
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gst_play_cache_empty (GstElement *element, GstElement *pipeline)
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{
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GstElement *autobin;
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GstElement *filesrc;
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GstElement *cache;
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GstElement *new_element;
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fprintf (stderr, "have cache empty\n");
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gst_element_set_state (pipeline, GST_STATE_PAUSED);
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filesrc = gst_bin_get_by_name (GST_BIN (pipeline), "disk_source");
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autobin = gst_bin_get_by_name (GST_BIN (pipeline), "autobin");
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cache = gst_bin_get_by_name (GST_BIN (autobin), "cache");
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new_element = gst_bin_get_by_name (GST_BIN (autobin), "new_element");
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gst_element_disconnect (filesrc, "src", cache, "sink");
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gst_element_disconnect (cache, "src", new_element, "sink");
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gst_bin_remove (GST_BIN (autobin), cache);
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gst_element_connect (filesrc, "src", new_element, "sink");
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gst_element_set_state (pipeline, GST_STATE_PLAYING);
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fprintf (stderr, "done with cache_empty\n");
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}
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</programlisting>
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<para>
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The cache empty function simply removes the autoplugcache element from
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the pipeline and reconnects the filesrc to the autoplugged element.
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@ -249,19 +247,23 @@ gst_play_cache_empty (GstElement *element, GstElement *pipeline)
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To compile the helloworld2 example, use:
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</para>
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<programlisting>
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gcc -Wall `gstreamer-config --cflags --libs` helloworld2.c \
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gcc -Wall `pkg-config gstreamer --cflags --libs` helloworld2.c \
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-o helloworld2
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</programlisting>
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<para>
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You can run the example with (substitute helloworld.mp3 with you favorite MP3 file):
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You can run the example with
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(substitute helloworld.mp3 with you favorite audio file):
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</para>
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<programlisting>
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./helloworld2 helloworld.mp3
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</programlisting>
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<para>
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You can also try to use an AVI or MPEG file as its input. Using autoplugging,
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<application>GStreamer</application> will automatically figure out how to
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handle the stream. Remember that only the audio part will be played because
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You can also try to use an AVI or MPEG file as its input.
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Using autoplugging,
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<application>GStreamer</application>
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will automatically figure out how to
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handle the stream.
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Remember that only the audio part will be played because
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we have only added an osssink to the pipeline.
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</para>
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<programlisting>
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