new_pad_created (GstElement *parse, GstPad *pad, GstElement *pipeline)
{
GstElement *decode_video = NULL;
- GstElement *decode_audio, *play, *show;
+ GstElement *decode_audio, *play, *color, *show;
GstElement *audio_queue, *video_queue;
GstElement *audio_thread, *video_thread;
audio_queue = gst_element_factory_make ("queue", "audio_queue");
g_return_if_fail (audio_queue != NULL);
- gst_bin_add_many (GST_BIN (audio_thread), audio_queue, decode_audio, play, NULL);
+ gst_bin_add_many (GST_BIN (audio_thread),
+ audio_queue, decode_audio, play, NULL);
/* set up pad connections */
gst_element_add_ghost_pad (audio_thread,
decode_video = gst_element_factory_make ("mpeg2dec", "decode_video");
g_return_if_fail (decode_video != NULL);
+ color = gst_element_factory_make ("colorspace", "color");
+ g_return_if_fail (color != NULL);
+
+
show = gst_element_factory_make ("xvideosink", "show");
g_return_if_fail (show != NULL);
/* create the thread and pack stuff into it */
video_thread = gst_thread_new ("video_thread");
g_return_if_fail (video_thread != NULL);
- gst_bin_add_many (GST_BIN (video_thread), video_queue, decode_video, show, NULL);
+ gst_bin_add_many (GST_BIN (video_thread), video_queue,
+ decode_video, color, show, NULL);
/* set up pad connections */
gst_element_add_ghost_pad (video_thread,
gst_element_get_pad (video_queue, "sink"),
"sink");
gst_element_connect (video_queue, decode_video);
- gst_element_connect (decode_video, show);
+ gst_element_connect_many (decode_video, color, show, NULL);
gst_bin_add (GST_BIN (pipeline), video_thread);
<para>
We will create a second version of the helloworld application using
autoplugging. Its source code is a bit more complicated but
- it can handle many more data types.
+ it can handle many more data types. It can even play the audio track
+ of a video file.
</para>
<para>
- We start by creating the main() of our program:
+ Here is the full program listing. Start by looking at the main ()
+ function.
</para>
<programlisting>
-/* example-begin helloworld.c */
+/* example-begin helloworld2.c */
#include <gst/gst.h>
static void gst_play_have_type (GstElement *typefind, GstCaps *caps, GstElement *pipeline);
static void gst_play_cache_empty (GstElement *element, GstElement *pipeline);
+static void
+gst_play_have_type (GstElement *typefind, GstCaps *caps, GstElement *pipeline)
+{
+ GstElement *osssink;
+ GstElement *new_element;
+ GstAutoplug *autoplug;
+ GstElement *autobin;
+ GstElement *filesrc;
+ GstElement *cache;
+
+ GST_DEBUG (0,"GstPipeline: play have type");
+
+ gst_element_set_state (pipeline, GST_STATE_PAUSED);
+
+ filesrc = gst_bin_get_by_name (GST_BIN (pipeline), "disk_source");
+ autobin = gst_bin_get_by_name (GST_BIN (pipeline), "autobin");
+ cache = gst_bin_get_by_name (GST_BIN (autobin), "cache");
+
+ // disconnect the typefind from the pipeline and remove it
+ gst_element_disconnect (cache, typefind);
+ gst_bin_remove (GST_BIN (autobin), typefind);
+
+ /* and an audio sink */
+ osssink = gst_element_factory_make ("osssink", "play_audio");
+ g_assert(osssink != NULL);
+
+ autoplug = gst_autoplug_factory_make ("staticrender");
+ g_assert (autoplug != NULL);
+
+ new_element = gst_autoplug_to_renderers (autoplug, caps, osssink, NULL);
+
+ if (!new_element) {
+ g_print ("could not autoplug, no suitable codecs found...\n");
+ exit (-1);
+ }
+
+ gst_element_set_name (new_element, "new_element");
+
+ gst_bin_add (GST_BIN (autobin), new_element);
+
+ g_object_set (G_OBJECT (cache), "reset", TRUE, NULL);
+
+ gst_element_connect (cache, new_element);
+
+ gst_element_set_state (pipeline, GST_STATE_PLAYING);
+}
+
+static void
+gst_play_cache_empty (GstElement *element, GstElement *pipeline)
+{
+ GstElement *autobin;
+ GstElement *filesrc;
+ GstElement *cache;
+ GstElement *new_element;
+
+ fprintf (stderr, "have cache empty\n");
+
+ gst_element_set_state (pipeline, GST_STATE_PAUSED);
+
+ filesrc = gst_bin_get_by_name (GST_BIN (pipeline), "disk_source");
+ autobin = gst_bin_get_by_name (GST_BIN (pipeline), "autobin");
+ cache = gst_bin_get_by_name (GST_BIN (autobin), "cache");
+ new_element = gst_bin_get_by_name (GST_BIN (autobin), "new_element");
+
+ gst_element_disconnect (filesrc, cache);
+ gst_element_disconnect (cache, new_element);
+ gst_bin_remove (GST_BIN (autobin), cache);
+ gst_element_connect (filesrc, new_element);
+
+ gst_element_set_state (pipeline, GST_STATE_PLAYING);
+
+ fprintf (stderr, "done with cache_empty\n");
+}
+
int
main (int argc, char *argv[])
{
gst_bin_add (GST_BIN (autobin), cache);
gst_bin_add (GST_BIN (autobin), typefind);
- gst_element_connect (cache, "src", typefind, "sink");
- gst_element_add_ghost_pad (autobin, gst_element_get_pad (cache, "sink"), "sink");
+ gst_element_connect (cache, typefind);
+ gst_element_add_ghost_pad (autobin,
+ gst_element_get_pad (cache, "sink"), "sink");
gst_bin_add (GST_BIN( pipeline), autobin);
- gst_element_connect (filesrc, "src", autobin, "sink");
+ gst_element_connect (filesrc, autobin);
/* start playing */
gst_element_set_state( GST_ELEMENT (pipeline), GST_STATE_PLAYING);
exit(0);
}
-/* example-end helloworld.c */
+/* example-end helloworld2.c */
</programlisting>
<para>
We start by constructing a 'filesrc' element and an 'autobin' element that
</para>
<para>
We attach the "cache_empty" signal to gst_play_cache_empty and the
- "have_type" to our gst_play_have_type function (defined below).
+ "have_type" to our gst_play_have_type function.
</para>
- <programlisting>
-static void
-gst_play_have_type (GstElement *typefind, GstCaps *caps, GstElement *pipeline)
-{
- GstElement *osssink;
- GstElement *new_element;
- GstAutoplug *autoplug;
- GstElement *autobin;
- GstElement *filesrc;
- GstElement *cache;
-
- GST_DEBUG (0,"GstPipeline: play have type");
-
- gst_element_set_state (pipeline, GST_STATE_PAUSED);
-
- filesrc = gst_bin_get_by_name (GST_BIN (pipeline), "disk_source");
- autobin = gst_bin_get_by_name (GST_BIN (pipeline), "autobin");
- cache = gst_bin_get_by_name (GST_BIN (autobin), "cache");
-
- // disconnect the typefind from the pipeline and remove it
- gst_element_disconnect (cache, "src", typefind, "sink");
- gst_bin_remove (GST_BIN (autobin), typefind);
-
- /* and an audio sink */
- osssink = gst_element_factory_make("osssink", "play_audio");
- g_assert(osssink != NULL);
-
- autoplug = gst_autoplug_factory_make ("staticrender");
- g_assert (autoplug != NULL);
-
- new_element = gst_autoplug_to_renderers (autoplug,
- caps,
- osssink,
- NULL);
-
- if (!new_element) {
- g_print ("could not autoplug, no suitable codecs found...\n");
- exit (-1);
- }
-
- gst_element_set_name (new_element, "new_element");
-
- gst_bin_add (GST_BIN (autobin), new_element);
-
- g_object_set (G_OBJECT (cache), "reset", TRUE, NULL);
-
- gst_element_connect (cache, "src", new_element, "sink");
-
- gst_element_set_state (pipeline, GST_STATE_PLAYING);
-}
- </programlisting>
<para>
- The _have_type function first sets the pipeline to the PAUSED state so that
- it can safely modify the pipeline. It then finds the elements it is going to
- manipulate in the pipeline with:
+ The _have_type function first sets the pipeline to the PAUSED state
+ so that it can safely modify the pipeline. It then finds the elements
+ it is going to manipulate in the pipeline with:
</para>
<programlisting>
filesrc = gst_bin_get_by_name (GST_BIN (pipeline), "disk_source");
the next step.
</para>
<para>
- We don't need the typefind element anymore so we remove it from the pipeline:
+ We don't need the typefind element anymore so we remove it from
+ the pipeline:
</para>
<programlisting>
- // disconnect the typefind from the pipeline and remove it
+ /* disconnect the typefind from the pipeline and remove it */
gst_element_disconnect (cache, "src", typefind, "sink");
gst_bin_remove (GST_BIN (autobin), typefind);
</programlisting>
<para>
Finally we set the pipeline back to the playing state. At this point the
cache will replay the buffers. We will be notified when the cache is empty
- with the gst_play_cache_empty callback function:
+ by the gst_play_cache_empty callback function.
</para>
- <programlisting>
-static void
-gst_play_cache_empty (GstElement *element, GstElement *pipeline)
-{
- GstElement *autobin;
- GstElement *filesrc;
- GstElement *cache;
- GstElement *new_element;
-
- fprintf (stderr, "have cache empty\n");
-
- gst_element_set_state (pipeline, GST_STATE_PAUSED);
-
- filesrc = gst_bin_get_by_name (GST_BIN (pipeline), "disk_source");
- autobin = gst_bin_get_by_name (GST_BIN (pipeline), "autobin");
- cache = gst_bin_get_by_name (GST_BIN (autobin), "cache");
- new_element = gst_bin_get_by_name (GST_BIN (autobin), "new_element");
-
- gst_element_disconnect (filesrc, "src", cache, "sink");
- gst_element_disconnect (cache, "src", new_element, "sink");
- gst_bin_remove (GST_BIN (autobin), cache);
- gst_element_connect (filesrc, "src", new_element, "sink");
-
- gst_element_set_state (pipeline, GST_STATE_PLAYING);
-
- fprintf (stderr, "done with cache_empty\n");
-}
- </programlisting>
-
<para>
The cache empty function simply removes the autoplugcache element from
the pipeline and reconnects the filesrc to the autoplugged element.
To compile the helloworld2 example, use:
</para>
<programlisting>
- gcc -Wall `gstreamer-config --cflags --libs` helloworld2.c \
+ gcc -Wall `pkg-config gstreamer --cflags --libs` helloworld2.c \
-o helloworld2
</programlisting>
<para>
- You can run the example with (substitute helloworld.mp3 with you favorite MP3 file):
+ You can run the example with
+ (substitute helloworld.mp3 with you favorite audio file):
</para>
<programlisting>
./helloworld2 helloworld.mp3
</programlisting>
<para>
- You can also try to use an AVI or MPEG file as its input. Using autoplugging,
- <application>GStreamer</application> will automatically figure out how to
- handle the stream. Remember that only the audio part will be played because
+ You can also try to use an AVI or MPEG file as its input.
+ Using autoplugging,
+ <application>GStreamer</application>
+ will automatically figure out how to
+ handle the stream.
+ Remember that only the audio part will be played because
we have only added an osssink to the pipeline.
</para>
<programlisting>
projects / platform / upstream / gstreamer.git / commitdiff