diff options
Diffstat (limited to 'docs')
-rw-r--r-- | docs/manual/advanced-dataaccess.xml | 87 |
1 files changed, 86 insertions, 1 deletions
diff --git a/docs/manual/advanced-dataaccess.xml b/docs/manual/advanced-dataaccess.xml index 774f06782..28fc56ca3 100644 --- a/docs/manual/advanced-dataaccess.xml +++ b/docs/manual/advanced-dataaccess.xml @@ -1050,14 +1050,99 @@ main (int argc, char *argv[]) </para> <para> Below is an example of how you can change the caps of a pipeline - while in the PLAYING state. + while in the PLAYING state: </para> <programlisting> <!-- example-begin dynformat.c --> <![CDATA[ +#include <stdlib.h> + +#include <gst/gst.h> + +#define MAX_ROUND 100 + +int +main (int argc, char **argv) +{ + GstElement *pipe, *filter; + GstCaps *caps; + gint width, height; + gint xdir, ydir; + gint round; + GstMessage *message; + + gst_init (&argc, &argv); + + pipe = gst_parse_launch_full ("videotestsrc ! capsfilter name=filter ! " + "ximagesink", NULL, GST_PARSE_FLAG_NONE, NULL); + g_assert (pipe != NULL); + + filter = gst_bin_get_by_name (GST_BIN (pipe), "filter"); + g_assert (filter); + + width = 320; + height = 240; + xdir = ydir = -10; + + for (round = 0; round < MAX_ROUND; round++) { + gchar *capsstr; + g_print ("resize to %dx%d (%d/%d) \r", width, height, round, MAX_ROUND); + + /* we prefer our fixed width and height but allow other dimensions to pass + * as well */ + capsstr = g_strdup_printf ("video/x-raw, width=(int)%d, height=(int)%d", + width, height); + + caps = gst_caps_from_string (capsstr); + g_free (capsstr); + g_object_set (filter, "caps", caps, NULL); + gst_caps_unref (caps); + + if (round == 0) + gst_element_set_state (pipe, GST_STATE_PLAYING); + + width += xdir; + if (width >= 320) + xdir = -10; + else if (width < 200) + xdir = 10; + + height += ydir; + if (height >= 240) + ydir = -10; + else if (height < 150) + ydir = 10; + + message = + gst_bus_poll (GST_ELEMENT_BUS (pipe), GST_MESSAGE_ERROR, + 50 * GST_MSECOND); + if (message) { + g_print ("got error \n"); + + gst_message_unref (message); + } + } + g_print ("done \n"); + + gst_object_unref (filter); + gst_element_set_state (pipe, GST_STATE_NULL); + gst_object_unref (pipe); + + return 0; +} ]]> <!-- example-end dynformat.c --> </programlisting> + <para> + Note how we use <function>gst_bus_poll()</function> with a + small timeout to get messages and also introduce a short + sleep. + </para> + <para> + It is possible to set multiple caps for the capsfilter separated + with a ;. The capsfilter will try to renegotiate to the first + possible format from the list. + </para> </sect2> </sect1> |