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iamlow/dynamic_changing_element.c

Created August 1, 2018 03:43
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dynamic_changing_element.c
/*
* dynamic_changing_element
*/
#include <gst/gst.h>
static gchar *opt_effects = NULL;
#define DEFAULT_EFFECTS "identity,exclusion,navigationtest," \
"agingtv,videoflip,vertigotv,gaussianblur,shagadelictv,edgetv"
static GstPad *blockpad;
static GstElement *conv_before;
static GstElement *conv_after;
static GstElement *cur_effect;
static GstElement *pipeline;
static GQueue effects = G_QUEUE_INIT;
static GstPadProbeReturn
event_probe_cb (GstPad * pad, GstPadProbeInfo * info, gpointer user_data)
{
GMainLoop *loop = user_data;
GstElement *next;
if (GST_EVENT_TYPE (GST_PAD_PROBE_INFO_DATA (info)) != GST_EVENT_EOS)
return GST_PAD_PROBE_PASS;
gst_pad_remove_probe (pad, GST_PAD_PROBE_INFO_ID (info));
/* push current effect back into the queue */
g_queue_push_tail (&effects, gst_object_ref (cur_effect));
/* take next effect from the queue */
next = g_queue_pop_head (&effects);
if (next == NULL) {
GST_DEBUG_OBJECT (pad, "no more effects");
g_main_loop_quit (loop);
return GST_PAD_PROBE_DROP;
}
g_print ("Switching from '%s' to '%s'..\n", GST_OBJECT_NAME (cur_effect),
GST_OBJECT_NAME (next));
gst_element_set_state (cur_effect, GST_STATE_NULL);
/* remove unlinks automatically */
GST_DEBUG_OBJECT (pipeline, "removing %" GST_PTR_FORMAT, cur_effect);
gst_bin_remove (GST_BIN (pipeline), cur_effect);
GST_DEBUG_OBJECT (pipeline, "adding %" GST_PTR_FORMAT, next);
gst_bin_add (GST_BIN (pipeline), next);
GST_DEBUG_OBJECT (pipeline, "linking..");
gst_element_link_many (conv_before, next, conv_after, NULL);
gst_element_set_state (next, GST_STATE_PLAYING);
cur_effect = next;
GST_DEBUG_OBJECT (pipeline, "done");
return GST_PAD_PROBE_DROP;
}
static GstPadProbeReturn
pad_probe_cb (GstPad * pad, GstPadProbeInfo * info, gpointer user_data)
{
GstPad *srcpad, *sinkpad;
GST_DEBUG_OBJECT (pad, "pad is blocked now");
/* remove the probe first */
gst_pad_remove_probe (pad, GST_PAD_PROBE_INFO_ID (info));
/* install new probe for EOS */
srcpad = gst_element_get_static_pad (cur_effect, "src");
gst_pad_add_probe (srcpad, GST_PAD_PROBE_TYPE_BLOCK |
GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM, event_probe_cb, user_data, NULL);
gst_object_unref (srcpad);
/* push EOS into the element, the probe will be fired when the
* EOS leaves the effect and it has thus drained all of its data */
sinkpad = gst_element_get_static_pad (cur_effect, "sink");
gst_pad_send_event (sinkpad, gst_event_new_eos ());
gst_object_unref (sinkpad);
return GST_PAD_PROBE_OK;
}
static gboolean
timeout_cb (gpointer user_data)
{
gst_pad_add_probe (blockpad, GST_PAD_PROBE_TYPE_BLOCK_DOWNSTREAM,
pad_probe_cb, user_data, NULL);
return TRUE;
}
static gboolean
bus_cb (GstBus * bus, GstMessage * msg, gpointer user_data)
{
GMainLoop *loop = user_data;
switch (GST_MESSAGE_TYPE (msg)) {
case GST_MESSAGE_ERROR:{
GError *err = NULL;
gchar *dbg;
gst_message_parse_error (msg, &err, &dbg);
gst_object_default_error (msg->src, err, dbg);
g_clear_error (&err);
g_free (dbg);
g_main_loop_quit (loop);
break;
}
default:
break;
}
return TRUE;
}
int
main (int argc, char **argv)
{
GOptionEntry options[] = {
{"effects", 'e', 0, G_OPTION_ARG_STRING, &opt_effects,
"Effects to use (comma-separated list of element names)", NULL},
{NULL}
};
GOptionContext *ctx;
GError *err = NULL;
GMainLoop *loop;
GstElement *src, *q1, *q2, *effect, *filter1, *filter2, *sink;
gchar **effect_names, **e;
ctx = g_option_context_new ("");
g_option_context_add_main_entries (ctx, options, NULL);
g_option_context_add_group (ctx, gst_init_get_option_group ());
if (!g_option_context_parse (ctx, &argc, &argv, &err)) {
g_print ("Error initializing: %s\n", err->message);
g_clear_error (err);
g_option_context_free (ctx);
return 1;
}
g_option_context_free (ctx);
if (opt_effects != NULL)
effect_names = g_strsplit (opt_effects, ",", -1);
else
effect_names = g_strsplit (DEFAULT_EFFECTS, ",", -1);
for (e = effect_names; e != NULL && *e != NULL; ++e) {
GstElement *el;
el = gst_element_factory_make (*e, NULL);
if (el) {
g_print ("Adding effect '%s'\n", *e);
g_queue_push_tail (&effects, el);
}
}
pipeline = gst_pipeline_new ("pipeline");
src = gst_element_factory_make ("videotestsrc", NULL);
g_object_set (src, "is-live", TRUE, NULL);
filter1 = gst_element_factory_make ("capsfilter", NULL);
gst_util_set_object_arg (G_OBJECT (filter1), "caps",
"video/x-raw, width=320, height=240, "
"format={ I420, YV12, YUY2, UYVY, AYUV, Y41B, Y42B, "
"YVYU, Y444, v210, v216, NV12, NV21, UYVP, A420, YUV9, YVU9, IYU1 }");
q1 = gst_element_factory_make ("queue", NULL);
blockpad = gst_element_get_static_pad (q1, "src");
conv_before = gst_element_factory_make ("videoconvert", NULL);
effect = g_queue_pop_head (&effects);
cur_effect = effect;
conv_after = gst_element_factory_make ("videoconvert", NULL);
q2 = gst_element_factory_make ("queue", NULL);
filter2 = gst_element_factory_make ("capsfilter", NULL);
gst_util_set_object_arg (G_OBJECT (filter2), "caps",
"video/x-raw, width=320, height=240, "
"format={ RGBx, BGRx, xRGB, xBGR, RGBA, BGRA, ARGB, ABGR, RGB, BGR }");
sink = gst_element_factory_make ("nvoverlaysink", NULL);
gst_bin_add_many (GST_BIN (pipeline), src, filter1, q1, conv_before, effect,
conv_after, q2, sink, NULL);
gst_element_link_many (src, filter1, q1, conv_before, effect, conv_after,
q2, sink, NULL);
gst_element_set_state (pipeline, GST_STATE_PLAYING);
loop = g_main_loop_new (NULL, FALSE);
gst_bus_add_watch (GST_ELEMENT_BUS (pipeline), bus_cb, loop);
g_timeout_add_seconds (1, timeout_cb, loop);
g_main_loop_run (loop);
gst_element_set_state (pipeline, GST_STATE_NULL);
gst_object_unref (pipeline);
return 0;
}
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