기본예제1

#include <gst/gst.h>

int main(int argc, char *argv[]) {
    GstElement *pipeline;
    GstBus *bus;
    GstMessage *msg;

    /* Initialize GStreamer */
    gst_init (&argc, &argv);

    /* Build the pipeline */
    pipeline = gst_parse_launch ("playbin uri=https://www.freedesktop.org/software/gstreamer-sdk/data/media/sintel_trailer-480p.webm", NULL);

    /* Start playing */
    gst_element_set_state (pipeline, GST_STATE_PLAYING);

    /* Wait until error or EOS */
    bus = gst_element_get_bus (pipeline);
    msg = gst_bus_timed_pop_filtered (bus, GST_CLOCK_TIME_NONE, (GstMessageType)(GST_MESSAGE_ERROR | GST_MESSAGE_EOS));

    /* Free resources */
    if (msg != NULL)
        gst_message_unref (msg);
    gst_object_unref (bus);
    gst_element_set_state (pipeline, GST_STATE_NULL);
    gst_object_unref (pipeline);
    return 0;
}

#CC = arm-linux-gnueabihf-g++
CC = g++
CXXFLAGS = -std=c++14


TARGET = testpgr
TARGET_SRC = gstream.cpp
FLAGS = `pkg-config --cflags --libs gstreamer-1.0`

all : $(TARGET)

$(TARGET): $(TARGET_SRC)
        $(CC) $(CXXFLAGS) -o [email protected] -c $(TARGET_SRC) $(FLAGS)
        $(CC) $(CXXFLAGS) [email protected] -o $@ $(FLAGS)

clean:
    rm $(TARGET)

앞에서 다뤘던 GStreamer-tools 에 대한 내용을 코드로 간단히 짠 형태가 위와 같다.

명령어로 나타내면

gst-launch-1.0 playbin uri=https://www.freedesktop.org/software/gstreamer-sdk/data/media/sintel_trailer-480p.webm

기본예제 2

#include <gst/gst.h>

int main(int argc, char *argv[]) {
    GstElement *pipeline, *source, *sink;
    GstBus *bus;
    GstMessage *msg;
    GstStateChangeReturn ret;

    /* Initialize GStreamer */
    gst_init (&argc, &argv);

    /* Create the elements */
    source = gst_element_factory_make ("videotestsrc", "source");
    sink = gst_element_factory_make ("autovideosink", "sink");

    /* Create the empty pipeline */
    pipeline = gst_pipeline_new ("test-pipeline");

    if (!pipeline || !source || !sink) {
        g_printerr ("Not all elements could be created.\n");
        return -1;
    }

    /* Build the pipeline */
    gst_bin_add_many (GST_BIN (pipeline), source, sink, NULL);
    if (gst_element_link (source, sink) != TRUE) {
        g_printerr ("Elements could not be linked.\n");
        gst_object_unref (pipeline);
        return -1;
    }

    /* Modify the source's properties */
    g_object_set (source, "pattern", 0, NULL);

    /* Start playing */
    ret = gst_element_set_state (pipeline, GST_STATE_PLAYING);
    if (ret == GST_STATE_CHANGE_FAILURE) {
        g_printerr ("Unable to set the pipeline to the playing state.\n");
        gst_object_unref (pipeline);
        return -1;
    }

    /* Wait until error or EOS */
    bus = gst_element_get_bus (pipeline);
    msg = gst_bus_timed_pop_filtered (bus, GST_CLOCK_TIME_NONE, GST_MESSAGE_ERROR | GST_MESSAGE_EOS);

    /* Parse message */
    if (msg != NULL) {
        GError *err;
        gchar *debug_info;

        switch (GST_MESSAGE_TYPE (msg)) {
            case GST_MESSAGE_ERROR:
                gst_message_parse_error (msg, &err, &debug_info);
                g_printerr ("Error received from element %s: %s\n", GST_OBJECT_NAME (msg->src), err->message);
                g_printerr ("Debugging information: %s\n", debug_info ? debug_info : "none");
                g_clear_error (&err);
                g_free (debug_info);
                break;
            case GST_MESSAGE_EOS:
                g_print ("End-Of-Stream reached.\n");
                break;
            default:
                /* We should not reach here because we only asked for ERRORs and EOS */
                g_printerr ("Unexpected message received.\n");
                break;
        }
        gst_message_unref (msg);
    }

    /* Free resources */
    gst_object_unref (bus);
    gst_element_set_state (pipeline, GST_STATE_NULL);
    gst_object_unref (pipeline);
    return 0;
}

위 코드는 아래 명령어와 거의 동일하다.

gst-launch-1.0 videotestsrc ! autovideosink

코드에 property 지정하는 곳이 있는데 마찬가지로 하려면 videotestsrc pattern=0 을 쓰면 될 것이다.