使用videotestsrc, h264parse, openh264dec, autovideosink完成播放, c代码, 想想

以下是使用 GStreamer C 语言 API 实现播放的示例代码：

#include <gst/gst.h>

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

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

    /* Create the elements */
    source = gst_element_factory_make("videotestsrc", "source");
    parser = gst_element_factory_make("h264parse", "parser");
    decoder = gst_element_factory_make("openh264dec", "decoder");
    sink = gst_element_factory_make("autovideosink", "sink");

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

    /* Add the elements to the pipeline */
    gst_bin_add_many(GST_BIN(pipeline), source, parser, decoder, sink, NULL);

    /* Link the elements */
    gst_element_link_many(source, parser, decoder, sink, NULL);

    /* Set the pipeline to the playing state */
    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);

    /* 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;
}

这段代码使用 `videotestsrc` 作为视频源，`h264parse` 解析 H.264 格式的视频流，`openh264dec` 解码视频流，`autovideosink` 自动选择合适的视频输出设备进行播放。在代码中，我们创建了一个 GStreamer 管道，将这些元素连接起来，并将管道设置为播放状态。最后，我们等待管道发出错误或 EOS 事件，然后释放资源并退出程序。