DeepStream整理

#include <gst/gst.h>
 
int
main (int argc, char *argv[])
{
  GstElement *pipeline; //构建一个媒体管道的基本块,包含了各种element，如source,sink
  GstBus *bus;  //总线
  GstMessage *msg;  //总线消息
 
  /* Initialize GStreamer */
  gst_init (&argc, &argv); //初始化GStreamer
 
  /* Build the pipeline */
  /* playbin是一个element，它既是source，也是sink，能同时处理整个管道(pipeline)事务
     gst_parse_launch建立一个管道 */
  pipeline =
      gst_parse_launch
      ("playbin uri=https://www.freedesktop.org/software/gstreamer-sdk/data/media/sintel_trailer-480p.webm",
      NULL);
 
  /* Start playing */
  /* 每一个element都有一个状态，这里是播放这个element的流媒体
  gst_element_set_state (pipeline, GST_STATE_PLAYING);
 
  /* Wait until error or EOS */
  /* 获取通道element总线 */
  bus = gst_element_get_bus (pipeline);
  /* gst_bus_timed_pop_filtered会阻塞到遇到错误或者流媒体播放结束，并且得到一个消息 */
  msg =
      gst_bus_timed_pop_filtered (bus, GST_CLOCK_TIME_NONE,
      GST_MESSAGE_ERROR | GST_MESSAGE_EOS);
 
  /* Free resources */
  /* 释放资源 */
  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;
}

APP:= basic-tutorial-1

TARGET_DEVICE = $(shell gcc -dumpmachine | cut -f1 -d -)

NVDS_VERSION:=5.0

LIB_INSTALL_DIR?=/opt/nvidia/deepstream/deepstream-$(NVDS_VERSION)/lib/
APP_INSTALL_DIR?=/opt/nvidia/deepstream/deepstream-$(NVDS_VERSION)/bin/

ifeq ($(TARGET_DEVICE),aarch64)
  CFLAGS:= -DPLATFORM_TEGRA
endif

SRCS:= $(wildcard *.c)

INCS:= $(wildcard *.h)

PKGS:= gstreamer-1.0

OBJS:= $(SRCS:.c=.o)

CFLAGS+= -I../../../includes

CFLAGS+= `pkg-config --cflags $(PKGS)`

LIBS:= `pkg-config --libs $(PKGS)`

LIBS+= -L$(LIB_INSTALL_DIR) -lnvdsgst_meta -lnvds_meta \
       -Wl,-rpath,$(LIB_INSTALL_DIR)

all: $(APP)

%.o: %.c $(INCS) Makefile
	$(CC) -c -o $@ $(CFLAGS) $<

$(APP): $(OBJS) Makefile
	$(CC) -o $(APP) $(OBJS) $(LIBS)

install: $(APP)
	cp -rv $(APP) $(APP_INSTALL_DIR)

clean:
	rm -rf $(OBJS) $(APP)

make