Deepstream4.0的deepstream-test2程序运行和讲解
deepstream-test2程序注释
一、首先是运行这个程序：
拷贝sample_720p.h264到deepstream-test2
cd deepstream-test2/
make
./deepstream-test2-app sample_720p.h264
deepstream-test2相对deepstream-test1多了目标跟踪和分类。所以运行速度较慢。五个模型对视频的处理（目标跟踪模型以库的形式提供）。如下图：
运行效果如下图：
二、理解代码需要Gstreamer的知识，还需要C语言的基础
代码如下：
#include \n" , argv[0]);
return -1;
}
/* Standard GStreamer initialization */
gst_init (&argc, &argv);
loop = g_main_loop_new (NULL, FALSE);
/* Create gstreamer elements */
/* Create Pipeline element that will be a container of other elements */
pipeline = gst_pipeline_new ("dstest2-pipeline");
//通过gst_pipeline_new创建pipeline，参数为pipeline的名字。
/* Source element for reading from the file */
source = gst_element_factory_make ("filesrc", "file-source");
//创建一个element 类型是filesrc，名字是file-source。
//该element用于读取文件
/* Since the data format in the input file is elementary h264 stream,
* we need a h264parser */
h264parser = gst_element_factory_make ("h264parse", "h264-parser");
//创建一个element 类型是h264parse，名字是h264-parser。
//该element用于解析h264文件
/* Use nvdec_h264 for hardware accelerated decode on GPU */
decoder = gst_element_factory_make ("nvv4l2decoder", "nvv4l2-decoder");
//该element用于调用GPU硬件加速解码h264文件
/* Create nvstreammux instance to form batches from one or more sources. */
streammux = gst_element_factory_make ("nvstreammux", "stream-muxer");
//该element用于把输入按照参数处理成一系列的视频帧
if (!pipeline || !streammux) {
g_printerr ("One element could not be created. Exiting.\n");
return -1;
}
/* Use nvinfer to run inferencing on decoder's output,
* behaviour of inferencing is set through config file */
pgie = gst_element_factory_make ("nvinfer", "primary-nvinference-engine");
//目标检测的模型，对输入图像进行推理，通过推理的配置文件
/* We need to have a tracker to track the identified objects */
nvtracker = gst_element_factory_make ("nvtracker", "tracker");
//跟踪器 跟踪识别出来的目标
/* We need three secondary gies so lets create 3 more instances of
nvinfer */
sgie1 = gst_element_factory_make ("nvinfer", "secondary1-nvinference-engine");
//分类器--车的颜色
sgie2 = gst_element_factory_make ("nvinfer", "secondary2-nvinference-engine");
//分类器--车的厂家
sgie3 = gst_element_factory_make ("nvinfer", "secondary3-nvinference-engine");
//分类器--车的类型
/* Use convertor to convert from NV12 to RGBA as required by nvosd */
nvvidconv = gst_element_factory_make ("nvvideoconvert", "nvvideo-converter");
//视频颜色格式转换
/* Create OSD to draw on the converted RGBA buffer */
nvosd = gst_element_factory_make ("nvdsosd", "nv-onscreendisplay");
//处理RGBA buffer 绘制ROI，绘制识别对象的Bounding Box，绘制识别对象的文字标签（字体、颜色、标示框）
/* Finally render the osd output */
#ifdef PLATFORM_TEGRA
transform = gst_element_factory_make ("nvegltransform", "nvegl-transform");
// 转换成 EGLImage instance 给nveglglessink使用
#endif
sink = gst_element_factory_make ("nveglglessink", "nvvideo-renderer");
if (!source || !h264parser || !decoder || !pgie ||
!nvtracker || !sgie1 || !sgie2 || !sgie3 || !nvvidconv || !nvosd || !sink) {
g_printerr ("One element could not be created. Exiting.\n");
return -1;
}
#ifdef PLATFORM_TEGRA
if(!transform) {
g_printerr ("One tegra element could not be created. Exiting.\n");
return -1;
}
#endif
/* Set the input filename to the source element */
g_object_set (G_OBJECT (source), "location", argv[1], NULL);
//设置source的位置，source是视频文件
g_object_set (G_OBJECT (streammux), "width", MUXER_OUTPUT_WIDTH, "height",
MUXER_OUTPUT_HEIGHT, "batch-size", 1,
"batched-push-timeout", MUXER_BATCH_TIMEOUT_USEC, NULL);
//设置视频格式，如分辨率等
/* Set all the necessary properties of the nvinfer element,
* the necessary ones are : */
g_object_set (G_OBJECT (pgie), "config-file-path", PGIE_CONFIG_FILE, NULL);//目标检测的配置文件
g_object_set (G_OBJECT (sgie1), "config-file-path", SGIE1_CONFIG_FILE, NULL);//颜色分类的配置文件
g_object_set (G_OBJECT (sgie2), "config-file-path", SGIE2_CONFIG_FILE, NULL);//车厂分类的配置文件
g_object_set (G_OBJECT (sgie3), "config-file-path", SGIE3_CONFIG_FILE, NULL);//车型分类的配置文件
/* Set necessary properties of the tracker element. */
//设置目标跟踪器
if (!set_tracker_properties(nvtracker)) {
g_printerr ("Failed to set tracker properties. Exiting.\n");
return -1;
}
/* we add a message handler */
bus = gst_pipeline_get_bus (GST_PIPELINE (pipeline));
bus_watch_id = gst_bus_add_watch (bus, bus_call, loop);//指定消息处理函数
gst_object_unref (bus);
/* Set up the pipeline */
/* we add all elements into the pipeline */
/* decoder | pgie1 | nvtracker | sgie1 | sgie2 | sgie3 | etc.. */
#ifdef PLATFORM_TEGRA
gst_bin_add_many (GST_BIN (pipeline),
source, h264parser, decoder, streammux, pgie, nvtracker, sgie1, sgie2, sgie3,
nvvidconv, nvosd, transform, sink, NULL);//element加入到pipeline
#else
gst_bin_add_many (GST_BIN (pipeline),
source, h264parser, decoder, streammux, pgie, nvtracker, sgie1, sgie2, sgie3,
nvvidconv, nvosd, sink, NULL);
#endif
GstPad *sinkpad, *srcpad;
gchar pad_name_sink[16] = "sink_0";
gchar pad_name_src[16] = "src";
sinkpad = gst_element_get_request_pad (streammux, pad_name_sink);
if (!sinkpad) {
g_printerr ("Streammux request sink pad failed. Exiting.\n");
return -1;
}//获取指定element中的指定pad 该element为 streammux
srcpad = gst_element_get_static_pad (decoder, pad_name_src);
if (!srcpad) {
g_printerr ("Decoder request src pad failed. Exiting.\n");
return -1;
}
if (gst_pad_link (srcpad, sinkpad) != GST_PAD_LINK_OK) {
g_printerr ("Failed to link decoder to stream muxer. Exiting.\n");
return -1;
}
gst_object_unref (sinkpad);
gst_object_unref (srcpad);
/* Link the elements together */
if (!gst_element_link_many (source, h264parser, decoder, NULL)) {
g_printerr ("Elements could not be linked: 1. Exiting.\n");
return -1;
}
#ifdef PLATFORM_TEGRA
if (!gst_element_link_many (streammux, pgie, nvtracker, sgie1,
sgie2, sgie3, nvvidconv, nvosd, transform, sink, NULL)) {
g_printerr ("Elements could not be linked. Exiting.\n");
return -1;
}
#else
if (!gst_element_link_many (streammux, pgie, nvtracker, sgie1,
sgie2, sgie3, nvvidconv, nvosd, sink, NULL)) {
g_printerr ("Elements could not be linked. Exiting.\n");
return -1;
}
#endif
/* Lets add probe to get informed of the meta data generated, we add probe to
* the sink pad of the osd element, since by that time, the buffer would have
* had got all the metadata. */
osd_sink_pad = gst_element_get_static_pad (nvosd, "sink");
if (!osd_sink_pad)
g_print ("Unable to get sink pad\n");
else
gst_pad_add_probe (osd_sink_pad, GST_PAD_PROBE_TYPE_BUFFER,
osd_sink_pad_buffer_probe, NULL, NULL);
//osd_sink_pad_buffer_probe 创建探针
//以上都是设置属性，连接Elements，设置消息等操作，先把整个的视频处理流程勾勒出来。
/* Set the pipeline to "playing" state */
g_print ("Now playing: %s\n", argv[1]);
gst_element_set_state (pipeline, GST_STATE_PLAYING);//运行
/* Iterate */
g_print ("Running...\n");
g_main_loop_run (loop);//bus_call 消息处理函数可以结束loop
/* Out of the main loop, clean up nicely */
g_print ("Returned, stopping playback\n");
gst_element_set_state (pipeline, GST_STATE_NULL);//释放为pipeline分配的所有资源
g_print ("Deleting pipeline\n");
gst_object_unref (GST_OBJECT (pipeline));
g_source_remove (bus_watch_id);
g_main_loop_unref (loop);//销毁loop对象
return 0;
}
参考文献
[1].https://docs.nvidia.com/metropolis/deepstream/plugin-manual/index.html
[2].https://docs.nvidia.com/metropolis/deepstream/dev-guide/DeepStream_Development_Guide/baggage/index.html