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0 背景

在做 deepstream 功能测试时，常常需要将结果保存为 mp4 视频文件，而 sdk 中并未直接提供相关代码，不熟悉功能的同学改起来有点困难，因此，今天整理一下修改 pipeline 的方法，在 deepstream-test1 的 pipeline 基础上调整为视频文件输出，其它代码类似

1 原 pipeline

在 sdk 中，deepstream-test1 的pipeline 如下所示，最终结果是输出到屏幕显示

filesrc→decode解码→nvstreammux→nvinfer（主检测器）→nvosd→renderer渲染器

如果导出 pipeline 结构图（方法），可以看到结构如下

 我们要做的是把最后一部分修改，修改方法是把 osd 之后的插件修改一下

将

...! nvdsosd ! nvegltransform ! nveglglessink

修改为

 ...! nvdsosd ! nvvideoconvert ! 'video/x-raw(memory:NVMM),format=NV12' ! nvv4l2h264enc ! h264parse ! qtmux ! filesink

2 修改代码

从上边的修改方法可以看出，需要在 osd 之后连接 nvvideconvert、nvv4l2h264enc、h264parse、 qtmux、filesink 几个插件，首先先定义这几个插件

  GstElement *nvvideoconvert = NULL, *nvv4l2h264enc = NULL, *h264parse = NULL, *qtmux = NULL;nvvideoconvert = gst_element_factory_make("nvvideoconvert", "nvvideo-converter2");nvv4l2h264enc = gst_element_factory_make("nvv4l2h264enc", "nvv4l2-h264enc");h264parse = gst_element_factory_make("h264parse", "h264-parse");qtmux = gst_element_factory_make("qtmux", "qtmux");

将原来的 sink 修改，并设置输出文件的名字

  // sink = gst_element_factory_make ("nveglglessink", "nvvideo-renderer");sink = gst_element_factory_make ("filesink", "filesink");g_object_set (G_OBJECT (sink), "location", "./result.mp4", NULL);

将新增的 element 添加到 pipeline 中

  /* Set up the pipeline *//* we add all elements into the pipeline */// if(prop.integrated) {//   gst_bin_add_many (GST_BIN (pipeline),//       source, h264parser, decoder, streammux, pgie,//       nvvidconv, nvosd, transform, sink, NULL);// }// else {// gst_bin_add_many (GST_BIN (pipeline),//     source, h264parser, decoder, streammux, pgie,//     nvvidconv, nvosd, sink, NULL);// }gst_bin_add_many (GST_BIN (pipeline),source, h264parser, decoder, streammux, pgie,nvvidconv, nvosd, nvvideoconvert, nvv4l2h264enc, h264parse, qtmux , sink, NULL);

link 连接起来

  // if(prop.integrated) {//   if (!gst_element_link_many (streammux, pgie,//       nvvidconv, nvosd, transform, sink, NULL)) {//     g_printerr ("Elements could not be linked: 2. Exiting.\n");//     return -1;//   }// }// else {//   if (!gst_element_link_many (streammux, pgie,//       nvvidconv, nvosd, sink, NULL)) {//     g_printerr ("Elements could not be linked: 2. Exiting.\n");//     return -1;//   }// }gst_element_link_many (streammux, pgie, nvvidconv, nvosd, nvvideoconvert, nvv4l2h264enc, h264parse, qtmux , sink, NULL));

重新编译，运行即可，完整代码如下

int
main (int argc, char *argv[])
{GMainLoop *loop = NULL;GstElement *pipeline = NULL, *source = NULL, *h264parser = NULL,*decoder = NULL, *streammux = NULL, *sink = NULL, *pgie = NULL, *nvvidconv = NULL,*nvosd = NULL;GstElement *nvvideoconvert = NULL, *nvv4l2h264enc = NULL, *h264parse = NULL, *qtmux = NULL;nvvideoconvert = gst_element_factory_make("nvvideoconvert", "nvvideo-converter2");nvv4l2h264enc = gst_element_factory_make("nvv4l2h264enc", "nvv4l2-h264enc");h264parse = gst_element_factory_make("h264parse", "h264-parse");qtmux = gst_element_factory_make("qtmux", "qtmux");GstElement *transform = NULL;GstBus *bus = NULL;guint bus_watch_id;GstPad *osd_sink_pad = NULL;int current_device = -1;cudaGetDevice(&current_device);struct cudaDeviceProp prop;cudaGetDeviceProperties(&prop, current_device);/* Check input arguments */if (argc != 2) {g_printerr ("Usage: %s <H264 filename>\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 form a connection of other elements */pipeline = gst_pipeline_new ("dstest1-pipeline");/* Source element for reading from the file */source = gst_element_factory_make ("filesrc", "file-source");/* Since the data format in the input file is elementary h264 stream,* we need a h264parser */h264parser = gst_element_factory_make ("h264parse", "h264-parser");/* Use nvdec_h264 for hardware accelerated decode on GPU */decoder = gst_element_factory_make ("nvv4l2decoder", "nvv4l2-decoder");/* Create nvstreammux instance to form batches from one or more sources. */streammux = gst_element_factory_make ("nvstreammux", "stream-muxer");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");/* Use convertor to convert from NV12 to RGBA as required by nvosd */nvvidconv = gst_element_factory_make ("nvvideoconvert", "nvvideo-converter");/* Create OSD to draw on the converted RGBA buffer */nvosd = gst_element_factory_make ("nvdsosd", "nv-onscreendisplay");/* Finally render the osd output */if(prop.integrated) {transform = gst_element_factory_make ("nvegltransform", "nvegl-transform");}// sink = gst_element_factory_make ("nveglglessink", "nvvideo-renderer");// sink = gst_element_factory_make ("fakesink", "nvvideo-renderer");sink = gst_element_factory_make ("filesink", "filesink");g_object_set (G_OBJECT (sink), "location", "./result.mp4", NULL);if (!source || !h264parser || !decoder || !pgie|| !nvvidconv || !nvosd || !sink) {g_printerr ("One element could not be created. Exiting.\n");return -1;}if(!transform && prop.integrated) {g_printerr ("One tegra element could not be created. Exiting.\n");return -1;}/* we set the input filename to the source element */g_object_set (G_OBJECT (source), "location", argv[1], NULL);g_object_set (G_OBJECT (streammux), "batch-size", 1, NULL);g_object_set (G_OBJECT (streammux), "width", MUXER_OUTPUT_WIDTH, "height",MUXER_OUTPUT_HEIGHT,"batched-push-timeout", MUXER_BATCH_TIMEOUT_USEC, NULL);/* Set all the necessary properties of the nvinfer element,* the necessary ones are : */g_object_set (G_OBJECT (pgie),"config-file-path", "dstest1_pgie_config.txt", NULL);/* we add a message handler */bus = gst_pipeline_get_bus (GST_PIPELINE (pipeline));bus_watch_id = gst_bus_add_watch (bus, bus_call, loop);gst_object_unref (bus);/* Set up the pipeline *//* we add all elements into the pipeline */// if(prop.integrated) {//   gst_bin_add_many (GST_BIN (pipeline),//       source, h264parser, decoder, streammux, pgie,//       nvvidconv, nvosd, transform, sink, NULL);// }// else {// gst_bin_add_many (GST_BIN (pipeline),//     source, h264parser, decoder, streammux, pgie,//     nvvidconv, nvosd, sink, NULL);// }gst_bin_add_many (GST_BIN (pipeline),source, h264parser, decoder, streammux, pgie,nvvidconv, nvosd, nvvideoconvert, nvv4l2h264enc, h264parse, qtmux , sink, NULL);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;}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);/* we link the elements together *//* file-source -> h264-parser -> nvh264-decoder ->* nvinfer -> nvvidconv -> nvosd -> video-renderer */if (!gst_element_link_many (source, h264parser, decoder, NULL)) {g_printerr ("Elements could not be linked: 1. Exiting.\n");return -1;}// if(prop.integrated) {//   if (!gst_element_link_many (streammux, pgie,//       nvvidconv, nvosd, transform, sink, NULL)) {//     g_printerr ("Elements could not be linked: 2. Exiting.\n");//     return -1;//   }// }// else {//   if (!gst_element_link_many (streammux, pgie,//       nvvidconv, nvosd, sink, NULL)) {//     g_printerr ("Elements could not be linked: 2. Exiting.\n");//     return -1;//   }// }if(!gst_element_link_many (streammux, pgie, nvvidconv, nvosd, nvvideoconvert, nvv4l2h264enc, h264parse, qtmux , sink, NULL)){g_printerr("Elements could not be linked. Exiting.\n");return -1;}/* 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");elsegst_pad_add_probe (osd_sink_pad, GST_PAD_PROBE_TYPE_BUFFER,osd_sink_pad_buffer_probe, NULL, NULL);gst_object_unref (osd_sink_pad);/* Set the pipeline to "playing" state */g_print ("Now playing: %s\n", argv[1]);gst_element_set_state (pipeline, GST_STATE_PLAYING);GST_DEBUG_BIN_TO_DOT_FILE(GST_BIN(pipeline), GST_DEBUG_GRAPH_SHOW_ALL, "pipeline-test1");/* Wait till pipeline encounters an error or EOS */g_print ("Running...\n");g_main_loop_run (loop);/* Out of the main loop, clean up nicely */g_print ("Returned, stopping playback\n");gst_element_set_state (pipeline, GST_STATE_NULL);g_print ("Deleting pipeline\n");gst_object_unref (GST_OBJECT (pipeline));g_source_remove (bus_watch_id);g_main_loop_unref (loop);return 0;
}