Hello,
I am trying to write a C application on my Jetson Orin Nano. The final application will utilize deepstream to perform inference on a CSI camera’s video feed, but for now I’m just trying to get the camera to work. I need my final video output to the model to have a resolution of 960x540, so I was hoping to use caps filters to size down and properly format my video. I have constructed the following gst-launch-1.0 command which works great.
gst-launch-1.0 nvarguscamerasrc sensor-id=0 ! "video/x-raw(memory:NVMM), width=(int)1920, height=(int)1080, format=(string)NV12, framerate=30/1" ! nvvidconv flip-method=2 ! "video/x-raw(memory:NVMM), width=(int)960, height=(int)540" ! nvvidconv ! queue ! autovideosink sync=false
However, when I tried to replicate this functionality in my C code, an error gets thrown when I try to link the camera source, caps, and first nvvidconv element. My C code is below.
#include <gst/gst.h>
int main(int argc, char *argv[]) {
GstElement *pipeline, *source, *conv1, *conv2, *queue, *sink;
GstCaps *caps1, *caps2;
GstBus *bus;
GstMessage *msg;
GstStateChangeReturn ret;
gchar *caps_str;
/* Initialize GStreamer */
gst_init(&argc, &argv);
/* Create the elements */
source = gst_element_factory_make("nvarguscamerasrc", "source");
conv1 = gst_element_factory_make("nvvidconv", "conv1");
conv2 = gst_element_factory_make("nvvidconv", "conv2");
queue = gst_element_factory_make("queue", "queue");
sink = gst_element_factory_make("autovideosink", "sink");
/* Create the empty pipeline */
pipeline = gst_pipeline_new("test-pipeline");
if (!pipeline || !source || !conv1 || !conv2 || !queue || !sink) {
g_printerr("Not all elements could be created.\n");
return -1;
}
/* Configure nvarguscamerasrc */
g_object_set(source, "sensor-id", 0, NULL);
/* Configure caps for nvarguscamerasrc to nvvidconv */
caps1 = gst_caps_new_simple("video/x-raw",
"memory", G_TYPE_STRING, "NVMM",
"width", G_TYPE_INT, 1920,
"height", G_TYPE_INT, 1080,
"format", G_TYPE_STRING, "NV12",
"framerate", GST_TYPE_FRACTION, 30, 1,
NULL);
caps_str = gst_caps_to_string(caps1);
g_print("Caps1: %s\n", caps_str);
g_free(caps_str);
/* Configure caps for nvvidconv to nvvidconv */
caps2 = gst_caps_new_simple("video/x-raw",
"memory", G_TYPE_STRING, "NVMM",
"width", G_TYPE_INT, 960,
"height", G_TYPE_INT, 540,
NULL);
caps_str = gst_caps_to_string(caps2);
g_print("Caps2: %s\n", caps_str);
g_free(caps_str);
/* Set up the pipeline */
gst_bin_add_many(GST_BIN(pipeline), source, conv1, conv2, queue, sink, NULL);
g_object_set(conv1, "flip-method", 2, NULL);
/* Link with caps filters */
if (!gst_element_link_filtered(source, conv1, caps1)) {
g_printerr("Failed to link source and conv1 with specified caps.\n");
gst_caps_unref(caps1);
gst_object_unref(pipeline);
return -1;
}
gst_caps_unref(caps1);
if (!gst_element_link_filtered(conv1, conv2, caps2)) {
g_printerr("Failed to link conv1 and conv2 with specified caps.\n");
gst_caps_unref(caps2);
gst_object_unref(pipeline);
return -1;
}
gst_caps_unref(caps2);
/* Link the rest of the pipeline */
if (!gst_element_link_many(conv2, queue, sink, NULL)) {
g_printerr("Failed to link conv2, queue, and sink.\n");
gst_object_unref(pipeline);
return -1;
}
/* 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);
/* Handle 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:
g_printerr("Unexpected message received.\n");
break;
}
gst_message_unref(msg);
}
/* Clean up */
gst_object_unref(bus);
gst_element_set_state(pipeline, GST_STATE_NULL);
gst_object_unref(pipeline);
return 0;
}
What am I doing wrong here? How can I get the caps to work correctly? For the record, if I completely remove the caps and just link the elements using gst_element_link() everything works fine.