For clarification, I use this code then modified it. I also currently learning gstreamer functions and its pipeline. Mind that I primarily use python on here.
For the updates, I’ve already modifed the code using MQTT and tracker. However, for MQTT, I copied the whole osd_sink_pad_buffer_probe
function and differentiate them. So it ended up like this:
in main
...
osdsinkpad1 = nvosd[0].get_static_pad("sink")
osdsinkpad2 = nvosd[1].get_static_pad("sink")
if not osdsinkpad1:
sys.stderr.write(" Unable to get sink pad of nvosd \n")
osdsinkpad1.add_probe(Gst.PadProbeType.BUFFER, osd_sink_pad_buffer_probe1, 0)
osdsinkpad2.add_probe(Gst.PadProbeType.BUFFER, osd_sink_pad_buffer_probe2, 0)
...
while in each osd_sink_pad_buffer_probe
i placed MQTT program. For the results, the MQTT can publish properly to the broker for now. However, because i placed directly on the probe. The publish has no fixed period which I assume the publish speed is the same as stream FPS (I haven’t tried FPS check on the code, but I won’t discuss the FPS for now).
For the specifics:
def osd_sink_pad_buffer_probe(pad,info,u_data): #i have two different function names with same function but different mqtt topic
frame_number=0
#Intiallizing object counter with 0.
obj_counter = {
PGIE_CLASS_ID_VEHICLE:0,
PGIE_CLASS_ID_PERSON:0,
PGIE_CLASS_ID_BICYCLE:0,
PGIE_CLASS_ID_ROADSIGN:0
}
num_rects=0
gst_buffer = info.get_buffer()
if not gst_buffer:
print("Unable to get GstBuffer ")
return
# Retrieve batch metadata from the gst_buffer
# Note that pyds.gst_buffer_get_nvds_batch_meta() expects the
# C address of gst_buffer as input, which is obtained with hash(gst_buffer)
batch_meta = pyds.gst_buffer_get_nvds_batch_meta(hash(gst_buffer))
l_frame = batch_meta.frame_meta_list
while l_frame is not None:
try:
# Note that l_frame.data needs a cast to pyds.NvDsFrameMeta
# The casting is done by pyds.NvDsFrameMeta.cast()
# The casting also keeps ownership of the underlying memory
# in the C code, so the Python garbage collector will leave
# it alone.
frame_meta = pyds.NvDsFrameMeta.cast(l_frame.data)
except StopIteration:
break
frame_number=frame_meta.frame_num
num_rects = frame_meta.num_obj_meta
l_obj=frame_meta.obj_meta_list
while l_obj is not None:
try:
# Casting l_obj.data to pyds.NvDsObjectMeta
obj_meta=pyds.NvDsObjectMeta.cast(l_obj.data)
except StopIteration:
break
obj_counter[obj_meta.class_id] += 1
try:
l_obj=l_obj.next
except StopIteration:
break
# Acquiring a display meta object. The memory ownership remains in
# the C code so downstream plugins can still access it. Otherwise
# the garbage collector will claim it when this probe function exits.
display_meta=pyds.nvds_acquire_display_meta_from_pool(batch_meta)
display_meta.num_labels = 1
py_nvosd_text_params = display_meta.text_params[0]
# Setting display text to be shown on screen
# Note that the pyds module allocates a buffer for the string, and the
# memory will not be claimed by the garbage collector.
# Reading the display_text field here will return the C address of the
# allocated string. Use pyds.get_string() to get the string content.
py_nvosd_text_params.display_text = "Frame Number={} Number of Objects={} Vehicle_count={} Person_count={}".format(frame_number, num_rects, obj_counter[PGIE_CLASS_ID_VEHICLE], obj_counter[PGIE_CLASS_ID_PERSON])
# Now set the offsets where the string should appear
py_nvosd_text_params.x_offset = 10
py_nvosd_text_params.y_offset = 12
# Font , font-color and font-size
py_nvosd_text_params.font_params.font_name = "Serif"
py_nvosd_text_params.font_params.font_size = 10
# set(red, green, blue, alpha); set to White
py_nvosd_text_params.font_params.font_color.set(1.0, 1.0, 1.0, 1.0)
# Text background color
py_nvosd_text_params.set_bg_clr = 1
# set(red, green, blue, alpha); set to Black
py_nvosd_text_params.text_bg_clr.set(0.0, 0.0, 0.0, 1.0)
# Using pyds.get_string() to get display_text as string
print(pyds.get_string(py_nvosd_text_params.display_text))
pyds.nvds_add_display_meta_to_frame(frame_meta, display_meta)
### i insterted MQTT program here
try:
l_frame=l_frame.next
except StopIteration:
break
### i copied tracker (from deepstream-test2) here
return Gst.PadProbeReturn.OK