def meta_copy_func(data, user_data):
logging.debug("meta_copy_func: BEGIN")
# Cast data to pyds.NvDsUserMeta
user_meta = pyds.NvDsUserMeta.cast(data)
src_meta_data = user_meta.user_meta_data
# Cast src_meta_data to pyds.NvDsEventMsgMeta
srcmeta = pyds.NvDsEventMsgMeta.cast(src_meta_data)
# Duplicate the memory contents of srcmeta to dstmeta
# First use pyds.get_ptr() to get the C address of srcmeta, then
# use pyds.memdup() to allocate dstmeta and copy srcmeta into it.
# pyds.memdup returns C address of the allocated duplicate.
dstmeta_ptr = pyds.memdup(pyds.get_ptr(srcmeta),
sys.getsizeof(pyds.NvDsEventMsgMeta))
# Cast the duplicated memory to pyds.NvDsEventMsgMeta
dstmeta = pyds.NvDsEventMsgMeta.cast(dstmeta_ptr)
# Duplicate contents of ts field. Note that reading srcmeta.ts
# returns its C address. This allows to memory operations to be
# performed on it.
dstmeta.ts = pyds.strdup(srcmeta.ts)
# Copy the sensorStr. This field is a string property.
# The getter (read) returns its C address. The setter (write)
# takes string as input, allocates a string buffer and copies
# the input string into it.
# pyds.get_string() takes C address of a string and returns
# the reference to a string object and the assignment inside the binder copies content.
dstmeta.sensorStr = pyds.get_string(srcmeta.sensorStr)
if srcmeta.objSignature.size > 0:
dstmeta.objSignature.signature = pyds.memdup(
srcmeta.objSignature.signature, srcMeta.objSignature.size)
dstmeta.objSignature.size = srcmeta.objSignature.size
if srcmeta.extMsgSize > 0:
if srcmeta.objType == pyds.NvDsObjectType.NVDS_OBJECT_TYPE_VEHICLE:
srcobj = pyds.NvDsVehicleObject.cast(srcmeta.extMsg)
obj = pyds.alloc_nvds_vehicle_object()
obj.type = pyds.get_string(srcobj.type)
obj.make = pyds.get_string(srcobj.make)
obj.model = pyds.get_string(srcobj.model)
obj.color = pyds.get_string(srcobj.color)
obj.license = pyds.get_string(srcobj.license)
obj.region = pyds.get_string(srcobj.region)
dstmeta.extMsg = obj
dstmeta.extMsgSize = sys.getsizeof(pyds.NvDsVehicleObject)
elif srcmeta.objType == pyds.NvDsObjectType.NVDS_OBJECT_TYPE_PERSON:
srcobj = pyds.NvDsPersonObject.cast(srcmeta.extMsg)
obj = pyds.alloc_nvds_person_object()
obj.age = srcobj.age
obj.gender = pyds.get_string(srcobj.gender)
obj.cap = pyds.get_string(srcobj.cap)
obj.hair = pyds.get_string(srcobj.hair)
obj.apparel = pyds.get_string(srcobj.apparel)
dstmeta.extMsg = obj
dstmeta.extMsgSize = sys.getsizeof(pyds.NvDsVehicleObject)
logging.debug("meta_copy_func: END")
return dstmeta
def create_pyds_string(s):
"""Create a C zero-terminated string from the provided Python string.
The caller is responsible for freeing the string."""
sb = ctypes.create_string_buffer(s.encode("utf-8"))
return pyds.strdup(ctypes.addressof(sb))