此存储库包含DeepStream SDK的Python绑定和示例应用程序。
绑定和应用当前位于Alpha v0.5中。 预计在将来的版本中会更改API。
支持的SDK版本：4.0.1
USB相机Demo
GStreamer插件结构图
代码
#!/usr/bin/env python3
################################################################################
# Copyright (c) 2020, NVIDIA CORPORATION. All rights reserved.
#
# Permission is hereby granted, free of charge, to any person obtaining a
# copy of this software and associated documentation files (the "Software"),
# to deal in the Software without restriction, including without limitation
# the rights to use, copy, modify, merge, publish, distribute, sublicense,
# and/or sell copies of the Software, and to permit persons to whom the
# Software is furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
# THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
# DEALINGS IN THE SOFTWARE.
################################################################################
import sys
sys.path.append('../')
import gi
gi.require_version('Gst', '1.0')
from gi.repository import GObject, Gst
from common.is_aarch_64 import is_aarch64
from common.bus_call import bus_call
import pyds
PGIE_CLASS_ID_VEHICLE = 0
PGIE_CLASS_ID_BICYCLE = 1
PGIE_CLASS_ID_PERSON = 2
PGIE_CLASS_ID_ROADSIGN = 3
def osd_sink_pad_buffer_probe(pad,info,u_data):
frame_number=0
# Intiallizing object counter with 0.
# 用0初始化对象计数器
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
'''
从gst_buffer检索批处理元数据
'''
# Note that pyds.gst_buffer_get_nvds_batch_meta() expects the
'''
请注意，pyds.gst_buffer_get_nvds_batch_meta()期望
'''
# C address of gst_buffer as input, which is obtained with hash(gst_buffer)
'''
gst_buffer的C地址作为输入，该地址通过哈希（gst_buffer）获得
'''
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\
'''
请注意，l_frame.data需要强制转换为pyds.NvDsFrameMeta
'''
# The casting is done by pyds.NvDsFrameMeta.cast()
'''
投射由pyds.NvDsFrameMeta.cast（）完成
'''
# The casting also keeps ownership of the underlying memory
# in the C code, so the Python garbage collector will leave
# it alone.
'''
casting还将底层内存的所有权保留在C代码中，
因此Python垃圾收集器将不处理它。
'''
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
'''
将l_obj.data转换为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.
'''
获取显示元对象。内存所有权保留在C代码中，因此下游插件仍然可以访问它。
否则，垃圾收集器将在此探测函数退出时声明它。
'''
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
'''
设置要在屏幕上显示的显示文本
'''
# Note that the pyds module allocates a buffer for the string, and the
# memory will not be claimed by the garbage collector.
'''
请注意，pyds模块为该字符串分配了一个缓冲区，垃圾回收器不会声明该内存。
'''
# Reading the display_text field here will return the C address of the
# allocated string. Use pyds.get_string() to get the string content.
'''
在此处读取display_text字段将返回分配的字符串的C地址.
使用pyds.get_string()获取字符串内容。
'''
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
'''
现在设置字符串应该出现的偏移量
'''
py_nvosd_text_params.x_offset = 10
py_nvosd_text_params.y_offset = 12
# Font , font-color and font-size
'''
字体、字体颜色和字体大小
'''
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
'''
设置（红色、绿色、蓝色、alpha）；设置为白色
'''
py_nvosd_text_params.font_params.font_color.set(1.0, 1.0, 1.0, 1.0)
# Text background color
'''
文字背景颜色
'''
py_nvosd_text_params.set_bg_clr = 1
# set(red, green, blue, alpha); set to Black
'''
设置（红色、绿色、蓝色、alpha）；设置为黑色
'''
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
'''
使用pyds.get_字符串（）获取显示为字符串的文本
'''
print(pyds.get_string(py_nvosd_text_params.display_text))
pyds.nvds_add_display_meta_to_frame(frame_meta, display_meta)
try:
l_frame=l_frame.next
except StopIteration:
break
return Gst.PadProbeReturn.OK
def main(args):
# Check input arguments
'''
检查输入参数
'''
if len(args) != 2:
sys.stderr.write("usage: %s <v4l2-device-path>\n" % args[0])
sys.exit(1)
# Standard GStreamer initialization
'''
标准GStreamer初始化
'''
GObject.threads_init()
Gst.init(None)
# Create gstreamer elements
'''
创建gstreamer元素
'''
# Create Pipeline element that will form a connection of other elements
'''
创建将形成其他元素连接的Pipeline元素
'''
print("Creating Pipeline \n ")
pipeline = Gst.Pipeline()
if not pipeline:
sys.stderr.write(" Unable to create Pipeline \n")
# Source element for reading from the file
'''
从文件读取的源元素
'''
print("Creating Source \n ")
source = Gst.ElementFactory.make("v4l2src", "usb-cam-source")
if not source:
sys.stderr.write(" Unable to create Source \n")
caps_v4l2src = Gst.ElementFactory.make("capsfilter", "v4l2src_caps")
if not caps_v4l2src:
sys.stderr.write(" Unable to create v4l2src capsfilter \n")
print("Creating Video Converter \n")
# Adding videoconvert -> nvvideoconvert as not all
# raw formats are supported by nvvideoconvert;
# Say YUYV is unsupported - which is the common
# raw format for many logi usb cams
# In case we have a camera with raw format supported in
# nvvideoconvert, GStreamer plugins' capability negotiation
# shall be intelligent enough to reduce compute by
# videoconvert doing passthrough (TODO we need to confirm this)
# videoconvert to make sure a superset of raw formats are supported
'''
视频转换以确保支持原始格式的超集
'''
vidconvsrc = Gst.ElementFactory.make("videoconvert", "convertor_src1")
if not vidconvsrc:
sys.stderr.write(" Unable to create videoconvert \n")
# nvvideoconvert to convert incoming raw buffers to NVMM Mem (NvBufSurface API)
'''
nvvideoconvert将传入的原始缓冲区转换为NVMM Mem（NvBufSurface API）
'''
nvvidconvsrc = Gst.ElementFactory.make("nvvideoconvert", "convertor_src2")
if not nvvidconvsrc:
sys.stderr.write(" Unable to create Nvvideoconvert \n")
caps_vidconvsrc = Gst.ElementFactory.make("capsfilter", "nvmm_caps")
if not caps_vidconvsrc:
sys.stderr.write(" Unable to create capsfilter \n")
# Create nvstreammux instance to form batches from one or more sources.
'''
创建nvstreamux实例以从一个或多个源形成批处理。
'''
streammux = Gst.ElementFactory.make("nvstreammux", "Stream-muxer")
if not streammux:
sys.stderr.write(" Unable to create NvStreamMux \n")
# Use nvinfer to run inferencing on camera's output,
'''
使用nvinfer在相机的输出上运行推断
'''
# behaviour of inferencing is set through config file
'''
通过配置文件设置推断行为
'''
pgie = Gst.ElementFactory.make("nvinfer", "primary-inference")
if not pgie:
sys.stderr.write(" Unable to create pgie \n")
# Use convertor to convert from NV12 to RGBA as required by nvosd
'''
根据nvosd的要求，使用转换器将NV12转换为RGBA
'''
nvvidconv = Gst.ElementFactory.make("nvvideoconvert", "convertor")
if not nvvidconv:
sys.stderr.write(" Unable to create nvvidconv \n")
# Create OSD to draw on the converted RGBA buffer
'''
创建OSD以在已转换的RGBA缓冲区上绘制
'''
nvosd = Gst.ElementFactory.make("nvdsosd", "onscreendisplay")
if not nvosd:
sys.stderr.write(" Unable to create nvosd \n")
# Finally render the osd output
'''
最后呈现osd输出
'''
if is_aarch64():
transform = Gst.ElementFactory.make("nvegltransform", "nvegl-transform")
print("Creating EGLSink \n")
sink = Gst.ElementFactory.make("nveglglessink", "nvvideo-renderer")
if not sink:
sys.stderr.write(" Unable to create egl sink \n")
print("Playing cam %s " %args[1])
caps_v4l2src.set_property('caps', Gst.Caps.from_string("video/x-raw, framerate=30/1"))
caps_vidconvsrc.set_property('caps', Gst.Caps.from_string("video/x-raw(memory:NVMM)"))
source.set_property('device', args[1])
streammux.set_property('width', 1920)
streammux.set_property('height', 1080)
streammux.set_property('batch-size', 1)
streammux.set_property('batched-push-timeout', 4000000)
pgie.set_property('config-file-path', "dstest1_pgie_config.txt")
# Set sync = false to avoid late frame drops at the display-sink
'''
设置sync=false以避免在显示接收器处延迟帧丢失
'''
sink.set_property('sync', False)
print("Adding elements to Pipeline \n")
pipeline.add(source)
pipeline.add(caps_v4l2src)
pipeline.add(vidconvsrc)
pipeline.add(nvvidconvsrc)
pipeline.add(caps_vidconvsrc)
pipeline.add(streammux)
pipeline.add(pgie)
pipeline.add(nvvidconv)
pipeline.add(nvosd)
pipeline.add(sink)
if is_aarch64():
pipeline.add(transform)
# we link the elements together
'''
我们把元素联系在一起
'''
# v4l2src -> nvvideoconvert -> mux ->
# nvinfer -> nvvideoconvert -> nvosd -> video-renderer
print("Linking elements in the Pipeline \n")
source.link(caps_v4l2src)
caps_v4l2src.link(vidconvsrc)
vidconvsrc.link(nvvidconvsrc)
nvvidconvsrc.link(caps_vidconvsrc)
sinkpad = streammux.get_request_pad("sink_0")
if not sinkpad:
sys.stderr.write(" Unable to get the sink pad of streammux \n")
srcpad = caps_vidconvsrc.get_static_pad("src")
if not srcpad:
sys.stderr.write(" Unable to get source pad of caps_vidconvsrc \n")
srcpad.link(sinkpad)
streammux.link(pgie)
pgie.link(nvvidconv)
nvvidconv.link(nvosd)
if is_aarch64():
nvosd.link(transform)
transform.link(sink)
else:
nvosd.link(sink)
# create an event loop and feed gstreamer bus mesages to it
'''
创建事件循环并将gstreamer总线消息馈送给它
'''
loop = GObject.MainLoop()
bus = pipeline.get_bus()
bus.add_signal_watch()
bus.connect ("message", bus_call, loop)
# 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.
'''
让我们添加探针以通知生成的元数据，然后将探针添加到osd元素的接收盘，
因为到那时，缓冲区将已经获得了所有元数据。
'''
osdsinkpad = nvosd.get_static_pad("sink")
if not osdsinkpad:
sys.stderr.write(" Unable to get sink pad of nvosd \n")
osdsinkpad.add_probe(Gst.PadProbeType.BUFFER, osd_sink_pad_buffer_probe, 0)
# start play back and listen to events
'''
开始回放并收听事件
'''
print("Starting pipeline \n")
pipeline.set_state(Gst.State.PLAYING)
try:
loop.run()
except:
pass
# cleanup
'''
清理
'''
pipeline.set_state(Gst.State.NULL)
if __name__ == '__main__':
sys.exit(main(sys.argv))