@robigregorio
As @zhliunycm2 mentioned in comment #6, to use a webcam (USB camera), one of the DeepStream test sample apps could be modified according to your end use-case to read from the USB device using GStreamer plugin “v4l2src”.
The modified “deepstream-test1” sample pipeline would be:
v4l2src → videoconvert → nvvideoconvert → mux → nvinfer → nvvideoconvert → nvosd → video-renderer
To achieve this, you can merge the following code snippet into def main in apps/deepstream-test1/deepstream_test_1.py.
The diff with apps/deepstream-test1/deepstream_test_1.py should show the additional GStreamer plugins introduced into the pipeline and linked to support reading from UVC devices in general.
def main(args):
# Check input arguments
if len(args) != 2:
sys.stderr.write("usage: %s <v4l2-device-path>\n" % args[0])
sys.exit(1)
# Standard GStreamer initialization
GObject.threads_init()
Gst.init(None)
# Create gstreamer elements
# Create Pipeline element that will form a connection of other elements
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
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
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)
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.
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,
# behaviour of inferencing is set through config file
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
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
nvosd = Gst.ElementFactory.make("nvdsosd", "onscreendisplay")
if not nvosd:
sys.stderr.write(" Unable to create nvosd \n")
# Finally render the osd output
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
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
# 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
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.
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
print("Starting pipeline \n")
pipeline.set_state(Gst.State.PLAYING)
try:
loop.run()
except:
pass
# cleanup
pipeline.set_state(Gst.State.NULL)
Once merged you could run (assuming UVC device at /dev/video0):
python3 deepstream_test_1.py /dev/video0