single_network.rst

Single Network Pipeline Structure

This page provides a drill-down into the template of our single network pipelines with a focus on explaining the GStreamer pipeline.

Example Pipeline

gst-launch-1.0 \
    filesrc location=$video_device ! decodebin ! videoconvert ! \
    videoscale ! \
    queue leaky=no max-size-buffers=30 max-size-bytes=0 max-size-time=0 ! \
    hailonet hef-path=$hef_path is-active=true ! \
    queue leaky=no max-size-buffers=30 max-size-bytes=0 max-size-time=0 ! \
    hailofilter function-name=yolov5 so-path=$POSTPROCESS_SO qos=false ! \
    queue leaky=no max-size-buffers=30 max-size-bytes=0 max-size-time=0 ! \
    hailooverlay ! \
    videoconvert ! \
    fpsdisplaysink video-sink=xvimagesink name=hailo_display sync=true text-overlay=false

The pipeline functionality will be explained section by section:

filesrc location=$video_device ! decodebin ! videoconvert !

Specifies the location of the video used, then decodes and converts to the required format.

   videoscale ! \

Re-scale the video dimensions to fit the input of the network. The video scale finds out the requires width and height using caps negotiation with ``hailonet``.

queue leaky=no max-size-buffers=30 max-size-bytes=0 max-size-time=0 ! \

Before sending the frames into the hailonet element, set a queue so no frames are lost (Read more about queues here)

hailonet hef-path=$hef_path is-active=true ! \
queue leaky=no max-size-buffers=30 max-size-bytes=0 max-size-time=0 ! \

Performs the inference on the Hailo-8 device.

hailofilter function-name=$POSTPROCESS_NAME so-path=$POSTPROCESS_SO qos=false ! \
queue name=hailo_draw0 leaky=no max-size-buffers=30 max-size-bytes=0 max-size-time=0 ! \
hailooverlay  ! \

hailofilter performs a given post-process to extract the objects. The following hailooverlay element is able to draw standard HailoObjects to the buffer.

videoconvert ! \
fpsdisplaysink video-sink=xvimagesink name=hailo_display sync=true text-overlay=false

Apply the final convert to let GStreamer utilize the format required by the fpsdisplaysink element

Example Pipeline with Resolution Preservation

Using this template the source resolution would be preserved, this is an extension to our Example pipeline

An example for pipelines who preserve the original resolution:

gst-launch-1.0 \
    $source_element ! videoconvert ! \
    tee name=t hailomuxer name=mux \
    t. ! queue leaky=no max-size-buffers=30 max-size-bytes=0 max-size-time=0 ! mux. \
    t. ! videoscale ! \
    queue leaky=no max-size-buffers=30 max-size-bytes=0 max-size-time=0 ! \
    hailonet hef-path=$hef_path is-active=true ! \
    queue leaky=no max-size-buffers=30 max-size-bytes=0 max-size-time=0 ! \
    hailofilter function-name=$network_name so-path=$postprocess_so qos=false ! mux. \
    mux. ! queue leaky=no max-size-buffers=30 max-size-bytes=0 max-size-time=0 ! \
    hailooverlay ! queue leaky=no max-size-buffers=30 max-size-bytes=0 max-size-time=0 ! \
    videoconvert ! \
    fpsdisplaysink video-sink=$video_sink_element name=hailo_display sync=$sync_pipeline text-overlay=false

Example Pipeline Single Network with Tiling

Tiling introduces two new elements:

• hailotilecropper which splits the frame into tiles by separating the frame into rows and columns

  (given as parameters to the element).

• hailotileaggregator which aggregates the cropped tiles and stitches them back to the original resolution.

An example for the pipeline itself could be found on our Tiling app.