Gst-nvdsvideotemplate

The OSS Gst-nvdsvideotemplate plugin is a template plugin which provides a custom library hooking interface for single/batched video frame(s) processing. Custom lib implementation may have algorithms to transform or process input buffers depending upon the use case. It can support NV12 and RGBA inputs. The plugin accepts batched NVMM HW and RAW SW buffers, and outputs batched NVMM HW buffers.

Inputs and Outputs

Inputs
- NVMM or RAW Gst Buffers. Supported formats are NV12 and RGBA
Control parameters
- customlib-name
- gpu-id
- customlib-props
Output
- Transformed Gst Buffer

Features

The following table summarizes the features of the plugin.

Gst-nvdsvideotemplate features

Feature	Description	Release
Simplified APIs	Simplified interface to implement custom library to add any algorithm without implementing new plugin	DS 5.1
Easy Data Accessing	Easy access to GstBuffer and it’s metadata inside custom library	DS 5.1
Synchronous and Asynchronous Buffer Processing	Buffer_Ok is the responsibility of the plugin to push the buffer downstream. Buffer_Async is the responsibility of the custom library to push the buffer downstream. Buffer_Error and Buffer_Drop are currently not implemented	DS 5.1
Reference Impl.	Reference implementation of custom library provides transform, transform-ip, metadata handling etc. which can be modified as per the use case.	DS 5.1
Abstraction APIs	Bufferpool creation, caps handling provided as an abstraction API inside customlib base class	DS 5.1

customlib_impl Interfaces

SetInitParams => Based on the negotiated caps, this API creates output buffer pool of the negotiated resolution
HandleEvent => This API handles standard Gstreamer events as well as custom events such as PAD_ADDED PAD_DELETED etc.
GetCompatibleCaps => This API returns the fixated caps to be set on either SINK / SRC pad of the plugin
ProcessBuffer => This API passes the GstBuffer to customlib for further processing
SetProperty => This API sets the customlib properties that are used by the underlying library for processing

Gst Properties

The following table describes the Gst properties of the Gst-nvdsvideotemplate plugin.

Gst-nvsvideotemplate gst properties

Property	Meaning	Type and Range	Example/Notes	Platforms
gpu-id	Device ID of GPU to use for decoding.	Integer, 0 to 4,294,967,295	gpu-id=0	dGPU
customlib-name	custom library Name to be used	String	Default: null	dGPU
customlib-props	Custom Library Properties (key:value) string, can be set multiple times,vector is maintained internally	String	Default: null	dGPU
dummy-meta-insert	Set to enable dummy meta data insertion	Boolean	Default: false	dGPU
fill-dummy-batch-meta	Set to fill dummy batch meta data sent from nvstreammux	Boolean	Default: false	dGPU
config-file	Set config file path to load properties from (takes precedence over individual properties)	String	Default: null	dGPU
name	The name of the object	String	Default: “nvdsvideotemplate0	dGPU
parent	The parent of the object	Object of type “GstObject	Default: null	dGPU
qos	Handle Quality-of-Service events	Boolean	Default: false	dGPU

Sample pipelines

For single stream:

gst-launch-1.0 filesrc location=/home/nvidia/sample_720p.mp4 ! decodebin ! \
 nvvideoconvert ! nvdsvideotemplate customlib-name="libcustom_impl.so" \
 customlib-props="scale-factor:2.0" ! nveglglessink

For Multi-stream:

gst-launch-1.0 filesrc location= ~/sample_720p.mp4 ! decodebin ! m.sink_0 \
 nvstreammux name=m width=640 height=480 batch-size=4 ! nvinfer config-file-path=config_infer_primary.txt \
 ! nvdsvideotemplate customlib-name="libcustom_impl.so" customlib-props="scale-factor:2.0" \
 ! nvmultistreamtiler ! nvvideoconvert ! "video/x-raw(memory:NVMM),width=320, height=240" ! nvdsosd ! nveglglessink \
 filesrc location= ~/sample_720p.mp4 ! decodebin ! m.sink_1