> This page is for version 9.2 (default). > For other versions, use one of these documentation indexes: > - 9.2 (default): https://docs.nvidia.com/deepstream/9.2/llms.txt > - Archives: https://docs.nvidia.com/deepstream/archives/llms.txt > For clean Markdown of any page, append .md to the page URL. > For a complete documentation index, see https://docs.nvidia.com/deepstream/llms.txt. > For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.nvidia.com/deepstream/_mcp/server. # Gst-nvdspostprocess The `Gst-nvdspostprocess` plugin is a customizable plugin which provides a custom library interface for post processing on Tensor output of inference plugins (`nvinfer/nvinferserver`). Currently the plugin supports detection and classification models for parsing. The plugin connects to post processing lib provided as plugin parameter. The parsing parameters can be specified via a config file. Refer to section [Gst-nvdspostprocess File Configuration Specifications](/text/DS_plugin_gst-nvdspostprocess#gst-nvdspostprocess-file-configuration-specifications) below for more details. For the plugin to perform parsing of inference tensor output, it is necessary to attach tensor output by setting `output-tensor-meta` as `1` in inference configuration file and disabling parsing in the inference plugin by setting `network-type` as `100` i.e. network type other. Similarly, in `Gst-nvinferserver` we can enable the following configs in the configuration file. `output_control { output_tensor_meta : true }` and to disable native post processing, update: `infer_config { postprocess { other {} } }`. Default plugin implementation provides following functionalities. 1. It parses the tensor meta attached to frame meta or object meta. 2. Attaches the output of tensor parsing either to frame meta or object meta. The default custom library (postprocesslib_impl) provided with the plugin implements these functionalities. It can be configured to parse detection and classification networks. For multiple inference plugins in pipeline require multiple post process plugin instances corresponding to them. ![Gst-nvdspostprocess](/deepstream/_fern-img/83898de79419072d46f7b7e3ad50d213e7e6f17efb2e867d9839ceeaafc4281e.webp) ## Inputs and Outputs * Inputs * Input Video Gst Buffers * Metadata (NvDsBatchMeta) * Tensor Meta (NvDsInferTensorMeta) * Control parameters * postprocesslib-config-file * postprocesslib-name * gpu-id * Output * Output Video Gst Buffers * Original Metadata (NvDsBatchMeta) (with addition of Object Meta/Classifier Meta) ## Features The following table summarizes the features of the plugin. **Gst-nvdspostprocess features** | Feature | Description | Release | | ------------------------------------------------- | ---------------------------------------------------------------------------------------------- | ------- | | Detection output parsing | Parses detector tensor data and attaches the results as object metadata | DS 6.1 | | Classification output parsing | Parses Classification tensor data and attaches the result as classifier attributes in metadata | DS 6.1 | | Yolo detector (YoloV3/V3-tiny/V2/V2-tiny) parsing | Support for parsing of Yolo detector output | DS 6.1 | | FasterRCNN output parsing | --- | DS 6.1 | | Single Shot Detector (SSD) output parsing | --- | DS 6.1 | ## Gst-nvdspostprocess File Configuration Specifications The Gst-nvdspreprocess configuration file uses a “YAML” format Refer to examples like `config_detector.yml, config_classifier_car_color.yml` located at `/opt/nvidia/deepstream/deepstream/sources/gst-plugins/gst-nvdspostprocess/`. The `property` group configures the general behavior of the plugin. The `class-attrs-all` group configures parameters for all classes for detector post processor. The `class-attrs-` group configures parameters `` specific class for detector post processor. The following two tables describes the keys supported for `property` groups and `class-attrs-` groups respectively. **Gst-nvdspostprocess property Group Supported Keys** | Property | Meaning | Type and Range | Example | | -------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------ | ---------------------------------------------------------------- | -------------------------------------------------------------------------------------------- | | gpu-id | GPU to be used for processing | Integer | gpu-id: 0 | | process-mode | Mode of operation Full Frame (Primary 1) or on Object (Secondary 2) | Integer 1=Primary(On Full Frame) ,2=Secondary (On Object) | process-mode: 1 | | gie-unique-id | Perform tensor meta parsing on output of gie-unique-id | Integer >0 | gie-unique-id: 1 | | num-detected-classes | Number of classes detected by Detector network | Integer >0 | num-detected-classes: 4 | | cluster-mode | Clustering mode to be used on detector output | Integer 1=DBSCAN 2=NMS 3=DBSCAN+NMS Hybrid 4=None(No Clustering) | cluster-mode: 2 | | output-blob-names | Array of output layer names which are to be parsed | String delimited by semicolon | output-blob-names: conv2d_bbox;conv2d_cov/Sigmoid | | network-type | Type of network to be parsed | Integer 0=Detector 1=Classifier | network-type: 1 | | labelfile-path | Pathname of a text file containing the labels for the model | String | labelfile-path: /opt/nvidia/deepstream/deepstream/samples/models/Primary_Detector/labels.txt | | classifier-threshold | Minimum threshold label probability. The GIE outputs the label having the highest probability if it is greater than this threshold | Float, >0.0 | classifier-threshold: 0.4 | | operate-on-gie-id | Unique ID of the GIE on whose metadata (bounding boxes) this GIE is to operate on, applicable for process-mode=2 | Integer >0 | operate-on-gie-id: 1 | | parse-classifier-func-name | Name of the custom classifier output parsing function. If not specified, post process lib uses the parsing function for softmax layers. | String | parse-classifier-func-name: NvDsPostProcessClassiferParseCustomSoftmax | | parse-bbox-func-name | Name of the custom bounding box parsing function. If not specified, post process lib uses the function for the resnet model provided by the SDK | String | parse-bbox-func-name: NvDsPostProcessParseCustomResnet | **`Gst-nvdspostprocess class-attr- Group Supported Keys`** | Property | Meaning | Type and Range | Example | | ---------------------- | ------------------------------------------------------------------------------------------------------------ | -------------------------- | --------------------------- | | topk | Keep only top K objects with highest detection scores. | Integer, >0. -1 to disable | topk: 10 | | nms-iou-threshold | Maximum IOU score between two proposals after which the proposal with the lower confidence will be rejected. | Float, >0.0 | nms-iou-threshold: 0.2 | | pre-cluster-threshold | Detection threshold to be applied prior to clustering operation | Float, >0.0 | pre-cluster-threshold: 0.5 | | post-cluster-threshold | Detection threshold to be applied post clustering operation | Float, >0.0 | post-cluster-threshold: 0.5 | | eps | Epsilon values for DBSCAN algorithm | Float, >0.0 | eps: 0.2 | | dbscan-min-score | Minimum sum of confidence of all the neighbors in a cluster for it to be considered a valid cluster. | Float, >0.0 | dbscan-min-score: 0.7 | ## Gst Properties The following table describes the Gst properties of the Gst-nvdspostprocess plugin. **Gst-nvspostprocess gst properties** | Property | Meaning | Type and Range | Example notes | | -------------------------- | --------------------------------------------------------------------- | ----------------------- | ---------------------------------------------------------------- | | gpu-id | Device ID of GPU to use for post-processing (dGPU only) | Integer,0-4,294,967,295 | gpu-id=1 | | postprocesslib-name | Low level Post process library to be used for output parsing | string | postprocesslib-name=./postprocesslib_impl/libpostprocess_impl.so | | postprocesslib-config-file | Set postprocess yaml config file to be used | string | postprocesslib-config-file= config_detector.yml | | preprocessor-support | Enables postprocessor parsing support for custom preprocessor tensors | Boolean | preprocessor-support=0 | ## Sample pipelines Given below are some sample pipelines, please set appropriate configuration file and library paths. **For multi-stream detector and classifier (dGPU):** ``` gst-launch-1.0 uridecodebin \ uri=file:///opt/nvidia/deepstream/deepstream/samples/streams/sample_1080p_h264.mp4 \ ! m.sink_0 nvstreammux name=m width=1920 height=1080 batch-size=2 ! \ nvinfer config-file-path=config_infer_primary_post_process.txt \ ! nvdspostprocess \ postprocesslib-config-file=config_detector.yml \ postprocesslib-name= ./postprocesslib_impl/libpostprocess_impl.so \ ! queue ! nvinfer \ config-file-path= config_infer_secondary_vehiclemake_postprocess.txt \ ! nvdspostprocess \ postprocesslib-config-file= config_classifier_vehicle_make.yml \ postprocesslib-name= ./postprocesslib_impl/libpostprocess_impl.so ! queue ! nvinfer \ config-file-path= config_infer_secondary_vehicletypes_postprocess.txt \ ! nvdspostprocess postprocesslib-config-file= \ config_classifier_vehicle_type.yml postprocesslib-name= \ ./postprocesslib_impl/libpostprocess_impl.so ! queue ! nvmultistreamtiler ! nvvideoconvert \ gpu-id=0 ! nvdsosd ! nveglglessink sync=1 -v uridecodebin \ uri=file:///opt/nvidia/deepstream/deepstream/samples/streams/sample_1080p_h264.mp4 ! m.sink_1 ``` **For multi-stream detector and classifier (Jetson):** ``` gst-launch-1.0 uridecodebin \ uri=file:///opt/nvidia/deepstream/deepstream/samples/streams/sample_1080p_h264.mp4 \ ! m.sink_0 nvstreammux name=m width=1920 height=1080 batch-size=2 ! \ nvinfer config-file-path=config_infer_primary_post_process.txt \ ! nvdspostprocess \ postprocesslib-config-file=config_detector.yml \ postprocesslib-name= ./postprocesslib_impl/libpostprocess_impl.so \ ! queue ! nvinfer \ config-file-path= config_infer_secondary_vehiclemake_postprocess.txt \ ! nvdspostprocess \ postprocesslib-config-file=config_classifier_vehicle_make.yml \ postprocesslib-name= ./postprocesslib_impl/libpostprocess_impl.so ! queue ! nvinfer \ config-file-path= config_infer_secondary_vehicletypes_postprocess.txt \ ! nvdspostprocess postprocesslib-config-file= \ config_classifier_vehicle_type.yml postprocesslib-name= \ ./postprocesslib_impl/libpostprocess_impl.so ! queue ! nvmultistreamtiler ! nvvideoconvert \ gpu-id=0 ! nvdsosd ! nv3dsink sync=1 -v uridecodebin \ uri=file:///opt/nvidia/deepstream/deepstream/samples/streams/sample_1080p_h264.mp4 ! m.sink_1 ```