|  | NVIDIA DeepStream SDK API Reference6.1.1 Release | 
| ▼Buffer Management API module | This section describes types and functions of NvBufSurface application programming interface | 
| NvBufSurfTransform Types and Functions | Defines types and functions of the NvBufSurfTransform application programming interface | 
| NvBufSurface Types and Functions | Defines types and functions of NvBufSurface application programming interface | 
| ▼Custom Gstreamer APIs | This section defines custom Gstreamer APIs | 
| DeepStream Metadata Extension | Defines an API for managing GStreamer DeepStream metadata | 
| DeepStream Yaml Parser API | Defines an API for the GStreamer NvDsYaml plugin | 
| NvDsPreProcess Plugin | Defines an API for the GStreamer NvDsPreProcess plugin | 
| NvInfer Plugin | Defines an API for the GStreamer NvInfer plugin | 
| Smart Record | Specifies APIs relating to smart recording | 
| DBScan Based Object Clustering API | Defines the API for DBScan-based object clustering | 
| ▼Events, Messages and Query based APIs | Defines Events, Messages and Query-based APIs | 
| Events: Custom Events API | Specifies GStreamer custom event functions, used to map events to individual sources which are batched together by Gst-nvstreammux | 
| Messages: Custom Message Functions API | Helper functions for custom GStreamer messages posted by DeepStream GStreamer plugins | 
| Query Functions | Gets information such as the batch size and the number of streams | 
| Gst-infer API Common Elements | Defines common elements used in the API exposed by the Gst-inference plugin | 
| Import Transfer Learning Toolkit Encoded Models | Defines an API for importing Transfer Learning Toolkit encoded models | 
| Inference Interface API | Defines the DeepStream inference interface API | 
| Logging API | Defines an API for logging and debugging DeepStream applications | 
| Messaging API | Defines an API for exchanging messages with remote entities and services | 
| ▼Metadata APIs | This section describes types and functions of Metadata APIs programming interface | 
| Analytics Metadata | Defines metadata concerning nvdsanalytics plugin | 
| Dewarping Metadata | Defines metadata concerning dewarping | 
| Latency Measurement API | Defines an API for measuring latency in modules | 
| Metadata Extension Structures | Defines metadata structures used to describe metadata objects | 
| Metadata Structures | Define structures that hold metadata | 
| Optical flow metadata | Defines the optical flow metadata | 
| Tracker Metadata | Specifies metadata concerning tracking | 
| NvDsNmos API Common Elements | Defines common elements used in the API exposed by the NvDsNmos library | 
| Object Encoder API | Defines APIs for Object Encoder | 
| Object Tracker API | Defines the DeepStream object tracker API | 
| ▼On-Screen Display API | Defines the functions of On-screen Display APIs | 
| On-Screen Display API | Defines the NvOSD library to be used to draw rectangles and text over the frame | 
| On-Screen Display Manager | Defines the NvOSD library to be used to draw rectangles and text over the frame | 
| Pre-Process Metadata | Specifies metadata concerning ROIs used in nvdspreprocess plugin | 
| Utilities: Gstreamer utilities API | Specifies GStreamer utilities functions, used to configure the source to generate NTP Sync values | 
| Version Number API | Defines the API used to get the current version number of DeepStream and its dependencies |