Gst-nvmultistreamtiler

The Gst-nvmultistreamtiler plugin composites a 2D tile from batched buffers. The plugin accepts batched NV12/RGBA data from upstream components. The plugin composites the tile based on stream IDs, obtained from NvDsBatchMeta and NvDsFrameMeta in row-major order (starting from source 0, left to right across the top row, then across the next row). Each source frame is scaled to the corresponding location in the tiled output buffer. The plugin can reconfigure if a new source is added and it exceeds the space allocated for tiles. It also maintains a cache of old frames to avoid display flicker if one source has a lower frame rate than other sources.

Inputs and Outputs

Inputs
Gst Buffer batched buffer
NvDsBatchMeta with Gst Buffer batched (batch is one or more buffers)
Formats supported: NV12/RGBA
Control Parameters
rows
columns
width
height
gpu-id (dGPU only)
compute-hw (Jetson only)
show-source
nvbuf-memory-type
custom-tile-config
square-seq-grid
Output
Gst Buffer (single frame) with composited input frames
Transformed metadata (NvDsBatchMeta)
Formats supported: NV12/RGBA

Features

The following table summarizes the features of the plugin.

Gst-nvmultistreamtiler features

Feature	Description	Release
Composites a 2D tile of input buffers	—	DS 2.0
Scales bounding box with metadata coordinates according to scaling and position in tile	—	DS 2.0
Multi-GPU support	—	DS 2.0
Shows expanded preview for a single source	—	DS 2.0
User configurable CUDA memory type (Pinned/Device/Unified) for output buffers	—	DS 3.0
Reconfigures 2D tile for new sources added at runtime	—	DS 3.0

Gst Properties

The following table describes the Gst-nvmultistreamtiler plugin’s Gst properties.

Gst-nvmultistreamtiler gst properties

Property	Meaning	Type and Range	Example Notes
rows	Number of rows in 2D tiled output	Integer, 1 to 4,294,967,295	row=2
columns	Number of columns in 2D tiled output	Integer, 1 to 4,294,967,295	columns=2
width	Width of 2D tiled output in pixels	Integer, 1 to 4,294,967,295	width=1920
height	Height of 2D tiled output in pixels	Integer, 1 to 4,294,967,295	height=1080
show-source	Scale and show frames from a single source. -1: composite and show all sources For values ≥0, frames from that source are zoomed.	Signed integer, −1 to 2,147,483,647	show-source=2
gpu-id	ID of the GPU on which device/unified memory is to be allocated, and in which buffers are copied or scaled. (dGPU only.)	Integer, 1 to 4,294,967,295	gpu-id=1
nvbuf-memory-type	Type of CUDA memory to be allocated. For dGPU: 0 (nvbuf-mem-default): Default memory, cuda-device 1 (nvbuf-mem-cuda-pinned): Pinned/Host CUDA memory 2 (nvbuf-mem-cuda-device) Device CUDA memory 3 (nvbuf-mem-cuda-unified): Unified CUDA memory For Jetson: 0 (nvbuf-mem-default): Default memory, surface array 4 (nvbuf-mem-surface-array): Surface array memory	Integer, 0-4	nvbuf-memory-type=1
custom-tile-config	Custom tile position and resolution. Can be configured programmatically for all or none of the sources.	Values of enum CustomTileConfig	Reserved for future use. Default: null.
compute-hw	Compute Scaling HW to use. Applicable only for Jetson. dGPU systems uses GPU by default. 0 (Default): Default, GPU for Tesla, VIC for Jetson 1 (GPU): GPU 2 (VIC): VIC	Integer: 0-2	compute-hw=1
square-seq-grid	Enable automatic square tiling according to number of sources. The tiles are placed sequentially on the grid with empty tiles at the end	Boolean	square-seq-grid=1
buffer-pool-size	Size of the nvtiler output buffer pool	Integer, 4 to 10	buffer-pool-size=4
interpolation-method	Interpolation method used for scaling; see Gst-nvvideoconvert for the shared enum values	Enum	interpolation-method=1