DxGather

DXGather is an element designed to merge multiple branches of a stream that originates from the same source, typically split using a GstTee. It recombines these branches back into a single synchronized output stream, ensuring efficient handling of shared content in multi-branch pipelines.

This makes DXGather ideal for scenarios where duplicated streams need to be reunited after parallel processing (e.g., detection, tracking, or visualization).

Key Features

PTS-Based Buffer Merging

• Merges buffers from multiple sink pads only when their Presentation Timestamps (PTS) match.
• Ensures that only synchronized frames are merged together.

Buffer and Metadata Handling

• Assumes that buffer content is identical across all input branches.
• Retains one buffer while others are unreferenced.
• Merges metadata from all branches into the resulting output buffer.

Source Stream Assumption

• Only supports streams split from the same source (e.g., using GstTee).
• Not suitable for merging streams from different sources.

Hierarchy

GObject
 +----GInitiallyUnowned
       +----GstObject
             +----GstElement
                   +----GstAggregator
                         +----GstDxGather

Pad Templates

Sink (input, request pad sink_%u)

Property	Value
Format	video/x-raw

Src (output, always pad src)

Property	Value
Format	video/x-raw

Properties

Name	Description	Type	Default Value
name	Sets the unique name of the DxGather element.	String	"dxgather0"

DxInputSelector Placement

dxgather must not be placed downstream of DxInputSelector (i.e., it cannot be used inside the multi-stream domain). dxgather is designed to merge multiple branches that originate from the same source (e.g., split by tee), not to demultiplex multiple distinct streams. Inside the domain, buffers carry per-stream DXFrameMeta and dxgather has no notion of stream-id. See Multi-Stream Domain.

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