JLAB SRO Output

The jlabsro format writes packed binary frame records in the Jefferson Lab Streaming Readout (SRO) format. It is used when GEMC simulates time-ordered frame snapshots rather than individual events.

Configuration

gstreamer:
  - format: jlabsro
    filename: myrun
    type: stream

The type: stream sub-key is required; this format only supports frame-stream output.

Produces one .ev file per plugin instance:

myrun.ev

Frame record structure

Each frame record is a contiguous binary block consisting of:

1. A packed DataFrameHeader (56 bytes):

   Field	Type	Description
   source_id	uint32	Source identifier
   total_length	uint32	Total frame length in bytes
   payload_length	uint32	Payload length in bytes
   compressed_length	uint32	Compressed length (0 = uncompressed)
   magic	uint32	Format magic number
   format_version	uint32	Format version
   flags	uint32	Status flags
   record_counter	uint64	Frame sequence number
   ts_sec	uint64	Timestamp seconds
   ts_nsec	uint64	Timestamp nanoseconds

2. The frame payload: the integral payload words from the active sensitive detectors.

All fields are written in the byte order native to the host platform.

When to use JLAB SRO

Use this format when:

• Simulating the JLab streaming readout DAQ pipeline.
• The downstream software expects .ev binary frames produced by JLab SRO hardware.
• Your digitization plugin produces GIntegralPayload objects via a stream-mode sensitive detector.

For standard event-based simulation, use csv, root, or hipo instead.