File examples

OSF example files

The examples/ directory in the repository contains two kinds of files for learning the format and checking a reader piece by piece: generated reference files (synthetic, one feature per file) and field samples (real recordings from optiMEAS measurement devices).

Generated reference files

The files under examples/generated/ are produced by the Delphi reference implementation (reproducible non-interactively with OSFGeneratorCLI). Each file targets one feature, and each exists as an OSF4 variant (XML header) and an OSF5 variant (JSON header):

File (OSF4 / OSF5)	Demonstrates
osf4_equidistant.osf / osf5_equidistant.osf	Equidistant channel (fixed sample rate)
osf4_scalar_numeric.osf / osf5_scalar_numeric.osf	Timestamped floating-point scalar channels
osf4_scalar_int64.osf / osf5_scalar_int64.osf	Signed 64-bit integer channel
osf4_scalar_unsigned.osf / osf5_scalar_unsigned.osf	Unsigned integer channels
osf4_gpslocation.osf / osf5_gpslocation.osf	GPS location channel
osf4_timestamped_string.osf / osf5_timestamped_string.osf	Timestamped string payloads
osf4_timestamped_binary.osf / osf5_timestamped_binary.osf	Timestamped binary blobs
osf4_mixed.osf / osf5_mixed.osf	Several channel types in one file
— / osf5_mixed_extended.osf	Extended mixed OSF5 file

In total 17 files (8 OSF4 + 9 OSF5). A correct reader must process all of them without error. These files are the cross-language read fixtures; the OSF4/OSF5 pairing also exercises the version-deterministic rules — for example the null-termination of string/binary payloads (OSF4 with, OSF5 without a trailing 0x00).

Field samples — real recordings

Real data from optiMEAS devices. They cover what synthetic files cannot: large channel counts, real timestamp patterns and abruptly ending streams. A reader should read them without crashing and return the data that is present.

Path	Format	Description
motorbike.osf	OSF4	81 channels of motorbike telemetry — speeds, temperatures, GPS, system status
steam_loco.osf (+ .csv)	OSF4	123 channels from a steam-locomotive recording (the .csv is a reference export of the same data)
weather_station.osfz	OSF4, gzip	28 channels, gzip-compressed OSFZ — exercises transparent decompression on read
Testdata Motorbike/	OSFZ	Multi-day motorbike recordings in daily subfolders (YYYYMMDD/…) — robustness/bulk read tests

Opening a file

The quickest way is with the Python package osfdata:

import osf

mgr = osf.load("examples/steam_loco.osf")
print(f"{len(mgr)} channels")
for ch in mgr.channels:
    print(ch.name, ch.data_type, ch.sample_count)

The files can equally be opened with the Rust (cargo run --example inspect -- <path>), C++ or Delphi implementation (osftool info). For a format introduction see the chapter OSF format.