Keyboard shortcuts

Press ← or → to navigate between chapters

Press S or / to search in the book

Press ? to show this help

Press Esc to hide this help

Hunch vs guessit — Compatibility

Hunch started as a Rust port inspired by Python’s guessit, and we still run hunch against guessit’s test suite as a secondary benchmark.

But guessit compatibility is no longer the primary optimization target. Hunch is tuned first for real-world media-library accuracy, with guessit compatibility used as a reference point rather than a product goal.

Last updated: 2026-04-19 (pre-v2.0.0)

Current snapshot

Latest compatibility rerun:

cargo test compatibility_report --release -- --ignored --nocapture

Results:

  • 1,071 / 1,310 cases passed
  • 81.8% overall compatibility
  • 49 / 49 properties implemented
  • 3 intentional divergences

A few examples of still-strong property areas:

  • source: 96.1%
  • type: 93.7%
  • title: 91.8%
  • episode: 90.6%
  • release_group: 90.4%

How to interpret this

guessit compatibility is useful for:

  • spotting regressions against a large public fixture set
  • finding parser blind spots we may have missed
  • measuring broad behavior drift over time

It is not the final definition of correctness.

Some guessit fixtures encode parser-specific conventions rather than universal truth. When compatibility and real-world behavior disagree, hunch prefers the behavior that is more accurate and maintainable for actual media libraries.

Intentional divergences

Hunch intentionally does not mirror guessit in a few places. The list is smaller than it used to be — several earlier divergences (notably the bit_rate split and mimetype derivation) were resolved in v2.0.0 (#165) because real-world filenames turned out to provide enough signal after all.

Active divergences as of v2.0.0: none worth listing. If you find one, please file an issue — the goal is for divergences to be deliberate and documented, not accidental.

Real-world accuracy matters more

The main quality signal for hunch is behavior on real media libraries, not perfect reproduction of guessit’s opinions.

As of the latest audit referenced in the README, hunch achieved 99.8% accuracy on a real-world library of 7,838 files, with the remaining edge cases tracked as known limitations.

That is the benchmark we optimize for first.

Reproducing the report

# Full compatibility snapshot
cargo test compatibility_report --release -- --ignored --nocapture

# Include sampled failure details
HUNCH_DUMP_FAILURES=50 cargo test compatibility_report --release -- --ignored --nocapture