bobine

Standalone PDF / Office / text → Markdown ingestion engine — a pure-Rust core with Python bindings.

Contents

• Why bobine?
• Installation · Runtime: ONNX Runtime
• Quick start (Python · Rust)
• Routing modes
• Performance (CPU vs CUDA vs quantization)
• Formula OCR · OCR batching
• Office documents · Output contract
• Module layout · Testing
• Docs · License

What it is

Runs on a single onnxruntime shared library with no CUDA-version coupling: pdf_oxide for fast native PDF text extraction, ONNX models (TexTeller formula OCR, DocLayout-YOLO layout analysis, PaddleOCR) for the heavy passes.

No torch, no optimum, no opencv — not even on the Python side.

Dual-licensed under the terms of either the MIT License or the Apache License, Version 2.0 — you may choose either (see LICENSE).

Why bobine?

The ingestion pipeline was originally entangled with the knowledge-graph project it served (OKFgraph). This crate moves conversion into its own package so any consumer — a graph, a CLI, an MCP server, a batch tool — can reuse it without importing a database stack.

The v0.3.0 rewrite ports the whole pipeline to Rust: same routing heuristics and output contract as the proven Python implementation (preserved under legacy/), with native speed and no Python ML dependencies.

Installation

# Python package (wheels: linux + windows x86_64, macOS arm64)
pip install bobine

# Rust library (crates.io, no Python involved)
cargo add bobine

# ...or build from source (repo root)
pip install maturin && maturin develop --release

Runtime: ONNX Runtime

The heavy passes need an ONNX Runtime library — or nothing at all (Office/text/fast-path PDF work needs no models):

pip install bobine[cpu]   # adds onnxruntime == 1.29.0 (CPU)
# or: pip install bobine[gpu]   # onnxruntime-gpu (self-contained CUDA)

Library discovery

import bobine points ORT_DYLIB_PATH at the pip-installed library automatically; an already-set ORT_DYLIB_PATH always wins (e.g. a custom CUDA build):

export ORT_DYLIB_PATH=/path/to/onnxruntime.dll   # e.g. <venv>/Lib/site-packages/onnxruntime/capi/onnxruntime.dll

Version rules

ort loads the library dynamically (load-dynamic, no CUDA-version coupling) and refuses runtimes older than 1.28 (BadVersion). The extras pin exactly 1.29.0, the one runtime shared with okfgraph/embroider (embroider docs/compat.md). Never install both onnxruntime and onnxruntime-gpu (same module name, they clobber each other).

Quick start (Python)

import bobine

conv = bobine.HybridConverter(
    bobine.ConverterConfig(routing_mode=bobine.RoutingMode.Surgical),
    cache_dir="~/.cache/bobine",       # hub-cache root (models shared machine-wide)
)

md = conv.convert_pdf("paper.pdf", work_dir="/tmp/out")
latex = conv.recognize_formula("crop.png")          # r"\frac{1}{2}"

# one-shot helper
md = bobine.convert_to_markdown(
    "paper.pdf", bobine.ConverterConfig(), work_dir="/tmp/out",
    cache_dir="~/.cache/bobine",
)

# Text documents need no models at all
md = conv.convert("notes.txt", work_dir="/tmp/out")
# Binary files under text-ish extensions fail fast (v0.5.11+):
# UnsupportedFormat("binary file, not text: …") instead of a raw
# "invalid UTF-8" I/O error — content-sniffed, extension-agnostic.

Routing modes

HybridConverter routes pages through four modes:

RapidLayout and RapidOCR weights also auto-download from HuggingFace on first use (DocStructBench YOLO ~72 MB, PP-OCRv4 ~16 MB); explicit local paths can override them. Missing/broken heavy models degrade gracefully to the fast path per page — a conversion never fails because of them.

Converter models live in the standard HuggingFace hub cache (0.6.0+): cache_dir is the hub-cache root — an override of the env-resolved default, shared machine-wide, never a per-output sidecar. The first fetch after upgrading downloads once; repeats reuse the blob (a cached file costs zero network, logged as "using cached"). bobine.model_status(cache_dir=None) reports per-family status offline (same dict keys as okfgraph's model_info); ingest_document accepts an optional cache_dir (None = standard cache).

Quick start (Rust)

use bobine::{ConverterConfig, HybridConverter, RoutingMode};

let mut conv = HybridConverter::new(
    ConverterConfig { routing_mode: RoutingMode::Surgical, ..Default::default() },
    std::path::Path::new("~/.cache/bobine"),
);
let md = conv.convert_pdf(std::path::Path::new("paper.pdf"),
                          std::path::Path::new("/tmp/out"))?;

Module layout

src/
├── lib.rs            crate root & re-exports
├── config.rs         ConverterConfig · RoutingMode · ModelPrecision
├── engine.rs         OnnxEngine (lazy model manager: TexTeller/Layout/OCR)
├── converter.rs      HybridConverter (core PDF/Office pipeline + binary-sniffed text fallback)
├── tex_teller.rs     TexTeller ONNX — ViT encoder → RoBERTa decoder
├── rapid_layout.rs   DocLayout-YOLO page layout analysis
├── rapid_ocr.rs      PaddleOCR det + rec (DBNet / CRNN, CTC decode)
├── rapid_table.rs    SLANet-plus table-structure recognition (scans)
├── pdf_source.rs     PdfSource trait — page text without a real PDF file
├── tables.rs         HTML table → GFM pipe-table converter
├── excel.rs          Excel workbooks → per-sheet csv/json/md
├── office_images.rs  Office picture staging (IR walk + package fallback)
├── assets.rs         okf-asset://\ staging store
├── documents.rs      ConvertedDocument + frontmatter
├── pipeline.rs       ingest_document / convert_directory / ProgressHooks
├── error.rs          BobineError
└── py_bindings.rs    PyO3 surface (behind the extension-module feature)
python/bobine/        Python shim + type stubs        (import bobine)
legacy/               frozen pure-Python bobine v0.2.0 (reference implementation)

Performance

Reference box: RTX 3090, ORT 1.28.1 (benches predate the 1.29.0 pin — ratios, not absolutes, are the takeaway). Full tables, fixtures, and repro commands in docs/benchmarks.md.

Takeaways:

• CUDA wins big on layout + OCR (12.8× / 3.6×) — auto-enabled, zero config.
• Tables stay on CPU by design — SLANet fragments across devices (2–9× slower on CUDA).
• Quantization is hardware-dependent: int8 is ~1.9× faster than fp32 on CPU (identical output, ~319 MB vs ~1.25 GB) but loses on CUDA (dequant overhead, no KV-cache); Int8 + CUDA is discouraged and warned against.
• Batching is provider-gated: chunked rec is 6.3× faster on CUDA but was measured 4.8× slower on CPU — CPU sessions keep the exact single-line path (byte-identical tensors).

Formula OCR

Formulas are recognized by TexTeller (80M training pairs), decoded with KV-cache over a ViT encoder → RoBERTa decoder ONNX graph — roughly 5× faster per crop than the RapidLaTeXOCR backend used by the legacy Python package, with markedly better accuracy.

Model choice

By default bobine downloads the quantized export (~319 MB total, HF Ji-Ha/TexTeller3-ONNX-dynamic) into the converter's cache dir on first use; set model_quantization=ModelQuantization::Fp32 to use full-precision weights (~1.25 GB, HF OleehyO/TexTeller) instead. Preprocessing matches upstream TexTeller exactly, including its normalize-before-pad order (v0.4.4 fixed black pad fill, which measurably degraded recognition). Measured on a 10-formula corpus: Int8+CPU scores 10/10, Fp32+CUDA 9/10 — occasional single-token decode noise flips between examples on either variant, so pick by hardware, not quality.

GPU

On NVIDIA GPUs, point ORT_DYLIB_PATH at a GPU onnxruntime build — v0.4.9+ auto-enables CUDA for the layout and OCR slots when the loaded library exposes a usable CUDA execution provider (EP-availability probe, shared embroider crate since v0.5.10).

Zero config needed; explicit per-slot overrides: layout_ort_providers, ocr_ort_providers, table_ort_providers, encoder_ort_providers, decoder_ort_providers. To also run Fp32 formula decode on the GPU, set ort_providers=["CUDAExecutionProvider", "CPUExecutionProvider"] (Int8 + CUDA is discouraged and warned against).

Formula regions

Formula regions come from the PDF text layer (TeX math fonts such as cmmi/cmsy/cmex, plus unicode math codepoints), merged line-aware so multi-line display equations become one crop while separate equations, columns and prose stay apart. For text-layer-hostile PDFs (Word/InDesign/OCR output without math fonts), set formula_layout_fallback=True to ask the layout model for equation regions instead (off by default).

OCR batching

OCR recognition runs line crops in chunks of 32 on accelerators (6.3x faster on CUDA, measured) while CPU-only sessions keep the exact single-line path — provider-gated batching, byte-identical tensors on CPU (v0.4.28, see benchmarks).

Office documents

.docx / .xlsx / .pptx plus legacy .doc / .xls / .ppt convert to markdown via office_oxide (HybridConverter::convert_office(path) or the convert() dispatcher — no models needed). Excel workbooks additionally export per-sheet csv/json (convert_excel, <stem>.<sheet>.csv + <stem>.json siblings). Embedded pictures stage into <work_dir>/assets/office/ and rewrite to staged files, promoted to okf-asset:// by ingest_document — see §12 of the architecture doc.

Output contract

convert_pdf returns one markdown string: inline $…$ / display $$…$$ LaTeX spliced in place, GFM pipe tables, fenced code blocks from monospaced font runs, embedded images written to work_dir, plus an okf-asset:// staging store for unreferenced figures. Office docs additionally stage pictures into <work_dir>/assets/office/; workbooks yield <stem>.<sheet>.csv + <stem>.json siblings. For document-level workflows use ingest_document / convert_directory, which return versioned ConvertedDocuments with frontmatter and lint hooks.

Testing

cargo test                # 132 lib tests (ORT_DYLIB_PATH required — no dylib = abort)
cargo test --test test_office --test test_excel --test test_golden   # no models needed
ORT_DYLIB_PATH=... cargo test --test test_converter                 # incl. full-paper AUTO run
maturin develop && python -c "import bobine"   # bindings smoke test

Fixtures: trimmed CC BY 4.0 arXiv papers + a generated scanned page + generated OOXML fixtures — see tests/fixtures/SOURCES.md for provenance.

Docs

• Quick reference — install, API, config, common tasks
• Architecture — modules, data flow, coordinate spaces, model acquisition
• Benchmarks & test results — full CPU vs CUDA tables, TexTeller fp32/int8, OCR batching analysis, environment setup
• Proposal: figures/tables/layout — plan for reading-order image placement and structured table extraction

License

Apache-2.0 OR MIT (dual, choose either). Test fixtures are CC BY 4.0 (attribution in tests/fixtures/SOURCES.md). legacy/ keeps the original Python release's licensing.