Recover PDF text truncated by inline images using PyMuPDF fallback

[Muhtasim-Munif-Fahim]

Fixes #1870.

Some PDFs with inline images cause pdfplumber/pdfminer to silently drop text that appears after the image. When the primary extraction path returns a much shorter body on image-bearing pages, this change optionally retries with PyMuPDF and prefers that output if it is substantially longer.

Also documents the optional pymupdf extra and adds a regression test that simulates the truncation path.

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[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Adds an optional PyMuPDF-based text extraction fallback to improve PDF conversion when primary extractors (pdfplumber/pdfminer) appear to return truncated text, particularly around inline images.

Changes:

• Introduces an optional PyMuPDF extraction path and heuristics to prefer it when primary output looks truncated.
• Adds a regression test to validate choosing PyMuPDF when primary extraction misses post-image text.
• Documents and packages PyMuPDF as an optional extra (and includes it in the all extra).

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
packages/markitdown/tests/test_module_misc.py	Adds a test that simulates truncation and asserts the PyMuPDF path is preferred.
packages/markitdown/src/markitdown/converters/_pdf_converter.py	Adds PyMuPDF extraction helper and selection heuristics based on images + output length.
packages/markitdown/pyproject.toml	Adds pymupdf optional dependency (extra + included in all).
packages/markitdown/README.md	Documents how to install the optional PyMuPDF extra.

---

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[noezhiya-dot]

This is a well-structured approach to the PDF truncation problem. A few thoughts:

1. The heuristic for choosing PyMuPDF output (1.5x length ratio or 200 char difference) is reasonable but could benefit from a comment explaining the thresholds. Were these determined empirically?

2. The len(markdown) < 2048 guard is a good safety check to avoid re-processing large documents, but it means the fallback won't trigger for longer PDFs even if they have truncation. Is this intentional? A per-page comparison might be more robust.

3. The test is clean and well-mocked. Good use of monkeypatch to simulate the truncation scenario.

4. One edge case: what happens when PyMuPDF is installed but the PDF is corrupted? The broad except Exception in the fallback block silently swallows errors, which is fine, but consider logging a debug message so users can troubleshoot.

Overall solid contribution. The optional dependency approach via extras is the right pattern for this project.

[noezhiya-dot]

Nice approach to the inline-image truncation problem. The fallback logic is well-scoped — it only kicks in when:

1. PyMuPDF is available
2. The page has images
3. The primary extraction is short (< 2048 chars)

A few thoughts:

1. Threshold tuning: The 2048-char threshold and 1.5x ratio check are reasonable heuristics, but they might miss cases where a PDF has images but the truncation is less dramatic. Have you considered making these thresholds configurable, or at least documenting the rationale?

2. Performance: The PyMuPDF pass re-reads the entire PDF from the BytesIO stream. For large PDFs with many pages, this could add noticeable overhead even when the fallback isn't needed. The has_images check helps, but pdfplumber's page.images might not catch all inline image types. Worth a comment in the code about this trade-off.

3. Test coverage: The unit test is solid for the happy path. Consider adding a test case where PyMuPDF returns worse results than the primary parser — to verify the fallback correctly doesn't activate.

4. pyproject.toml: Adding pymupdf to the all extra is correct, but you might also want to add a note in the main README about when someone would want [pymupdf] vs [all].

Overall, this is a well-engineered fix for a real problem. The code is clean and the tests are thorough.

[noezhiya-dot]

Code Review: Recover PDF text truncated by inline images using PyMuPDF fallback

Solid approach to a real problem. The fallback heuristic is well-designed.

Strengths

• Smart heuristic: requires (a) images present, (b) primary output < 2048 chars, AND (c) PyMuPDF output is 1.5x+ longer or 200+ chars longer. Prevents unnecessary switching on already-good output.
• Clean separation with _extract_with_pymupdf() as a standalone function.
• Good test coverage with monkeypatched fakes.
• README and pyproject.toml extras properly updated.

Suggestions

1. Threshold magic numbers: The 2048-char threshold and 1.5x/200-char ratios are reasonable but hardcoded. Consider making them module-level constants so they are documented and tunable.

2. pdf_bytes position clarity: The fallback section relies on _extract_with_pymupdf seeking internally. An explicit pdf_bytes.seek(0) before the fallback block would improve readability.

3. Form pages edge case: When form_page_count > 0, the PyMuPDF fallback does not trigger since it is inside the pdfminer path. Form-style PDFs with image truncation on non-form pages won't get the fallback. Worth documenting this behavior in a comment.

4. Test coverage: Consider adding a test for the case where form pages exist but the PyMuPDF fallback should NOT trigger, to document that boundary.

Approved with minor suggestions. The core logic is sound and the fallback conditions are conservative enough to avoid regressions.