---
name: file-converter
description: Convert, merge, split, and compress files across formats — documents, images, audio, and more.
---
# File Converter
Convert between data, document, image, audio formats, and ZIP archives. One-liners for each conversion pair.
## Tool Map
| Domain | Tool | Install |
|---|---|---|
| CSV/JSON/Excel/Parquet | `pandas` | `pip install pandas openpyxl pyarrow` |
| YAML | `pyyaml` | `pip install pyyaml` |
| XML ↔ dict | `xmltodict` | `pip install xmltodict` |
| Any doc format ↔ any | **pandoc** (CLI) | `apt install pandoc` or `pip install pypandoc_binary` |
| Markdown → HTML | `markdown` | `pip install markdown` |
| HTML → Markdown | `markdownify` | `pip install markdownify` |
| .docx read/write | `python-docx` | `pip install python-docx` |
| PDF → text/tables | `pdfplumber` | `pip install pdfplumber` |
| PDF → images | `pdf2image` | `pip install pdf2image` + `apt install poppler-utils` |
| PDF manipulation | `pypdf` | `pip install pypdf` |
| Images | `Pillow` | `pip install Pillow` |
| SVG → PNG | `cairosvg` | `pip install cairosvg` |
| HEIC → JPG | `pillow-heif` | `pip install pillow-heif` |
| Audio formats | `pydub` | `pip install pydub` + `apt install ffmpeg` |
| EPUB ↔ other | **pandoc** or `ebooklib` | `pip install ebooklib` |
| HTML → PDF | `weasyprint` | `pip install weasyprint` |
| GIF creation | `Pillow` or `imageio` | `pip install imageio[ffmpeg]` |
| PDF → SVG | `pdf2image` + `potrace` or `pymupdf` | `pip install pymupdf` |
| ZIP archives | `zipfile` (stdlib) | built-in, no install needed |
## File Input Handling
When a user wants to convert a file that can't be attached directly in the chat (e.g., `.heic`, `.flac`, `.epub`, `.psd`, `.m4a`, `.wma`, `.parquet`), ask them to upload it to the project's file system. Uploaded files typically appear in `attached_assets/` or the project root. Always check both locations. If the file isn't found, ask the user where they saved it.
Common unsupported-in-chat but convertible formats: `.heic`, `.avif`, `.webp`, `.flac`, `.ogg`, `.m4a`, `.wma`, `.aiff`, `.epub`, `.parquet`, `.psd`, `.svg`, `.zip`
## Data Formats
```python
import pandas as pd, json, yaml, xmltodict
# --- CSV ↔ JSON ---
pd.read_csv("in.csv").to_json("out.json", orient="records", indent=2)
pd.read_json("in.json").to_csv("out.csv", index=False)
# --- CSV → Excel / Excel → CSV ---
pd.read_csv("in.csv").to_excel("out.xlsx", index=False, engine="openpyxl")
pd.read_excel("in.xlsx", sheet_name="Sheet1").to_csv("out.csv", index=False)
# All sheets: pd.read_excel("in.xlsx", sheet_name=None) → dict of DataFrames
# --- CSV → Parquet (columnar, compressed) ---
pd.read_csv("in.csv").to_parquet("out.parquet", engine="pyarrow", compression="snappy")
# --- YAML ↔ JSON ---
data = yaml.safe_load(open("in.yaml")) \# ALWAYS safe_load, never load()
json.dump(data, open("out.json", "w"), indent=2)
yaml.safe_dump(json.load(open("in.json")), open("out.yaml", "w"), sort_keys=False)
# --- XML ↔ JSON ---
data = xmltodict.parse(open("in.xml").read())
json.dump(data, open("out.json", "w"), indent=2)
open("out.xml", "w").write(xmltodict.unparse(data, pretty=True))
# --- JSONL (one JSON object per line) ---
pd.read_json("in.jsonl", lines=True).to_csv("out.csv", index=False)
```
**Encoding gotchas:**
- `pd.read_csv("f.csv", encoding="utf-8-sig")` strips the BOM that Excel inserts
- Auto-detect: `import chardet; enc = chardet.detect(open("f.csv","rb").read())["encoding"]`
- CSV delimiter sniffing: `pd.read_csv("f.csv", sep=None, engine="python")`
**Nested JSON → flat CSV:**
```python
pd.json_normalize(data, sep=".").to_csv("out.csv", index=False) \# {"a":{"b":1}} → column "a.b"
```
## Document Formats — pandoc is the Swiss Army knife
```bash
# Markdown → PDF (requires LaTeX: apt install texlive-xetex)
pandoc input.md -o output.pdf --pdf-engine=xelatex
# Markdown → DOCX
pandoc input.md -o output.docx
# DOCX → Markdown (extracts images to ./media/)
pandoc input.docx -o output.md --extract-media=.
# HTML → Markdown
pandoc input.html -o output.md -t gfm
# Any → Any (pandoc supports ~40 formats)
pandoc -f docx -t rst input.docx -o output.rst
```
```python
# From Python
import pypandoc
pypandoc.convert_file("in.md", "docx", outputfile="out.docx")
```
**Without pandoc (pure Python):**
```python
# Markdown → HTML
import markdown
html = markdown.markdown(open("in.md").read(), extensions=["tables", "fenced_code", "toc"])
# HTML → Markdown
from markdownify import markdownify
md = markdownify(html, heading_style="ATX") \# ATX = \# headers, not underlines
```
## PDF Operations
```python
# --- Extract text + tables ---
import pdfplumber
with pdfplumber.open("in.pdf") as pdf:
text = "\n".join(p.extract_text() or "" for p in pdf.pages)
tables = pdf.pages[0].extract_tables() \# list of list-of-rows
# --- PDF → images (one PNG per page) ---
from pdf2image import convert_from_path
for i, img in enumerate(convert_from_path("in.pdf", dpi=200)):
img.save(f"page_{i+1}.png")
# --- Merge / split / rotate ---
from pypdf import PdfReader, PdfWriter
writer = PdfWriter()
for path in ["a.pdf", "b.pdf"]:
for page in PdfReader(path).pages:
writer.add_page(page)
writer.write("merged.pdf")
# Extract pages 2–5
reader = PdfReader("in.pdf")
writer = PdfWriter()
for p in reader.pages[1:5]:
writer.add_page(p)
writer.write("pages_2-5.pdf")
```
**PDF gotchas:**
- `pdf2image` needs `poppler-utils` installed system-wide (not a pip package)
- Scanned PDFs have no text layer — pdfplumber returns `None`. Use `pytesseract` OCR on pdf2image output.
- `PyPDF2` is deprecated → use `pypdf` (same API, maintained fork)
## Image Formats
```python
from PIL import Image
# --- Basic conversion ---
Image.open("in.png").convert("RGB").save("out.jpg", quality=90)
# convert("RGB") is REQUIRED: JPEG can't store alpha channel, will raise OSError
# --- WebP (best web format) ---
Image.open("in.jpg").save("out.webp", quality=85, method=6) \# method 0-6, 6=best compression
# --- AVIF (smallest, Pillow 11+) ---
Image.open("in.jpg").save("out.avif", quality=75)
# --- HEIC (iPhone photos) → JPG ---
from pillow_heif import register_heif_opener
register_heif_opener()
Image.open("in.heic").convert("RGB").save("out.jpg", quality=90)
# --- SVG → PNG ---
import cairosvg
cairosvg.svg2png(url="in.svg", write_to="out.png", output_width=1024)
# --- Batch convert directory ---
from pathlib import Path
for p in Path("imgs").glob("*.png"):
Image.open(p).convert("RGB").save(p.with_suffix(".jpg"), quality=85)
```
**Image gotchas:**
- PNG → JPG: **must** `convert("RGB")` first or transparency crashes the save
- `quality` for PNG is meaningless (lossless) — use `optimize=True, compress_level=9`
- Pillow can't open `.svg` natively — use `cairosvg` or `svglib`
- GIF → MP4 is a video operation: `ffmpeg -i in.gif -pix_fmt yuv420p out.mp4`
## Audio Formats
```python
from pydub import AudioSegment
# --- MP3 ↔ WAV ---
AudioSegment.from_mp3("in.mp3").export("out.wav", format="wav")
AudioSegment.from_wav("in.wav").export("out.mp3", format="mp3", bitrate="192k")
# --- FLAC → MP3 ---
AudioSegment.from_file("in.flac", format="flac").export("out.mp3", format="mp3", bitrate="320k")
# --- OGG → MP3 ---
AudioSegment.from_ogg("in.ogg").export("out.mp3", format="mp3", bitrate="192k")
# --- M4A / AAC → MP3 ---
AudioSegment.from_file("in.m4a", format="m4a").export("out.mp3", format="mp3", bitrate="256k")
# --- Any → Any (pydub supports mp3, wav, ogg, flac, m4a, aac, wma, aiff) ---
AudioSegment.from_file("in.wma", format="wma").export("out.flac", format="flac")
# --- Trim audio (first 30 seconds) ---
audio = AudioSegment.from_file("in.mp3")
audio[:30000].export("first_30s.mp3", format="mp3") \# milliseconds
# --- Merge / concatenate ---
combined = AudioSegment.from_file("a.mp3") + AudioSegment.from_file("b.mp3")
combined.export("merged.mp3", format="mp3")
# --- Adjust volume ---
audio = AudioSegment.from_file("in.mp3")
louder = audio + 6 \# +6 dB
quieter = audio - 6 \# -6 dB
louder.export("louder.mp3", format="mp3")
# --- Get audio info ---
audio = AudioSegment.from_file("in.mp3")
print(f"Duration: {len(audio)/1000:.1f}s, Channels: {audio.channels}, "
f"Sample rate: {audio.frame_rate}Hz, Sample width: {audio.sample_width*8}bit")
# --- Batch convert directory ---
from pathlib import Path
for p in Path("audio").glob("*.wav"):
AudioSegment.from_wav(str(p)).export(p.with_suffix(".mp3"), format="mp3", bitrate="192k")
```
**Audio gotchas:**
- `pydub` requires `ffmpeg` installed system-wide for non-WAV formats
- Bitrate options: "128k" (small/low quality), "192k" (balanced), "256k" (high), "320k" (max for MP3)
- WAV files are uncompressed — expect 10x larger file sizes than MP3
- For sample rate conversion: `audio.set_frame_rate(44100).export("out.wav", format="wav")`
- Mono to stereo: `audio.set_channels(2)` / Stereo to mono: `audio.set_channels(1)`
## ZIP Archives
```python
import zipfile
from pathlib import Path
# --- Create ZIP from files ---
with zipfile.ZipFile("archive.zip", "w", zipfile.ZIP_DEFLATED) as zf:
zf.write("file1.txt")
zf.write("file2.csv")
zf.write("images/photo.jpg")
# --- Create ZIP from entire directory ---
import shutil
shutil.make_archive("archive", "zip", root_dir="my_folder") \# creates archive.zip
# --- Extract all ---
with zipfile.ZipFile("archive.zip", "r") as zf:
zf.extractall("output_dir")
# --- Extract single file ---
with zipfile.ZipFile("archive.zip", "r") as zf:
zf.extract("file1.txt", "output_dir")
# --- List contents without extracting ---
with zipfile.ZipFile("archive.zip", "r") as zf:
for info in zf.infolist():
print(f"{info.filename} {info.file_size:,} bytes {info.compress_size:,} compressed")
# --- Read file from ZIP without extracting ---
with zipfile.ZipFile("archive.zip", "r") as zf:
content = zf.read("file1.txt").decode("utf-8")
# --- Add files to existing ZIP ---
with zipfile.ZipFile("archive.zip", "a") as zf:
zf.write("new_file.txt")
# --- Create ZIP with password (read-only, use pyzipper for write) ---
# pip install pyzipper
import pyzipper
with pyzipper.AESZipFile("secure.zip", "w", compression=pyzipper.ZIP_DEFLATED,
encryption=pyzipper.WZ_AES) as zf:
zf.setpassword(b"my_password")
zf.write("secret.txt")
# --- Batch: ZIP all PDFs in a directory ---
with zipfile.ZipFile("all_pdfs.zip", "w", zipfile.ZIP_DEFLATED) as zf:
for p in Path(".").glob("**/*.pdf"):
zf.write(p)
```
**ZIP gotchas:**
- `zipfile` is in Python's standard library — no install needed
- Always use `ZIP_DEFLATED` compression (default is `ZIP_STORED` = no compression)
- For password-protected ZIPs, stdlib `zipfile` can only read (not write) — use `pyzipper` for encrypted writes
- Max file size in standard ZIP is 4 GB; use `allowZip64=True` (default in Python 3) for larger files
- `shutil.make_archive` is the simplest way to ZIP an entire directory tree
## EPUB Formats
```python
# --- EPUB → other formats (via pandoc) ---
# pandoc is the easiest way to convert EPUB
import pypandoc
# EPUB → Markdown
pypandoc.convert_file("in.epub", "markdown", outputfile="out.md")
# EPUB → HTML
pypandoc.convert_file("in.epub", "html", outputfile="out.html")
# EPUB → DOCX
pypandoc.convert_file("in.epub", "docx", outputfile="out.docx")
# EPUB → plain text
pypandoc.convert_file("in.epub", "plain", outputfile="out.txt")
# --- Other formats → EPUB ---
# Markdown → EPUB
pypandoc.convert_file("in.md", "epub", outputfile="out.epub",
extra_args=["--metadata", "title=My Book"])
# HTML → EPUB
pypandoc.convert_file("in.html", "epub", outputfile="out.epub",
extra_args=["--metadata", "title=My Book"])
# DOCX → EPUB
pypandoc.convert_file("in.docx", "epub", outputfile="out.epub")
```
```bash
# --- CLI equivalents ---
pandoc in.epub -o out.md
pandoc in.epub -o out.pdf --pdf-engine=xelatex
pandoc in.md -o out.epub --metadata title="My Book"
pandoc in.html -o out.epub --metadata title="My Book" --epub-cover-image=cover.jpg
```
```python
# --- Pure Python: read/write EPUB with ebooklib ---
from ebooklib import epub
# Read EPUB
book = epub.read_epub("in.epub")
for item in book.get_items_of_type(9): \# 9 = ITEM_DOCUMENT (HTML chapters)
print(item.get_name())
html_content = item.get_content().decode("utf-8")
# Create EPUB from scratch
book = epub.EpubBook()
book.set_identifier("id123")
book.set_title("My Book")
book.set_language("en")
book.add_author("Author Name")
ch1 = epub.EpubHtml(title="Chapter 1", file_name="ch1.xhtml", lang="en")
ch1.content = "Chapter 1
Hello world.
"
book.add_item(ch1)
book.toc = [epub.Link("ch1.xhtml", "Chapter 1", "ch1")]
book.add_item(epub.EpubNcx())
book.add_item(epub.EpubNav())
book.spine = ["nav", ch1]
epub.write_epub("out.epub", book)
```
**EPUB gotchas:**
- `pandoc` is the simplest for format-to-format EPUB conversion
- Always add `--metadata title="..."` when creating EPUB — readers require a title
- EPUB is essentially a ZIP of HTML files — `ebooklib` gives you fine-grained control
- For EPUB → PDF, pandoc needs a LaTeX engine (`texlive-xetex`)
- Cover images: use `--epub-cover-image=cover.jpg` with pandoc
## HTML to PDF
```python
# --- weasyprint (best CSS support, no browser needed) ---
from weasyprint import HTML
# Simple file conversion
HTML("in.html").write_pdf("out.pdf")
# From URL
HTML("https://example.com").write_pdf("page.pdf")
# From HTML string
HTML(string="Hello
World
").write_pdf("out.pdf")
# With custom CSS
HTML("in.html").write_pdf("out.pdf", stylesheets=["custom.css"])
# With page size and margins
from weasyprint import CSS
HTML("in.html").write_pdf("out.pdf", stylesheets=[
CSS(string="@page { size: A4; margin: 2cm; }")
])
# Landscape orientation
HTML("in.html").write_pdf("out.pdf", stylesheets=[
CSS(string="@page { size: A4 landscape; margin: 1.5cm; }")
])
```
```bash
# --- CLI alternatives ---
# pandoc (simpler, less CSS fidelity)
pandoc in.html -o out.pdf --pdf-engine=xelatex
# weasyprint CLI
weasyprint in.html out.pdf
weasyprint https://example.com page.pdf
```
**HTML to PDF gotchas:**
- `weasyprint` supports CSS3 including flexbox, grid, and `@page` rules — best for styled documents
- `weasyprint` does NOT run JavaScript — for JS-heavy pages, use `playwright` or `pyppeteer` instead
- For JS-rendered pages: `playwright` → `page.pdf()` is the most reliable option
- pandoc HTML → PDF goes through LaTeX, so complex CSS layouts may not render correctly
- Large HTML files with many images: use `HTML(filename="in.html", base_url=".")` so relative image paths resolve
## GIF Creation
```python
from PIL import Image
import imageio.v3 as iio
from pathlib import Path
# --- Images → animated GIF (Pillow) ---
frames = [Image.open(f"frame_{i}.png") for i in range(10)]
frames[0].save("out.gif", save_all=True, append_images=frames[1:],
duration=100, loop=0) \# duration in ms, loop=0 means infinite
# --- Images → GIF with optimization ---
frames = [Image.open(f"frame_{i}.png").convert("RGBA") for i in range(10)]
frames[0].save("out.gif", save_all=True, append_images=frames[1:],
duration=100, loop=0, optimize=True)
# --- Directory of images → GIF ---
frame_paths = sorted(Path("frames").glob("*.png"))
frames = [Image.open(p) for p in frame_paths]
frames[0].save("out.gif", save_all=True, append_images=frames[1:],
duration=100, loop=0)
# --- GIF → individual frames ---
gif = Image.open("in.gif")
for i in range(gif.n_frames):
gif.seek(i)
gif.save(f"frame_{i}.png")
# --- Resize GIF ---
gif = Image.open("in.gif")
resized_frames = []
for i in range(gif.n_frames):
gif.seek(i)
resized_frames.append(gif.copy().resize((320, 240), Image.LANCZOS))
resized_frames[0].save("small.gif", save_all=True, append_images=resized_frames[1:],
duration=gif.info.get("duration", 100), loop=0)
# --- Video → GIF (imageio + ffmpeg) ---
import imageio.v3 as iio
frames = iio.imread("in.mp4", plugin="pyav")
iio.imwrite("out.gif", frames, plugin="pillow", duration=40, loop=0)
# --- GIF → MP4 (ffmpeg CLI, much smaller file) ---
# ffmpeg -i in.gif -pix_fmt yuv420p -vf "scale=trunc(iw/2)*2:trunc(ih/2)*2" out.mp4
```
**GIF gotchas:**
- GIF is limited to 256 colors per frame — complex images lose quality
- Use `optimize=True` to reduce file size, but large GIFs are still huge compared to MP4
- `duration` is per-frame in milliseconds (100ms = 10 FPS, 40ms = 25 FPS)
- `loop=0` means infinite loop; `loop=1` plays once then stops
- For video → GIF, consider downscaling first — full-resolution GIFs are enormous
- Pillow GIF output doesn't support transparency well — use `imageio` for better results
- For best quality: create GIF from video with ffmpeg: `ffmpeg -i in.mp4 -vf "fps=15,scale=480:-1" out.gif`
## PDF to SVG
```python
# --- PyMuPDF (fitz) — best quality, vector-preserving ---
import fitz \# pip install pymupdf
# Single page
doc = fitz.open("in.pdf")
page = doc[0]
svg_text = page.get_svg_image()
with open("page_1.svg", "w") as f:
f.write(svg_text)
# All pages
doc = fitz.open("in.pdf")
for i, page in enumerate(doc):
svg_text = page.get_svg_image()
with open(f"page_{i+1}.svg", "w") as f:
f.write(svg_text)
doc.close()
# With custom resolution (matrix scales the output)
doc = fitz.open("in.pdf")
page = doc[0]
mat = fitz.Matrix(2, 2) \# 2x scale for higher detail
svg_text = page.get_svg_image(matrix=mat)
with open("page_hires.svg", "w") as f:
f.write(svg_text)
```
```bash
# --- CLI alternatives ---
# pdf2svg (if installed)
pdf2svg in.pdf out.svg 1 \# page number
# Inkscape CLI
inkscape in.pdf --export-type=svg --export-filename=out.svg
# pdftocairo (from poppler-utils)
pdftocairo -svg in.pdf out.svg
```
**PDF to SVG gotchas:**
- `pymupdf` (imported as `fitz`) produces true vector SVGs — text stays as text, paths stay as paths
- Scanned PDFs produce SVGs with embedded raster images (no vector data to extract)
- Large PDFs with complex graphics produce very large SVG files
- `pdf2svg` CLI tool is simple but must be installed separately (`apt install pdf2svg`)
- For rasterized SVG (simpler but not truly vector): render PDF to PNG first, then embed in SVG
## Validation
Always verify output:
```python
# Row count parity
assert len(pd.read_csv("out.csv")) == len(pd.read_json("in.json"))
# JSON well-formed
json.load(open("out.json"))
# Image opens
Image.open("out.jpg").verify()
```