---
id: fileseq
version: "3.3.0"
license: MIT
license_treatment: permissive
maintenance: active
---

# Fileseq — A Python library for parsing frame ranges and file sequences commonly used in VFX and Animation applications.

License: permissive · Maintenance: active · Downloads: 236.8K/mo

## What it is and what it does

Fileseq is a Python library that decodes frame range shorthand and file sequence patterns used throughout VFX and animation production. It parses compact notations like "1-100x5" (every 5th frame), "1-100y5" (5 frames at a time), and various padding styles (#, @, printf %04d, Houdini $F, UDIM) into expanded sequences of frame numbers or file paths. The library provides FrameSet for working with frame ranges as lists and FileSequence for associating ranges with file paths, supporting both string paths and pathlib.Path objects.

It also includes utilities to discover existing sequences on disk by pattern matching and to format sequences for different VFX software conventions. With no external dependencies, it integrates easily into render management, asset tracking, and pipeline automation scripts where frame sequences are a core data structure.

Use it for:

- Generate render output paths from compact frame notation in a render submission tool or asset manager.
- Parse user-provided frame ranges in a VFX pipeline UI and expand them into lists of files to process.
- Discover all image sequences in a render directory and organize them by shot or version for review.
- Convert between different padding conventions (e.g., Houdini $F4 to printf %04d) when integrating tools.
- Validate and normalize frame ranges in a production database or asset tracking system.
- Iterate over subframe sequences (e.g., 1001-1066x0.25) for motion blur or simulation output.

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

Parses frame ranges and file sequences using VFX-industry notation (e.g., 1-10#.exr, 1-100x5) and generates expanded file paths or frame lists for animation and visual effects pipelines.

Yes. Fileseq is actively maintained, has no dependencies, and solves a real and narrow problem in VFX pipelines where frame sequence notation is ubiquitous. It's production-stable since its early releases, supports current Python versions, carries no known vulnerabilities, and is licensed permissively. Install it if you work with render sequences, animation output, or VFX asset pipelines.

## Install

pip install fileseq
uv add fileseq
poetry add fileseq

## Installing Fileseq

Before you install: Low friction: pure Python wheel with no runtime dependencies. Active maintenance with a release 40 days ago and consistent commit history; supports Python 3.8 through 3.12.

License in practice: MIT license permits unrestricted use, modification, and distribution in commercial and private projects with minimal obligations.

Quickstart:

import fileseq

# Parse a frame range with padding notation
seq = fileseq.FileSequence("/foo/bar.1-10#.exr")

# Iterate expanded file paths
for path in seq:
    print(path)  # /foo/bar.0001.exr, /foo/bar.0002.exr, ...

# Or work with just the frame set
fs = fileseq.FrameSet("1-100x5")
print(fs.start(), fs.end())

Verify before relying:

- Whether the library handles Windows path separators and UNC paths correctly in production VFX pipelines.
- Performance characteristics when parsing very large frame ranges or deeply nested directory structures.

## Package facts

- License: MIT (permissive)
- Python support: supports_current
- Install friction: low
- Maintenance: active
- Downloads: 236.8K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

frame range parsing, vfx file sequences, animation frame notation, sequence path generation, frame number padding, render file sequences, vfx pipeline tools, vfx-pipeline, animation, file-sequences

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