Configurable chunk sizing
Splits large media files into sequential chunks sized to stay below a configurable upper limit, with a default target of 200 MB.
MediaSeg
MediaSeg is a local macOS utility that splits large media files into upload-ready chunks while trying to preserve original quality. It is aimed at NotebookLM-style and other size-limited upload workflows.
What MediaSeg does
MediaSeg is a local macOS utility that splits large media files into upload-ready chunks while trying to preserve the original quality. Its main purpose is to help people prepare long-form media for NotebookLM and similar workflows that impose file-size limits.
The project ships with a command-line entry point and a PySide6 desktop interface. The repository describes support for MP4 and WEBM inputs, uses local ffmpeg and ffprobe for probing and splitting, and defaults to a 200 MB target chunk size with an optional override.
Core features
Target-based output sizing
Uses a target-range strategy that aims for chunks close to the configured limit while keeping the limit as a hard upper bound.
Local-first operation
Processes files locally instead of uploading them to a remote service, which keeps the workflow on the user’s machine.
CLI and desktop UI
Supports a CLI entry point for command-line use and a PySide6 desktop interface for drag-and-drop workflows.
Media format handling
Handles MP4 and WEBM inputs through local ffmpeg and ffprobe tooling, with WEBM converted before splitting.
macOS app packaging
Packages as a macOS app with SVG icon assets and release-oriented build scripts in the repository.
Practical use cases
Size-limited uploads
Prepare long-form recordings for NotebookLM or another service that rejects files above a size threshold.
Media splitting without re-encoding
Break a large video into ordered parts while keeping the original quality wherever ffmpeg stream copy is possible.
Command-line batch runs
Run the splitter from a script or terminal with a specific `--max-size` value when you need repeatable output sizes.
Interactive desktop workflow
Use the desktop app to choose an input file, monitor processing states, and save chunks to a selected output folder.
Pros and Cons
Pros
- Keeps the workflow local on macOS rather than relying on cloud processing.
- Offers both a CLI and a desktop UI, which covers scripted and interactive use.
- Uses target-based chunk sizing to stay under the configured limit while aiming for consistent chunk sizes.
- Documents a simple default of 200 MB with a command-line override for smaller or larger targets.
Cons
- The repository only documents MP4 and WEBM support today, with other formats listed as planned.
- WEBM conversion can take longer and use more CPU than MP4 processing, especially on large recordings.
- The default build does not bundle FFmpeg, so the target machine needs ffmpeg and ffprobe installed and available in PATH.
FAQ
What is MediaSeg used for?
MediaSeg is a local macOS utility for splitting large media files into upload-ready chunks. The repository frames its main use case as preparing long-form media for NotebookLM and other size-limited upload workflows.
Which file formats does MediaSeg support?
The repository documents MP4 and WEBM support. WEBM files are converted locally before splitting, while MP4 files are processed with local ffmpeg tools.
Does MediaSeg run locally or use the cloud?
MediaSeg is built around local file processing. The README says it works entirely on local files, and the default build does not bundle FFmpeg, so ffmpeg and ffprobe need to be available on the target Mac.
Can I change the chunk size?
The command-line entry point accepts an input file path and an optional `--max-size` value in decimal MB. The default target chunk size is 200 MB.
What happens if ffmpeg is missing?
The project README says the app shows a dependency warning if ffmpeg or ffprobe is missing, and the Start Splitting action stays disabled until the dependency is available.
Quick Facts
- Category
- Developer Tool
- Platform
- macOS on Apple Silicon
- Primary use
- Split media into upload-ready chunks
- Source domain
- github.com
- License/pricing
- Open-source GitHub repository; no paid plan is described on the project page
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