py100mbify

Based on: 100mbify.sh. Rewrite in Python.

A command-line tool written in Python to compress video files to a precise target size, built primarily for creating high-quality WebM (VP9/Opus) files for platforms with file size limits like Discord.

The core of this script is a powerful 2-pass VP9 encoding routine wrapped around FFmpeg, allowing you to hit a file size target (e.g., 100 MiB) while maintaining the best possible quality.

Features

• Target Size Compression: Calculate the exact video bitrate needed to hit a specified file size (e.g., --size 50 MiB).
• WebM (VP9/Opus): Optimized for creating modern, efficient WebM files.
• Audit & History: Automatically logs completion status, final size, and encoding speed to py100mbify_history.log for long-term tracking.
• Smart Scaling: Automatically detects integer-ratio scaling (e.g., 4K -> 1080p) and uses neighbor for pixel-perfect sharpness, or falls back to bicubic.
• Trimming & Manipulation: Supports trimming (--start, --end), scaling (--scale), speed adjustment (--speed), and rotation.
• Hardsub Support: Easily burn in subtitles from the input file, automatically handling sync even when trimming mid-video.
• Web Compatibility Mode: One-flag fix (--target-web) to force 8-bit color and Profile 0.
• Prototype Mode: Quickly test cuts and filters using a fast single-pass CRF encode (--proto).
• Command Inspection: Use --print to output the exact FFmpeg commands for debugging.

Installation and Setup

Prerequisites

You must have FFmpeg and FFprobe installed and accessible in your system's $PATH.

• Windows: Use Scoop (scoop install ffmpeg) or manually add to %PATH%.
• Linux: sudo apt install ffmpeg.

Optional: Install psutil via pip if you wish to use the --cpu-priority feature on Windows.

Installation

Navigate to the root directory and install in editable mode:

pip install -e .

Usage

Command Categories

The CLI is organized into functional groups for better clarity:

1. Target Options

Argument	Description	Default
--size	Target output size in MiB.	100.0
--audio-bitrate	Bitrate for the libopus audio stream in kbps.	192
--mute	Completely strip audio from the output.	False

2. Clipping & Transformation

Argument	Description	Example
--start	Start offset (HH:MM:SS.mmm or seconds).	--start 00:01:30
--end	End timestamp (HH:MM:SS.mmm or seconds).	--end 120
--speed	Playback speed multiplier (e.g., 2.0).	--speed 1.5
--scale	Resizes the smallest dimension (maintains aspect).	--scale 720
--rotate	Rotate video clockwise by degrees.	--rotate 90

3. Quality & Filtering

Argument	Description
--hard-sub	Burn subtitles from the input file.
--target-web	Force 8-bit color (Profile 0) for browser compatibility.
--prepend-filters	FFmpeg video filters to apply BEFORE scaling.
--append-filters	FFmpeg video filters to apply AFTER internal logic.

4. Execution Control

Argument	Description
--cpu-priority	Set process priority (low or high).
--proto [CRF]	Fast single-pass encode for testing. Default CRF: 30.
--print	Print FFmpeg commands to stdout without running them.

Informative Reporting

For long-running jobs (hours or days), py100mbify provides detailed feedback:

• Encoding Speed: Calculated as a ratio (e.g., 0.50x means encoding takes twice as long as the video duration).
• Accuracy: Compares final file size against the requested target.
• History Log: Check py100mbify_history.log for a persistent audit trail of all completed encodes.

License

None. Use at your own risk!