How to Create Videos Like the Demo (52 seconds in just 736kB!)

This guide explains how I created such a small yet effective demonstration video, being only 736kB for a 52-second video!

https://github.com/user-attachments/assets/9e4fc237-a3cd-46bd-b82c-c608336d6411

What You Need

A background image (bg.jpg)
The subtitle file (.srt) (created by Abogen)
The audio recording (.wav) (created by Abogen)
Python and FFmpeg installed on your computer:

# Windows
winget install ffmpeg

# MacOS
brew install ffmpeg

# Linux
sudo apt install ffmpeg

Step 1: Process the Subtitle File

Run this command to process Abogen's subtitle file:

python convert.py your_subtitle.srt

This creates a properly formatted subtitle file called "your_subtitle_demo.ass" with centered text and appropriate styling.

Step 2: Create the Video (.webm)

Run this FFmpeg command to create the tiny video:

ffmpeg -loop 1 -framerate 24 -i bg.jpg -i audio.wav -vf "ass=your_subtitle_demo.ass" -c:v libvpx-vp9 -b:v 0 -crf 30 -c:a libopus -shortest demo.webm

That's it! The magic happens because:

We use a single static background image instead of many frames
The subtitles are stored as text (vector data), not as pixels
VP9 video codec with Opus audio provides excellent compression

For Higher Quality (But Larger) Video (.mp4)

If you need better quality for distribution, use this command instead:

ffmpeg -loop 1 -framerate 24 -i bg.jpg -i audio.wav -vf "ass=your_subtitle_demo.ass" -c:v libx264 -preset slow -crf 18 -movflags +faststart -c:a copy -shortest demo.mp4

This creates an MP4 file that's compatible with more devices but larger in size.