make_video

Combine an audio file and a folder of 16:9 images into a single looping MP4 — locally, no upload.

Each image shows for 13 seconds with a slow Ken Burns zoom, the images loop in numeric filename order (1, 2, 3 …), and the video is trimmed to exactly the length of the audio (no trailing silence).

Prerequisites

• FFmpeg (provides ffmpeg + ffprobe):

  brew install ffmpeg

• Python 3.9+ — already on macOS. No pip install needed; the script uses only the standard library.

Usage

python3 make_video.py <audio_file> <images_folder> <output_file> [--res HEIGHT] [--zoom MODE] [--fade SECONDS] [--no-normalize]

Example:

python3 make_video.py audio.mp3 ./images ./output/story.mp4 --res 480 --zoom alternate

Options:

Flag	Effect
--res HEIGHT	Output resolution: 480 (default), 720, 1080, 360. Lower = much faster + smaller.
--zoom MODE	Ken Burns effect: alternate (default), in, out, inout, none
--fade SECONDS	Fade in/out (video + audio); 0 disables (default 1)
--no-normalize	Skip loudness normalization (default: normalize to −14 LUFS)

Speed tip: resolution is by far the biggest factor in render time — 1080p is roughly 12× slower than the 480p default. Storytelling over static images looks fine at 480p, so that's the default; bump to 720p/1080p only if you need it sharper.

--zoom modes: alternate = image 1 zooms in, image 2 out, …; in/out = every image the same way; inout = zoom in then back out; none = static. All zooming modes also add a gentle alternating pan. The output folder is created automatically if it doesn't exist.

Web interface

Prefer clicking to typing? Run the local web app:

python3 app.py

It opens http://localhost:8000 in your browser. Choose an audio file and your images, click Create video, watch the progress bar, then preview and download the MP4. To use a different port: PORT=8080 python3 app.py.

• Same engine as the CLI (identical encode settings) — it just adds a UI and a live progress bar.
• Binds to localhost only, so it is not exposed to your network.
• Stdlib only (no pip install). Needs Python ≤ 3.12 because it uses the standard-library cgi module for uploads; the CLI works on any Python 3.9+.
• Rendered videos are saved under renders/<id>/output.mp4, so download links keep working even if you restart the server. This folder is your render history — delete old subfolders (or the whole renders/ folder) anytime to free space.

Notes

• Images must be 16:9. They are scaled to 1920×1080 (no padding/letterboxing); any other aspect ratio will be stretched.
• Image order: numeric by filename (1.png, 2.png … 10.png), then they loop until the audio ends.
• Supported image formats: .jpg, .jpeg, .png, .webp.
• Supported audio formats: .mp3, .wav, .m4a (anything ffprobe can read).
• Output: 1920×1080 H.264 (CRF 18, preset fast, yuv420p) MP4 with AAC 192k audio and +faststart, trimmed to the audio duration.
• A temporary _concat.txt is written next to the output and deleted automatically.

Tips

• For best results, use consistently sized images (1920x1080 recommended).
• Name images numerically starting from 1 for predictable ordering.
• Use --zoom alternate to vary the Ken Burns direction between images.
• Longer audio files will loop the image set automatically.