bg-audio

name: bg-audio description: Render a carousel of 30-second Instagram videos from images + mp3s in scripts/bg-audio/. Use when the user wants to make playlist carousel videos, render carousel videos, or invokes /bg-audio.

You are babysitting the interactive pnpm bg-audio script for the user. It pairs images with mp3s and renders 30-second 1080x1350 H.264 videos.

Step 1 — Pick the folder

List subdirectories of scripts/bg-audio/ with ls scripts/bg-audio/.
If there is exactly one, use it. Otherwise use AskUserQuestion to let the user pick. The question header should be "Carousel" and each option should be a folder name.
If $ARGUMENTS (the text after /bg-audio) contains a folder name that matches, skip the question and use that.

Step 2 — Inspect contents

Run ls scripts/bg-audio/<folder>/ and identify the images (.png, .jpg, .jpeg, .webp) and audio (.mp3, .m4a, .wav). Files are typically named like quincy post 1.png and song 1.mp3 — the trailing number determines the pairing.

For each mp3, get its duration with ffprobe:

ffprobe -v error -show_entries format=duration -of default=nw=1:nk=1 "scripts/bg-audio/<folder>/<song>.mp3"

Run all ffprobe calls in parallel.

Step 3 — Confirm pairings and collect timestamps

Show the user the detected pairings (image N ↔ song N by trailing number) in a single message, with each song's duration. Then ask for timestamps with a single AskUserQuestion if there are ≤4 songs, or by asking in plain text if there are more.

Accept timestamps in mm:ss or seconds. If the user gives them all at once like "0:30, 1:15, 0:45, 2:00", parse that.

If a pairing isn't 1↔1 (e.g. mismatched counts, non-sequential names), ask the user to confirm pairings first.

Step 4 — Run the script with --auto

Use the --auto flag with comma-separated timestamps (assumes 1↔1 default pairings):

pnpm bg-audio "scripts/bg-audio/<folder>" --auto 29,0,24,0

Quote the folder path (it usually has spaces or underscores). Timestamps can be mm:ss or seconds (e.g. 1:23 or 83). The script needs exactly one timestamp per image.

If the user wanted non-default pairings (rare), fall back to running the interactive prompts manually in their own terminal — Claude's piped stdin doesn't work reliably with readline.

Re-rendering individual videos with --only

When the user wants to redo just one (or a few) videos — e.g. "redo post 5 with an 8s start" — use --only instead of --auto. It renders only the listed images and leaves the rest untouched:

pnpm bg-audio "scripts/bg-audio/<folder>" --only 6:8
pnpm bg-audio "scripts/bg-audio/<folder>" --only 6:0:08,3:1:15

Each spec is index:timestamp, comma-separated. The index is 1-based, matching the [N] image list the script prints — it is not the trailing number in the filename. Translate the user's reference into the right index:

Files sort numerically, so Instagram post - 0.png is index [1], post - 1 is [2], … post - N is [N+1].
So "post 5" → index 6, "post 0" → index 1.

Timestamps accept mm:ss or seconds; only the first colon splits the spec, so 6:1:15 means image 6 at 1:15.

Step 5 — Report results

When ffmpeg finishes, list the generated .mp4 files in scripts/bg-audio/<folder>/render/ and tell the user they're ready to AirDrop. For an --only re-render, just report the videos that were re-rendered.

Notes

Don't read or edit scripts/make-bg-audio.js unless something is broken — just drive it.
ffmpeg and ffprobe are already allowlisted in .claude/settings.local.json.
If a render fails, surface the ffmpeg error directly; don't retry silently.