Free YouTube Shorts Maker — AI Clip Extractor

ViralMint is a free YouTube Shorts maker and AI clip extractor — an Opus Clip and Submagic alternative that turns long videos into viral-scored shorts with hook classification and word-by-word animated captions.

How the viral-clip picker chooses what to keep

{
  "tool": "ViralMint Viral Clip Extractor",
  "input": "long-form video (any length, any source) + Whisper transcript",
  "selection_axes": ["hook_strength", "retention_curve", "emotion_peaks", "keyword_density"],
  "outlier_tiers": {
    "OUTLIER":  "3x channel median",
    "STRONG":   "5x channel median",
    "BREAKOUT": "10x channel median",
    "MONSTER":  "20x channel median"
  },
  "clip_duration_range_seconds": [15, 90],
  "output_format": "mp4 + word-by-word ASS captions burned",
  "max_clips_per_run": 8,
  "aspect_ratios_supported": ["9:16", "16:9", "1:1"]
}

Tier thresholds: outlier_detection_service.py. Clip selector: clip_extraction_service.py. See outlier tiers in the glossary.

Why ViralMint for this

01

Whisper + AI ranking, not random splits

Most free clippers chop a long video into equal-length pieces. ViralMint runs Whisper locally to get a word-level transcript, then an AI scorer ranks every candidate clip on a 0–10 virality scale and classifies its hook type (curiosity_gap, contrarian, emotional_peak, shocking_claim, actionable_tip, story_loop, etc.). You get the strongest clips first, with a one-line virality_reason explaining why each one was picked — not just N clips of equal length and unequal quality.

02

Free AND open source, not free-trial bait

OpusClip's free tier is 60 minutes/month of source video — enough for one podcast episode. Submagic and Vizard cap monthly minutes too. ViralMint's Clip Studio ships in the free desktop app with no minute cap, no per-clip cost, and no watermark on the output. The underlying code is AGPL-3.0 on GitHub — you can read it, fork it, or run the whole thing on your own hardware.

03

Per-clip metadata drafted, not just clips

Every produced clip arrives with an AI-drafted YouTube title, description, tags, AND a TikTok caption — copy-paste-ready for whichever platform you're posting to. The hook_type field tells you what rhetorical pattern the AI matched so you know why a particular clip should land before you watch it. The clips themselves are 9:16 by default with the viral caption style burned in.

How it works

  1. Download or import the long video

    Paste a YouTube / TikTok / Bilibili / podcast URL into ViralMint to download via yt-dlp, or drag a local mp4/mov into the Downloaded Videos page. The source needs to be at least 20 seconds long; 5–60 minutes of podcast or interview is the sweet spot.

  2. Open Clip Studio on that source

    Click the source video in the Downloaded Videos page, then Extract Clips. Pick a max-clips number (default auto-derives ~1 clip per 30 seconds of source, min 3, max 99) and your caption style preset (viral / classic / bold). Optionally enable remove_silence for podcasts — strips silent gaps + filler words before captioning.

  3. Wait for the pipeline

    Whisper transcription runs locally first (~1–3 min for a 10-min source on a typical laptop CPU), then the AI clip-picker selects + scores candidate moments. The runner renders each pick as its own 9:16 mp4 with captions baked in. A 10-minute source typically produces 5–15 clips in 3–6 minutes total.

  4. Review by virality score and ship

    The Clips page lists every produced clip with clip_virality_score (0–10), clip_hook_type, and clip_virality_reason. Sort by score, preview the top picks, and copy the AI-drafted YouTube title / description / tags or TikTok caption for posting. Use the Multi-Platform Export tool to ship one clip across TikTok + YouTube Shorts + Instagram in one click.

How ViralMint compares

Last updated July 2026

Capability OpusClipVizardSubmagic ViralMint
Pricing $19–$59/mo$15.83–$50/mo$14–$29/mo Free (desktop app)
Monthly source-video cap 60 min (free) / scales by plan60 min (free) / scales by planMinute cap on every plan None
Watermark on free output YesYes (free plan)Yes (free trial) Never
AI virality score per clip YesYesYes Yes — 0–10 with hook classification + reason
Hook-type classification NoNoNo Yes — 9 categories (curiosity_gap, contrarian, …)
Where transcription runs CloudCloudCloud Locally (faster-whisper, your machine)
Word-by-word animated captions YesYesYes Yes — 3 presets (viral / classic / bold)
Multi-platform export in one click Yes (bundled)YesManual Yes (9:16 / 16:9 / 1:1 ZIP via repurpose_for_platforms)
Open source NoNoNo Yes (AGPL-3.0)

highlighted column = clearer fit for that capability. Tied capabilities are left unmarked.

Frequently asked

How does ViralMint pick which moments to clip?

After Whisper produces a word-level transcript, an AI scorer evaluates every candidate window against a virality rubric (hook strength, emotional peak, actionable tip, contrarian claim, story loop, number promise, shocking claim, curiosity gap, etc.) and assigns each a 0–10 score. The picker prefers high-score clips while spreading hook types so you don't end up with five curiosity_gaps in a row. Each produced clip carries its score, its hook_type label, and a one-line virality_reason explaining the pick.

What length does the AI pick clips at?

Default is 15–60 seconds — the sweet spot for TikTok / Shorts / Reels. You can override the min and max in the Clip Studio settings (min_duration ≥ 10s, max_duration ≥ 15s, min < max). For podcasts you may want max_duration: 75 to keep a complete argument intact; for fast-paced talking-head content 30 is often enough.

Can it handle landscape source videos?

Yes. Enable force_vertical to convert 16:9 source to 9:16 with blur-fill backdrop on each produced clip. Without that flag, ViralMint preserves the source aspect. Most podcast hosts use 16:9 cameras + want 9:16 output — that's exactly what force_vertical handles.

How long does extraction actually take?

Whisper transcription dominates: ~1 minute of CPU time per 5–8 minutes of source on a typical laptop. After that, clip selection is fast (seconds), and rendering each clip with captions runs ~5–15 seconds per produced clip. End-to-end for a 30-minute podcast producing 10 clips: about 8–12 minutes total. You can walk away — the desktop app pushes a notification when it's done.

Does Clip Studio cost anything per clip?

No. Whisper transcription runs locally, the AI clip picker runs against the cloud chat API (~$0.01 of cloud call per extraction job regardless of how many clips you produce), and rendering uses FFmpeg locally. The only billable parts of ViralMint are the optional paid AI voice (Gemini 3.1 Flash TTS), AI music (Lyria 3 Pro), and AI video clips (Sora 2 Pro / Veo 3.1 / etc.) — none of which Clip Studio uses.

Can I extract clips from a YouTube URL I don't own?

Technically yes — yt-dlp downloads any public video, ViralMint processes it. Whether that's appropriate is up to you: respect the source creator's preferences, fair-use rules in your jurisdiction, and the target platform's rules around third-party clips. For your own content, this is the workflow most creators use to repurpose long-form into shorts.

How does ViralMint compare to OpusClip?

OpusClip is a great SaaS tool with strong AI clip selection. The differences worth knowing: OpusClip is subscription-based ($19–$59/mo with monthly minute caps), watermarks free output, and runs transcription in their cloud. ViralMint's Clip Studio is free in the desktop app with no minute cap, no watermark, no per-clip cost, runs transcription locally on your machine, and the code is AGPL-3.0 open source. Quality-wise both ship strong virality scoring; ViralMint adds hook-type classification (curiosity_gap / contrarian / etc.) and pairs naturally with our Multi-Platform Export for one-click cross-posting.

Is the AI clip picker open source too?

The desktop side (Whisper integration, clip extraction pipeline, caption rendering, FFmpeg orchestration) is AGPL-3.0 at github.com/openclaw-easy/ViralMint. The AI scoring uses an LLM prompt that runs against our cloud chat handler — the prompt itself is in the repo; only the cloud routing is closed.

Get ViralMint

The Viral Clip Extractor ships inside the free ViralMint desktop app — no subscription, no watermark, no per-minute cap. Download once, use on as many videos as you want.

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