How to Turn a Phone Video into a Short with Castream

📱 You don't have to go live to make a short.

Maybe you filmed a workout, a sermon, a podcast segment, or just a good moment on your phone and never posted it. It's sitting in your camera roll, too long for a short and too good to leave there. That's exactly what Castream AI Shorts is for — and you don't need to be a live streamer to use it.

🎬 Pick a video from your camera roll

Upload a video from your phone. Long videos are included, so don't worry about trimming it down first or picking only short clips. AI Shorts listens to the whole video and finds the strongest moments itself.

A teacher filming a lesson, a fitness coach filming a class, a podcaster filming a conversation — all of them start here, with a video they already have.

⏸️ If your upload stops, it picks up where it left off

Long uploads are sent in parts. If one stops — a shaky connection, a closed app, life happening — it picks up where it left off when you reopen the app. You don't start from zero, and you don't have to babysit the upload.

That matters most for the videos you'd otherwise avoid uploading: the full class, the full sermon, the long take. Those are also the videos most likely to contain a great short.

✨ What you get back

Up to 3 shorts per video, up to 60 seconds each, in vertical 9:16 format. Each one comes with:

• Word-by-word captions, in the style you picked before cutting
• An on-screen hook line at the top
• A title, a description, and hashtags to paste when you post

Pick your caption style before your shorts are cut — Classic, Bold, Boxed, or Clean. The details are in AI Shorts Captions: Styles and Word-by-Word Highlighting.

💳 What it costs for a phone video

Same rule as everywhere in AI Shorts: 1 credit = 1 minute of video, however many shorts come out of it. A 20-minute camera-roll video uses 20 credits. A 45-minute one uses 45.

If a job fails or you cancel it, every credit goes back to your balance. Caption edits never use credits. The full breakdown is in Castream AI Shorts Credits and Pricing Explained.

📤 Keep, download, or share

Keep the shorts you like, delete the rest, and download the ones you want to keep for good — shorts are kept for 30 days. Share a short to TikTok, Instagram, or YouTube from the share sheet, with its title and hashtags ready to paste. See AI Shorts Titles, Hooks and Hashtags: How to Post Your Shorts.

🧭 A few starting points

• The video you almost posted. If you filmed something and thought "this is too long," that's a candidate, not a reject.
• The video with a clear moment. One strong story, one good answer, one reaction — AI Shorts only needs a moment, not a whole performance.
• The video in another language. Transcription and captions work best in English, Spanish, French, German, Portuguese, Italian, Dutch, Russian, Hindi, and Japanese, including videos that switch between them.

Phone videos don't have chat, so AI Shorts leans on the audio and content to find moments — unlike past streams, where chat reactions add a second signal. That's explained in How Castream AI Shorts Finds Your Best Moments.

The overview, if you want the whole feature in one place, is Castream AI Shorts: Turn Streams and Phone Videos into Vertical Shorts. Or see Castream AI Shorts.