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How to export a 9:16 MP4 ready for TikTok, Reels, and YouTube Shorts

Export a 9:16 H.264 MP4 (typically 1080×1920) with AAC audio, play it locally, then upload through your scheduler or each app. ReelWorkshop can produce that file in the browser after you preview an edit plan — it does not guarantee every network will accept every encode.

Last reviewed September 23, 2026

For TikTok, Instagram Reels, and YouTube Shorts, the practical delivery is a vertical 9:16 MP4 using H.264 video and AAC audio, most often at 1080×1920. In ReelWorkshop, choose that resolution on export after you have previewed a plan, keep or mute source audio deliberately, download the file, and verify playback locally before you schedule or upload.

Platform acceptance rules change. Treat the steps below as a stable production habit, and confirm current length, size, and codec rules on each network’s official help pages when something rejects.

SettingDefault choiceWhen to change
Aspect ratio9:16Only if a destination explicitly wants another ratio
Resolution1080×1920Use 720×1280 for lighter files or slower uploads
Video codecH.264 in MP4Do not switch unless a destination documents another requirement
AudioAAC from source, or mutedMute when you will add music in another app
LengthMatch your previewed plan (60/75/90s)Trim further if a network rejects duration
1080×1920 is the usual first try

Most short-form uploads expect full HD vertical. Drop to 720×1280 when file size or upload reliability is the bottleneck, not as a creative default.

Export steps in ReelWorkshop

  1. Finish the plan first

    Import, trim, generate, and preview until the cut is the one you want. Export minutes are the scarce resource.

  2. Pick resolution and audio

    Select 1080×1920 or 720×1280 and decide whether source audio stays or is muted for this render.

  3. Render in the browser

    Rendering uses WebAssembly FFmpeg locally. Wait for completion; cancel or retry from the Exports page if needed.

  4. Download and play locally

    Open the MP4 on your machine. Check framing, audio, and that the file is not truncated.

  5. Hand off to publish

    Upload via native apps or a scheduler. ReelWorkshop does not publish for you.

QA checklist before TikTok / Reels / Shorts

  • No watermark from another editor unless you intend it.
  • Safe margins: faces and text not glued to the extreme edges.
  • Audio not clipping; silence intentional if muted.
  • Duration inside what you believe the destination currently allows.
  • Filename readable so the right cut reaches the right caption in your scheduler.

Cross-posting one export

One clean 9:16 master can feed TikTok, Reels, and Shorts when the cut and audio rights fit all three. Still write separate captions and stagger publish times. If one network needs a different end card or cover, branch a second export rather than hoping the same file covers every marketing need.

  1. Export the master at 1080×1920.
  2. Caption per network in your scheduler or native drafts.
  3. Stagger times by several hours when audiences overlap.
  4. Re-export only when a platform-specific visual change is required.

When export fails or looks wrong

  • Black frames or soft playback: re-download and compare file size to a known-good export; retry the render.
  • Network rejection on upload: check official duration/size/codec docs, then re-export shorter or lighter if needed.
  • Wrong aspect: confirm you selected a vertical resolution, not a landscape source left uncropped in an earlier tool.
  • No audio: you may have muted on purpose — re-export with audio kept if that was a mistake.

What this page is not claiming

An export setting does not guarantee algorithmic distribution, monetization eligibility, or acceptance on every account type. ReelWorkshop produces a downloadable vertical MP4; each platform still applies its own rules. Prefer primary documentation over screenshots from random blogs when a file is rejected.

Is 1080×1920 required?

It is the usual best first export for Reels, TikTok, and Shorts. 720×1280 is a valid lighter alternative when you need it.

Does ReelWorkshop upload the MP4 for me?

No. Download the file, then use native upload or a scheduler.

H.264 or H.265?

ReelWorkshop exports H.264 MP4 for broad compatibility. Do not assume H.265 unless you have a specific pipeline that needs it.