Video
Compress Video for X (Twitter) on Mac: Limits and Settings
To compress a video for X on a Mac, export an MP4 with H.264 video and AAC audio, at 1080p or lower, with a moderate CRF around 23 to 28. That passes X’s upload checks for most clips and keeps the file small.
X’s exact size and length limits depend on account type and change, so check its help page before you rely on a number.
What is the X (Twitter) video size limit?
We could not load X’s help or developer pages when we wrote this, so we are not quoting limits from memory. Many sites list outdated ones. The limits vary by account type, by app or web upload, and X has changed them before.
Look at the current figures on X Help under video uploads, then aim well inside them. A video that is comfortably small uploads faster, fails less on mobile data, and plays sooner for viewers.
What matters more than the cap is the format. X accepts MP4 and MOV, and H.264 video with AAC audio is the safest pairing. H.265 plays on many devices, but it is the more likely to fail or be re-encoded oddly, so use H.264 for X.
What settings should I use for X?
- Container: MP4.
- Video codec: H.264. See H.265 vs H.264 for why.
- Audio: AAC, 128 kbps is plenty for speech.
- Resolution: 1080p at most. Phones show X video small, so 720p often looks identical and is much smaller.
- Quality: CRF 23 for a clean upload, CRF 28 when size matters most.
X re-encodes everything you upload. Feeding it a huge, pristine file does not give a better result. Feeding it a heavily compressed file loses quality twice. A moderate CRF avoids both. Background on the numbers is in video bitrate explained.
How much smaller does a video get?
We encoded one synthetic 6-second 1080p30 clip without audio to H.264, and a 1280-wide version, with free ffmpeg. Synthetic footage is a rough guide, not a promise for your clips.
| Setting | File size |
|---|---|
| 1080p, CRF 18 | 12.8 MB |
| 1080p, CRF 23 | 7.0 MB |
| 1080p, CRF 28 | 3.0 MB |
| 720p, CRF 28 | 0.7 MB |
Going from CRF 23 to 28 cut the file by more than half. Dropping to 720p cut it by about three quarters again. For a tweet, 720p at CRF 28 is the best size-to-quality trade on this clip.
How do I compress a video for X on a Mac for free?
QuickTime Player: open the video, choose File > Export As, and pick 1080p or 720p. Quick, but no quality control, and the codec it writes can be HEVC rather than H.264 on some options.
Finder: select the file, right-click, and choose Encode Selected Video Files. Pick a resolution setting. Check that it is a standard MP4 or MOV afterward.
Terminal with ffmpeg (install it first, it is not included with macOS):
ffmpeg -i in.mov -vf scale=-2:720 -crf 26 -c:a aac -b:a 128k out.mp4That uses ffmpeg’s default H.264 encoder. More methods are in how to compress video on Mac.
What about GIFs on X?
GIFs are the wrong format for size. A GIF stores every frame as an image. X also converts uploaded GIFs to video on its side, and keeps its own cap for them that we did not verify. If your GIF is too big, convert it to a short MP4 first: it is usually far smaller. See converting GIF to MP4.
What if the clip is too long, not too big?
X caps video length as well as file size, and compression does not fix length. Trim first. In QuickTime Player, open the clip and choose Edit > Trim (Command-T), drag the yellow handles, press Trim, then File > Export As. Cutting dead air at the start and end often saves more than any setting.
If you must keep a long recording, a lower resolution and a higher CRF help size but not duration. Split it into parts, or post it elsewhere and link it. Screen recordings are a special case: they compress very well because most of the frame is still. See compressing screen recordings.
Last, test the upload. Post it from a private or locked account, or as a draft if the app offers one, and watch it on your phone before sharing publicly. Look at text, fast motion and dark areas, where compression artifacts show first.
When is Smol the wrong tool for this?
For one clip, QuickTime Player or Finder’s Encode Selected Video Files is enough, and free. You do not need to pay to post a video.
Smol earns its $29 (once, one Mac) when you post video often or work in batches. You choose H.264, a quality label or an exact CRF, and a lower resolution, then drop in a folder, or use the Finder right-click Quick Action. Nothing is uploaded. See the best video compressor for Mac or buy Smol.
How we checked this
Encoded a generated 6 s 1080p30 clip to H.264 at CRF 18, 23 and 28, plus a 720p CRF 28 version, with ffmpeg on a Mac. X limit pages could not be fetched, so no X limits are quoted. Facts last checked . We make Smol, so treat our claims about it with the same care as any vendor’s, and see our editorial policy.
Video for X: common questions
Does X compress videos I upload?
Yes. X re-encodes uploads for its own delivery, so quality is lost on its side regardless of what you send. That is why a very high bitrate file gains nothing, and an already over-compressed file looks worse. Send a clean, moderately compressed H.264 MP4.
What format should I upload to X from a Mac?
MP4 with H.264 video and AAC audio is the safest choice. MOV also works, but screen recordings and iPhone clips can use HEVC, which can fail or look wrong on some devices. If in doubt, convert the file to an H.264 MP4 before uploading.
Why does my video fail to upload to X?
The usual causes are a file over your account's size limit, a clip over the length limit, or an unusual codec or frame rate. Re-export as an H.264 MP4 at 1080p or lower, trim the clip if needed, and check the current limits on X Help.
What resolution is best for X videos?
720p or 1080p. Most people watch on a phone, where 720p is hard to tell from 1080p, and the file is far smaller. In our test, 720p at CRF 28 was about a quarter of the size of 1080p at the same CRF.
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