Manatee

A video that plays sideways or upside down on a Mac

· 6 min read

A video plays sideways or upside down because the camera stores every frame the same way round and adds a short note saying how far to turn the picture for display. When that note is wrong, missing, or ignored by the player, the picture lands on its side. On a Mac the fix takes about a minute: open the clip in QuickTime Player, choose Edit, then Rotate Left or Rotate Right, and save. The rest of this post is about making that fix hold on every other screen the video goes to.

Why a video ends up on its side

A camera sensor is fixed inside the body. Hold a phone upright and the sensor still records a wide frame, turned on its side. Instead of redrawing every frame, the phone writes one value into the file (0, 90, 180 or 270 degrees) and expects the player to read it and turn the picture.

That leaves three ways for things to go wrong.

  • The camera guessed wrong. The orientation is decided when recording starts and stays fixed for the whole clip. If the phone was pointing down at a table or up at the ceiling at that moment, it had no real sense of which way was up and used whatever it believed last.
  • The camera could not know. An action camera mounted under a handlebar, a dashcam fitted the other way up, or a camera fixed to a ceiling records upside down and often writes no note at all.
  • The note is right, but the player ignores it. The video looks correct on your Mac and your phone, then plays sideways on a TV, in an upload form’s preview, or in older software on another computer.

Find out which case you have

Open the file in QuickTime Player, which reads the rotation note and obeys it.

  • If the video is sideways in QuickTime Player, the note is wrong or missing. Rotate it with the steps in the next section.
  • If it is upright in QuickTime Player and sideways somewhere else, the note is fine and the other player is ignoring it. Skip to the section on making the rotation permanent.
  • If QuickTime Player will not open the file at all, you have a format problem before you have a rotation problem. What to do when QuickTime says the file isn’t compatible covers that.

Rotate the video in QuickTime Player

  1. Right-click the video in Finder and choose Open With, then QuickTime Player.
  2. Choose Edit, Rotate Left or Edit, Rotate Right. Each one turns the picture 90 degrees, so use it twice for a clip that is upside down. Flip Horizontal and Flip Vertical are in the same menu for mirrored footage.
  3. Choose File, Save. QuickTime Player writes the corrected video as a new movie, so give it a new name and keep the original until you have watched the result from start to finish.

Saving this way does not recompress the picture. The frames are the ones the camera recorded, and only the note changes, which is why it is quick and costs no quality.

Two other built-in routes do the same job.

  • Finder. Select the video, right-click, and choose Quick Actions, Rotate Left. Repeat until it is upright. This acts on the file itself instead of making a copy, so duplicate the video first with Command-D.
  • Photos. If the video lives in your Photos library, double-click it, click Edit, and use the rotate button in the toolbar. Hold Option to turn it the other way. Photos keeps the original, and Revert to Original brings it back.

Make the rotation permanent for players that ignore the note

When the destination ignores the note, correcting the note achieves nothing. The frames themselves have to be redrawn upright, and that means re-encoding: every frame is decoded, turned, and compressed again. It takes longer and costs a little quality, so do it once, from the original.

  • iMovie. Create a movie project and add the clip. iMovie shows it the right way up if the note is correct; if it does not, click the Crop button above the viewer and use the rotate buttons. Then choose File, Share, File. iMovie builds a widescreen movie, so a clip filmed upright usually comes out with bars at the sides.
  • Terminal. If you have ffmpeg installed, ffmpeg -i input.mov output.mp4 re-encodes the video and applies the rotation note to the frames as it goes. The new file is upright, with no note left for a player to ignore.

QuickTime Player’s File, Export As re-encodes too, but an export can carry the note forward instead of turning the frames, so do not rely on it for this without testing.

Whichever route you take, play the new file on the device or site that got it wrong before you delete anything.

Where Manatee fits, and where it does not

One honest limit first: Manatee is not a video editor. It has no rotate control, so it cannot correct a clip whose note is wrong. Fix that in QuickTime Player.

Where it helps is the step after. QuickTime Player saves a MOV, and plenty of upload forms and TVs want an MP4. Open Manatee, choose Convert, drop the rotated file in, and pick MP4. If the file is over a size limit, Shrink takes a size in MB and finds the quality that fits; how to shrink a video to a specific file size explains what to expect from that.

Either way the result is a new copy beside the original, which is never modified. Everything runs on the Mac, with no upload and no account. It is free for 24 hours with every feature, then $9 once. As with any converter, check the copy on the screen it is meant for.

Avoid it next time

  • Hold the phone the way you mean to film for a second before you press record. The icons in the camera app turn to match the orientation the phone has detected, so a glance tells you what it believes.
  • Do not start recording while the phone points straight down or straight up. Start with it upright, then tilt.
  • On an action camera or dashcam, look in the settings for an orientation or upside down option, and set it to match how the camera is mounted.

Photos have the same problem with a different tag. A photo that turns sideways after you send or convert it covers that case.

Questions

Does rotating a video reduce its quality? Not when only the note changes, which is what Save in QuickTime Player and Rotate Left in Finder do. Re-encoding costs a little, so do it once from the original and not from a copy that was already converted.

Why does the video look right on my Mac but sideways after I upload it? The site’s processing ignored the rotation note and showed the frames as stored. Upload a re-encoded copy whose frames are upright.

Can I rotate only part of a video? Not with a rotation note, which applies to the whole clip. That is an editing job: split the clip in iMovie and rotate each piece on its own.