Flip & rotate video

Phone cameras automatically set an orientation flag in the video file's metadata, but that flag is not always respected. A video filmed portrait that opens as landscape, or a clip from a camera mounted upside down in a car, needs a rotation applied at the codec level to work reliably across all players and platforms.

Mirroring (horizontal flip) comes up in a different set of situations: recording yourself with a front-facing camera produces a mirrored image that reads backward to viewers, instructional videos filmed in front of a whiteboard need the text reversed, and some action camera mounts produce inverted footage that needs both axes corrected.

Each transformation maps to a specific FFmpeg video filter. Rotate right 90 degrees uses transpose=1. Rotate left 90 degrees uses transpose=2. Rotate 180 degrees uses hflip,vflip, which applies both a horizontal and vertical flip in a single pass (equivalent to two consecutive 90-degree transposes but more efficient). Horizontal flip uses hflip alone. Vertical flip uses vflip alone. All five transformations re-encode using libx264 at CRF 23 with the ultrafast preset and AAC audio at 128 Kbps.

If your video plays correctly on your phone but appears sideways in a browser or editor, the issue is usually that the rotation is stored only in the container metadata (the display matrix) and not applied to the actual pixel data. Both approaches are valid, but this tool always bakes the rotation into the pixel data, which is compatible with every player regardless of metadata support.

For 180-degree corrections (cameras mounted upside down), the hflip,vflip approach used here is marginally faster than two sequential transpose operations because it computes both in a single pixel loop.

Most video editors rotate video non-destructively by changing a display flag, which does not help when the destination platform ignores that flag. QuickTime Player can export with rotation baked in but only on macOS. This tool applies the rotation at the codec level on any platform in a single pass, with output that plays correctly in every context regardless of metadata support.