Problem
Video metadata reports the wrong rotation, causing some players to display the file sideways.
Solution
Root Cause / Diagnostic:
Smartphones and action cameras record physical orientation via internal gyro sensors and embed an MP4 rotation metadata tag (e.g., 90° or 270° clockwise) into the file header while writing horizontal pixel arrays. When an editor rotates the clip manually inside the NLE without clearing the container's rotation metadata flag on export, web browsers, media players, and social platforms interpret the flag inconsistently. Some platforms rotate the already-rotated video, displaying it sideways or inverted.
Actionable Fix:
1. Strip container rotation flags before export, or ensure the NLE's export container settings are configured to write zero-degree rotation metadata for vertical 9:16 sequences.
2. Use FFmpeg to reset the rotation flag without re-encoding: ffmpeg -i input.mp4 -c copy -metadata:s:v:0 rotate=0 output.mp4.
3. Open the exported video across multiple players (QuickTime, VLC, Chrome browser) to confirm that the video opens upright in proper vertical orientation.
Pro Tip:
For mobile footage ingest, conform rotation flags at the OS level using lossless metadata stripping utilities before importing media into editing timelines.
Smartphones and action cameras record physical orientation via internal gyro sensors and embed an MP4 rotation metadata tag (e.g., 90° or 270° clockwise) into the file header while writing horizontal pixel arrays. When an editor rotates the clip manually inside the NLE without clearing the container's rotation metadata flag on export, web browsers, media players, and social platforms interpret the flag inconsistently. Some platforms rotate the already-rotated video, displaying it sideways or inverted.
Actionable Fix:
1. Strip container rotation flags before export, or ensure the NLE's export container settings are configured to write zero-degree rotation metadata for vertical 9:16 sequences.
2. Use FFmpeg to reset the rotation flag without re-encoding: ffmpeg -i input.mp4 -c copy -metadata:s:v:0 rotate=0 output.mp4.
3. Open the exported video across multiple players (QuickTime, VLC, Chrome browser) to confirm that the video opens upright in proper vertical orientation.
Pro Tip:
For mobile footage ingest, conform rotation flags at the OS level using lossless metadata stripping utilities before importing media into editing timelines.