Rotation & Album Art

Rotation — fixing portrait videos that play sideways

Phones write a rotation flag in the metadata; some players honor it, some don't. Two ways to fix:

Strip the flag and re-encode rotated: -vf transpose=1 (90° clockwise).
Just update the flag: -metadata:s:v rotate=0 + remux. No re-encode.

Album art on audio files

MP3 / M4A can carry a cover image. Useful for podcast episodes, music files. Add via -i cover.png -map 0 -map 1 -disposition:v:0 attached_pic.

Code

Rotation fixes·bash

# Rotate 90° clockwise (re-encode)
ffmpeg -i sideways.mp4 -vf "transpose=1" \
  -c:v libx264 -crf 20 -preset slow -c:a copy upright.mp4

# Rotate 90° counter-clockwise
ffmpeg -i sideways.mp4 -vf "transpose=2" \
  -c:v libx264 -crf 20 -preset slow -c:a copy upright.mp4

# Rotate 180°
ffmpeg -i upside.mp4 -vf "transpose=2,transpose=2" \
  -c:v libx264 -crf 20 -preset slow -c:a copy upright.mp4

# Just update the rotation tag, no re-encode
ffmpeg -i sideways.mp4 -metadata:s:v rotate=0 -c copy fixed.mp4

Attach album art·bash

# Cover art on MP3
ffmpeg -i podcast.wav -i cover.png \
  -map 0:a -map 1:v \
  -c:a libmp3lame -q:a 2 \
  -c:v copy \
  -id3v2_version 3 \
  -metadata:s:v title="Episode Cover" \
  -metadata:s:v comment="Cover (front)" \
  episode.mp3

# Same on M4A (AAC)
ffmpeg -i podcast.wav -i cover.png \
  -map 0:a -map 1:v \
  -c:a aac -b:a 192k \
  -c:v copy \
  -disposition:v:0 attached_pic \
  episode.m4a

Exercise

Take a portrait phone video that plays sideways. Fix it two ways: (a) re-encode with transpose=1, (b) just update the rotation tag with -metadata:s:v rotate=0 -c copy. Open both in VLC and Apple Photos — do both methods work in both players? Then attach album art to a podcast WAV and verify the cover shows in iTunes/Music.app.

Rotation — fixing portrait videos that play sideways

Album art on audio files

Code

External links

Exercise

Progress

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