Merge audio and video

Shell

4 hr. ago

Merge matching MP4 and MP3 files into a single MP4 without re-encoding the video.

audio

batch

ffmpeg

muxing

video

merge-audio-and-video.sh

# Input video file: "$f"
# Input audio file: matching base name with .mp3 extension
# Video codec: copy stream directly without re-encoding
# Audio codec: AAC (recommended for MP4 container compatibility)
# Map streams: explicit 0:v (video from mp4) and 1:a (audio from mp3)
# Shortest flag: automatically stops encoding when the shortest input stream (the video) ends
# Output file: replaces .mp4 extension with _audio.mp4
for f in *.mp4; do
  ffmpeg -i "$f" -i "${f%.mp4}.mp3" -c:v copy -c:a aac -map 0:v:0 -map 1:a:0 -shortest "${f%.mp4}_audio.mp4"
done