opus in MP4 support is experimental, add ‘-strict -2‘ if you want to use it. Could not write header

Use ffmpeg to merge video and audio to report an error:opus in MP4 support is experimental, add '-strict -2' if you want to use it. Could not write header Stream mapping: Stream #0:0 -> #0:0 (copy) Stream #1:0 -> #0:1 (copy) Last message repeated 1 times

Solution

1

But after testing, the merge speed is extremely slow

• Front desk merge

  ffmpeg -i x.mp4 -i y.mp3 -acodec copy -strict -2   xy.mp4 
  

  Background merge

  ffmpeg -i x.mp4 -i y.mp3 -acodec copy -strict -2   xy.mp4 -y -loglevel quiet
  

2

Tested to merge quickly

• Front desk merge

  ffmpeg -i x.mp4 -i y.mp3 -c:v copy -c:a aac -strict -2   xy.mp4  
  

  Background merge

  ffmpeg -i x.mp4 -i y.mp3 -c:v copy -c:a aac -strict -2  xy.mp4 -y -loglevel quiet