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I am using a typical ffmpeg command to concat two mp4 files:

ffmpeg -y -safe 0 -f concat -i !list.txt -c copy out.mp4

However,sometimes I can hear a "click" sound at the point where the two audio tracks join, because obviously a "level jump" occurs as the two audio-samples collide. Is it possible to have a very short fade-out at the end of the 1st clip and a very short fade-in at the start of the 2nd clip when concatenating?

Jackie Jim
  • 163

1 Answers1

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You need to use the afade out and afade in filter to create new files, and then concat them

Command to ADD fade-out to the first clip

ffmpeg -i input1.mp4 -af "afade=t=out:st=<fade_start_time>:d=<fade_duration>" -c:v copy output1_faded.mp4

Command to Add fade-in to the second clip

ffmpeg -i input2.mp4 -af "afade=t=in:st=0:d=<fade_duration>" -c:v copy output2_faded.mp4
Ashish Mohta
  • 150