I've got a bunch of spoken word mp3 files, which all have the same intro talking and music, and then the real content begins. So it goes roughly like this:
00:00 Standard intro spoken word
00:20 Standard intro music
00:35 The content
The timings are not always the same (can vary by 5 secs). So I'd to cut the first 25 seconds and then fade in the next five seconds. And then output the file in the same mp3 format. Is this possible with ffmpeg?
This command should work for you:
ffmpeg -ss 25 -i input.mp3 -af "afade=type=in:start_time=0:duration=5" -c:a libmp3lame output.mp3
-ss 25
will start the input after the first 25 seconds.
afade
filter will fade in the audio from the specified start time for the next 5 seconds.