ffmpeg -i 입력.m4a -acode copy 출력.mp3
실행하면 에러 발생
[mp3 @ 0x5652a01c7b00] Invalid audio stream. Exactly one MP3 audio stream is required.
Could not write header for output file #0 (incorrect codec parameters ?): Invalid argument
ffmpeg -i "입력.m4a" -c:a libmp3lame "출력.mp3"