ffmpeg: How to add two consecutive audio streams to a video file

Question

I have following files:

- video.mp4 (120sec, no audio)
- audio1.mp3 (70sec)
- audio2.mp3 (50sec)

I want to combine these files in such a way that audio1.mp3 will start at the begining of a video, and audio2.mp3 will start at 70 second of the video (when audio1.mp3 is finished). Video shouldn't be re-encoded. How can it be achieved with ffmpeg?

Answer 1

Two steps, first concatenate audios, then add it to your video file.

ffmpeg -i "concat:input1.mp3|input2.mp3" -c copy output.mp3
ffmpeg -i video.mp4 -i output.mp3 -map 0 -map 1 -codec copy -shortest output_video.mp4