To split a video in parts use the following syntax: ffmpeg -i original_video.mp4 -ss 00:00:00 -t 00:03:38 -vcodec copy -acodec copy part1.mp4 ffmpeg -i original_video.mp4 -ss 00:05:20 -t 00:00:15 -vcodec copy -acodec copy part2.mp4 The previous commands will extract into part1 and part2 two videos of 3:38 and 0:15 long. Taken at the starting points 00:00 and 05:20. This process done from a video file called original_video.mp4. If you want to merge these two parts together. Write into a file the following lines: file part1.mp4 file part2.mp4 So if you execute cat ifile.txt you will see the previous two lines. Next. Run the merge of them with: ffmpeg -f concat -safe 0 -i ifile.txt -c copy part1_and_part2.mp4 Later, you can edit the audio with audacity and reduce noise. Export the audio file as only_audio.mp3. To merge the processed audio with the video do as follows: MP4Box part1_and_part2.mp4 -single 1 -out video_only.mp4 MP4Box video_only.mp4 -add only_audio.mp3