FFmpeg

Have you ever needed to increment audio volume level from any of your videos? ok, it is not too common but anyway, there is a powerful tool to help us whit that task. FFmpeg, so I'm going to set the steps here.

1. Remove sound from a video file.

 ffmpeg -i source_video.ogv -an -vcodec mpeg4 -b 1200k just_video.mp4

2. Extract audio from video.

ffmpeg -i source_video.ogv -ab 128k just_audio.mp3

3. Increment volume from an mp3 audio

ffmpeg -i just_audio.mp3 -vol 2000 -ab 128k overninethousand_audio.mp3

4. Encode to the final video.

ffmpeg -i overninethousand_audio.mp3 -i just_video.mp4 -vcodec mpeg4 -b 1200k final_video.mp4

That's it, you have a new video with over nine thousand level.

FFmpeg site