ffmpeg

This tool rules.

Easy to convert audio/video types. To cut audio.

Use Cases

Reduce bg noise (afftn)

ffmpeg’s built-in afftdn (audio FFT denoising) filter to reduce static background noise without downloading external models.

bashffmpeg -i input.mp4 -af afftdn output.mp4

For better results, adjust the noise reduction strength:

bashffmpeg -i input.mp4 -af afftdn=nf=-25 output.mp4

Compress MP4

To compress the video, use the -crf flag (lower = better quality, higher = smaller file):

ffmpeg -i input.mp4 -vcodec libx264 -crf 23 output.mp4

• crf 23 is balanced (range: 0-51)
• Try crf 28 for more compression
• Try crf 18 for higher quality

Combine with audio compression:

ffmpeg -i input.mp4 -vcodec libx264 -crf 23 -acodec aac -b:a 128k output.mp4

For faster encoding (larger file):

ffmpeg -i input.mp4 -vcodec libx264 -crf 23 -preset fast output.mp4

Change preset from ultrafast to veryslow for better compression (slower encoding).