How to overlay/downmix two audio files using ffmpeg

audio ffmpeg mp3 cmd
Faisal picture Faisal · Jan 24, 2013 · Viewed 55.5k times · Source

Can I overlay/downmix two audio mp3 files into one mp3 output file using ffmpeg?

Answer

llogan picture llogan · Jan 25, 2013

stereo + stereo → stereo

Normal downmix

Normal downmix

Use the amix filter:

ffmpeg -i input0.mp3 -i input1.mp3 -filter_complex amix=inputs=2:duration=longest output.mp3

Or the amerge filter:

ffmpeg -i input0.mp3 -i input1.mp3 -filter_complex amerge=inputs=2 -ac 2 output.mp3

Downmix each input into specific output channel

Downmix each input into specific output channel

Use the amerge and pan filters:

ffmpeg -i input0.mp3 -i input1.mp3 -filter_complex "amerge=inputs=2,pan=stereo|c0<c0+c1|c1<c2+c3" output.mp3

mono + mono → stereo

mono + mono → stereo

Use the join filter:

ffmpeg -i input0.mp3 -i input1.mp3 -filter_complex join=inputs=2:channel_layout=stereo output.mp3

Or amerge:

ffmpeg -i input0.mp3 -i input1.mp3 -filter_complex amerge=inputs=2 output.mp3

mono + mono → mono

mono + mono → mono

Use the amix filter:

ffmpeg -i input0.mp3 -i input1.mp3 -filter_complex amix=inputs=2:duration=longest output.mp3

More info and examples

See FFmpeg Wiki: Audio Channels

Related questions

ffmpeg clip audio interval with starting and end time

I am trying to clip an MP3 between two starting points, like starting at 10 seconds and ending at 16 seconds (time interval of 6 seconds). I am using this command: ffmpeg -ss 10 -i input.mp3 -t 6 output.mp3 The resulting output.mp3 …

Read More
using FFMPEG with silencedetect to remove audio silence

I am trying to use the following command with the latest ffmpeg build to remove silence from my .mp3 files: ffmpeg -i SILENCE.mp3 -af silencedetect=n=-50dB:d=1 -y -ab 192k SILENCE_OUT.mp3 However, the following output …

Read More
How can I remove silence from an MP3 programmatically?

I have MP3 files that sometimes have silence at the end. I would like to remove this silence automatically. From what I can tell, it is "perfect" silence (0 amplitude), not background noise. The length of the content and the silence …

Read More