How to overlay/downmix two audio files using ffmpeg - audio

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

stereo + stereo → stereo
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
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
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
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

Check this out:
ffmpeg -y -i ad_sound/whistle.mp3 -i ad_sound/4s.wav -filter_complex "[0:0][1:0] amix=inputs=2:duration=longest" -c:a libmp3lame ad_sound/outputnow.mp3
I think it will help.

The amix filter helps to mix multiple audio inputs into a single output.
If you run the following command:
ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
This command will mix 3 input audio streams (I used two mp3 files, in the example below) into a single output with the same duration as the first input and a dropout transition time of 3 seconds.
The amix filter accepts the following parameters:
inputs:
The number of inputs. If unspecified, it defaults to 2.
duration:
How to determine the end-of-stream.
longest:
The duration of the longest input. (default)
shortest:
The duration of the shortest input.
first:
The duration of the first input.
dropout_transition:
The transition time, in seconds, for volume renormalization when an input stream ends. The default value is 2 seconds.
For example, I ran the following command in Ubuntu:
FFMPEG version: 3.2.1-1
UBUNTU 16.04.1
ffmpeg -i background.mp3 -i bSound.mp3 -filter_complex amix=inputs=2:duration=first:dropout_transition=0 -codec:a libmp3lame -q:a 0 OUTPUT.mp3
-codec:a libmp3lame -q:a 0 was used to set a variable bit rate. Remember that, you need to install the libmp3lame library, if is necessary. But, it will work even without the -codec:a libmp3lame -q:a 0 part.
Reference: https://ffmpeg.org/ffmpeg-filters.html#amix

For merging two audio files with different volumes and different duration following command will work:
ffmpeg -y -i audio1.mp3 -i audio2.mp3 -filter_complex "[0:0]volume=0.09[a];[1:0]volume=1.8[b];[a][b]amix=inputs=2:duration=longest" -c:a libmp3lame output.mp3
Here duration can be change to longest or to shortest, you can also change the volume levels according to your need.
If you're looking to add background music to some voice use the following command as in the gaps the music will become loud automatically:
ffmpeg -i bgmusic.mp3 -i audio.mp3 -filter_complex "[1:a]asplit=2[sc][mix];[0:a][sc]sidechaincompress=threshold=0.003:ratio=20[bg]; [bg][mix]amerge[final]" -map [final] final.mp3
In this threshold is something whose value will decide how much loud the audio should be, the less the threshold more the audio will be. Ratio gives how much the other audio should be compressed, the more the ratio the more the compression is.

If they are different length, you can use apad to add a silent sound to the shortest one

With Bash
set 'amovie=a.mp3 [gg]; amovie=b.mp3 [hh]; [gg][hh] amerge'
ffmpeg -f lavfi -i "$1" -q 0 c.mp3
Example

You can use the following command arguments:
// Command is here
let commandValue = "-y -i \(recordedAudioPath) -i \(backgroundAudio) -filter_complex [\(0):a][\(1):a]amerge=inputs=\(2)[a] -map [a] -ac \(2) -shortest -preset ultrafast \(outputPath)"
MobileFFmpeg.execute(commandValue)

Related

Optimize ffmpeg overlay and loop filters

I have a video, video.mp4, of 30 seconds, and I have an audio that can change in length, audio.mp3.
My final idea is to have an output video of a loop of video.mp4 for the total length of the audio.mp3, and an overlay of the waveform of the audio.mp3. What I've done is this, in a bash script:
# calculate length of the audio and of the video
tot=$(ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 audio.mp3)
vid=$(ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 video.mp4)
# how many base video we need to loop into the waveform video?
repeattime=`echo "scale=0; ($tot+$vid-1)/$vid" | bc`
# ffmpeg final command
ffmpeg -stream_loop $repeattime -i video.mp4 -i audio.mp3 -filter_complex "[1:a]showwaves=s=1280x100:colors=Red:mode=cline:rate=25:scale=sqrt[outputwave]; [0:v][outputwave] overlay=0:main_h-overlay_h [out]" -map '[out]' -map '1:a' -c:a copy -y output.mp4
Is there a better way to do it in a single ffmpeg command? I know it exists the loop filter in ffmpeg, but it loops frames and I don't know the number of frames of the video.mp4. Also, using $repeattime can result in a number of loop longer then needed (because math calculation is done round up)
-shortest helps you:
#!/bin/bash
ffmpeg -hide_banner -stream_loop -1 -i "input 1.mp4" -i "input 1.mp3" -filter_complex "
[1:a]showwaves=s=1280x100:colors=Red:mode=cline:rate=25:scale=sqrt[outputwave];
[0:v][outputwave] overlay=0:main_h-overlay_h [v]
" -map [v] -map 1:a -c:a copy -shortest -y output.mp4
You can use the shortest option in overlay.
ffmpeg -stream_loop -1 -i video.mp4 -i audio.mp3 -filter_complex "[1:a]showwaves=s=1280x100:colors=Red:mode=cline:rate=25:scale=sqrt[outputwave]; [0:v][outputwave] overlay=0:main_h-overlay_h:shortest=1 [out]" -map '[out]' -map '1:a' -c:a copy -y output.mp4

Concat mp4 videos and merge their audios to the final output

I have several videos and photos and need to merge them with the cross-dissolve effect. The algorithm is next:
Create videos from images and add silent audio to them (so they will also have a sound stream):
ffmpeg -y -f lavfi -i anullsrc -loop 1 -i /tmp/media/import-2020-Aug-19-Wednesday-05-40-34/ea5c93fd-d946-4742-b8f7-ea9ae4d43441.jpg -c:v libx264 -t 10 -pix_fmt yuv420p -vf scale=750:1280 /tmp/media/import-2020-Aug-19-Wednesday-05-40-34/ea5c93fd-d946-4742-b8f7-ea9ae4d43441.mp4
Combine all the videos and audios into one using this command:
ffmpeg
-i /tmp/media/import-2020-Aug-19-Wednesday-05-40-34/temp_68d437c0-f5e2-4651-b07e-91533480b6ef.mp4
-i /tmp/media/import-2020-Aug-19-Wednesday-05-40-34/temp_48f3c111-610d-40c7-ac71-6ce2fbb16184.mp4
-i /tmp/media/import-2020-Aug-19-Wednesday-05-40-34/temp_1593b5d8-7e16-417d-9372-2267581cd504.mp4
-i /tmp/media/import-2020-Aug-19-Wednesday-05-40-34/temp_1ac7f6be-1b12-4e31-b904-1491cc9b9494.mp4
-i /tmp/media/import-2020-Aug-19-Wednesday-05-40-34/temp_ea5c93fd-d946-4742-b8f7-ea9ae4d43441.mp4
-filter_complex
"[0:v]trim=start=0:end=8.032,setpts=PTS-STARTPTS[clip0];
[1:v]trim=start=2:end=13.047,setpts=PTS-STARTPTS[clip1];
[2:v]trim=start=2:end=13.558,setpts=PTS-STARTPTS[clip2];
[3:v]trim=start=2:end=13.186,setpts=PTS-STARTPTS[clip3];
[4:v]trim=start=2,setpts=PTS-STARTPTS[clip4];
[0:v]trim=start=9.032:end=10.032,setpts=PTS-STARTPTS[out0];
[1:v]trim=start=14.047:end=15.047,setpts=PTS-STARTPTS[out1];
[2:v]trim=start=14.558:end=15.558,setpts=PTS-STARTPTS[out2];
[3:v]trim=start=14.186:end=15.186,setpts=PTS-STARTPTS[out3];
[1:v]trim=start=0:end=2,setpts=PTS-STARTPTS[in1];
[2:v]trim=start=0:end=2,setpts=PTS-STARTPTS[in2];
[3:v]trim=start=0:end=2,setpts=PTS-STARTPTS[in3];
[4:v]trim=start=0:end=2,setpts=PTS-STARTPTS[in4];
[in1]format=pix_fmts=yuva420p,fade=t=in:st=0:d=2:alpha=1[fadein1];
[in2]format=pix_fmts=yuva420p,fade=t=in:st=0:d=2:alpha=1[fadein2];
[in3]format=pix_fmts=yuva420p,fade=t=in:st=0:d=2:alpha=1[fadein3];
[in4]format=pix_fmts=yuva420p,fade=t=in:st=0:d=2:alpha=1[fadein4];
[out0]format=pix_fmts=yuva420p,fade=t=out:st=0:d=2:alpha=1[fadeout0];
[out1]format=pix_fmts=yuva420p,fade=t=out:st=0:d=2:alpha=1[fadeout1];
[out2]format=pix_fmts=yuva420p,fade=t=out:st=0:d=2:alpha=1[fadeout2];
[out3]format=pix_fmts=yuva420p,fade=t=out:st=0:d=2:alpha=1[fadeout3];
[fadein1]fifo[fadein1fifo];
[fadein2]fifo[fadein2fifo];
[fadein3]fifo[fadein3fifo];
[fadein4]fifo[fadein4fifo];
[fadeout0]fifo[fadeout0fifo];
[fadeout1]fifo[fadeout1fifo];
[fadeout2]fifo[fadeout2fifo];
[fadeout3]fifo[fadeout3fifo];
[fadeout0fifo][fadein1fifo]overlay[crossfade0];
[fadeout1fifo][fadein2fifo]overlay[crossfade1];
[fadeout2fifo][fadein3fifo]overlay[crossfade2];
[fadeout3fifo][fadein4fifo]overlay[crossfade3];
[clip0][crossfade0][clip1][crossfade1][clip2][crossfade2][clip3][crossfade3][clip4]concat=n=9[output];
[0:a][1:a]acrossfade=d=10:c1=tri:c2=tri[A1];
[A1][2:a]acrossfade=d=10:c1=tri:c2=tri[A2];
[A2][3:a]acrossfade=d=10:c1=tri:c2=tri[A3];
[A3][4:a]acrossfade=d=10:c1=tri:c2=tri[audio] "
-vsync 0 -map "[output]" -map "[audio]" /tmp/media/final/some_filename_d0d2aab0-792a-4540-b2d3-e64abe98bf5c.mp4
And all works pretty well, but if I have, for example:
picture
video
video
picture
Then the sound from the second video is mapping to the first picture and sound from the third video to second video. And the third video actually goes without sound.
It seems like it's happening because the silent sound of the first picture is pretty short. An I right?
If so, how can I increase its duration?
I would much appreciate any help with this!
Assuming 5 inputs of 10 seconds each, all with audio streams*, with ffmpeg 4.3 or newer, use the xfade and acrossfade filters.
ffmpeg
-i in1.mp4
-i in2.mp4
-i in3.mp4
-i in4.mp4
-i in5.mp4
-filter_complex
" [0][1]xfade=transition=fade:duration=2:offset=8[V01];
[V01][2]xfade=transition=fade:duration=2:offset=16[V02];
[V02][3]xfade=transition=fade:duration=2:offset=24[V03];
[V03][4]xfade=transition=fade:duration=2:offset=32[video];
[0:a][1:a]acrossfade=d=2:c1=tri:c2=tri[A01];
[A01][2:a]acrossfade=d=2:c1=tri:c2=tri[A02];
[A02][3:a]acrossfade=d=2:c1=tri:c2=tri[A03];
[A03][4:a]acrossfade=d=2:c1=tri:c2=tri[audio]"
-vsync 0 -map "[video]" -map "[audio]" out.mp4
*if there's no existing audio stream, add one using the command in step 1.
If the existing audio stream of a file isn't 10 seconds long, use these filters on it before acrossfade.
[input]aresample=async=1:first_pts=0,apad,atrim=0:10[filtered]
and then use this filtered stream as input.

Include audio from FFmpeg overlay in output

I'm using the following command to combine two video files together, overlaying the second one at a certain point in the first file. The result is what I want except the audio from the overlayed file is missing.
ffmpeg.exe -y -hide_banner -ss 00:00:00.067 -i promo.mov -i tag.mov -filter_complex "[1:v]setpts=PTS+6.5/TB[a];[0:v][a]overlay=enable=gte(t\,6.5)[out]" -map [out] -map 0:a -map 1:a -c:v mpeg2video -c:a pcm_s16le -ar 48000 -af loudnorm=I=-20:print_format=summary -preset ultrafast -q:v 0 -t 10 complete.mxf
Without the -map 0:a I get no audio at all, but the second -map 1:a does not pass the audio from -i tag.mov
I have also tried amix but that combines audio from both clips starting at the beginning, and I want the audio from the second file to begin when that file starts overlaying.
It would also be helpful if I could make the audio from the first clip drop lower at the time of the overlay.
amix doesn't support introducing an input mid-way, so the workaround is to add leading silence. You can use the adelay filter to do this.
make the audio from the first clip drop lower at the time of the overlay
This is possible using a sidechaincompressor which takes two inputs and lowers the volume of the first input based on the volume of the second input.
So use,
ffmpeg.exe -y -hide_banner -ss 00:00:00.067 -i promo.mov -i tag.mov -filter_complex "[1:v]setpts=PTS+6.5/TB[1v];[0:v][1v]overlay=enable=gte(t\,6.5)[vout];[1:a]adelay=6.5s,apad,asplit=2[1amix][1aref];[0:a][1aref]sidechaincompress[0asc];[0asc][1amix]amix=inputs=2:duration=first[aout]" -map [vout] -map [aout] -c:v mpeg2video -c:a pcm_s16le -ar 48000 -af loudnorm=I=-20:print_format=summary -preset ultrafast -q:v 0 -t 10 complete.mxf

Adjust volume of both input mp3 files while merging using ffmpeg

I am using the following command to merge two audio files (mp3) into one output.mp3
-i /sdcard/NNR/input1.mp3 -i /sdcard/NNR/input2.mp3
-filter_complex amerge -ac 2 -c:a libmp3lame
-q:a 4 /sdcard/NNR/output.mp3
Kindly suggest me how to adjust volume level of both input files to some specific level.
I have found the following filter variable but don't exactly know how to adjust into my command.
ffmpeg -i a.mp3 -i b.mp3
-filter_complex "[0:a]volume=.25[A];[1:a][A]amerge[out]"
-map [out] -c:a pcm_s16le out.wav
Any help will be much appreciated.Thanks
You would use
-i /sdcard/NNR/input1.mp3 -i /sdcard/NNR/input2.mp3
-filter_complex "[0]volume=0.5,pan=2c[a];[1]volume=0.7,pan=2c[b];[a][b]amix=duration=shortest"
-ac 2 -c:a libmp3lame -q:a 4 /sdcard/NNR/output.mp3

Singler line FFMPEG cmd to Merge Video /Audio and retain both audios

I have a project that requires merging of a video file with another audio file. The expected out put is an video file that will have both the audio from actual video and the merged audio file. The length of the output video file will be same to the size of the actual video file.
Is there a single line FFMPEG command to achieve this using copy and -map parameters ?
The video form I will be using is either flv or mp4
And the audio file format will be mp3
There can be achieved without using map also.
ffmpeg -i video.mp4 -i audio.mp3 output.mp4
In case you want the output.mp4 to stop as soon as one of the input stops (audio/video)
then use
-shortest
For example: ffmpeg -i video.mp4 -i audio.mp3 -shortest output.mp4
This will make sure that the output stops as and when any one of the inputs is completed.
Since you have asked that you want to do it with map. this is how you do it:
ffmpeg -i video.mp4 -i audio.mp3 -map 0:0 -map 1:0 -shortest output.mp4
Now, since you want to retain the audio of the video file, consider you want to merge audio.mp3 and video.mp4. These are the steps:
Extract audio from the video.mp4
ffmpeg -i video.mp4 1.mp3
Merge both audio.mp3 and 1.mp3
ffmpeg -i audio.mp3 -i 1.mp3 -filter_complex amerge -c:a libmp3lame -q:a 4 audiofinal.mp3
Remove the audio from video.mp4 (this step is not required. but just to do it properly)
ffmpeg -i video.mp4 -an videofinal.mp4
Now merge audiofinal.mp3 and videofinal.mp4
ffmpeg -i videofinal.mp4 -i audiofinal.mp3 -shortest final.mp4
note: in the latest version of ffmpeg it will only prompt you to use '-strict -2' in case it does then use this:
ffmpeg -i videofinal.mp4 -i audiofinal.mp3 -shortest -strict -2 final.mp4
hope this helps.
You can not do that using one cmd.
1. Get the audio from video file, the audio file name is a.mp3
ffmpeg.exe -i video.mp4 a.mp3
2. Merge two audio files(audio.mp3+a.mp3=audiofinal.mp3)
ffmpeg.exe -i audio.mp3 -i a.mp3 -filter_complex amerge -c:a libmp3lame -q:a 4 audiofinal.mp3
3. Merge video file and audio file(video.mp4+audiofinal.mp3=output.mp4)
ffmpeg.exe -i video.mp4 -i audiofinal.mp3 -map 0:v -map 1:a -c copy -y output.mp4
I don't think extracting the audio from the video is necessary. We can just use -filter_complex amix to merge both audios:
ffmpeg -i videowithaudio.mp4 -i audiotooverlay.mp3 -filter_complex amix -map 0:v -map 0:a -map 1:a -shortest videowithbothaudios.mp4
-filter_complex amix overlays the audio from the first input file on top of audio in the second input file.
-map 0:v video stream of the first input file.
-map 0:a audio stream of the first input file.
-map 1:a audio stream of the second input file.
-shortest the length of the output is the length of the shortest input
Use case:
add music to your background
you rendered a video, but muted some part of it, so you don't want to render it again(coz it's too long), instead you render only audio track(fast) and wanna merge it with original video.
Assuming
you have your video with you speech (or just audio track, whatever)
your music_file is not loud. Otherwise, you will not hear yourself D:
Steps:
1) Extract audio from the video
ffmpeg -i test.mp4 1.mp3
test.mp4 - your file
2) Merge both audio.mp3 and 1.mp3
ffmpeg -i audio.mp3 -i 1.mp3 -filter_complex amerge -c:a libmp3lame -q:a 4 audiofinal.mp3
audiofinal.mp3 - audio with music
3) Delete audio from original
ffmpeg -i example.mkv -c copy -an example-nosound.mkv
example-nosound.mkv - your video without audio
4) Merge with proper audio
ffmpeg -i audiofinal.mp3 -i example-nosound.wmv -c:v copy -vcodec copy final.wmv
final.wmv - your perfect video.
This is very easy with FFmpeg:
ffmpeg -i vid.mp4 -i audio.mp3 -codec:a libmp3lame -ar 44100 -ab 64k -ac 1 -q:v 1 -pix_fmt yuv420p -map 0:0 -map 1:0
First remove the sound from video if you are not able to merge video and audio by using this command:
ffmpeg -i video.mp4 -an videofinal.mp4

Resources