FFMpeg merge video and audio at specific time into another video - audio

Question

I have a standard mp4 (audio + video)
I am trying to merge a 1.4 second mini mp4 clip into this track, replacing the video for the length of the mini clip but merging the audios together at a specific time
Would anyone know how to do this using ffmpeg?
I've tried quite a few different filters, however can't seem to get what I want
V <------->
miniclip.mp4 A <=======>
V <-----------> ↓ + ↓ <--->
standard.mp4 A <=========================>

Answer 1

Example to show miniclip.mp4 (1.4 seconds long) at timestamp 5.
ffmpeg -i main.mp4 -i miniclip.mp4 -filter_complex "[0:v]drawbox=t=fill:enable='between(t,5,6.4)'[bg];[1:v]setpts=PTS+5/TB[fg];[bg][fg]overlay=x=(W-w)/2:y=(H-h)/2:eof_action=pass;[1:a]adelay=5s:all=1[a1];[0:a][a1]amix" output.mp4
drawbox covers the main video with black. Only needed if miniclip.mp4 has a smaller width or height than main.mp4. You can omit it if miniclip.mp4 width and height is ≥ than main.mp4. Alternatively you could use the scale2ref filter to make miniclip.mp4 have the same width and height as main.mp4.
setpts add a 5 second offset to miniclip.mp4 video.
overlay overlays miniclip.mp4 video over main.mp4 video.
adelay adds a 5 second delay to miniclip.mp4 audio.
amix mixes miniclip.mp4 and main.mp4 audio.
More info
See FFmpeg Filter Documentation for info on each filter.
How to get video duration

Answer 2

Edited (now I understood the question):
First Get 1.4 seconds of standard.mp4 and audio1.mp3
-ss is the start for get the small video that will be 1.4 seconds of length (with -t option you can specify the duration, in this case 1.4 seconds) summary: cut video from min 5, 1.4 seconds
-an is for audio none copy, because you want to add a new audio1.mp3
video_only.mp4
ffmpeg -ss 00:05:00 -i standard.mp4 -t 1.4 -map 0:v -c copy -an small_only_video.mp4
audio_only.mp4
ffmpeg -ss 00:05:00 -i audio1.mp3 -t 1.4 -c copy small_only_audio.mp3
now you can to create a small_clip_audiovideo.mp4
ffmpeg -i small_only_video.mp4 -c:a mp3 -i small_only_audio.mp3 -c copy -map 0:v -map 1:a:0 -disposition:a:0 default -disposition:a:1 default -strict -2 -sn -dn -map_metadata -1 -map_chapters -1 -movflags faststart small_clip_audiovideo.mp4

Answer 3

V <------->
miniclip.mp4 A <=======>
V <-----------> ↓ + ↓ <------->
standard.mp4 A <=============================>
|--|--|--|--|--|--|--|--|--|--|
0 1 2 3 4 5 6 7 8 9 10
standard.mp4 have 10 seconds (aprox) of duration, have audio and video
miniclip.mp4 have 03 seconds (aprox) of duration, have video and audio
ffmpeg -i standard.mp4 |
} have same codes of video and audio?*
ffmpeg -i miniclip.mp4 |
if are not a same audio code or video code of files standard.mp4 and miniclip.mp4, you will be to recode for continue, if you want a good work.
ffmpeg -ss 00:00:00 -i standard.mp4 -t 4 -c copy 01.part_project.mp4
and 7 to 10, in 03.part_project.mp4
ffmpeg -ss 00:00:04.000 -i standard.mp4 -t 3.0000 -c copy 03.part_project.mp4
changue name or create a copy of miniclip.mp4 to 02.part_project.mp4
cp miniclip.mp4 02.part_project.mp4
(the part of 4 second to 7 seconds, of standard.mp4 will be used if you choice the OPTION 2 copy only the audio, santadard_part2_audio.mp4)
NOW THE OPTION N 1: IS TO CONTACT (UNITED) the 3 video parts
make a folder "option1" and copy 01.part_project.mp4 02.part_project.mp4 03.part_project.mp4
mkdir option1 && cp 01.part_project.mp4 02.part_project.mp4 03.part_project.mp4 ./option1 && cd ./option1
now you concat 01.part_project.mp4 + 02.part_project.mp4 + 03.part_project.mp4 into a unique file fin_option1.mp4
ffmpeg -f concat -safe 0 -i <(for f in ./*.mp4; do echo "file '$PWD/$f'"; done) -c copy fin_option1.mp4
V <------->
miniclip.mp4 A <=======>
V <-----------> ↓ + ↓ <------->
standard.mp4 A <============XXXXXXXXX========>
|--|--|--|--|--|--|--|--|--|--|
0 1 2 3 4 5 6 7 8 9 10
THE SECOND OPTION IS TO CONTACT (UNITED) the 3 video parts, BUT MIX
THE AUDIO OF miniclip.mp4 with santadard_part2_audio.mp4
get the audio stream from santadard_part2_audio.mp4 and get the audio
file only from miniclip.mp4
ffmpeg -i santadard_part2_audio.mp4 -map 0:a -c copy -vn -strict -2 mix_audio_santadad.mp4
ffmpeg -i miniclip.mp4 -map 0:a -c copy -vn -strict -2 mix_audio_miniclip.mp4
MIX ALL AUDIOS** IN ONE AND PUT THE VIDEO FROM miniclip.mp4
ffmpeg -i mix_audio_miniclip.mp4 -i mix_audio_santadad.mp4 -filter_complex amix=inputs=2:duration=longest -strict -2 audio_mixed_miniclip.mp4
get only video from miniclip.mp4
ffmpeg -i miniclip.mp4 -c copy -an miniclip_video.mp4
and get miniclip but with mixed audios, I think that it is the solution that you are looking for
ffmpeg -i miniclip_video.mp4 -i audio_mixed_miniclip.mp4 -c copy -map 0:v -map 1:a:0 -disposition:a:0 default -disposition:a:1 default -strict -2 -sn -dn -map_metadata -1 -map_chapters -1 -movflags faststart 02.part_project_OPTION2.mp4
santadard_part2_audio.mp4
+
audio_miniclip.mp4
V <------->
miniclip.mp4 A <MMMMMMMM> (audio miniclip mixed with standard.mp4)
V <-----------> ↓ + ↓ <------->
standard.mp4 A <============ ========>
|--|--|--|--|--|--|--|--|--|--|
0 1 2 3 4 5 6 7 8 9 10
make a folder "option2" and copy 01.part_project.mp4 02.part_project_OPTION2.mp4 03.part_project.mp4
mkdir option2 && cp 01.part_project.mp4 02.part_project_OPTION2.mp4 03.part_project.mp4 ./option2 && cd ./option2
ffmpeg -f concat -safe 0 -i <(for f in ./*.mp4; do echo "file '$PWD/$f'"; done) -c copy fin_option2.mp4
NOTES
** YOU CAN USE A LOT OF AUDIO MANIPULATIONS https://trac.ffmpeg.org/wiki/AudioChannelManipulation