FFMPEG: How to combine multiple video files into one and replace audio with new audio file

audioffmpegvideo

I have a question about ffmpeg
I have many shot mp4 video file and one mp3 audio (example: 1 hour long )
I want to combine random mp4 video file to one output file (length match mp3 length) and replace audio with that mp3 file to one output mp4 file.

Best Answer

Short answer is yes. Yes you can.

See https://stackoverflow.com/questions/11779490/how-to-add-a-new-audio-not-mixing-into-a-video-using-ffmpeg

Specifically The section "To manually choose specific streams"

Once you combine the video (mp4) files in the order and length you want, you then combine the video (mp4) and audio (mp3) files together and use the -map option to choose the video stream and audio stream you want in the final output. This will then give you the video you want, and the audio from the mp3 file you have

EDIT

To answer your comment, you can use the concat command in ffmpeg to combine video's together

Put this in a text file (we will call it list.txt) file 'path/to/file1.mp4' file 'path/to/file2.mp4' file 'path/to/file3.mp4'
then ffmpeg -f concat -i list.txt -c copy output.mp4

Related Solutions

FFmpeg – How to Mix Audio/Video File with Audio File with Offset

I have successfully used the adelay filter to do this. Here is the command:

ffmpeg \
    -i video_and_audio.webm \
    -i audio_only.webm \
    -c:v copy \
    -filter_complex '[1:a] adelay=2500|2500 [delayed]; [0:a] [delayed] amix [out]' \
    -map 0:v \
    -map '[out]' \
    out.webm

Note that when using the adelay filter, the delay must be specified in milliseconds and must be specified individually for each audio channel. In this example, the audio is stereo (2-channel) so the delay is specified twice.

Line by line explanation:

first input file
second input file
copy video directly to output without any changes
complex filter which takes the audio of the second input, delays it, and then mixes that with the audio of the first input
selects the video stream from the first file to output
selects the mixed audio stream to output
output file name

You may not actually need the -map lines, but I prefer to use them.

FFMPEG – Combine multiple audio files and one video in to the multi language video

ffmpeg -i video -i audio1 -i audio2 -i audio3 -i audio4 -i audio5 \
-map 0:v -map 1:a -map 2:a -map 3:a -map 4:a -map 5:a \
-metadata:s:a:0 language=eng -metadata:s:a:0 title="Title 1" \
-metadata:s:a:1 language=sme -metadata:s:a:1 title="Title 2" \
-metadata:s:a:2 language=ipk -metadata:s:a:2 title="Title 3" \
-metadata:s:a:3 language=nob -metadata:s:a:3 title="Title 4" \
-metadata:s:a:4 language=swa -metadata:s:a:4 title="Title 5" \
-c:v copy -c:a libopus output.mkv

In this case you can't rely on the default stream selection behavior, so use the -map option to choose each desired stream.
You can set the language and/or title metadata for each audio stream. See ISO 639-2/T for the 3 letter code.
This example will stream copy (re-mux) the video instead of re-encoding it.
You did not specify the required output formats, so I just chose the encoder libopus and Matroska output container format.

Best Answer

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FFmpeg – How to Mix Audio/Video File with Audio File with Offset

FFMPEG – Combine multiple audio files and one video in to the multi language video

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