How to convert MP4 video to MP3 audio with FFmpeg

ffmpeg

I need to extract an MP3 audio track from an MP4 video with ffmpeg. I can do this for .flv -> mp3, but I don't know the command line parameters for mp4->mp3. For example, flv -> mp3:

ffmpeg -i video.flv -acodec copy audio.mp3

What parameters should I use for mp4 -> mp3?

Best Answer

The basic command is:

ffmpeg -i filename.mp4 filename.mp3

ffmpeg -i video.mp4 -b:a 192K -vn music.mp3

Check this URL: MP4 Video to MP3 File Using ffmpeg (Ubuntu 9.10 Karmic Koala)

Note: Ubuntu does not supply FFmpeg, but the fork named Libav. The syntax is the same – just use avconv instead of ffmpeg for the above examples.

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FFMPEG get mono WAV audio 8khz 16 bit out of mp4 video

Use -ac 1 (See the FFmpeg wiki, or the man page with man ffmpeg) to limit the output to one channel.

Then use -ar 8000 for 8kHz and -acodec pcm_s16le for 16 bit.

Concatenating videos with ffmpeg produces silent video when the first video has no audio track

For anyone that stumbles onto this and wants to achieve the same thing as I do, I solved it as follows:

ffmpeg -i "1.mp4" -f lavfi -i aevalsrc=0 -shortest -y "new_1.mp4"

What this says is:

Take 1.mp4 (which is the video clip without audio) (-i "1.mp4")
Generate the minimum silence required (-f lavfi -i aevalsrc=0 -shortest)
Output the result (-y "new_1.mp4")

From here I concatenate as I did before, but replacing "1.mp4" in clips.txt with "new_1.mp4"

Best Answer

Related Solutions

FFMPEG get mono WAV audio 8khz 16 bit out of mp4 video

Concatenating videos with ffmpeg produces silent video when the first video has no audio track

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