Converting mp4 to mp3

Question

I have a video I need to convert to mp3 (from the command line - not GUI): video.mp4

I tried:

ffmpeg -i -b 192 video.mp4 video.mp3

with no success. I get the following error:

WARNING: library configuration mismatch
Seems stream 0 codec frame rate differs from container frame rate: 59.83 (29917/500) -> 59.75 (239/4)
WARNING: The bitrate parameter is set too low. It takes bits/s as argument, not kbits/s 
Encoder (codec id 86017) not found for output stream #0.0

so I tried lame:

lame -h -b 192 video.mp4 video.mp3

I get:

Warning: unsupported audio format

Am I missing something?

Solution 1

For FFmpeg with Constant Bitrate Encoding (CBR):

ffmpeg -i video.mp4 -vn \
       -acodec libmp3lame -ac 2 -ab 160k -ar 48000 \
        audio.mp3

or if you want to use Variable Bitrate Encoding (VBR):

ffmpeg -i video.mp4 -vn \
       -acodec libmp3lame -ac 2 -qscale:a 4 -ar 48000 \
        audio.mp3

The VBR example has a target bitrate of 165 Kbit/s with a bitrate range of 140...185.

Solution 2

soundconverter

is the leading audio file converter for the GNOME Desktop. It reads anything GStreamer can read (Ogg Vorbis, AAC, MP3, FLAC, WAV, AVI, MPEG, MOV, M4A, AC3, DTS, ALAC, MPC, Shorten, APE, SID, MOD, XM, S3M, etc...), and writes to WAV, FLAC, MP3, AAC, and Ogg Vorbis files, or use a GNOME Audio Profile.

SoundConverter aims to be simple to use, and very fast. Thanks to its multithreaded design, it will use as many cores as possible to speed up the conversion. It can also extract the audio from videos.

How to Convert MP4 to MP3 with VLC

• Open VLC Media Player. Click "Media" > "Convert" to enter the "Open Media" window. Click the "Add" button on the right side of the screen to enter Windows Explorer. Locate the MP4 on your hard drive you want to convert. Click the "Convert" button at the bottom of the screen.

• Select the name of the Target file.

• Click the "Audio Codec" tab and select "MP3" from the "Codec" drop down box. Press the "Start" button to begin converting your MP4 to MP3 audio.

• Click Start

Solution 3

I have a shell-script that uses mplayer (so it can convert anything mplayer can play) to extract the audio, and then encode it using lame. Here is the code:

#! /bin/bash
# any2mp3.sh
# Converts to mp3 anything mplayer can play
# Needs mplayer amd lame installed

[ $1 ] || { echo "Usage: $0 file1.wma file2.wma"; exit 1; }

for i in "$@"
do
    [ -f "$i" ] || { echo "File $i not found!"; exit 1; }
done

[ -f audiodump.wav ] && {
    echo "file audiodump.wav already exists"
    exit 1
}

for i in "$@"
do
    ext=`echo $i | sed 's/[^.]*\.\([a-zA-Z0-9]\+\)/\1/g'`
    j=`basename "$i" ".$ext"`
    j="$j.mp3"
    echo
    echo -n "Extracting audiodump.wav from $i... "
    mplayer -vo null -vc null -af resample=44100 -ao pcm:waveheader:fast \
    "$i" >/dev/null 2>/dev/null || {
        echo "Problem extracting file $i"
        exit 1
    }
    echo "done!"
    echo -n "Encoding to mp3... "
    lame -m s audiodump.wav -o "$j" >/dev/null 2>/dev/null
    echo "done!"
    echo "File written: $j"
done
# delete temporary dump file
rm -f audiodump.wav

First you need to apt-get install mplayer lame. After that, put the code in a file named ''any2mp3.sh'', give permission to execute, and put that in your $PATH, and you will be able to do:

$ any2mp3.sh file.mp4 another-file.wma yet-another.file.ogg

It will convert each file passed to an mp3 with the same name.

It's a little rough, but does the job.

Solution 4

I think the problem is with your syntax of the ffmpeg command.

ffmpeg -i source_filename -vn -ab 192k -acodec libmp3lame -ac 2 output_filename

should work.

Solution 5

I use this small script for converting m4a to mp3.

#!/bin/bash
for i in *.m4a; do
    avconv -i "$i" -vn -acodec libmp3lame -ac 2 -ab 160k -ar 48000 "`basename "$i" .m4a`.mp3"
done

View more solutions

Comments

[duffydack]

change -b to -ab

[aki]

i get: Expected number for ac but found: liblamemp3

[aki]

i did everything and i get: -rw-r--r-- 1 aki aki 7104 2011-12-02 10:41 video.mp3 which does not play

[elias]

that's weird... it seems that lame couldn't convert the wav. try removing the >/dev/null 2>/dev/null from the code to see the error message.

[aki]

no luck, here's the output: pastebin.com/ALrTqCmk of both conversions

[elias]

And does the audiodump.wav plays? If it doesn't, mplayer couldn't play the video.mp4 file, and then you're really out of luck. Maybe the file you are trying to convert is corrupted, can you test the process with another file?

[aki]

no, the wav does not play, nor the mp4 from mplayer

[elias]

Yeah, if mplayer can't play the mp4, then the conversion won't work with this method. :/

[elias]

ah! you're welcome, glad you solved it! :)

[Darth Egregious]

Assuming that lame is already installed.

[aki]

ha thanks, that is exactly what i am looking for

[Jason Scheirer]

The only extra step to this is sudo apt-get install libavcodec-extra-53

[thomasrutter]

Or since this is Ubuntu, ubuntu-restricted-extras, which includes libavcodec-extra-53 among other things. You may have installed this already as the installation CD prompts to do so.

[Nathan Osman]

But the OP asked for a command-line solution.

[andrew.46]

My edit added in a VBR example and labelled the fixed bitrate example as CBR...

[Jakke]

For Ubuntu 14 users: askubuntu.com/questions/432542/… => use avconv instead

[sanoJ]

If it says avconv if not found install ffmpeg and replace it with ffmpeg

[Eric]

This is great !!!

[Timo]

What is the difference between CBR and VBR? When it comes to selecting VBR vs. CBR, It is almost always recommended that you use VBR encoding for your media files as it provides higher quality files. We would suggest that you do not use CBR unless you have a specific need for playback on a device that only supports CBR.

[Timo]

Maybe you can leave ar, which should be in Hz and also leave -qscale:a