ffmpeg to extract audio from video

I tried the following command to extract audio from video:
ffmpeg -i Sample.avi -vn -ar 44100 -ac 2 -ab 192k -f mp3 Sample.mp3

ffmpeg -i Sample.avi -vn -ar 44100 -ac 2 -ab 192k -f mp3 Sample.mp3

but i get output as

libavutil 50.15. 1 / 50.15. 1
libavcodec 52.72. 2 / 52.72. 2
libavformat 52.64. 2 / 52.64. 2
libavdevice 52. 2. 0 / 52. 2. 0
libavfilter 1.19. 0 / 1.19. 0
libswscale 0.11. 0 / 0.11. 0
libpostproc 51. 2. 0 / 51. 2. 0
SamplE.avi: Invalid data found when processing input


Can anyone help, please?

9 Answers
9

To extract the audio stream without re-encoding:

ffmpeg -i input-video.avi -vn -acodec copy output-audio.aac


-vn

-acodec copy

Read the output to see what codec it is, to set the right filename extension.

To encode a high quality MP3 from an AVI best using -q:a for variable bit rate.

ffmpeg -i sample.avi -q:a 0 -map a sample.mp3


If you want to extract a portion of audio from a video use the -ss option to specify the starting timestamp, and the -t option to specify the encoding duration, eg from 3 minutes and 5 seconds in for 45 seconds

ffmpeg -i sample.avi -ss 00:03:05 -t 00:00:45.0 -q:a 0 -map a sample.mp3


The timestamps need to be in HH:MM:SS.xxx format or in seconds.

If you don't specify the -t option it will go to the end.

Another popular request is extracting images from videos, here is the command for frames per second to images:

ffmpeg.exe -i simpsonsRockBottom.mp4 -r 1/1 $filename%03d.jpg -ss 00:00:52 -t 00:01:52


-q:a

The command line is correct and works on a valid video file. I would make sure that you have installed the correct library to work with mp3, install lame o probe with another audio codec.

Usually

ffmpeg -formats


or

ffmpeg -codecs


would give sufficient information so that you know more.

ffmpeg -i sample.avi will give you the audio/video format info for your file. Make sure you have the proper libraries configured to parse the input streams. Also, make sure that the file isn't corrupt.

ffmpeg -i sample.avi

To encode mp3 audio ffmpeg.org shows the following example:

ffmpeg -i input.wav -codec:a libmp3lame -qscale:a 2 output.mp3


I extracted the audio from a video just by replacing input.wav with the video filename. The 2 means 190 kb/sec. You can see the other quality levels at my link above.

input.wav

2

Just a guess:

-ab 192


should be

-ab 192k


Seems like that could be a problem, but maybe ffmpeg is smart enough to correct it.

If the audio wrapped into the avi is not mp3-format to start with, you may need to specify -acodec mp3 as an additional parameter. Or whatever your mp3 codec is (on Linux systems its probably -acodec libmp3lame). You may also get the same effect, platform-agnostic, by instead specifying -f mp3 to "force" the format to mp3, although not all versions of ffmpeg still support that switch. Your Mileage May Vary.

-acodec mp3

-acodec libmp3lame

-f mp3

Use -b:a instead of -ab as -ab is outdated now.Make sure your input file path is correct.

-b:a

-ab

-ab

To extract audio from a video I have used below command and its working fine.

String complexCommand = "-y", "-i", inputFileAbsolutePath, "-vn", "-ar", "44100", "-ac", "2", "-b:a", "256k", "-f", "mp3", outputFileAbsolutePath;


Here,

-y

Overwrite output files without asking.

-i

ffmpeg reads from an arbitrary number of input “files” specified by the -i option

-vn

Disable video recording

-ar

sets the sampling rate for audio streams if encoded

-ac

Set the number of audio channels.

-b:a

Set the audio bitrate

-f

format

Check out this for my complete sample ffmpeg android project on github.

To extract without conversion I use a context menu entry - as file manager custom action in Linux - to run the following (after having checked what audio type the video contains; example for video containing ogg audio):

ogg

bash -c 'ffmpeg -i "$0" -map 0:a -c:a copy "$0%%.*".ogg' %f


which is based on the ffmpeg command ffmpeg -i INPUT -map 0:a -c:a copy OUTPUT.

ffmpeg -i INPUT -map 0:a -c:a copy OUTPUT

I have used -map 0:1 in that without problems, but, as said in a comment by @LordNeckbeard, "Stream 0:1 is not guaranteed to always be audio. Using -map 0:a instead of -map 0:1 will avoid ambiguity."

-map 0:1

0:1

-map 0:a

-map 0:1

0:1

-map 0:a

-map 0:1

Thank you for your interest in this question.
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