How can I extract audio from video with ffmpeg? [closed] - parsing

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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
but I get the following output
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?

Answer 1

To extract the audio stream without re-encoding:
ffmpeg -i input-video.avi -vn -acodec copy output-audio.aac
-vn is no video.
-acodec copy says use the same audio stream that's already in there.
Read the output to see what codec it is, to set the right filename extension.

Answer 2

To encode a high quality MP3 or MP4 audio from a movie file (eg AVI, MP4, MOV, etc) or audio file (eg WAV), I find it's best to use -q:a 0 for variable bit rate and it's good practice to specify -map a to exclude video/subtitles and only grab audio:
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.
You can use the -to option instead of the -t option, if you want to specify the range, eg for 45 seconds: 00:03:05 + 45 = 00:03:50
Working example:
Download ffmpeg
Open a Command Prompt (Start > Run > CMD) or on a Mac/Linux open a Terminal
cd (the change directory command) to the directory with the ffmeg.exe, as depicted.
Issue your command and wait for the output file (or troubleshoot any errors)
Windows
Mac/Linux

Answer 3

Extract all audio tracks / streams
This puts all audio into one file:
ffmpeg -i input.mov -map 0:a -c copy output.mov
-map 0:a selects all audio streams only. Video and subtitles will be excluded.
-c copy enables stream copy mode. This copies the audio and does not re-encode it. Remove -c copy if you want the audio to be re-encoded.
Choose an output format that supports your audio format. See comparison of container formats.
Extract a specific audio track / stream
Example to extract audio stream #4:
ffmpeg -i input.mkv -map 0:a:3 -c copy output.m4a
-map 0:a:3 selects audio stream #4 only (ffmpeg starts counting from 0).
-c copy enables stream copy mode. This copies the audio and does not re-encode it. Remove -c copy if you want the audio to be re-encoded.
Choose an output format that supports your audio format. See comparison of container formats.
Extract and re-encode audio / change format
Similar to the examples above, but without -c copy. Various examples:
ffmpeg -i input.mp4 -map 0:a output.mp3
ffmpeg -i input.mkv -map 0:a output.m4a
ffmpeg -i input.avi -map 0:a -c:a aac output.mka
ffmpeg -i input.mp4 output.wav
Extract all audio streams individually
This input in this example has 4 audio streams. Each audio stream will be output as single, individual files.
ffmpeg -i input.mov -map 0:a:0 output0.wav -map 0:a:1 output1.wav -map 0:a:2 output2.wav -map 0:a:3 output3.wav
Optionally add -c copy before each output file name to enable stream copy mode.
Extract a certain channel
Use the channelsplit filter. Example to get the Front Right (FR) channel from a stereo input:
ffmpeg -i stereo.wav -filter_complex "[0:a]channelsplit=channel_layout=stereo:channels=FR[right]" -map "[right]" front_right.wav
channel_layout is the channel layout of the input. It is not automatically detected so you must provide the layout name.
channels lists the channel(s) you want to extract.
See ffmpeg -layouts for audio channel layout names (for channel_layout) and channel names (for channels).
Using stream copy mode (-c copy) is not possible to use when filtering, so the audio must be re-encoded.
See FFmpeg Wiki: Audio Channels for more examples.
What's the difference between -map and -vn?
ffmpeg has a default stream selection behavior that will select 1 stream per stream type (1 video, 1 audio, 1 subtitle, 1 data).
-vn is an old, legacy option. It excludes video from the default stream selection behavior. So audio, subtitles, and data are still automatically selected unless told not to with -an, -sn, or -dn.
-map is more complicated but more flexible and useful. -map disables the default stream selection behavior and ffmpeg will only include what you tell it to with -map option(s). -map can also be used to exclude certain streams or stream types. For example, -map 0 -map -0:v would include all streams except all video.
See FFmpeg Wiki: Map for more examples.
Errors
Invalid audio stream. Exactly one MP3 audio stream is required.
MP3 only supports 1 audio stream. The error means you are trying to put more than 1 audio stream into MP3. It can also mean you are trying to put non-MP3 audio into MP3.
WAVE files have exactly one stream
Similar to above.
Could not find tag for codec in stream #0, codec not currently supported in container
You are trying to put an audio format into an output that does not support it, such as PCM (WAV) into MP4.
Remove -c copy, choose a different output format (change the file name extension), or manually choose the encoder (such as -c:a aac).
See comparison of container formats.
Could not write header for output file #0 (incorrect codec parameters ?): Invalid argument
This is a useless, generic error. The actual, informative error should immediately precede this generic error message.

Answer 4

Seems like you're extracting audio from a video file & downmixing to stereo channel.
To just extract audio (without re-encoding):
ffmpeg.exe -i in.mp4 -vn -c:a copy out.m4a
To extract audio & downmix to stereo (without re-encoding):
ffmpeg.exe -i in.mp4 -vn -c:a copy -ac 2 out.m4a
To generate an mp3 file, you'd re-encode audio:
ffmpeg.exe -i in.mp4 -vn -ac 2 out.mp3
-c (select codecs) & -map (select streams) options:
-c:a -> select best supported audio (transcoded)
-c:a copy -> best supported audio (copied)
-map 0:a -> all audio from 1st (audio) input file (transcoded)
-map 0:0 -> 1st stream from 1st input file (transcoded)
-map 1:a:0 -> 1st audio stream from 2nd (audio) input file (transcoded)
-map 1:a:1 -c:a copy -> 2nd audio stream from 2nd (audio)input file (copied)

Answer 5

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.

Answer 6

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.

Answer 7

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.

Answer 8

For people looking for the simpler way to extract audio from a video file while retaining the original video file's parameters, you can use:
ffmpeg -i <video_file_name.extension> <audio_file_name.extension>
For example, running:
ffmpeg -i screencap.mov screencap.mp3
extracts an mp3 audio file from a mov video file.

Answer 9

Here's what I just used:
ffmpeg -i my.mkv -map 0:3 -vn -b:a 320k my.mp3
Options explanation:
my.mkv is a source video file, you can use other formats as well
-map 0:3 means I want 3rd stream from video file. Put your N there - video files often has multiple audio streams; you can omit it or use -map 0:a to take the default audio stream. Run ffprobe my.mkv to see what streams does the video file have.
my.mp3 is a target audio filename, and ffmpeg figures out I want an MP3 from its extension. In my case the source audio stream is ac3 DTS and just copying wasn't what I wanted
320k is a desired target bitrate
-vn means I don't want video in target file

Answer 10

Creating an audio book from several video clips
First, extracting the audio (as `.m4a) from a bunch of h264 files:
for f in *.mp4; do ffmpeg -i "$f" -vn -c:a copy "$(basename "$f" .mp4).m4a"; done
the -vn output option disables video output (automatic selection or mapping of any video stream). For full manual control see the -map option.
Optional
If there's an intro of, say, 40 seconds, you can skip it with the -ss parameter:
for f in *.m4a; do ffmpeg -i "$f" -ss 00:00:40 -c copy crop/"$f"; done
To combine all files in one:
ffmpeg -f concat -safe 0 -i <(for f in ./*.m4a; do echo "file '$PWD/$f'"; done) -c copy output.m4a

Answer 11

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.

Answer 12

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):
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.
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."

Answer 13

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