How can I extract audio from video with ffmpeg

Question

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

User · Answer

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

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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

User · Answer

To encode a high quality MP3 or MP4 audio from a movie file  eg AVI  MP4  MOV  etc   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  gt  Run  gt  CMD  or on a Linux Mac open a Terminal cd to the directory with the ffmeg exe Issue your command and wait for the output file  or troubleshoot any errors

User · Answer

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

User · Answer

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

User · Answer

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

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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  lt video file name extension gt   lt audio file name extension gt    For example  running   ffmpeg -i screencap mov screencap mp3   extracts an mp3 audio file from a mov video file

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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  quot  0 a channelsplit channel layout stereo channels FR right  quot  -map  quot  right  quot  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

User · Answer

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

User · Answer

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

User · Answer

Seems like you re extracting audio from a video file  amp  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  amp  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

User · Answer

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

User · Answer

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

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

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