unable to extract audio from .flv
 

Hi,

Well, I don't know if this falls within the purview of this forum. However here it is -

I have downloaded a video from youtube which is saved as a .flv file. I am trying to extract the soundtrack as follows -

$ mplayer -dumpaudio infile.flv -dumpfile infile.mp3

However, the dumpfile doesn't seem to be an mp3 file as is evident from the output of -

$ file infile.mp3

which gives -

infile.mp3: \012- Assembler source

and this doesn't play in mplayer or any other audio player.

How can I set right this? Awaiting your valuable suggestions,

Is it really an mp3 file? Use mplayer -identify file.flv to check. Does mplayer play the flv file on its own?

Try -
mplayer -vo null -vc null -ao pcm:fast:file=audio.wav file.flv
This doesn't dump the stream, but decodes it to pcm wav file.

I use the following 'flash2avi' script:

!#/bin/sh

if [ -z "$1" ]; then
echo "Usage: $0 {-divx|-xvid} list_of_flv_files"
exit 1
fi

# video encoding bit rate
V_BITRATE=1000

while [ "$1" ]; do
case "$1" in
-divx)
MENC_OPTS="-ovc lavc -lavcopts vcodec=mpeg4:vbitrate=$V_BITRATE:mbd=2:v4mv:autoaspect"
;;
-xvid)
MENC_OPTS="-ovc xvid -xvidencopts bitrate=$V_BITRATE:autoaspect"
;;
*)
if file "$1" | grep -q "Macromedia Flash Video"; then
mencoder "$1" $MENC_OPTS -vf pp=lb -oac mp3lame -lameopts fast:preset=standard -o "`basename $1 .flv`.avi"
else
echo "$1 is not Flash Video. Skipping"
fi
;;
esac
shift
done

Nice little script!

Hi,

Thanks for the prompt reply!

gives the following output -

and it plays the .flv file without any problem. However, the file audio.wav dumped by the following command,

is unplayable by mplayer. When I try to play the .wav file, I can only hear a short burst of sound as though the whole file has been played in a fraction of a second with the following output
The script flash2avi outputs the following message -

should this be -

The script posted above wasn't wrapped in code tags and had bbcode enabled.

It should read -
AUDIO_FORMAT=255 I believe is aac audio. According to http://www2.mplayerhq.hu/DOCS/codecs-status.html#ac you need either libfaad2 or ffmpeg with aac support.
http://slackbuilds.org/repository/12.2/audio/faad2/

I find it quite strange that mplayer can play the original flv file with sound, but can not do a simple dump. As using dumpaudio, and -ao pcm:fast:file=audio.wav is actually no different than playing the file back. Playing the file back it has to be decoded, dumpaudio demuxes without decoding, -ao pcm:$ dumps the decoded stream. If mplayer can play the file, it should be able to dump it.

Why not just grab video downloader helper for FF from this link -> https://addons.mozilla.org/en-US/firefox/addon/3006 This will download and convert files from youtube with a couple of mouse clicks

from MPlayer.SlackBuild

"The Slackware package is built with "USE_PATENTS=NO" i.e. without using
the lame mp3, faac, AMR and dvdcss libraries."

Maybe you could use this:
That would seem the simplest way unless you want to use mplayer for a specific reason (I've never done this with mplayer, but I use ffmpeg all the time).

When the old -dumpaudio failed to work for the .mp4 files, I started using the following script to extract their audio; it seems to work for .flv files as well:

Here $1 is the .flv file and $2 is the output filename.

Ok! Now this command works and I am getting mplayer-playable .mp3 files. That's a major achievement. Thanks Ilgar!

However, I want to upload these mp3s to my Samsung Ultra Touch S8300 mobile. When I do this, and try to play them using the music player app in my mobile, I get the following message -

Any suggestions?

I'm pretty sure mplayer outputs audio to raw pcm format. I've ripped audio from flv like that. I then use some mp3 encoder to turn it into an mp3.

Yes I think so,

gives the following output -

Oops yes, I forgot to add, you'll get a wav file that way (as you'll notice from the file size).