transform mp3s

tux008 · 08-04-2011, 03:28 AM

Hello, everybody!

I have a small collection of mp3 files that have a "huge" bit rate (320kbps). I would like to transform all the files so they would have a "normal" bit rate of, say, 128 kbps and simultaneously keep the ID3 tags. I think this can be done by a bash script, but I don't know exactly how.

Any help is very appreciated!

Thanks!

devnull10 · 08-04-2011, 04:08 AM

I use "Lame" for this and have a shell script wrapper around it. One thing though, it doesn't preserve ID3 tags - need to sort that out when I get time or you can modify the below to do that.

Code:

#!/bin/bash

if [ $# -eq 1 ]
then
  dir=./
  br=$1
elif [ $# -eq 2 ]
then
  dir=$1

  if [ $2 == 'vbr' ]
  then
    br='standard'
  else
    br="cbr $2"
  fi
else
  echo "Usage: $0 [directory] New_Bitrate"
  exit -1
fi

if [ ! -d $dir ]
then
  echo "$dir is not a directory"
  exit -1
fi

echo "Converting files in $dir to bitrate: $br"

find "$dir" -name "*.mp3" | sort | while read i
do
  tmpfile=$(mktemp)
  lame --mp3input --preset $br -S --add-id3v2 "$i" "$tmpfile"
  mv "$tmpfile" "$i"
  chmod 644 "$i"
  echo "Sucessfully converted $i"
done

exit 0

cascade9 · 08-04-2011, 04:34 AM

320k isnt that big, in these days of 2TB+ HDDs and very cheap flash media.

I wouldnt convert them, if only because a lossy-> lossy transcode will sound worse than an original rip.

But if you really want to do it, you could write some script, or you could use a program with a GUI, like soundconverter (Gtk) or soundkonverter (Qt).

David the H. · 08-04-2011, 07:10 AM

Search the site. Get on Google. The number of people who've wanted to do exactly the same thing must number in the tens of thousands by now. And I know at least a few of them found solutions and have posted them for others to use.

But overall I concur with cascade9. If you don't need to convert a lossy file, don't. It's better to go back to the original lossless source, assuming it exists, and simply rip it again.

tux008 · 08-12-2011, 11:03 AM

Thank you all very much!