loadmp3: Copy .ogg/.mp3 files to a hardware mp3 player

Goals

I have a Creative nomad MP3 player. It's a very cute device: plugs into USB, shows a USB mass storage file system, I mount it as a VFAT file system, write .mp3 files onto it.

The trouble is that I mostly have .ogg music files. And, the device has only 64 Meg, so one wants low res .mp3 files to be generated and put on the player.

loadmp3 is a program which accepts commandline args, and writes .mp3 files into a USB Mass Storage MP3 player. It allows you to have an ogg database while using an mp3 player.

Features:

• Copies .mp3 files blindly, but knows how to convert .ogg files into .mp3 files of a stated resolution.
• Tests whether you have enough room for the files. Offers a flag -check which only talks about projected flash usage.
• Fully automates mount... convert... copy... umount.
• Takes some care to keep the USB bus humming, for writes to not just go into Unix caches and then generate a long delay at umount.
• Moves data in pipes, doesn't use disk space for intermediate files.
• When the filenames supplied on the commandline do NOT use up all available space, it will randomly pick files from your music collection and put them onto the device. Hence, saying `loadmp3.pl' with no args would be tantamount to asking him to only use his randomised selection.
• It checks that in randomisation, it doesn't reuse a file which was already taken.

Usage

      $ loadmp3.pl [-check] filenames

If the -check flag is enabled, the ONLY thing it does it to test whether your specified filelist fits into your MP3 device. It does no mount/umount activities.

What is going on here is:

• You supply it a set of commandline args of files you want to push down.
• It first checks whether there is enough room for them.
• If there is room, it goes over the files. If it's a .mp3 file, this is just copied into the device. If it's a .ogg file, this is converted into a MP3 file at your stated bit rate first.
• Once it has finished putting in all the files that you specified, it tries to randomly pick tracks to fill up the remaining space. In doing this, it tries to avoid duplicates.

So if you say

$ sudo loadmp3.pl afewfiles

it will first place your few files, and then fill up the remaining space with randomised selection. If, on the other hand, you just say

$ sudo loadmp3.pl

then it will only do randomised selection and placement.

Watch me run it. I tell him to place the album 'Dark Side of the Moon'. Beyond that, he does his own thing.

$ sudo ~ajayshah/BIN/loadmp3.pl /home/music/Pink_Floyd/Dark_Side_Of_The_Moon/*
Okay, your files add up to 26361852, and I will allocate 37126148.
Mounting MP3 device...
Processing /home/music/Pink_Floyd/Dark_Side_Of_The_Moon/01_Speak_To_Me.ogg...
Processing /home/music/Pink_Floyd/Dark_Side_Of_The_Moon/02_Breathe.ogg...
Processing /home/music/Pink_Floyd/Dark_Side_Of_The_Moon/03_On_The_Run.ogg...
Processing /home/music/Pink_Floyd/Dark_Side_Of_The_Moon/04_Time.ogg...
Processing /home/music/Pink_Floyd/Dark_Side_Of_The_Moon/05_The_Great_Gig_In_The_Sky.ogg...
Processing /home/music/Pink_Floyd/Dark_Side_Of_The_Moon/07_Us_And_Them.ogg...
Processing /home/music/Pink_Floyd/Dark_Side_Of_The_Moon/08_Any_Colour_You_Like.ogg...
Processing /home/music/Pink_Floyd/Dark_Side_Of_The_Moon/09_Brain_Damage.ogg...
Processing /home/music/Pink_Floyd/Dark_Side_Of_The_Moon/10_Eclipse.ogg...
Processing /home/music/Led_Zeppelin/08_The_Song_Remains_The_Same.ogg...
Processing /home/music/U2/War/07_Two_Hearts_Beat_As_One.ogg...
Processing /home/music/Roger_Waters/In_The_Flesh_Disc_2/10_Eclipse.ogg...
Processing /home/music/Joni_Mitchell/Both_Sides_Now/05_Answer_Me,_My_Love.ogg...
Processing /home/music/Pink_Floyd/Dark_Side_Of_The_Moon/07_Us_And_Them.ogg...
Processing /home/music/Don_Henley/01_The_End_Of_The_Innocence.mp3...
Processing /home/music/Asia/06_Wildest_Dreams.mp3...
Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/sda1                61904     61792       112 100% /mnt/ums
Umounting...

Requirements

• You have to obviously have a USB Mass Storage MP3 device which mounts and umounts successfully.
• You have to have the following binaries:
  ogginfo
  ogg123
  bladeenc
  df
  id
  
  In Debian, these come from the following packages:
  vorbis-tools
  bladeenc
  fileutils
  shellutils
  

Todo

• Right now it wants to be root, thinking that only root can mount..umount. That's not true in general.
• Right now it panics if a filename contains special characters. Need to fix this.
• Right now, it assumes that after it has done 'rm *mp3' on the device, there is no gunk left lying around. If you had used the MP3 player as portable media, and you had some files lying around, it just breaks. It does not CHECK that there is nothing on the device after doing "rm *mp3".
• Right now, it merely keeps track of the exact string for the name of a file that was 'used up'. Strictly, thanks to relative addressing in filepaths, some nonunique files could still slip through.

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Ajay Shah
ajayshah at mayin dot org