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Archive for April 13th, 2019

Multiprocess Book-on-CD Ripping

The most recent iteration of ripping a book-on-CD to bits suitable for a small MP3 player begins by defining the metadata:

author="Whoever Wrote It"
title="Whatever It May Be About"

Set up a suitable directory for the MP3 files, with a subdirectory for the WAV files direct from the CD:

mkdir "$author - $title"
cd "$author - $title"
mkdir waves

Then unleash cdparanoia on each disk, but with its error checking dialed back to a minimum because most errors don’t produce much audible damage:

d=01 ; cdparanoia -v -Y --never-skip=1 -B "1-" waves/D$d.wav ; eject cdrom

In some cases, however, a nasty gouge (the previous owners being careless, alas) can jam cdparanoia midway through a track, so I fetch all the remaining tracks:

d=10 ; cdparanoia -v -Y --never-skip=1 -B "6-" waves/D$d.wav

Sometimes re-cleaning the disc and re-reading the offending track produces a better outcome:

d=10 ; cdparanoia -v -Y --never-skip=1 -B "5-5" waves/D$d.wav

With all the WAV files collected, I now know how to unleash multiple lame conversions for all the tracks on each disc:

for d in {01..12} ; do for t in {01..19} ; do if [[ -f waves/track$t.D$d.wav ]] ; then lame --silent --preset tape --tt "D${d}:T${t}" --ta "$author" --tl "$title" --tn $t --tg "Audio Book" --add-id3v2 waves/track${t}.D${d}.wav D${d}-T${t}.mp3  & fi ; done ; wait ; done

The disc and track ranges correspond to notes written on paper while ripping the CDs, there being no automagic way to collect the information.

That may be easier to read with the control structures spread out:

for d in {01..12}
 do for t in {01..19}
  do if [[ -f waves/track$t.D$d.wav ]]
   then
    lame --silent --preset tape --tt "D${d}:T${t}" --ta "$author" --tl "$title" --tn $t --tg "Audio Book" --add-id3v2 waves/track${t}.D${d}.wav D${d}-T${t}.mp3  &
   fi
  done
 wait
done

Affixing an ampersand (&) to the lame command drops it into the background, where it runs as CPU time becomes available. The wait after the first loop stalls until all of the lame instances for each CD finish.

The kernel scheduler manages to keep the GUI responsive while a four-core CPU makes short work of the entire CD.

When it’s all done, transfer the MP3 files to the player:

cd ..
sudo mount -o uid=ed /dev/sde1 /mnt/part
rsync -vrtu --progress --exclude="waves" "$author - $title"  /mnt/part/Music
sync
sudo umount /mnt/part

Fetching commands from history eliminates the need to remember all that, but now it’s written down where I can find it for the next desktop box.

Life is good!

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