There are tons of different audio formats, each with its own properties. Some
of the most popular ones are WAV, MIDI, MP3, Real Audio, ASF, WMA, audio tapes,
and CDA formats. We’ll talk about converting these formats using tools that
are available on the Internet either as freeware or shareware. Many of them are
not distributable, that’s why we’ve given the URLs from where you can
download them. Their sizes vary between a few kB to 6-7 MB.
Before converting, keep in mind that there will always be
some data loss when you convert one format to another. In this article, we’ll
take uncompressed WAV as a ‘base’ format (because it’s easy to edit) and
then encode/convert all others with reference to it. Technically, almost all
formats can be transformed using a combination of the three processes of
encoding, compressing, and recording.
WAV to MP3
You can use this conversion to store recorded live music
performances or speeches as small files in your collection. For this, you can
use the popular Winamp Player (any version). Simply download the MP3 output
plugin for Winamp, install it and go. Set the Winamp output plugin to MP3 and
create a WAV file playlist to be encoded. Hit the play button and there you are.
Be sure to install an MP3 codec (Fraunhofer IIS, Radium or any other) before you
attempt this. Other options are software like Streambox Ripper, MusicMatch
Jukebox or BladeEnc, which let you do the same. Note here that the parameters
you use for encoding will determine the final quality of the MP3, the best being
CD-quality, that is, 44.1 kHz at 128 kbps stereo. Higher bit rates are also
possible, but they increase the file size and should be used only by
professionals. Typically, the same file encoded at 256 kbps is twice the size of
one at 128kbps.
MP3 to WAV
This is the process of decompressing an MP3 to a WAV file.
For instance, if you want to edit your MP3 file, like mixing your own drum beats
in it, you’ll need to first convert it to a WAV file. Winamp again comes to
the rescue here. Set the output plugin as Disk Writer plugin and create the MP3
playlist that needs to be converted. Hit play and there you have it. Note that
if the MP3 file used was itself converted from a WAV file, then don’t expect
it to reproduce the original WAV upon reconversion. That’s because data lost
during any conversion can’t be retrieved. For editing WAV files, software like
GoldWave is available that lets you add effects, increase volume, invert
channels, mix two WAV files, etc.
Audio CD to MP3
For starters, converting audio CDs to MP3 is simple enough.
You can do this in two ways: either, by first ripping the CD tracks and then
encoding them to MP3s, or by ripping and encoding on-the-fly. The first uses CD
ripping software like Audio Grabber or Easy CDDA Extractor. This is stored as a
huge WAV file that can then be encoded to MP3. However, certain software like
the StreamBox Ripper, or Goldwave for that matter, can use an MP3 codec in
conjunction and hence create MP3 files directly. Most CD rippers support most
IDE and SCSI CD drives. Note, however, that the quality of the final MP3 is
limited to CD-quality because the tracks on the audio CD are CD-quality!
Audio tapes to MP3
This can be useful if you have some sound tracks on tapes or
on antique LP records that you want to preserve. For this conversion, you need a
stereo audio cable to connect your cassette tape player to the sound card on
your PC and a WAV recording software like Windows sound recorder. Connect the
Line-out/Headphone-out from the cassette player to the Line-in of your sound
card. Start the WAV recorder software, play the tape and it gets recorded. Save
the huge WAV file and then follow the process described in the WAV to MP3
conversion above. The whole process may take time as it involves adjusting the
volumes on the player and recording volumes on your sound card mixer.
WAV to WMA
When we talk of MP3, we should also be talking of WMA, the
compression format from Microsoft. Software like StreamBox Ripper lets you
convert WAV, audio CD tracks or even MP3s to WMA format. The encoding quality
depends on the parameters you select. However, in our tests we found that the
playback sound was crisper in MP3 and echoed a bit in the WMA format.
MIDI to WAV
Theoretically, you can’t convert/encode MIDI files to WAV
or any other format. This is because an MIDI file contains instructions and no
audio data. No software let’s you do this directly. However, there’s a
workaround to the problem. What if you could record the MIDI file being played
from your speakers? If you were to create physical connections, then you would
run a cable from the line-out of your sound card to the line-in. Well, doesn’t
sound like a very good idea. So, enter Total Recorder, a software that creates a
virtual audio cable between your card’s line-in and line-out. There are no
physical connections but it will record anything played on your speakers. So be
it MIDI, a streaming music clip or even the music score from your favorite game!
The software’s controls can be adjusted as per the sound quality you desire
and the setup you have. So play the MIDI file and press record on the Total
Recorder to record it into a WAV. By proxy, but it works!
Streaming Real Audio to WAV
Streaming multimedia content is gaining importance with
broadband coming in a big way. With streaming, you can listen to sample music
clips from the latest blockbusters. If you want them offline, then use Total
Recorder. You can even encode it to MP3 and add it to your Winamp playlist.
However, the bit rate for Real audio streams are often low (in the range of 20
kbps), and may also be mono to save on bandwidth. That’s because Real audio is
optimized for streaming so it cuts out a lot of audio data from the original
sound. So the final WAV or MP3 will also be of poor quality.
WAV to Streaming Real Audio
This is for you if you want to put streaming audio on your
Website. Your source could be audio CDs, WAV files or MP3s. you’ll use Real
Producer from RealNetworks, which allows you to do this. Just load the WAV and
it generates the RA file for you. You’ll have to set the parameters according
to the bandwidth you have for transmission.
There are a zillion other formats like the ATRAC3, A2B, and MPEG2-AAC that
are not in vogue but may become popular as the needs grow.