Matters Concerning Audio - A Practical Guide to Video and Audio Compression - page 168

7.9.2 Sampling Word Size = Quality

Bear in mind that some older audio sources such as music synthesizers only offer 8-bit
samples as their sound origination. Sampling analog signals that originated in 8-bit digi-
tal form with a 16-bit word size will not generate better audio than you started with. If you
are using some kind of synchronized MIDI signal to generate a sound track, make sure it
is being voiced out through hardware or software synthesizers that will generate a suit-
able signal.

7.9.3 Rights Issues on Re-Use

As rights protection is deployed more in the future, it is increasingly likely that you will
encounter copy-protection issues with some source formats such as CD or DVD disks.
Whether you can take music from commercial CD recordings depends on your rights to
repurpose that material. You cannot simply dub from any CD you happen to have lying
around. Stock audio libraries are designed to provide background music for programs, but
special permission is necessary if you want to use well-known commercial material.

7.10 Open-Source Audio-Processing Systems

If you use the Linux operating system and want to experiment with digital audio, you can
build a versatile home studio for much less than you would expect. Having the operating
system and hardware built shouldn't cost a lot of money. Adding sound cards is also quite
economical. The important glue that makes it all work is the software. Check out Ecasound,
Audacity, and Ardour as potential candidates for recording and mixing your tracks.
The Ecasound application is a command line tool for recording audio via the sound
card. This is useful for building automation systems because it is easy to incorporate into
a shell script. Audacity is useful for editing sound files. This tool works on Windows or
Mac OS as well as Linux. Mixing and mastering can be done with Ardour, which is free
and is being ported to operating systems other than Linux. The Mac OS port is currently
in progress. These are all available as source kits, which you can modify yourself.

7.11 Summary: Don't Tell Harry

Audio has some tricks and surprises just like video. Often it is written off as being of little
consequence, but if you have perfectly compressed video with a truly awful audio track,
that is no good at all. You have to be diligent with every aspect of the process whether it
is video, audio, or other multimedia assets. It is all important.

Ecasound: http://www.eca.cx/
Audacity: http://audacity.sourceforge.net/
Ardour: http://ardour.org/