comparing wav with mp3

7/24/2019 Comparing WAV With MP3

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Comparing WAV File Format with MP3 File Format

Introduction

An audio file format is a file format for storing digital data on a computer system or

digital media. This data can be stored uncompressed to preserve the fidelity or compressed to

reduce the file size. Over the years, there have been many file types introduced in the digital

recording world, but only a handful have actually caught on and remained in popular usage.

Every once in a while a new format shows up that catches on, the AAC format used by Apples

tunes store being the most recent, but the history of digital recording and distribution is full of

format that never made the cut. !ome of the most common file formats used in audio sounds

includes "A#, A$$, %&' and AAC. This paper presents some of the salient differences that

e(ist in audio sounds that are in %&' format file format and "A# file formats. To accomplish

this, the paper presents the uni)ue characteristic of each file and the differentiating

characteristics of each type of format based on a recording e(periment that undertoo* prior to

writing this paper.

Literature review

"aveform audio file format is a digital audio standard that windows Operating !ystems

can recognize and manipulate. This file format was conceived by %icrosoft and supports a

number of compressed and uncompressed audio formats +ichmond, -/, p. /'01."A# files are

playable on windows and %acintosh computers but because of their large size seldom uploaded

to the internet. "aveform Audio $ile format is uncompressed and provides the highest )uality

digital representation of sound. t is the most popular uncompressed audio format presently. t is

a fre)uently used format in audio signal2processing tools such as %AT3A4 +Cai, -/5, p. 61.


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%&' is a compressed audio file format that is very popular in the consumer mar*et.

These files are used for audio file sharing over the internet and in %&' players and also video

games +#iers, -//, p. /'61. The %&'s compression ratio allows for files to be tenth of the size

while maintaining a reasonable level of )uality. %&' is the file format that powered the

popularity of digital music. %&E7 /, 3ayer ', shortened to %&', is simply a standard set of

mathematical algorithms used for compressing sound files into an attractive format for

downloading or streaming across the internet. "hen the %&' algorithms are run through a set of

musical data, such as a digitally encoded recording, it eliminates virtually all of the s and /s the

human ear cannot reasonably discern, leaving only those s and /s that are recognizable +8ohn

9 8ohn, -/, p. :-;1. 4ecause about 0 percent of the data in a typical digitally encoded

musical recording are not essential to the reasonable listening e(perience, that 0 percent can be

removed, leaving a greatly compressed file having only a slight reduction in sound )uality.

Though an audiophile or sound engineer could determine the difference between the original

"A# file containing all the data of a recording and the compressed %&' version of the

recording, the latter, although degraded, still provides a )uite acceptable listening e(perience for

the average person. The %&' format offers )uite a lot of different compression and )uality

settings, so that a listener can fine tune the format to get better )uality, sacrificing hard drive

space as the )uality is dialed2up.

Method and Results


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To conduct the e(perimentation on the two formats of the audio files, that is , %&' and

"A#, the program that was employed is audacity, however, other programs such as "avosaur,

3inu( %ulti%edia !tudio, Traverso


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Comments on uncompressed vs% compressed audio ile$

"hile listening to the two different file formats, to the human ear the )ualities of the

sound are similar and indistinguishable. =owever, according to 8ohn and 8ohn +-/, p. :-;1,

sound engineer or listening through an audiophile can determine the difference between the

original "A# file containing all the data of a recording and the compressed %&' version of the

recording. The latter, although degraded, still provides a )uite acceptable listening e(perience for

the average person.

&iscussion and conclusion

The inability of the human ear to discern the differences in sound )uality of the two file

formats is attributable to the lossy method that is used to compress the audio files. The lossy

method removes non2audible fre)uencies and by removing less important signals. 4y removing


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non2audible fre)uencies, the compression removes what a normal human being ear cannot hear,

although this assumption is sub>ect to argument +4ove 9 hodes, -?, p. -'51.

Recorded Audio File Spectrum 'raph #eore Compression


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Recorded Audio File Spectrum 'raph ater Compression

Analysing of the spectrum graph obtained from the ecorded Audio $ile before and after

Compression, certain characteristics of the two file formats can be identified in terms of

fre)uencies, wave shape and phase.


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This assessment of the two graph observed the following uni)ue features@ first, the two

files differ in terms of their fre)uencies. The original "A# file that is in its raw uncompressed

format demonstrates a spectrum graph that boosts of well2defined and distinct fre)uencies this is

as opposed to the spectrum graph of the %&' file format. !econdly, the uncompressed "A# file

demonstrates a more pronounced fre)uency changes as e(hibited by the broad span of

fre)uencies that ranges from =z to -,=z. This is remar*ably large comparable with the

fre)uency e(hibited by the compressed %&' file whose range of fre)uency is =z to //,=z.

Thirdly and lastly, it can be observed from both the spectrum graphs that the compressed %&'

file is simply a mirror copy of the uncompressed file, only that it has a limited fre)uency range.

&iscussion and Conclusion

The two files can be considered to be mirror copies of each other only that the

compressed %&' file has a shorter fre)uency range, while its curves are more evened out and

pronounced. These differences can be attributed to the encoding of the %&' file which

compresses the original "A# file to a format that is smaller. The reduction in the fre)uency

range is attributed to the encoding process which removes audio fre)uencies which the human

ear cannot discern. The smoothening of the %&' spectrum graph in comparison to the "A# file

can also be attributed to the encoding process that uses the 3ossy method which removes non2

audible fre)uencies and by removing less important signals removes unnecessary sounds which

according to 4ove 9 hodes +-?, p. -'51 ma*es up to 0 percent of a "A# file.

Line graph or the audio ile #eore compression (Wav)


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-5000

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25000

WAV

Frequency (Hz) Level (dB)

Line graph or the audio ile ater compression (mp3)$

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2000

4000

6000

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10000

12000

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MP

Frequency (Hz) Level (dB)

*#servation


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The following could be observed from the line graph of the two files. $irst, the amplitude of the

uncompressed raw "A# file is higher reaching -?, as opposed to the amplitude of the

compressed %&' file which is relatively reduced by almost a half to /-,. !econdly, from the

line graphs it can be observed that the fre)uencies of both files, the "A# file and %&' file,

remain unchanged. 3astly, it can also be observed that the gradients for both files are similar, and

are in fact mirror images of each other.

&iscussion

"ith regards to the line graph observations, and as e(pected, the fre)uencies of sounds

usually remain unchanged after encoding.

Conclusion

n summary, it can be concluded that as opposed to an uncompressed raw "A# file which

are large and re)uire bigger storage space, compressed %&' file formats are smaller and lighter

in terms of the space they ta*e. As a result %&' file format are considered more durable. Apart

from the reduced sized, the other advantage of %&' is that it is almost universally recognized.

Bust about any media player or portable audio player can recognize and play an %&' file. This

ma*es the file format popular among users.

Recommendations

$rom the e(periment it was noticeable that indeed %&' file formats present a myriad of

advantages that are over and above a "A# file. An %&' file is leaner and produces a sound that

is of good )uality despite the reduced file size. %&' files are also recognizable and can be played

by >ust about any media player or portable audio player. t is thus the best recommendable file

format to *eep audio files.


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eferences

4ove, T., 9 hodes, C. +-?1. iPod & iTunes For Dummies.ew Dor*@ Bohn "iley 9 !ons.

Cai, D. +-/51.Ambient Diagnostics.CC &ress.

$rancis, 7. +-01.Home Recording for Beginners.ew Dor*@ Cengage 3earning.

8ohn, 4., 9 8ohn, A. +-/1.Kohn on Music Licensing.Aspen &ublishers.

%itra, . +-51.Introduction to Mutimedia !"stems.Academic &ress.


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ichmond, C. $. +-/1.Audio# $ideo# and Media in the Ministr".Thomas elson nc.

#iers, . +-//1. !ound %ffects Bibe.%ichael "iese &roductions.

"illiams, . C. +-51. indo's(P Digita Music For Dummies.ew Dor*@ Bohn "iley 9

!ons.

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