ITEC2110:Fall2010:PodcastProject:AYancey

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Alan Yancey's Podcast (Audacity) Project

Using 28.8Kbps for dialup downloading speed and 1.5Mbps for DSL downloading speed.

Uncompressed vs. Compressed

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Format

File size

Download time (Dialup)

Download time(DSL)

Link to Download

Using Audacity I produced a .wav format file which is:

41.7 MB

3 Hours 13 mins 3 sec

3 Min 42.4 sec

Click here to download this version

Using Audocity I produced a .mp3 format file which is:

3.73 MB

17 mins 16 sec 19.5 secs

Click here to download this version


Quantization and Sampling Rates

CD quality audios are usually sampled at 44,100 samples per second with a 2 byte quantization level.

Format

File size

Dialup download time

ADSL download time

Download

Using Audacity I produced a .wav format file which has a sample rate of 44100 samples per second and a quantization level of 32 bits:

10.2 MB

47 mins 13 sec

54.4sec

Click here to download this version

Using Audacity I produced a .wav format file which has a sample rate of 44100 samples per second and a quantization level of 16 bits:

10.2 MB

47 mins 13 sec

54.4 sec

Click here to download this version

Using Audacity I produced a .wav format file which has a sample rate of 8000 samples per second and a quantization level of 16 bits:

5.6 MB

25 mins 54 sec

1.55 sec

Click here to download this version


Reflection Questions

  • What's the difference between WAV format and MP3 format and how different formats affect downloading time ? (Hint: file size; compression)(Read the wiki page for more information)
Answer: WAV is uncompressed and mp3 is a compressed version of audio. Amount of compression with mp3 varies, but overall, mp3 download faster since they are compressed files.
  • Do you know any other audio format? Please list at least one.
Answer: Ogg is a different audio format. it is a open, public source and it is similar to mp3 in quality
  • How sampling and quantization affect audio quality?
Answer:Sampling creates values at discrete intervals in analog, quantization restricts these intervals to a fixed value on present scale. Audio quality relies on sampling rate, a low rate equals less accuracy which leads to lesser quality. Low quantization loses definition.


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Special thanks to Stephen Kent who re-organized the submission template.

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