COSC 414 Audio in Games Digital Audio -- Part 1 Sound Something vibrates in the air creating waves of pressure on your eardrums that your brain interprets as sound. Sound pressure measured in decibels , dB. 0 dB - Threshold of hearing 10 dB - Rustling leaves 20 dB - Whisper
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Digital Audio -- Part 1
Something vibrates in the air creating waves of pressure on your eardrums that your brain interprets as sound.
Sound pressure measured in decibels, dB.
0 dB - Threshold of hearing
10 dB - Rustling leaves
20 dB - Whisper
60 dB – Conversation
110 dB – Rock Concert
130 dB - Threshold of pain
160 dB – Instant perforation of eardrum
Analog = continuous
Digital = discrete
To convert from analog to digital: sample -
Look at amplitude at regular intervals
Convert to a number
Use number to play back the sound.
1Hz=1 Hertz = 1 cycle per second
Telephone Quality 11 KHz, 8 bit, mono
Radio Quality 22 KHz, 8bit, mono
CD Quality 44 KHz, 16 bit, stereo
As sample rate increases ...
File size increases
Fundamental Problem of Multimedia:
Balance file size with asset quality
2 bytes: +/- 32767 data points
1 minute of CD quality audio
44100 samples per second
X 2 bytes per sample
X 2 channels
X 60 seconds
10.5 Mb per minuteSampling Rates
Holy Grail of Audio:
Develop the best algorithm, one that combines high quality at low bitrates and works everywhere.
First standard in audio compression: MPEG
This algorithm was developed by the Motion Picture Experts Group (MPEG), as an International Organization for Standardization (ISO) standard for the high fidelity compression of digital audio.
How does the human audio perception influence compression?
Human hearing masks weaker signals whenever the presence of a strong audio signal makes a temporal or spectral neighborhood of weaker audio signals imperceptible.
Ambiance, Decay, Echo
Plan using the Storyboard
Get it all in one studio session
Professional Audio Editor