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Audio

Audio. Why Audio Essential tool for – Interface – Narrative – Setting & Mood

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Audio

Why Audio

• Essential tool for– Interface–Narrative– Setting & Mood

Sound as Interface

• Sound as supplemental channel – reinforce visuals

Sound as Interface

• Sound as alternative channel – avoid visual overload– provide information about hidden events

Sound as Interface

• Accessibility– Are sounds essential for game?

Voice Acting

• Specialists – outside actors– Need to fit non-linear narrative– Alternative takes to common lines

Film vs Game Score

• Film scores can be shaped to exact moments– Possible only in game cut scenes

Film vs Game Score

• General game music– Needs to play for undetermined time : looped– Want to adapt to situation• Layer or transition adaptively

Sound Files

How are sounds stored on a computer?

• Encoded as binary numbers (1’s and 0’s)• Two important encodings for our purposes:– MIDI sequences– Samples

MIDI• Musical Instrument Digital Interface– Sheet music for your computer

• Developed in 60’s• VERY compact: ~1% of mp3

• User’s sound card is responsible for creating the music. – Different sound cards = different sounds

Anvil Studio

• Anvil Studio is a free MIDI editor:

Samples

• Sounds are pressure waves:

Samples

• Sampling : convert pressure wave to discrete points - smaples

• Sample = intensity at point in time

Samples

• Sample rate: The rate at which the samples are captured or played back– measured in Hertz (Hz), or samples per second• More Hertz = higher quality and larger files• An audio CD has a sample rate of 44,100 Hz, or 44 KHz

• Sample rate = horizontal precision

Samples

• Sample format or sample size: the number of digits used to represent each sample– Measured in bits (binary digits - 1 or 0)• Audio CD = 16 bits• More bits = higher quality and higher file size

• Sample format = vertical precision

Sampled formats

• CD Audio = 16 bits x 44,000 times a second – ~10 megabytes per minute of stereo recording

• Bits stored into file either compressed or raw:– Compressed: PCM (wav, aiff)– Compressed: mp3, ogg, aac, etc…

PCM

• PCM : Pulse Code Modulation– Windows usually .wav – Macs usually aiff

• Very big• Easy to play

mp3 etc…

• Compressed formats– Reduce file size to ~ 1/10th the space.

• Playback takes more work (decode audio)

Gamemaker

• Gamemaker 8 deals best with wavs– MIDI, MP3 play only one at a time

• GM Studio– Coverts everything to .ogg– Legacy Sound : For HTML 5– GM:S Audio : New engine• 3d sound effects

Sounds in Gamemaker

• Normal : sound effects– Can have multiple playing at one time

• Background Music : only one plays at a time– Start a new background and the old background turns off