Audio and Labels - Learn SpriteBuilder for iOS Game Development - page 366

Table 11-1 . Differences between short sound effects played through
OpenAL and long audio played through AVAudioPlayer

Short Sound-Effects/
OpenAL

Long-Running Audio/AVAudi-
oPlayer

None or small delay, de-
pending on file size and
format

Playback Delay Small delay if not preloaded

Any software-decodable
format, or any hardware
format if using hardware

Any software-decodable
format

Format on Disk

Decoding During load During playback

Entire file loaded and de-
compressed into memory

File streamed in real time
(very low memory usage)

Memory Use

Simultaneous
Playback

32 simultaneous effects Limited only by CPU

Excellent with 1 track (hard-
ware decoding). Still good
with 2 or a few tracks, but ad-
ditional tracks tax the CPU
significantly.

Playback Per-
formance

Good

Looped Play-
back

Yes (specific number of loops,
unlimited loops, or off)

Yes (on or off)

Panning Yes (mono files only) Yes

Positional Audio Yes (mono files only) No

Modify Pitch Yes No

Audio Power
Metering

No Yes

44 or 22 kHz sample rate
with 16 bits per sample.
Uncompressed PCM.
Prefer mono. Containers:
.caf, .aiff or .wav. Dura-
tion: a fraction of a second
to a few seconds.

MP3 or AAC encoding, vari-
able or constant bitrate
between 80 kbps to 192 kbps.
Mono or stereo. Containers:
mp3, m4a, mp4. Duration: a
few seconds to several
minutes.

Recommended
Formats