Digital Audiovisual Properties - Extra

Peter Bubestinger-Steindl
(peter @ ArkThis.com)

April 2022

Signed / Unsigned

How does a computer deal with negative numbers?

  • unsigned = only positive (+) range
  • signed = positive/negative (±) range

but: signed = You lose a bit…

Signed / Unsigned

bits type range
8 unsigned 0..255
signed ± 127
16 unsigned 0..65535
signed ± 32768

signed = you also reduce to half the positive range

Audio Bits: Integer vs Float

  • Integer = Fixed grid/range for quiet & loud.
  • Float = Adjust value range to signal amplitude.
  • By “moving” (=floating) the decimal point

Endianness

  • 0x1234 is not 0x3412
  • Obviously.
  • So what?
If you get it wrong for audio:
white noise 😱️

Endianness

  • PC = Little Endian (LE)
  • Apple = Big Endian (BE)

PCM (Audio)

Pulse Code Modulation

Questions?

Comments?