Table 294 – Additional entries specific to a sound object

Key

Type

Value

Type

name

(Optional) The type of PDF object that this dictionary describes; if present, shall be Sound for a sound object.

R

number

(Required) The sampling rate, in samples per second.

C

integer

(Optional) The number of sound channels. Default value: 1.

B

integer

(Optional) The number of bits per sample value per channel. Default value: 8.

E

name

(Optional) The encoding format for the sample data:

Raw Unspecified or unsigned values in the range 0 to 2B − 1

Signed Twos-complement values

muLaw m-law–encoded samples

ALaw A-law–encoded samples

Default value: Raw.

CO

name

(Optional) The sound compression format used on the sample data. (This is separate from any stream compression specified by the sound object’s Filterentry; see Table 5 and 7.4, “Filters.” ) If this entry is absent, sound compression shall not be used; the data contains sampled waveforms that shall be played at R samples per second per channel.

CP

(various)

(Optional) Optional parameters specific to the sound compression format used.

No standard values have been defined for the CO and CP entries.