OBD:SNDD: Difference between revisions

:1 - (compressed; always the same in Vanilla Oni)

{{OBDtr| 0x0E | uint16  |FFFFC8| 00 00      | 0x0000    | padding (unused in Vanilla Oni) }}

{{OBDtr| 0x10 | uint32  |C8FFC8| 5E 2A 00 00 | 10846    | size of the part in the raw file, in bytes }}

{{OBDtr| 0x14 | offset  |C8FFFF| 00 B1 01 00 | 0x1B100  | at this position starts the part in the raw file }}

:The duration (number of game ticks) is rounded to the ''lower'' value (a.k.a. "floor") in Vanilla Oni data.<ref name="ticks">As an example, on Windows (both demo and retail), '''SNDDmus_ot7.aif''' consists of 152360 samples, which at 22.05 kHz corresponds to 6.90975 seconds, or 414.585 ticks; the duration, however, is indicated as 414 ticks and not 415. In other words, "duration" corresponds to the number of ''whole'' game ticks spanned by the sound's playback.</ref> In other words, it indicates the number of ''complete'' game ticks spanned by the sound's playback.

:1 - never used in Vanilla Oni; unknown (no effect?)

:2 - never used in Vanilla Oni; unknown (no effect?)

:4 - never used in Vanilla Oni; enables rudimentary format header and IMA4 decoding (overrules "8")

:8 - always used in Vanilla Oni; enables fully-featured format header and PCM / MS ADPCM decoding }}

{{OBDtr| 0x40 | uint32  |C8FFC8| 56 28 00 00 | 10326    | size of the part in the raw file in bytes }}

{{OBDtr| 0x44 | offset  |C8FFFF| 20 10 59 00 | 0x591020  | at this position starts the part in the raw file }}

:Same as for Windows demo and Mac, the duration (number of game ticks) is rounded to the ''lower'' value (a.k.a. "floor") in Vanilla Oni data.<ref name="ticks"/> In other words, it indicates the number of ''complete'' game ticks spanned by the sound's playback.

:As for '''compression''', Windows retail actually has ''three'' primary compression modes, commanded by the flag values. Only the first is used in Vanilla Oni.

If the "8" flag of the SNDD (at 0x08) is ON and the "4" flag is OFF (as is always the case in Vanilla Oni), the 50-byte block is interpreted as a standard "fmt " chunk that you find in WAVE files (see [[/wav|HERE]] for details).

:<small>'''N.B.''' At the time of writing, only "1" (linear PCM) and "2" (MS ADPCM) are known to work in Oni; in Vanilla Oni, only MS ADPCM is ever used.</small>}}

:<small>'''N.B.''' For ADPCM, Oni's Vanilla data always uses 512 bytes per channel for 22050 Hz waveforms, and 1024 bytes for 44.1 kHz mono (see below).}}

:Although Vanilla Oni SNDDs only ever use MS ADPCM waveforms, some mods have successfully used the (bloated!!!) PCM format.

Below are the three types of headers occurring for Vanilla Oni's sounds (MS ADPCM).

:The MS ADPCM data used by Vanilla Oni on Windows (both retail and demo) is somewhat coarser (lossier) than the IMA4 ADPCM used on Mac. This is because of the much larger block size, and how the same predictor must be used for the whole block: whenever a block spans both high- and low-amplitude samples, the predictor adapts to the higher amplitudes, and the low-amplitude resolution is lost.