axvpb.pb.srcSelect

Syntax

#define AX_PB_SRCSEL_POLYPHASE  0x0000  // N64 type polyphase filter (4-tap)
#define AX_PB_SRCSEL_LINEAR     0x0001  // Linear interpolator
#define AX_PB_SRCSEL_NONE       0x0002  // No SRC (1:1)

u16 srcSelect;

Description

The srcSelect function specifies which SRC (Sample Rate Converter) to use for the given voice:

• AX_PB_SRCSEL_POLYPHASE
  This SRC applies a four-tap polyphase FIR filter to eliminate aliasing/imaging components. While providing a very 'clean' signal, the signal has a truncated frequency band as dictated by the coefficients of the filter. You must select the coefficients using the axvpb.pb.coefSelect parameter. It is very similar to the SRC commonly used in N64 applications.
• AX_PB_SRCSEL_LINEAR
  Linear interpolation. Calculation precision is slightly below that of POLYPHASE, but the load on the DSP is lighter so you can use more voices. If there is no problem with sound quality when you listen to the actual audio, then we recommend you use LINEAR.
• AX_PB_SRCSEL_NONE
  This mode will bypass the SRC stage entirely. The mode is useful for samples which do not need to be pitch-shifted (e.g., software streams with 32-kHz sample rate).

See Also

axvpb.sync
axvpb.pb.coefSelect
AXSetVoiceSrcType

Revision History

2009/06/19 Revised the description for LINEAR.
2006/03/01 Initial version.

CONFIDENTIAL