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Remap type of polynomial interpolators for better polyphase

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coefficients quality:
- Linear interpolator for oversampling factor larger and equal
  than 4096 (log2 = 12).
- Quadratic interpolator for oversampling factor larger and equal
  than 256 (log2 = 8).

Default oversampling factor (128 ~ log2 = 7) will use OPT32X, which
provides better accuracy.
This commit is contained in:
ariff 2009-06-15 04:05:38 +00:00
parent d573bd048d
commit 548135de8c
1 changed files with 3 additions and 5 deletions
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8
sys/dev/sound/pcm/feeder_rate.c
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@ -789,13 +789,11 @@ z_resampler_sinc_len(struct z_info *info)
defined(Z_COEFF_INTER_BSPLINE) || defined(Z_COEFF_INTERP_OPT32X) || \
defined(Z_COEFF_INTERP_OPT16X) || defined(Z_COEFF_INTERP_OPT8X) || \
defined(Z_COEFF_INTERP_OPT4X) || defined(Z_COEFF_INTERP_OPT2X))
#if Z_DRIFT_SHIFT >= 8
#if Z_DRIFT_SHIFT >= 12
#define Z_COEFF_INTERP_LINEAR 1
#elif Z_DRIFT_SHIFT == 7
#elif Z_DRIFT_SHIFT >= 8
#define Z_COEFF_INTERP_QUADRATIC 1
#elif Z_DRIFT_SHIFT == 6
#define Z_COEFF_INTERP_HERMITE 1
#elif Z_DRIFT_SHIFT == 5
#elif Z_DRIFT_SHIFT >= 5
#define Z_COEFF_INTERP_OPT32X 1
#elif Z_DRIFT_SHIFT == 4
#define Z_COEFF_INTERP_OPT16X 1