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Fix shaped dither (#9342)

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This commit is contained in:
Robin Gareus 2023-05-22 04:48:53 +02:00
parent e9dc1335f9
commit f1f352a6e9
Signed by: rgareus
GPG Key ID: A090BCE02CF57F04
1 changed files with 18 additions and 12 deletions
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30
libs/audiographer/private/gdither/gdither.cc
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@ -189,7 +189,7 @@ gdither_innner_loop (const GDitherType dt,
uint8_t* o8 = (uint8_t*)y;
int16_t* o16 = (int16_t*)y;
int32_t* o32 = (int32_t*)y;
float tmp, r, ideal;
float tmp, r, err;
int64_t clamped;
i = channel;
@ -208,21 +208,24 @@ gdither_innner_loop (const GDitherType dt,
ts[channel] = r;
break;
case GDitherShaped:
/* Save raw value for error calculations */
assert (ss);
ideal = tmp;
/* Run FIR and add white noise */
ss->buffer[ss->phase] = gdither_noise () * 0.5f;
/* Run FIR */
tmp += ss->buffer[ss->phase] * shaped_bs[0]
+ ss->buffer[(ss->phase - 1) & GDITHER_SH_BUF_MASK] * shaped_bs[1]
+ ss->buffer[(ss->phase - 2) & GDITHER_SH_BUF_MASK] * shaped_bs[2]
+ ss->buffer[(ss->phase - 3) & GDITHER_SH_BUF_MASK] * shaped_bs[3]
+ ss->buffer[(ss->phase - 4) & GDITHER_SH_BUF_MASK] * shaped_bs[4];
/* Capture signal for error calculation before adding white noise */
err = tmp;
/* Add white noise */
tmp += (gdither_noise () + gdither_noise ()) * 0.5f;
/* Roll buffer and store last error */
ss->phase = (ss->phase + 1) & GDITHER_SH_BUF_MASK;
ss->buffer[ss->phase] = (float)lrintf (tmp) - ideal;
ss->buffer[ss->phase] = err - (float)lrintf (tmp);
break;
}
@ -259,7 +262,7 @@ gdither_innner_loop_fp (const GDitherType dt,
uint32_t pos, i;
float* oflt = (float*)y;
double* odbl = (double*)y;
float tmp, r, ideal;
float tmp, r, err;
double clamped;
i = channel;
@ -279,20 +282,23 @@ gdither_innner_loop_fp (const GDitherType dt,
break;
case GDitherShaped:
assert (ss);
/* Save raw value for error calculations */
ideal = tmp;
/* Run FIR and add white noise */
ss->buffer[ss->phase] = gdither_noise () * 0.5f;
/* Run FIR */
tmp += ss->buffer[ss->phase] * shaped_bs[0]
+ ss->buffer[(ss->phase - 1) & GDITHER_SH_BUF_MASK] * shaped_bs[1]
+ ss->buffer[(ss->phase - 2) & GDITHER_SH_BUF_MASK] * shaped_bs[2]
+ ss->buffer[(ss->phase - 3) & GDITHER_SH_BUF_MASK] * shaped_bs[3]
+ ss->buffer[(ss->phase - 4) & GDITHER_SH_BUF_MASK] * shaped_bs[4];
/* Capture signal for error calculation before adding white noise */
err = tmp;
/* Add white noise */
tmp += (gdither_noise () + gdither_noise ()) * 0.5f;
/* Roll buffer and store last error */
ss->phase = (ss->phase + 1) & GDITHER_SH_BUF_MASK;
ss->buffer[ss->phase] = (float)lrintf (tmp) - ideal;
ss->buffer[ss->phase] = err - (float)lrintf (tmp);
break;
}