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optimize rounding and clipping to int16 samples

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This commit is contained in:
derselbst 2018-10-31 09:23:39 +01:00
parent d8890038b6
commit b628115092
1 changed files with 24 additions and 66 deletions
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90
src/synth/fluid_synth.c
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@ -88,7 +88,7 @@ static void fluid_synth_update_presets(fluid_synth_t *synth);
static void fluid_synth_update_gain_LOCAL(fluid_synth_t *synth);
static int fluid_synth_update_polyphony_LOCAL(fluid_synth_t *synth, int new_polyphony);
static void init_dither(void);
static FLUID_INLINE int roundi(float x);
static FLUID_INLINE int16_t round_clip_to_i16(float x);
static int fluid_synth_render_blocks(fluid_synth_t *synth, int blockcount);
static fluid_voice_t *fluid_synth_free_voice_by_kill_LOCAL(fluid_synth_t *synth);
@ -3808,17 +3808,28 @@ init_dither(void)
}
/* A portable replacement for roundf(), seems it may actually be faster too! */
static FLUID_INLINE int
roundi(float x)
static FLUID_INLINE int16_t
round_clip_to_i16(float x)
{
long i;
if(x >= 0.0f)
{
return (int)(x + 0.5f);
i = (long)(x + 0.5f);
if (FLUID_UNLIKELY(i > 32767))
{
i = 32767;
}
}
else
{
return (int)(x - 0.5f);
i = (long)(x - 0.5f);
if (FLUID_UNLIKELY(i < -32768))
{
i = -32768;
}
}
return (int16_t)i;
}
/**
@ -3847,12 +3858,10 @@ fluid_synth_write_s16(fluid_synth_t *synth, int len,
void *rout, int roff, int rincr)
{
int i, j, k, cur;
signed short *left_out = (signed short *) lout;
signed short *right_out = (signed short *) rout;
int16_t *left_out = lout;
int16_t *right_out = rout;
fluid_real_t *left_in;
fluid_real_t *right_in;
int left_sample;
int right_sample;
double time = fluid_utime();
int di;
float cpu_load;
@ -3877,37 +3886,13 @@ fluid_synth_write_s16(fluid_synth_t *synth, int len,
cur = 0;
}
left_sample = roundi(left_in[0 * FLUID_BUFSIZE * FLUID_MIXER_MAX_BUFFERS_DEFAULT + cur] * 32766.0f + rand_table[0][di]);
right_sample = roundi(right_in[0 * FLUID_BUFSIZE * FLUID_MIXER_MAX_BUFFERS_DEFAULT + cur] * 32766.0f + rand_table[1][di]);
left_out[j] = round_clip_to_i16(left_in[0 * FLUID_BUFSIZE * FLUID_MIXER_MAX_BUFFERS_DEFAULT + cur] * 32766.0f + rand_table[0][di]);
right_out[k] = round_clip_to_i16(right_in[0 * FLUID_BUFSIZE * FLUID_MIXER_MAX_BUFFERS_DEFAULT + cur] * 32766.0f + rand_table[1][di]);
if(++di >= DITHER_SIZE)
{
di = 0;
}
/* digital clipping */
if(left_sample > 32767)
{
left_sample = 32767;
}
if(left_sample < -32768)
{
left_sample = -32768;
}
if(right_sample > 32767)
{
right_sample = 32767;
}
if(right_sample < -32768)
{
right_sample = -32768;
}
left_out[j] = (signed short) left_sample;
right_out[k] = (signed short) right_sample;
}
synth->cur = cur;
@ -3946,47 +3931,20 @@ fluid_synth_dither_s16(int *dither_index, int len, float *lin, float *rin,
void *rout, int roff, int rincr)
{
int i, j, k;
signed short *left_out = (signed short *) lout;
signed short *right_out = (signed short *) rout;
int left_sample;
int right_sample;
int16_t *left_out = lout;
int16_t *right_out = rout;
int di = *dither_index;
fluid_profile_ref_var(prof_ref);
for(i = 0, j = loff, k = roff; i < len; i++, j += lincr, k += rincr)
{
left_sample = roundi(lin[i] * 32766.0f + rand_table[0][di]);
right_sample = roundi(rin[i] * 32766.0f + rand_table[1][di]);
left_out[j] = round_clip_to_i16(lin[i] * 32766.0f + rand_table[0][di]);
right_out[k] = round_clip_to_i16(rin[i] * 32766.0f + rand_table[1][di]);
if(++di >= DITHER_SIZE)
{
di = 0;
}
/* digital clipping */
if(left_sample > 32767)
{
left_sample = 32767;
}
if(left_sample < -32768)
{
left_sample = -32768;
}
if(right_sample > 32767)
{
right_sample = 32767;
}
if(right_sample < -32768)
{
right_sample = -32768;
}
left_out[j] = (signed short) left_sample;
right_out[k] = (signed short) right_sample;
}
*dither_index = di; /* keep dither buffer continous */