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pcm/PcmMix: improved dithering

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Use the existing PcmDither library.
This commit is contained in:
Max Kellermann
2013-12-28 17:42:03 +01:00
parent afcf0795c4
commit da29298d4d
5 changed files with 48 additions and 25 deletions
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45
src/pcm/PcmMix.cxx
View File

@@ -25,41 +25,47 @@
#include "Traits.hxx"
#include "util/Clamp.hxx"
#include "PcmDither.cxx" // including the .cxx file to get inlined templates
#include <assert.h>
#include <math.h>
template<SampleFormat F, class Traits=SampleTraits<F>>
static typename Traits::value_type
PcmAddVolume(typename Traits::value_type _a, typename Traits::value_type _b,
PcmAddVolume(PcmDither &dither,
typename Traits::value_type _a, typename Traits::value_type _b,
int volume1, int volume2)
{
typename Traits::long_type a(_a), b(_b);
typename Traits::long_type c(a * volume1 + b * volume2);
typename Traits::value_type c = ((a * volume1 + b * volume2) +
pcm_volume_dither() + PCM_VOLUME_1S / 2)
/ PCM_VOLUME_1S;
return PcmClamp<F, Traits>(c);
return dither.DitherShift<typename Traits::long_type,
Traits::BITS + PCM_VOLUME_BITS,
Traits::BITS>(c);
}
template<SampleFormat F, class Traits=SampleTraits<F>>
static void
PcmAddVolume(typename Traits::pointer_type a,
PcmAddVolume(PcmDither &dither,
typename Traits::pointer_type a,
typename Traits::const_pointer_type b,
size_t n, int volume1, int volume2)
{
for (size_t i = 0; i != n; ++i)
a[i] = PcmAddVolume<F, Traits>(a[i], b[i], volume1, volume2);
a[i] = PcmAddVolume<F, Traits>(dither, a[i], b[i],
volume1, volume2);
}
template<SampleFormat F, class Traits=SampleTraits<F>>
static void
PcmAddVolumeVoid(void *a, const void *b, size_t size, int volume1, int volume2)
PcmAddVolumeVoid(PcmDither &dither,
void *a, const void *b, size_t size, int volume1, int volume2)
{
constexpr size_t sample_size = Traits::SAMPLE_SIZE;
assert(size % sample_size == 0);
PcmAddVolume<F, Traits>(typename Traits::pointer_type(a),
PcmAddVolume<F, Traits>(dither,
typename Traits::pointer_type(a),
typename Traits::const_pointer_type(b),
size / sample_size,
volume1, volume2);
@@ -80,7 +86,7 @@ pcm_add_vol_float(float *buffer1, const float *buffer2,
}
static bool
pcm_add_vol(void *buffer1, const void *buffer2, size_t size,
pcm_add_vol(PcmDither &dither, void *buffer1, const void *buffer2, size_t size,
int vol1, int vol2,
SampleFormat format)
{
@@ -91,22 +97,26 @@ pcm_add_vol(void *buffer1, const void *buffer2, size_t size,
return false;
case SampleFormat::S8:
PcmAddVolumeVoid<SampleFormat::S8>(buffer1, buffer2, size,
PcmAddVolumeVoid<SampleFormat::S8>(dither,
buffer1, buffer2, size,
vol1, vol2);
return true;
case SampleFormat::S16:
PcmAddVolumeVoid<SampleFormat::S16>(buffer1, buffer2, size,
PcmAddVolumeVoid<SampleFormat::S16>(dither,
buffer1, buffer2, size,
vol1, vol2);
return true;
case SampleFormat::S24_P32:
PcmAddVolumeVoid<SampleFormat::S24_P32>(buffer1, buffer2, size,
PcmAddVolumeVoid<SampleFormat::S24_P32>(dither,
buffer1, buffer2, size,
vol1, vol2);
return true;
case SampleFormat::S32:
PcmAddVolumeVoid<SampleFormat::S32>(buffer1, buffer2, size,
PcmAddVolumeVoid<SampleFormat::S32>(dither,
buffer1, buffer2, size,
vol1, vol2);
return true;
@@ -201,7 +211,7 @@ pcm_add(void *buffer1, const void *buffer2, size_t size,
}
bool
pcm_mix(void *buffer1, const void *buffer2, size_t size,
pcm_mix(PcmDither &dither, void *buffer1, const void *buffer2, size_t size,
SampleFormat format, float portion1)
{
float s;
@@ -217,5 +227,6 @@ pcm_mix(void *buffer1, const void *buffer2, size_t size,
int vol1 = s * PCM_VOLUME_1S + 0.5;
vol1 = Clamp<int>(vol1, 0, PCM_VOLUME_1S);
return pcm_add_vol(buffer1, buffer2, size, vol1, PCM_VOLUME_1S - vol1, format);
return pcm_add_vol(dither, buffer1, buffer2, size,
vol1, PCM_VOLUME_1S - vol1, format);
}

4
src/pcm/PcmMix.hxx
View File

@@ -25,6 +25,8 @@
#include <stddef.h>
class PcmDither;
/*
* Linearly mixes two PCM buffers. Both must have the same length and
* the same audio format. The formula is:
@@ -44,7 +46,7 @@
*/
gcc_warn_unused_result
bool
pcm_mix(void *buffer1, const void *buffer2, size_t size,
pcm_mix(PcmDither &dither, void *buffer1, const void *buffer2, size_t size,
SampleFormat format, float portion1);
#endif