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pcm/Volume: improved dithering

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Instead of just adding a rectangular random value before shifting back
to the normal scale, use the existing PcmDither library.
This commit is contained in:
Max Kellermann
2013-12-22 17:39:26 +01:00
parent 394e2815db
commit afcf0795c4
6 changed files with 59 additions and 22 deletions
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47
src/pcm/Volume.cxx
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@@ -25,62 +25,69 @@
#include "util/ConstBuffer.hxx"
#include "util/Error.hxx"
#include "PcmDither.cxx" // including the .cxx file to get inlined templates
#include <stdint.h>
#include <string.h>
template<SampleFormat F, class Traits=SampleTraits<F>>
static inline typename Traits::value_type
pcm_volume_sample(typename Traits::value_type _sample,
pcm_volume_sample(PcmDither &dither,
typename Traits::value_type _sample,
int volume)
{
typename Traits::long_type sample(_sample);
sample = (sample * volume + pcm_volume_dither() +
PCM_VOLUME_1S / 2)
>> PCM_VOLUME_BITS;
return PcmClamp<F, Traits>(sample);
return dither.DitherShift<typename Traits::long_type,
Traits::BITS + PCM_VOLUME_BITS,
Traits::BITS>(sample * volume);
}
template<SampleFormat F, class Traits=SampleTraits<F>>
static void
pcm_volume_change(typename Traits::pointer_type dest,
pcm_volume_change(PcmDither &dither,
typename Traits::pointer_type dest,
typename Traits::const_pointer_type src,
typename Traits::const_pointer_type end,
int volume)
{
while (src < end) {
const auto sample = *src++;
*dest++ = pcm_volume_sample<F, Traits>(sample, volume);
*dest++ = pcm_volume_sample<F, Traits>(dither, sample, volume);
}
}
static void
pcm_volume_change_8(int8_t *dest, const int8_t *src, const int8_t *end,
pcm_volume_change_8(PcmDither &dither,
int8_t *dest, const int8_t *src, const int8_t *end,
int volume)
{
pcm_volume_change<SampleFormat::S8>(dest, src, end, volume);
pcm_volume_change<SampleFormat::S8>(dither, dest, src, end, volume);
}
static void
pcm_volume_change_16(int16_t *dest, const int16_t *src, const int16_t *end,
pcm_volume_change_16(PcmDither &dither,
int16_t *dest, const int16_t *src, const int16_t *end,
int volume)
{
pcm_volume_change<SampleFormat::S16>(dest, src, end, volume);
pcm_volume_change<SampleFormat::S16>(dither, dest, src, end, volume);
}
static void
pcm_volume_change_24(int32_t *dest, const int32_t *src, const int32_t *end,
pcm_volume_change_24(PcmDither &dither,
int32_t *dest, const int32_t *src, const int32_t *end,
int volume)
{
pcm_volume_change<SampleFormat::S24_P32>(dest, src, end, volume);
pcm_volume_change<SampleFormat::S24_P32>(dither, dest, src, end,
volume);
}
static void
pcm_volume_change_32(int32_t *dest, const int32_t *src, const int32_t *end,
pcm_volume_change_32(PcmDither &dither,
int32_t *dest, const int32_t *src, const int32_t *end,
int volume)
{
pcm_volume_change<SampleFormat::S32>(dest, src, end, volume);
pcm_volume_change<SampleFormat::S32>(dither, dest, src, end, volume);
}
static void
@@ -143,28 +150,28 @@ PcmVolume::Apply(ConstBuffer<void> src)
gcc_unreachable();
case SampleFormat::S8:
pcm_volume_change_8((int8_t *)data,
pcm_volume_change_8(dither, (int8_t *)data,
(const int8_t *)src.data,
(const int8_t *)end,
volume);
break;
case SampleFormat::S16:
pcm_volume_change_16((int16_t *)data,
pcm_volume_change_16(dither, (int16_t *)data,
(const int16_t *)src.data,
(const int16_t *)end,
volume);
break;
case SampleFormat::S24_P32:
pcm_volume_change_24((int32_t *)data,
pcm_volume_change_24(dither, (int32_t *)data,
(const int32_t *)src.data,
(const int32_t *)end,
volume);
break;
case SampleFormat::S32:
pcm_volume_change_32((int32_t *)data,
pcm_volume_change_32(dither, (int32_t *)data,
(const int32_t *)src.data,
(const int32_t *)end,
volume);