331 lines
8.3 KiB
C
331 lines
8.3 KiB
C
|
/*
|
||
|
|
* Dither.h
|
||
|
|
* --------
|
||
|
|
* Purpose: Dithering when converting to lower resolution sample formats.
|
||
|
|
* Notes : (currently none)
|
||
|
|
* Authors: Olivier Lapicque
|
||
|
|
* OpenMPT Devs
|
||
|
|
* The OpenMPT source code is released under the BSD license. Read LICENSE for more details.
|
||
|
|
*/
|
||
|
|
|
||
|
|
|
||
|
|
#pragma once
|
||
|
|
|
||
|
|
#include "BuildSettings.h"
|
||
|
|
|
||
|
|
|
||
|
|
#include "SampleTypes.h"
|
||
|
|
#include "SampleFormatConverters.h"
|
||
|
|
#include "../common/mptRandom.h"
|
||
|
|
|
||
|
|
|
||
|
|
OPENMPT_NAMESPACE_BEGIN
|
||
|
|
|
||
|
|
|
||
|
|
enum DitherMode
|
||
|
|
{
|
||
|
|
DitherNone = 0,
|
||
|
|
DitherDefault = 1, // chosen by OpenMPT code, might change
|
||
|
|
DitherModPlug = 2, // rectangular, 0.5 bit depth, no noise shaping (original ModPlug Tracker)
|
||
|
|
DitherSimple = 3, // rectangular, 1 bit depth, simple 1st order noise shaping
|
||
|
|
NumDitherModes
|
||
|
|
};
|
||
|
|
|
||
|
|
|
||
|
|
struct Dither_None
|
||
|
|
{
|
||
|
|
public:
|
||
|
|
template <uint32 targetbits, typename Trng>
|
||
|
|
MPT_FORCEINLINE MixSampleInt process(MixSampleInt sample, Trng &)
|
||
|
|
{
|
||
|
|
return sample;
|
||
|
|
}
|
||
|
|
template <uint32 targetbits, typename Trng>
|
||
|
|
MPT_FORCEINLINE MixSampleFloat process(MixSampleFloat sample, Trng &)
|
||
|
|
{
|
||
|
|
return sample;
|
||
|
|
}
|
||
|
|
};
|
||
|
|
|
||
|
|
|
||
|
|
struct Dither_ModPlug
|
||
|
|
{
|
||
|
|
public:
|
||
|
|
template <uint32 targetbits, typename Trng>
|
||
|
|
MPT_FORCEINLINE MixSampleInt process(MixSampleInt sample, Trng &rng)
|
||
|
|
{
|
||
|
|
if constexpr(targetbits == 0)
|
||
|
|
{
|
||
|
|
MPT_UNREFERENCED_PARAMETER(rng);
|
||
|
|
return sample;
|
||
|
|
} else if constexpr(targetbits + MixSampleIntTraits::mix_headroom_bits() + 1 >= 32)
|
||
|
|
{
|
||
|
|
MPT_UNREFERENCED_PARAMETER(rng);
|
||
|
|
return sample;
|
||
|
|
} else
|
||
|
|
{
|
||
|
|
sample += mpt::rshift_signed(static_cast<int32>(mpt::random<uint32>(rng)), (targetbits + MixSampleIntTraits::mix_headroom_bits() + 1));
|
||
|
|
return sample;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
template <uint32 targetbits, typename Trng>
|
||
|
|
MPT_FORCEINLINE MixSampleFloat process(MixSampleFloat sample, Trng &prng)
|
||
|
|
{
|
||
|
|
SC::ConvertToFixedPoint<MixSampleInt, MixSampleFloat, MixSampleIntTraits::mix_fractional_bits()> conv1;
|
||
|
|
SC::ConvertFixedPoint<MixSampleFloat, MixSampleInt, MixSampleIntTraits::mix_fractional_bits()> conv2;
|
||
|
|
return conv2(process<targetbits>(conv1(sample), prng));
|
||
|
|
}
|
||
|
|
};
|
||
|
|
|
||
|
|
|
||
|
|
template<int ditherdepth = 1, bool triangular = false, bool shaped = true>
|
||
|
|
struct Dither_SimpleImpl
|
||
|
|
{
|
||
|
|
private:
|
||
|
|
int32 error = 0;
|
||
|
|
public:
|
||
|
|
template <uint32 targetbits, typename Trng>
|
||
|
|
MPT_FORCEINLINE MixSampleInt process(MixSampleInt sample, Trng &prng)
|
||
|
|
{
|
||
|
|
if constexpr(targetbits == 0)
|
||
|
|
{
|
||
|
|
MPT_UNREFERENCED_PARAMETER(prng);
|
||
|
|
return sample;
|
||
|
|
} else
|
||
|
|
{
|
||
|
|
static_assert(sizeof(MixSampleInt) == 4);
|
||
|
|
constexpr int rshift = (32-targetbits) - MixSampleIntTraits::mix_headroom_bits();
|
||
|
|
if constexpr(rshift <= 1)
|
||
|
|
{
|
||
|
|
MPT_UNREFERENCED_PARAMETER(prng);
|
||
|
|
// nothing to dither
|
||
|
|
return sample;
|
||
|
|
} else
|
||
|
|
{
|
||
|
|
constexpr int rshiftpositive = (rshift > 1) ? rshift : 1; // work-around warnings about negative shift with C++14 compilers
|
||
|
|
constexpr int round_mask = ~((1<<rshiftpositive)-1);
|
||
|
|
constexpr int round_offset = 1<<(rshiftpositive-1);
|
||
|
|
constexpr int noise_bits = rshiftpositive + (ditherdepth - 1);
|
||
|
|
constexpr int noise_bias = (1<<(noise_bits-1));
|
||
|
|
int32 e = error;
|
||
|
|
unsigned int unoise = 0;
|
||
|
|
if constexpr(triangular)
|
||
|
|
{
|
||
|
|
unoise = (mpt::random<unsigned int>(prng, noise_bits) + mpt::random<unsigned int>(prng, noise_bits)) >> 1;
|
||
|
|
} else
|
||
|
|
{
|
||
|
|
unoise = mpt::random<unsigned int>(prng, noise_bits);
|
||
|
|
}
|
||
|
|
int noise = static_cast<int>(unoise) - noise_bias; // un-bias
|
||
|
|
int val = sample;
|
||
|
|
if constexpr(shaped)
|
||
|
|
{
|
||
|
|
val += (e >> 1);
|
||
|
|
}
|
||
|
|
int rounded = (val + noise + round_offset) & round_mask;;
|
||
|
|
e = val - rounded;
|
||
|
|
sample = rounded;
|
||
|
|
error = e;
|
||
|
|
return sample;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
template <uint32 targetbits, typename Trng>
|
||
|
|
MPT_FORCEINLINE MixSampleFloat process(MixSampleFloat sample, Trng &prng)
|
||
|
|
{
|
||
|
|
SC::ConvertToFixedPoint<MixSampleInt, MixSampleFloat, MixSampleIntTraits::mix_fractional_bits()> conv1;
|
||
|
|
SC::ConvertFixedPoint<MixSampleFloat, MixSampleInt, MixSampleIntTraits::mix_fractional_bits()> conv2;
|
||
|
|
return conv2(process<targetbits>(conv1(sample), prng));
|
||
|
|
}
|
||
|
|
};
|
||
|
|
|
||
|
|
using Dither_Simple = Dither_SimpleImpl<>;
|
||
|
|
|
||
|
|
|
||
|
|
template <typename Tdither, std::size_t channels>
|
||
|
|
class MultiChannelDither
|
||
|
|
{
|
||
|
|
private:
|
||
|
|
std::array<Tdither, channels> DitherChannels;
|
||
|
|
public:
|
||
|
|
void Reset()
|
||
|
|
{
|
||
|
|
DitherChannels.fill(Tdither());
|
||
|
|
}
|
||
|
|
template <uint32 targetbits, typename Trng>
|
||
|
|
MPT_FORCEINLINE MixSampleInt process(std::size_t channel, MixSampleInt sample, Trng &prng)
|
||
|
|
{
|
||
|
|
return DitherChannels[channel].template process<targetbits>(sample, prng);
|
||
|
|
}
|
||
|
|
template <uint32 targetbits, typename Trng>
|
||
|
|
MPT_FORCEINLINE MixSampleFloat process(std::size_t channel, MixSampleFloat sample, Trng &prng)
|
||
|
|
{
|
||
|
|
return DitherChannels[channel].template process<targetbits>(sample, prng);
|
||
|
|
}
|
||
|
|
};
|
||
|
|
|
||
|
|
|
||
|
|
template <typename Tdither, std::size_t channels>
|
||
|
|
class DitherTemplate;
|
||
|
|
|
||
|
|
template <std::size_t channels>
|
||
|
|
class DitherTemplate<Dither_None, channels>
|
||
|
|
: public MultiChannelDither<Dither_None, channels>
|
||
|
|
{
|
||
|
|
struct {} prng;
|
||
|
|
public:
|
||
|
|
template <typename Trd>
|
||
|
|
DitherTemplate(Trd &)
|
||
|
|
{
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
template <uint32 targetbits>
|
||
|
|
MPT_FORCEINLINE MixSampleInt process(std::size_t channel, MixSampleInt sample)
|
||
|
|
{
|
||
|
|
return MultiChannelDither<Dither_None, channels>::template process<targetbits>(channel, sample, prng);
|
||
|
|
}
|
||
|
|
template <uint32 targetbits>
|
||
|
|
MPT_FORCEINLINE MixSampleFloat process(std::size_t channel, MixSampleFloat sample)
|
||
|
|
{
|
||
|
|
return MultiChannelDither<Dither_None, channels>::template process<targetbits>(channel, sample, prng);
|
||
|
|
}
|
||
|
|
};
|
||
|
|
|
||
|
|
template <std::size_t channels>
|
||
|
|
class DitherTemplate<Dither_ModPlug, channels>
|
||
|
|
: public MultiChannelDither<Dither_ModPlug, channels>
|
||
|
|
{
|
||
|
|
private:
|
||
|
|
mpt::rng::modplug_dither prng;
|
||
|
|
public:
|
||
|
|
template <typename Trd>
|
||
|
|
DitherTemplate(Trd &)
|
||
|
|
: prng(0, 0)
|
||
|
|
{
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
template <uint32 targetbits>
|
||
|
|
MPT_FORCEINLINE MixSampleInt process(std::size_t channel, MixSampleInt sample)
|
||
|
|
{
|
||
|
|
return MultiChannelDither<Dither_ModPlug, channels>::template process<targetbits>(channel, sample, prng);
|
||
|
|
}
|
||
|
|
template <uint32 targetbits>
|
||
|
|
MPT_FORCEINLINE MixSampleFloat process(std::size_t channel, MixSampleFloat sample)
|
||
|
|
{
|
||
|
|
return MultiChannelDither<Dither_ModPlug, channels>::template process<targetbits>(channel, sample, prng);
|
||
|
|
}
|
||
|
|
};
|
||
|
|
|
||
|
|
template <std::size_t channels>
|
||
|
|
class DitherTemplate<Dither_Simple, channels>
|
||
|
|
: public MultiChannelDither<Dither_Simple, channels>
|
||
|
|
{
|
||
|
|
private:
|
||
|
|
mpt::fast_prng prng;
|
||
|
|
public:
|
||
|
|
template <typename Trd>
|
||
|
|
DitherTemplate(Trd & rd)
|
||
|
|
: prng(mpt::make_prng<mpt::fast_prng>(rd))
|
||
|
|
{
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
template <uint32 targetbits>
|
||
|
|
MPT_FORCEINLINE MixSampleInt process(std::size_t channel, MixSampleInt sample)
|
||
|
|
{
|
||
|
|
return MultiChannelDither<Dither_Simple, channels>::template process<targetbits>(channel, sample, prng);
|
||
|
|
}
|
||
|
|
template <uint32 targetbits>
|
||
|
|
MPT_FORCEINLINE MixSampleFloat process(std::size_t channel, MixSampleFloat sample)
|
||
|
|
{
|
||
|
|
return MultiChannelDither<Dither_Simple, channels>::template process<targetbits>(channel, sample, prng);
|
||
|
|
}
|
||
|
|
};
|
||
|
|
|
||
|
|
|
||
|
|
class DitherNames
|
||
|
|
{
|
||
|
|
public:
|
||
|
|
static mpt::ustring GetModeName(DitherMode mode);
|
||
|
|
};
|
||
|
|
|
||
|
|
|
||
|
|
template <std::size_t channels>
|
||
|
|
class DitherChannels
|
||
|
|
: public DitherNames
|
||
|
|
{
|
||
|
|
|
||
|
|
private:
|
||
|
|
|
||
|
|
DitherTemplate<Dither_None, channels> ditherNone;
|
||
|
|
DitherTemplate<Dither_ModPlug, channels> ditherModPlug;
|
||
|
|
DitherTemplate<Dither_Simple, channels> ditherSimple;
|
||
|
|
|
||
|
|
DitherMode mode = DitherDefault;
|
||
|
|
|
||
|
|
public:
|
||
|
|
|
||
|
|
template <typename Trd>
|
||
|
|
DitherChannels(Trd & rd)
|
||
|
|
: ditherNone(rd)
|
||
|
|
, ditherModPlug(rd)
|
||
|
|
, ditherSimple(rd)
|
||
|
|
{
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
void Reset()
|
||
|
|
{
|
||
|
|
ditherModPlug.Reset();
|
||
|
|
ditherSimple.Reset();
|
||
|
|
}
|
||
|
|
|
||
|
|
DitherTemplate<Dither_None, channels> & NoDither()
|
||
|
|
{
|
||
|
|
MPT_ASSERT(mode == DitherNone);
|
||
|
|
return ditherNone;
|
||
|
|
}
|
||
|
|
DitherTemplate<Dither_ModPlug, channels> & DefaultDither()
|
||
|
|
{
|
||
|
|
MPT_ASSERT(mode == DitherDefault);
|
||
|
|
return ditherModPlug;
|
||
|
|
}
|
||
|
|
DitherTemplate<Dither_ModPlug, channels> & ModPlugDither()
|
||
|
|
{
|
||
|
|
MPT_ASSERT(mode == DitherModPlug);
|
||
|
|
return ditherModPlug;
|
||
|
|
}
|
||
|
|
DitherTemplate<Dither_Simple, channels> & SimpleDither()
|
||
|
|
{
|
||
|
|
MPT_ASSERT(mode == DitherSimple);
|
||
|
|
return ditherSimple;
|
||
|
|
}
|
||
|
|
|
||
|
|
template <typename Tfn>
|
||
|
|
auto WithDither(Tfn fn)
|
||
|
|
{
|
||
|
|
switch(GetMode())
|
||
|
|
{
|
||
|
|
case DitherNone: return fn(NoDither()); break;
|
||
|
|
case DitherModPlug: return fn(ModPlugDither()); break;
|
||
|
|
case DitherSimple: return fn(SimpleDither()); break;
|
||
|
|
case DitherDefault: return fn(DefaultDither()); break;
|
||
|
|
default: return fn(DefaultDither()); break;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
void SetMode(DitherMode mode_)
|
||
|
|
{
|
||
|
|
mode = mode_;
|
||
|
|
}
|
||
|
|
DitherMode GetMode() const
|
||
|
|
{
|
||
|
|
return mode;
|
||
|
|
}
|
||
|
|
|
||
|
|
};
|
||
|
|
|
||
|
|
|
||
|
|
using Dither = DitherChannels<4>;
|
||
|
|
|
||
|
|
|
||
|
|
OPENMPT_NAMESPACE_END
|