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Add a mono<->stereo converter

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This converter always outputs floats, and uses energy-preserving scaling.
This commit is contained in:
Chris Robinson 2017-04-11 07:25:55 -07:00
parent caae349fdc
commit bcdd1cee10
2 changed files with 134 additions and 0 deletions
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122
Alc/converter.c
View File

@ -330,3 +330,125 @@ ALsizei SampleConverterInput(SampleConverter *converter, const ALvoid **src, ALs
return pos;
}
ChannelConverter *CreateChannelConverter(enum DevFmtType srcType, enum DevFmtChannels srcChans, enum DevFmtChannels dstChans)
{
ChannelConverter *converter;
if(srcChans != dstChans && !((srcChans == DevFmtMono && dstChans == DevFmtStereo) ||
(srcChans == DevFmtStereo && dstChans == DevFmtMono)))
return NULL;
converter = al_calloc(DEF_ALIGN, sizeof(*converter));
converter->mSrcType = srcType;
converter->mSrcChans = srcChans;
converter->mDstChans = dstChans;
return converter;
}
void DestroyChannelConverter(ChannelConverter **converter)
{
if(converter)
{
al_free(*converter);
*converter = NULL;
}
}
#define DECL_TEMPLATE(T) \
static void MonoConvert##T(ALfloat *restrict dst, const T *src, ALsizei frames)\
{ \
const T *data = (T*)src; \
ALsizei i; \
\
for(i = 0;i < frames;i++) \
dst[i*2 + 1] = dst[i*2 + 0] = Sample_##T(data[i]) * 0.707106781187f; \
} \
\
static void StereoConvert##T(ALfloat *restrict dst, const T *src, ALsizei frames)\
{ \
const T *data = (T*)src; \
ALsizei i; \
\
for(i = 0;i < frames;i++) \
dst[i] = (Sample_##T(data[i*2 + 0])+Sample_##T(data[i*2 + 1])) * \
0.707106781187f; \
}
DECL_TEMPLATE(ALbyte)
DECL_TEMPLATE(ALubyte)
DECL_TEMPLATE(ALshort)
DECL_TEMPLATE(ALushort)
DECL_TEMPLATE(ALint)
DECL_TEMPLATE(ALuint)
DECL_TEMPLATE(ALfloat)
#undef DECL_TEMPLATE
void ChannelConverterInput(ChannelConverter *converter, const ALvoid *src, ALfloat *dst, ALsizei frames)
{
if(converter->mSrcChans == converter->mDstChans)
{
LoadSamples(dst, src, 1, converter->mSrcType,
frames*ChannelsFromDevFmt(converter->mSrcChans));
return;
}
if(converter->mSrcChans == DevFmtStereo && converter->mDstChans == DevFmtMono)
{
switch(converter->mSrcType)
{
case DevFmtByte:
MonoConvertALbyte(dst, src, frames);
break;
case DevFmtUByte:
MonoConvertALubyte(dst, src, frames);
break;
case DevFmtShort:
MonoConvertALshort(dst, src, frames);
break;
case DevFmtUShort:
MonoConvertALushort(dst, src, frames);
break;
case DevFmtInt:
MonoConvertALint(dst, src, frames);
break;
case DevFmtUInt:
MonoConvertALuint(dst, src, frames);
break;
case DevFmtFloat:
MonoConvertALfloat(dst, src, frames);
break;
}
}
else /*if(converter->mSrcChans == DevFmtMono && converter->mDstChans == DevFmtStereo)*/
{
switch(converter->mSrcType)
{
case DevFmtByte:
StereoConvertALbyte(dst, src, frames);
break;
case DevFmtUByte:
StereoConvertALubyte(dst, src, frames);
break;
case DevFmtShort:
StereoConvertALshort(dst, src, frames);
break;
case DevFmtUShort:
StereoConvertALushort(dst, src, frames);
break;
case DevFmtInt:
StereoConvertALint(dst, src, frames);
break;
case DevFmtUInt:
StereoConvertALuint(dst, src, frames);
break;
case DevFmtFloat:
StereoConvertALfloat(dst, src, frames);
break;
}
}
}

12
Alc/converter.h
View File

@ -35,6 +35,18 @@ void DestroySampleConverter(SampleConverter **converter);
ALsizei SampleConverterInput(SampleConverter *converter, const ALvoid **src, ALsizei *srcframes, ALvoid *dst, ALsizei dstframes);
ALsizei SampleConverterAvailableOut(SampleConverter *converter, ALsizei srcframes);
typedef struct ChannelConverter {
enum DevFmtType mSrcType;
enum DevFmtChannels mSrcChans;
enum DevFmtChannels mDstChans;
} ChannelConverter;
ChannelConverter *CreateChannelConverter(enum DevFmtType srcType, enum DevFmtChannels srcChans, enum DevFmtChannels dstChans);
void DestroyChannelConverter(ChannelConverter **converter);
void ChannelConverterInput(ChannelConverter *converter, const ALvoid *src, ALfloat *dst, ALsizei frames);
#ifdef __cpluspluc
}
#endif