167 lines
6.4 KiB
C++
167 lines
6.4 KiB
C++
/* _______ ____ __ ___ ___
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* \ _ \ \ / \ / \ \ / / ' ' '
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* | | \ \ | | || | \/ | . .
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* | | | | | | || ||\ /| |
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* | | | | | | || || \/ | | ' ' '
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* | | | | | | || || | | . .
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* | |_/ / \ \__// || | |
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* /_______/ynamic \____/niversal /__\ /____\usic /| . . ibliotheque
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* / \
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* / . \
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* resample.inc - Resampling helper template. / / \ \
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* | < / \_
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* By Bob and entheh. | \/ /\ /
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* \_ / > /
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* In order to find a good trade-off between | \ / /
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* speed and accuracy in this code, some tests | ' /
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* were carried out regarding the behaviour of \__/
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* long long ints with gcc. The following code
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* was tested:
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*
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* int a, b, c;
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* c = ((long long)a * b) >> 16;
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*
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* DJGPP GCC Version 3.0.3 generated the following assembly language code for
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* the multiplication and scaling, leaving the 32-bit result in EAX.
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*
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* movl -8(%ebp), %eax ; read one int into EAX
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* imull -4(%ebp) ; multiply by the other; result goes in EDX:EAX
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* shrdl $16, %edx, %eax ; shift EAX right 16, shifting bits in from EDX
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*
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* Note that a 32*32->64 multiplication is performed, allowing for high
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* accuracy. On the Pentium 2 and above, shrdl takes two cycles (generally),
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* so it is a minor concern when four multiplications are being performed
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* (the cubic resampler). On the Pentium MMX and earlier, it takes four or
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* more cycles, so this method is unsuitable for use in the low-quality
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* resamplers.
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*
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* Since "long long" is a gcc-specific extension, we use LONG_LONG instead,
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* defined in dumb.h. We may investigate later what code MSVC generates, but
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* if it seems too slow then we suggest you use a good compiler.
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*
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* FIXME: these comments are somewhat out of date now.
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*/
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void dumb_reset_resampler(DUMB_RESAMPLER *resampler, SRCTYPE *src, int src_channels, long pos, long start, long end)
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{
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int i;
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resampler->src = src;
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resampler->pos = pos;
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resampler->subpos = 0;
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resampler->start = start;
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resampler->end = end;
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resampler->dir = 1;
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resampler->pickup = NULL;
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resampler->pickup_data = NULL;
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resampler->min_quality = 0;
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resampler->max_quality = DUMB_RQ_N_LEVELS - 1;
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for (i = 0; i < src_channels*3; i++) resampler->X[i] = 0;
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resampler->overshot = -1;
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}
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DUMB_RESAMPLER *dumb_start_resampler(SRCTYPE *src, int src_channels, long pos, long start, long end)
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{
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DUMB_RESAMPLER *resampler = malloc(sizeof(*resampler));
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if (!resampler) return NULL;
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dumb_reset_resampler(resampler, src, src_channels, pos, start, end);
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return resampler;
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}
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/* Create mono source resampler. */
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#define SUFFIX2 _1
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#define SRC_CHANNELS 1
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#define DIVIDE_BY_SRC_CHANNELS(x) (x)
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#define COPYSRC(dstarray, dstindex, srcarray, srcindex) (dstarray)[dstindex] = (srcarray)[srcindex]
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#define COPYSRC2(dstarray, dstindex, condition, srcarray, srcindex) (dstarray)[dstindex] = condition ? (srcarray)[srcindex] : 0
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#define MONO_DEST_VOLUME_PARAMETERS float volume
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#define MONO_DEST_VOLUME_VARIABLES vol
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#define MONO_DEST_VOLUME_ZEROS 0
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#define SET_MONO_DEST_VOLUME_VARIABLES vol = (int)floor(volume * 65536.0 + 0.5)
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#define MONO_DEST_VOLUMES_ARE_ZERO (vol == 0)
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#define MONO_DEST_MIX_ALIAS(op, offset) *dst++ op ALIAS(x[offset], vol)
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#define STEREO_DEST_MIX_ALIAS(op, offset) { \
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int xm = x[offset]; \
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*dst++ op ALIAS(xm, lvol); \
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*dst++ op ALIAS(xm, rvol); \
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}
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#define MONO_DEST_MIX_LINEAR(op, o0, o1) *dst++ op MULSC(LINEAR(x[o0], x[o1]), vol)
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#define STEREO_DEST_MIX_LINEAR(op, o0, o1) { \
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int xm = LINEAR(x[o0], x[o1]); \
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*dst++ op MULSC(xm, lvol); \
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*dst++ op MULSC(xm, rvol); \
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}
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#define MONO_DEST_MIX_CUBIC(op, x0, x3, o0, o1, o2, o3) *dst++ op CUBICVOL(CUBIC(x0[o0], x[o1], x[o2], x3[o3]), vol)
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#define STEREO_DEST_MIX_CUBIC(op, x0, x3, o0, o1, o2, o3) { \
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int xm = CUBIC(x0[o0], x[o1], x[o2], x3[o3]); \
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*dst++ op CUBICVOL(xm, lvol); \
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*dst++ op CUBICVOL(xm, rvol); \
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}
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#include "resamp2.inc"
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/* Create stereo source resampler. */
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#define SUFFIX2 _2
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#define SRC_CHANNELS 2
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#define DIVIDE_BY_SRC_CHANNELS(x) ((x) >> 1)
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#define COPYSRC(dstarray, dstindex, srcarray, srcindex) { \
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(dstarray)[(dstindex)*2] = (srcarray)[(srcindex)*2]; \
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(dstarray)[(dstindex)*2+1] = (srcarray)[(srcindex)*2+1]; \
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}
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#define COPYSRC2(dstarray, dstindex, condition, srcarray, srcindex) { \
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if (condition) { \
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(dstarray)[(dstindex)*2] = (srcarray)[(srcindex)*2]; \
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(dstarray)[(dstindex)*2+1] = (srcarray)[(srcindex)*2+1]; \
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} else { \
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(dstarray)[(dstindex)*2] = 0; \
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(dstarray)[(dstindex)*2+1] = 0; \
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} \
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}
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#define MONO_DEST_VOLUME_PARAMETERS float volume_left, float volume_right
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#define MONO_DEST_VOLUME_VARIABLES lvol, rvol
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#define MONO_DEST_VOLUME_ZEROS 0, 0
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#define SET_MONO_DEST_VOLUME_VARIABLES { \
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lvol = (int)floor(volume_left * 65536.0 + 0.5); \
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rvol = (int)floor(volume_right * 65536.0 + 0.5); \
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}
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#define MONO_DEST_VOLUMES_ARE_ZERO (lvol == 0 && rvol == 0)
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#define MONO_DEST_MIX_ALIAS(op, offset) *dst++ op ALIAS(x[(offset)*2], lvol) + ALIAS(x[(offset)*2+1], rvol)
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#define STEREO_DEST_MIX_ALIAS(op, offset) { \
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*dst++ op ALIAS(x[(offset)*2], lvol); \
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*dst++ op ALIAS(x[(offset)*2+1], rvol); \
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}
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#define MONO_DEST_MIX_LINEAR(op, o0, o1) *dst++ op MULSC(LINEAR(x[(o0)*2], x[(o1)*2]), lvol) + MULSC(LINEAR(x[(o0)*2+1], x[(o1)*2+1]), rvol)
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#define STEREO_DEST_MIX_LINEAR(op, o0, o1) { \
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*dst++ op MULSC(LINEAR(x[(o0)*2], x[(o1)*2]), lvol); \
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*dst++ op MULSC(LINEAR(x[(o0)*2+1], x[(o1)*2+1]), rvol); \
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}
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#define MONO_DEST_MIX_CUBIC(op, x0, x3, o0, o1, o2, o3) *dst++ op \
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CUBICVOL(CUBIC(x0[(o0)*2], x[(o1)*2], x[(o2)*2], x3[(o3)*2]), lvol) + \
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CUBICVOL(CUBIC(x0[(o0)*2+1], x[(o1)*2+1], x[(o2)*2+1], x3[(o3)*2+1]), rvol)
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#define STEREO_DEST_MIX_CUBIC(op, x0, x3, o0, o1, o2, o3) { \
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*dst++ op CUBICVOL(CUBIC(x0[(o0)*2], x[(o1)*2], x[(o2)*2], x3[(o3)*2]), lvol); \
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*dst++ op CUBICVOL(CUBIC(x0[(o0)*2+1], x[(o1)*2+1], x[(o2)*2+1], x3[(o3)*2+1]), rvol); \
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}
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#include "resamp2.inc"
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void dumb_end_resampler(DUMB_RESAMPLER *resampler)
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{
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if (resampler)
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free(resampler);
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}
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#undef CUBICVOL
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#undef CUBIC
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#undef LINEAR
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#undef ALIAS
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#undef SRCBITS
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#undef SRCTYPE
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#undef SUFFIX
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