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Diffstat (limited to 'src/dither.c')
| -rw-r--r-- | src/dither.c | 533 |
1 files changed, 533 insertions, 0 deletions
diff --git a/src/dither.c b/src/dither.c new file mode 100644 index 0000000..50b5ba2 --- /dev/null +++ b/src/dither.c @@ -0,0 +1,533 @@ +/* +** Copyright (C) 2003,2005 Erik de Castro Lopo <erikd@mega-nerd.com> +** +** This program is free software; you can redistribute it and/or modify +** it under the terms of the GNU Lesser General Public License as published by +** the Free Software Foundation; either version 2.1 of the License, or +** (at your option) any later version. +** +** This program is distributed in the hope that it will be useful, +** but WITHOUT ANY WARRANTY; without even the implied warranty of +** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +** GNU Lesser General Public License for more details. +** +** You should have received a copy of the GNU Lesser General Public License +** along with this program; if not, write to the Free Software +** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. +*/ + +#include "sfconfig.h" + +#include <stdlib.h> + +#include "sndfile.h" +#include "sfendian.h" +#include "common.h" + +/*============================================================================ +** Rule number 1 is to only apply dither when going from a larger bitwidth +** to a smaller bitwidth. This can happen on both read and write. +** +** Need to apply dither on all conversions marked X below. +** +** Dither on write: +** +** Input +** | short int float double +** --------+----------------------------------------------- +** O 8 bit | X X X X +** u 16 bit | none X X X +** t 24 bit | none X X X +** p 32 bit | none none X X +** u float | none none none none +** t double | none none none none +** +** Dither on read: +** +** Input +** O | 8 bit 16 bit 24 bit 32 bit float double +** u --------+------------------------------------------------- +** t short | none none X X X X +** p int | none none none X X X +** u float | none none none none none none +** t double | none none none none none none +*/ + +#define SFE_DITHER_BAD_PTR 666 +#define SFE_DITHER_BAD_TYPE 667 + +typedef struct +{ int read_short_dither_bits, read_int_dither_bits ; + int write_short_dither_bits, write_int_dither_bits ; + double read_float_dither_scale, read_double_dither_bits ; + double write_float_dither_scale, write_double_dither_bits ; + + sf_count_t (*read_short) (SF_PRIVATE *psf, short *ptr, sf_count_t len) ; + sf_count_t (*read_int) (SF_PRIVATE *psf, int *ptr, sf_count_t len) ; + sf_count_t (*read_float) (SF_PRIVATE *psf, float *ptr, sf_count_t len) ; + sf_count_t (*read_double) (SF_PRIVATE *psf, double *ptr, sf_count_t len) ; + + sf_count_t (*write_short) (SF_PRIVATE *psf, const short *ptr, sf_count_t len) ; + sf_count_t (*write_int) (SF_PRIVATE *psf, const int *ptr, sf_count_t len) ; + sf_count_t (*write_float) (SF_PRIVATE *psf, const float *ptr, sf_count_t len) ; + sf_count_t (*write_double) (SF_PRIVATE *psf, const double *ptr, sf_count_t len) ; + + double buffer [SF_BUFFER_LEN / sizeof (double)] ; +} DITHER_DATA ; + +static sf_count_t dither_read_short (SF_PRIVATE *psf, short *ptr, sf_count_t len) ; +static sf_count_t dither_read_int (SF_PRIVATE *psf, int *ptr, sf_count_t len) ; + +static sf_count_t dither_write_short (SF_PRIVATE *psf, const short *ptr, sf_count_t len) ; +static sf_count_t dither_write_int (SF_PRIVATE *psf, const int *ptr, sf_count_t len) ; +static sf_count_t dither_write_float (SF_PRIVATE *psf, const float *ptr, sf_count_t len) ; +static sf_count_t dither_write_double (SF_PRIVATE *psf, const double *ptr, sf_count_t len) ; + +int +dither_init (SF_PRIVATE *psf, int mode) +{ DITHER_DATA *pdither ; + + pdither = psf->dither ; /* This may be NULL. */ + + /* Turn off dither on read. */ + if (mode == SFM_READ && psf->read_dither.type == SFD_NO_DITHER) + { if (pdither == NULL) + return 0 ; /* Dither is already off, so just return. */ + + if (pdither->read_short) + psf->read_short = pdither->read_short ; + if (pdither->read_int) + psf->read_int = pdither->read_int ; + if (pdither->read_float) + psf->read_float = pdither->read_float ; + if (pdither->read_double) + psf->read_double = pdither->read_double ; + return 0 ; + } ; + + /* Turn off dither on write. */ + if (mode == SFM_WRITE && psf->write_dither.type == SFD_NO_DITHER) + { if (pdither == NULL) + return 0 ; /* Dither is already off, so just return. */ + + if (pdither->write_short) + psf->write_short = pdither->write_short ; + if (pdither->write_int) + psf->write_int = pdither->write_int ; + if (pdither->write_float) + psf->write_float = pdither->write_float ; + if (pdither->write_double) + psf->write_double = pdither->write_double ; + return 0 ; + } ; + + /* Turn on dither on read if asked. */ + if (mode == SFM_READ && psf->read_dither.type != 0) + { if (pdither == NULL) + pdither = psf->dither = calloc (1, sizeof (DITHER_DATA)) ; + if (pdither == NULL) + return SFE_MALLOC_FAILED ; + + switch (psf->sf.format & SF_FORMAT_SUBMASK) + { case SF_FORMAT_DOUBLE : + case SF_FORMAT_FLOAT : + pdither->read_int = psf->read_int ; + psf->read_int = dither_read_int ; + + case SF_FORMAT_PCM_32 : + case SF_FORMAT_PCM_24 : + case SF_FORMAT_PCM_16 : + case SF_FORMAT_PCM_S8 : + case SF_FORMAT_PCM_U8 : + pdither->read_short = psf->read_short ; + psf->read_short = dither_read_short ; + + default : break ; + } ; + } ; + + /* Turn on dither on write if asked. */ + if (mode == SFM_WRITE && psf->write_dither.type != 0) + { if (pdither == NULL) + pdither = psf->dither = calloc (1, sizeof (DITHER_DATA)) ; + if (pdither == NULL) + return SFE_MALLOC_FAILED ; + + switch (psf->sf.format & SF_FORMAT_SUBMASK) + { case SF_FORMAT_DOUBLE : + case SF_FORMAT_FLOAT : + pdither->write_int = psf->write_int ; + psf->write_int = dither_write_int ; + + case SF_FORMAT_PCM_32 : + case SF_FORMAT_PCM_24 : + case SF_FORMAT_PCM_16 : + case SF_FORMAT_PCM_S8 : + case SF_FORMAT_PCM_U8 : + + default : break ; + } ; + + pdither->write_short = psf->write_short ; + psf->write_short = dither_write_short ; + + pdither->write_int = psf->write_int ; + psf->write_int = dither_write_int ; + + pdither->write_float = psf->write_float ; + psf->write_float = dither_write_float ; + + pdither->write_double = psf->write_double ; + psf->write_double = dither_write_double ; + } ; + + return 0 ; +} /* dither_init */ + +/*============================================================================== +*/ + +static void dither_short (const short *in, short *out, int frames, int channels) ; +static void dither_int (const int *in, int *out, int frames, int channels) ; + +static void dither_float (const float *in, float *out, int frames, int channels) ; +static void dither_double (const double *in, double *out, int frames, int channels) ; + +static sf_count_t +dither_read_short (SF_PRIVATE * UNUSED (psf), short * UNUSED (ptr), sf_count_t len) +{ + return len ; +} /* dither_read_short */ + +static sf_count_t +dither_read_int (SF_PRIVATE * UNUSED (psf), int * UNUSED (ptr), sf_count_t len) +{ + return len ; +} /* dither_read_int */ + +/*------------------------------------------------------------------------------ +*/ + +static sf_count_t +dither_write_short (SF_PRIVATE *psf, const short *ptr, sf_count_t len) +{ DITHER_DATA *pdither ; + int bufferlen, writecount, thiswrite ; + sf_count_t total = 0 ; + + if ((pdither = psf->dither) == NULL) + { psf->error = SFE_DITHER_BAD_PTR ; + return 0 ; + } ; + + switch (psf->sf.format & SF_FORMAT_SUBMASK) + { case SF_FORMAT_PCM_S8 : + case SF_FORMAT_PCM_U8 : + case SF_FORMAT_DPCM_8 : + break ; + + default : + return pdither->write_short (psf, ptr, len) ; + } ; + + bufferlen = sizeof (pdither->buffer) / sizeof (short) ; + + while (len > 0) + { writecount = (len >= bufferlen) ? bufferlen : (int) len ; + writecount /= psf->sf.channels ; + writecount *= psf->sf.channels ; + + dither_short (ptr, (short*) pdither->buffer, writecount / psf->sf.channels, psf->sf.channels) ; + + thiswrite = pdither->write_short (psf, (short*) pdither->buffer, writecount) ; + total += thiswrite ; + len -= thiswrite ; + if (thiswrite < writecount) + break ; + } ; + + return total ; +} /* dither_write_short */ + +static sf_count_t +dither_write_int (SF_PRIVATE *psf, const int *ptr, sf_count_t len) +{ DITHER_DATA *pdither ; + int bufferlen, writecount, thiswrite ; + sf_count_t total = 0 ; + + if ((pdither = psf->dither) == NULL) + { psf->error = SFE_DITHER_BAD_PTR ; + return 0 ; + } ; + + switch (psf->sf.format & SF_FORMAT_SUBMASK) + { case SF_FORMAT_PCM_S8 : + case SF_FORMAT_PCM_U8 : + case SF_FORMAT_PCM_16 : + case SF_FORMAT_PCM_24 : + + case SF_FORMAT_DPCM_8 : + case SF_FORMAT_DPCM_16 : + break ; + + default : + return pdither->write_int (psf, ptr, len) ; + } ; + + + bufferlen = sizeof (pdither->buffer) / sizeof (int) ; + + while (len > 0) + { writecount = (len >= bufferlen) ? bufferlen : (int) len ; + writecount /= psf->sf.channels ; + writecount *= psf->sf.channels ; + + dither_int (ptr, (int*) pdither->buffer, writecount / psf->sf.channels, psf->sf.channels) ; + + thiswrite = pdither->write_int (psf, (int*) pdither->buffer, writecount) ; + total += thiswrite ; + len -= thiswrite ; + if (thiswrite < writecount) + break ; + } ; + + return total ; +} /* dither_write_int */ + +static sf_count_t +dither_write_float (SF_PRIVATE *psf, const float *ptr, sf_count_t len) +{ DITHER_DATA *pdither ; + int bufferlen, writecount, thiswrite ; + sf_count_t total = 0 ; + + if ((pdither = psf->dither) == NULL) + { psf->error = SFE_DITHER_BAD_PTR ; + return 0 ; + } ; + + switch (psf->sf.format & SF_FORMAT_SUBMASK) + { case SF_FORMAT_PCM_S8 : + case SF_FORMAT_PCM_U8 : + case SF_FORMAT_PCM_16 : + case SF_FORMAT_PCM_24 : + + case SF_FORMAT_DPCM_8 : + case SF_FORMAT_DPCM_16 : + break ; + + default : + return pdither->write_float (psf, ptr, len) ; + } ; + + bufferlen = sizeof (pdither->buffer) / sizeof (float) ; + + while (len > 0) + { writecount = (len >= bufferlen) ? bufferlen : (float) len ; + writecount /= psf->sf.channels ; + writecount *= psf->sf.channels ; + + dither_float (ptr, (float*) pdither->buffer, writecount / psf->sf.channels, psf->sf.channels) ; + + thiswrite = pdither->write_float (psf, (float*) pdither->buffer, writecount) ; + total += thiswrite ; + len -= thiswrite ; + if (thiswrite < writecount) + break ; + } ; + + return total ; +} /* dither_write_float */ + +static sf_count_t +dither_write_double (SF_PRIVATE *psf, const double *ptr, sf_count_t len) +{ DITHER_DATA *pdither ; + int bufferlen, writecount, thiswrite ; + sf_count_t total = 0 ; + + if ((pdither = psf->dither) == NULL) + { psf->error = SFE_DITHER_BAD_PTR ; + return 0 ; + } ; + + switch (psf->sf.format & SF_FORMAT_SUBMASK) + { case SF_FORMAT_PCM_S8 : + case SF_FORMAT_PCM_U8 : + case SF_FORMAT_PCM_16 : + case SF_FORMAT_PCM_24 : + + case SF_FORMAT_DPCM_8 : + case SF_FORMAT_DPCM_16 : + break ; + + default : + return pdither->write_double (psf, ptr, len) ; + } ; + + + bufferlen = sizeof (pdither->buffer) / sizeof (double) ; + + while (len > 0) + { writecount = (len >= bufferlen) ? bufferlen : (double) len ; + writecount /= psf->sf.channels ; + writecount *= psf->sf.channels ; + + dither_double (ptr, (double*) pdither->buffer, writecount / psf->sf.channels, psf->sf.channels) ; + + thiswrite = pdither->write_double (psf, (double*) pdither->buffer, writecount) ; + total += thiswrite ; + len -= thiswrite ; + if (thiswrite < writecount) + break ; + } ; + + return total ; +} /* dither_write_double */ + +/*============================================================================== +*/ + +static void +dither_short (const short *in, short *out, int frames, int channels) +{ int ch, k ; + + for (ch = 0 ; ch < channels ; ch++) + for (k = ch ; k < channels * frames ; k += channels) + out [k] = in [k] ; + +} /* dither_short */ + +static void +dither_int (const int *in, int *out, int frames, int channels) +{ int ch, k ; + + for (ch = 0 ; ch < channels ; ch++) + for (k = ch ; k < channels * frames ; k += channels) + out [k] = in [k] ; + +} /* dither_int */ + +static void +dither_float (const float *in, float *out, int frames, int channels) +{ int ch, k ; + + for (ch = 0 ; ch < channels ; ch++) + for (k = ch ; k < channels * frames ; k += channels) + out [k] = in [k] ; + +} /* dither_float */ + +static void +dither_double (const double *in, double *out, int frames, int channels) +{ int ch, k ; + + for (ch = 0 ; ch < channels ; ch++) + for (k = ch ; k < channels * frames ; k += channels) + out [k] = in [k] ; + +} /* dither_double */ + +/*============================================================================== +*/ +#if 0 + +/* +** Not made public because this (maybe) requires storage of state information. +** +** Also maybe need separate state info for each channel!!!! +*/ + +int +DO_NOT_USE_sf_dither_short (const SF_DITHER_INFO *dither, const short *in, short *out, int frames, int channels) +{ int ch, k ; + + if (! dither) + return SFE_DITHER_BAD_PTR ; + + switch (dither->type & SFD_TYPEMASK) + { case SFD_WHITE : + case SFD_TRIANGULAR_PDF : + for (ch = 0 ; ch < channels ; ch++) + for (k = ch ; k < channels * frames ; k += channels) + out [k] = in [k] ; + break ; + + default : + return SFE_DITHER_BAD_TYPE ; + } ; + + return 0 ; +} /* DO_NOT_USE_sf_dither_short */ + +int +DO_NOT_USE_sf_dither_int (const SF_DITHER_INFO *dither, const int *in, int *out, int frames, int channels) +{ int ch, k ; + + if (! dither) + return SFE_DITHER_BAD_PTR ; + + switch (dither->type & SFD_TYPEMASK) + { case SFD_WHITE : + case SFD_TRIANGULAR_PDF : + for (ch = 0 ; ch < channels ; ch++) + for (k = ch ; k < channels * frames ; k += channels) + out [k] = in [k] ; + break ; + + default : + return SFE_DITHER_BAD_TYPE ; + } ; + + return 0 ; +} /* DO_NOT_USE_sf_dither_int */ + +int +DO_NOT_USE_sf_dither_float (const SF_DITHER_INFO *dither, const float *in, float *out, int frames, int channels) +{ int ch, k ; + + if (! dither) + return SFE_DITHER_BAD_PTR ; + + switch (dither->type & SFD_TYPEMASK) + { case SFD_WHITE : + case SFD_TRIANGULAR_PDF : + for (ch = 0 ; ch < channels ; ch++) + for (k = ch ; k < channels * frames ; k += channels) + out [k] = in [k] ; + break ; + + default : + return SFE_DITHER_BAD_TYPE ; + } ; + + return 0 ; +} /* DO_NOT_USE_sf_dither_float */ + +int +DO_NOT_USE_sf_dither_double (const SF_DITHER_INFO *dither, const double *in, double *out, int frames, int channels) +{ int ch, k ; + + if (! dither) + return SFE_DITHER_BAD_PTR ; + + switch (dither->type & SFD_TYPEMASK) + { case SFD_WHITE : + case SFD_TRIANGULAR_PDF : + for (ch = 0 ; ch < channels ; ch++) + for (k = ch ; k < channels * frames ; k += channels) + out [k] = in [k] ; + break ; + + default : + return SFE_DITHER_BAD_TYPE ; + } ; + + return 0 ; +} /* DO_NOT_USE_sf_dither_double */ + +#endif +/* +** Do not edit or modify anything in this comment block. +** The arch-tag line is a file identity tag for the GNU Arch +** revision control system. +** +** arch-tag: 673fad58-5314-421c-9144-9d54bfdf104c +*/ |