diff options
Diffstat (limited to 'libswresample/dither.c')
| -rw-r--r-- | libswresample/dither.c | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/libswresample/dither.c b/libswresample/dither.c new file mode 100644 index 0000000000..d0193dda46 --- /dev/null +++ b/libswresample/dither.c @@ -0,0 +1,147 @@ +/* + * Copyright (C) 2012-2013 Michael Niedermayer (michaelni@gmx.at) + * + * This file is part of libswresample + * + * libswresample 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. + * + * libswresample 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 libswresample; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include "libavutil/avassert.h" +#include "swresample_internal.h" + +#include "noise_shaping_data.c" + +void swri_get_dither(SwrContext *s, void *dst, int len, unsigned seed, enum AVSampleFormat noise_fmt) { + double scale = s->dither.noise_scale; +#define TMP_EXTRA 2 + double *tmp = av_malloc((len + TMP_EXTRA) * sizeof(double)); + int i; + + for(i=0; i<len + TMP_EXTRA; i++){ + double v; + seed = seed* 1664525 + 1013904223; + + switch(s->dither.method){ + case SWR_DITHER_RECTANGULAR: v= ((double)seed) / UINT_MAX - 0.5; break; + default: + av_assert0(s->dither.method < SWR_DITHER_NB); + v = ((double)seed) / UINT_MAX; + seed = seed*1664525 + 1013904223; + v-= ((double)seed) / UINT_MAX; + break; + } + tmp[i] = v; + } + + for(i=0; i<len; i++){ + double v; + + switch(s->dither.method){ + default: + av_assert0(s->dither.method < SWR_DITHER_NB); + v = tmp[i]; + break; + case SWR_DITHER_TRIANGULAR_HIGHPASS : + v = (- tmp[i] + 2*tmp[i+1] - tmp[i+2]) / sqrt(6); + break; + } + + v*= scale; + + switch(noise_fmt){ + case AV_SAMPLE_FMT_S16P: ((int16_t*)dst)[i] = v; break; + case AV_SAMPLE_FMT_S32P: ((int32_t*)dst)[i] = v; break; + case AV_SAMPLE_FMT_FLTP: ((float *)dst)[i] = v; break; + case AV_SAMPLE_FMT_DBLP: ((double *)dst)[i] = v; break; + default: av_assert0(0); + } + } + + av_free(tmp); +} + +int swri_dither_init(SwrContext *s, enum AVSampleFormat out_fmt, enum AVSampleFormat in_fmt) +{ + int i; + double scale = 0; + + if (s->dither.method > SWR_DITHER_TRIANGULAR_HIGHPASS && s->dither.method <= SWR_DITHER_NS) + return AVERROR(EINVAL); + + out_fmt = av_get_packed_sample_fmt(out_fmt); + in_fmt = av_get_packed_sample_fmt( in_fmt); + + if(in_fmt == AV_SAMPLE_FMT_FLT || in_fmt == AV_SAMPLE_FMT_DBL){ + if(out_fmt == AV_SAMPLE_FMT_S32) scale = 1.0/(1L<<31); + if(out_fmt == AV_SAMPLE_FMT_S16) scale = 1.0/(1L<<15); + if(out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1.0/(1L<< 7); + } + if(in_fmt == AV_SAMPLE_FMT_S32 && out_fmt == AV_SAMPLE_FMT_S16) scale = 1L<<16; + if(in_fmt == AV_SAMPLE_FMT_S32 && out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1L<<24; + if(in_fmt == AV_SAMPLE_FMT_S16 && out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1L<<8; + + scale *= s->dither.scale; + + if (out_fmt == AV_SAMPLE_FMT_S32 && s->dither.output_sample_bits) + scale *= 1<<(32-s->dither.output_sample_bits); + + s->dither.ns_pos = 0; + s->dither.noise_scale= scale; + s->dither.ns_scale = scale; + s->dither.ns_scale_1 = scale ? 1/scale : 0; + memset(s->dither.ns_errors, 0, sizeof(s->dither.ns_errors)); + for (i=0; filters[i].coefs; i++) { + const filter_t *f = &filters[i]; + if (fabs(s->out_sample_rate - f->rate) / f->rate <= .05 && f->name == s->dither.method) { + int j; + s->dither.ns_taps = f->len; + for (j=0; j<f->len; j++) + s->dither.ns_coeffs[j] = f->coefs[j]; + s->dither.ns_scale_1 *= 1 - exp(f->gain_cB * M_LN10 * 0.005) * 2 / (1<<(8*av_get_bytes_per_sample(out_fmt))); + break; + } + } + if (!filters[i].coefs && s->dither.method > SWR_DITHER_NS) { + av_log(s, AV_LOG_WARNING, "Requested noise shaping dither not available at this sampling rate, using triangular hp dither\n"); + s->dither.method = SWR_DITHER_TRIANGULAR_HIGHPASS; + } + + av_assert0(!s->preout.count); + s->dither.noise = s->preout; + s->dither.temp = s->preout; + if (s->dither.method > SWR_DITHER_NS) { + s->dither.noise.bps = 4; + s->dither.noise.fmt = AV_SAMPLE_FMT_FLTP; + s->dither.noise_scale = 1; + } + + return 0; +} + +#define TEMPLATE_DITHER_S16 +#include "dither_template.c" +#undef TEMPLATE_DITHER_S16 + +#define TEMPLATE_DITHER_S32 +#include "dither_template.c" +#undef TEMPLATE_DITHER_S32 + +#define TEMPLATE_DITHER_FLT +#include "dither_template.c" +#undef TEMPLATE_DITHER_FLT + +#define TEMPLATE_DITHER_DBL +#include "dither_template.c" +#undef TEMPLATE_DITHER_DBL |