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87 lines
3.1 KiB
87 lines
3.1 KiB
/* |
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* Copyright (C) 2012 Michael Niedermayer (michaelni@gmx.at) |
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* |
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* This file is part of libswresample |
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* |
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* libswresample is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* libswresample is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with libswresample; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#include "libavutil/avassert.h" |
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#include "swresample_internal.h" |
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void swri_get_dither(SwrContext *s, void *dst, int len, unsigned seed, enum AVSampleFormat out_fmt, enum AVSampleFormat in_fmt) { |
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double scale = 0; |
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#define TMP_EXTRA 2 |
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double *tmp = av_malloc((len + TMP_EXTRA) * sizeof(double)); |
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int i; |
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out_fmt = av_get_packed_sample_fmt(out_fmt); |
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in_fmt = av_get_packed_sample_fmt( in_fmt); |
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if(in_fmt == AV_SAMPLE_FMT_FLT || in_fmt == AV_SAMPLE_FMT_DBL){ |
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if(out_fmt == AV_SAMPLE_FMT_S32) scale = 1.0/(1L<<31); |
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if(out_fmt == AV_SAMPLE_FMT_S16) scale = 1.0/(1L<<15); |
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if(out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1.0/(1L<< 7); |
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} |
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if(in_fmt == AV_SAMPLE_FMT_S32 && out_fmt == AV_SAMPLE_FMT_S16) scale = 1L<<16; |
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if(in_fmt == AV_SAMPLE_FMT_S32 && out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1L<<24; |
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if(in_fmt == AV_SAMPLE_FMT_S16 && out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1L<<8; |
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scale *= s->dither_scale; |
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for(i=0; i<len + TMP_EXTRA; i++){ |
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double v; |
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seed = seed* 1664525 + 1013904223; |
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switch(s->dither_method){ |
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case SWR_DITHER_RECTANGULAR: v= ((double)seed) / UINT_MAX - 0.5; break; |
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case SWR_DITHER_TRIANGULAR : |
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case SWR_DITHER_TRIANGULAR_HIGHPASS : |
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v = ((double)seed) / UINT_MAX; |
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seed = seed*1664525 + 1013904223; |
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v-= ((double)seed) / UINT_MAX; |
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break; |
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default: av_assert0(0); |
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} |
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tmp[i] = v; |
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} |
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for(i=0; i<len; i++){ |
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double v; |
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switch(s->dither_method){ |
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case SWR_DITHER_RECTANGULAR: |
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case SWR_DITHER_TRIANGULAR : |
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v = tmp[i]; |
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break; |
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case SWR_DITHER_TRIANGULAR_HIGHPASS : |
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v = (- tmp[i] + 2*tmp[i+1] - tmp[i+2]) / sqrt(6); |
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break; |
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default: av_assert0(0); |
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} |
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v*= scale; |
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switch(in_fmt){ |
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case AV_SAMPLE_FMT_S16: ((int16_t*)dst)[i] = v; break; |
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case AV_SAMPLE_FMT_S32: ((int32_t*)dst)[i] = v; break; |
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case AV_SAMPLE_FMT_FLT: ((float *)dst)[i] = v; break; |
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case AV_SAMPLE_FMT_DBL: ((double *)dst)[i] = v; break; |
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default: av_assert0(0); |
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} |
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} |
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av_free(tmp); |
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}
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