kopia lustrzana https://github.com/f4exb/sdrangel
69 wiersze
2.0 KiB
C
69 wiersze
2.0 KiB
C
/*
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* Copyright (C) 2010 DSD Author
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* GPG Key ID: 0x3F1D7FD0 (74EF 430D F7F2 0A48 FCE6 F630 FAA2 635D 3F1D 7FD0)
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
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* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
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* AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
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* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
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* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
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* OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
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* PERFORMANCE OF THIS SOFTWARE.
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*/
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#include "dsd.h"
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void
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upsample (dsd_state * state, float invalue)
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{
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int i, j, sum;
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float *outbuf1, c, d;
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outbuf1 = state->audio_out_float_buf_p;
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outbuf1--;
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c = *outbuf1;
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d = invalue;
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// basic triangle interpolation
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outbuf1++;
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*outbuf1 = ((invalue * (float) 0.166) + (c * (float) 0.834));
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outbuf1++;
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*outbuf1 = ((invalue * (float) 0.332) + (c * (float) 0.668));
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outbuf1++;
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*outbuf1 = ((invalue * (float) 0.5) + (c * (float) 0.5));
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outbuf1++;
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*outbuf1 = ((invalue * (float) 0.668) + (c * (float) 0.332));
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outbuf1++;
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*outbuf1 = ((invalue * (float) 0.834) + (c * (float) 0.166));
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outbuf1++;
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*outbuf1 = d;
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outbuf1++;
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if (state->audio_out_idx2 > 24)
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{
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// smoothing
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outbuf1 -= 16;
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for (j = 0; j < 4; j++)
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{
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for (i = 0; i < 6; i++)
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{
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sum = 0;
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outbuf1 -= 2;
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sum += *outbuf1;
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outbuf1 += 2;
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sum += *outbuf1;
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outbuf1 += 2;
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sum += *outbuf1;
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outbuf1 -= 2;
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*outbuf1 = (sum / (float) 3);
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outbuf1++;
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}
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outbuf1 -= 8;
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}
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}
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}
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