Mercurial > hg > audiostuff
diff spandsp-0.0.6pre17/src/g711.c @ 4:26cd8f1ef0b1
import spandsp-0.0.6pre17
author | Peter Meerwald <pmeerw@cosy.sbg.ac.at> |
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date | Fri, 25 Jun 2010 15:50:58 +0200 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/spandsp-0.0.6pre17/src/g711.c Fri Jun 25 15:50:58 2010 +0200 @@ -0,0 +1,196 @@ +/* + * SpanDSP - a series of DSP components for telephony + * + * g711.c - A-law and u-law transcoding routines + * + * Written by Steve Underwood <steveu@coppice.org> + * + * Copyright (C) 2006 Steve Underwood + * + * All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License version 2.1, + * as published by the Free Software Foundation. + * + * 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., 675 Mass Ave, Cambridge, MA 02139, USA. + * + * $Id: g711.c,v 1.16 2009/02/10 13:06:46 steveu Exp $ + */ + +/*! \file */ + +#if defined(HAVE_CONFIG_H) +#include "config.h" +#endif + +#include <inttypes.h> +#include <stdlib.h> +#include <string.h> +#include <assert.h> + +#include "spandsp/telephony.h" +#include "spandsp/bit_operations.h" +#include "spandsp/g711.h" +#include "spandsp/private/g711.h" + +/* Copied from the CCITT G.711 specification */ +static const uint8_t ulaw_to_alaw_table[256] = +{ + 42, 43, 40, 41, 46, 47, 44, 45, 34, 35, 32, 33, 38, 39, 36, 37, + 58, 59, 56, 57, 62, 63, 60, 61, 50, 51, 48, 49, 54, 55, 52, 53, + 10, 11, 8, 9, 14, 15, 12, 13, 2, 3, 0, 1, 6, 7, 4, 26, + 27, 24, 25, 30, 31, 28, 29, 18, 19, 16, 17, 22, 23, 20, 21, 106, + 104, 105, 110, 111, 108, 109, 98, 99, 96, 97, 102, 103, 100, 101, 122, 120, + 126, 127, 124, 125, 114, 115, 112, 113, 118, 119, 116, 117, 75, 73, 79, 77, + 66, 67, 64, 65, 70, 71, 68, 69, 90, 91, 88, 89, 94, 95, 92, 93, + 82, 82, 83, 83, 80, 80, 81, 81, 86, 86, 87, 87, 84, 84, 85, 85, + 170, 171, 168, 169, 174, 175, 172, 173, 162, 163, 160, 161, 166, 167, 164, 165, + 186, 187, 184, 185, 190, 191, 188, 189, 178, 179, 176, 177, 182, 183, 180, 181, + 138, 139, 136, 137, 142, 143, 140, 141, 130, 131, 128, 129, 134, 135, 132, 154, + 155, 152, 153, 158, 159, 156, 157, 146, 147, 144, 145, 150, 151, 148, 149, 234, + 232, 233, 238, 239, 236, 237, 226, 227, 224, 225, 230, 231, 228, 229, 250, 248, + 254, 255, 252, 253, 242, 243, 240, 241, 246, 247, 244, 245, 203, 201, 207, 205, + 194, 195, 192, 193, 198, 199, 196, 197, 218, 219, 216, 217, 222, 223, 220, 221, + 210, 210, 211, 211, 208, 208, 209, 209, 214, 214, 215, 215, 212, 212, 213, 213 +}; + +/* These transcoding tables are copied from the CCITT G.711 specification. To achieve + optimal results, do not change them. */ + +static const uint8_t alaw_to_ulaw_table[256] = +{ + 42, 43, 40, 41, 46, 47, 44, 45, 34, 35, 32, 33, 38, 39, 36, 37, + 57, 58, 55, 56, 61, 62, 59, 60, 49, 50, 47, 48, 53, 54, 51, 52, + 10, 11, 8, 9, 14, 15, 12, 13, 2, 3, 0, 1, 6, 7, 4, 5, + 26, 27, 24, 25, 30, 31, 28, 29, 18, 19, 16, 17, 22, 23, 20, 21, + 98, 99, 96, 97, 102, 103, 100, 101, 93, 93, 92, 92, 95, 95, 94, 94, + 116, 118, 112, 114, 124, 126, 120, 122, 106, 107, 104, 105, 110, 111, 108, 109, + 72, 73, 70, 71, 76, 77, 74, 75, 64, 65, 63, 63, 68, 69, 66, 67, + 86, 87, 84, 85, 90, 91, 88, 89, 79, 79, 78, 78, 82, 83, 80, 81, + 170, 171, 168, 169, 174, 175, 172, 173, 162, 163, 160, 161, 166, 167, 164, 165, + 185, 186, 183, 184, 189, 190, 187, 188, 177, 178, 175, 176, 181, 182, 179, 180, + 138, 139, 136, 137, 142, 143, 140, 141, 130, 131, 128, 129, 134, 135, 132, 133, + 154, 155, 152, 153, 158, 159, 156, 157, 146, 147, 144, 145, 150, 151, 148, 149, + 226, 227, 224, 225, 230, 231, 228, 229, 221, 221, 220, 220, 223, 223, 222, 222, + 244, 246, 240, 242, 252, 254, 248, 250, 234, 235, 232, 233, 238, 239, 236, 237, + 200, 201, 198, 199, 204, 205, 202, 203, 192, 193, 191, 191, 196, 197, 194, 195, + 214, 215, 212, 213, 218, 219, 216, 217, 207, 207, 206, 206, 210, 211, 208, 209 +}; + +SPAN_DECLARE(uint8_t) alaw_to_ulaw(uint8_t alaw) +{ + return alaw_to_ulaw_table[alaw]; +} +/*- End of function --------------------------------------------------------*/ + +SPAN_DECLARE(uint8_t) ulaw_to_alaw(uint8_t ulaw) +{ + return ulaw_to_alaw_table[ulaw]; +} +/*- End of function --------------------------------------------------------*/ + +SPAN_DECLARE(int) g711_decode(g711_state_t *s, + int16_t amp[], + const uint8_t g711_data[], + int g711_bytes) +{ + int i; + + if (s->mode == G711_ALAW) + { + for (i = 0; i < g711_bytes; i++) + amp[i] = alaw_to_linear(g711_data[i]); + /*endfor*/ + } + else + { + for (i = 0; i < g711_bytes; i++) + amp[i] = ulaw_to_linear(g711_data[i]); + /*endfor*/ + } + /*endif*/ + return g711_bytes; +} +/*- End of function --------------------------------------------------------*/ + +SPAN_DECLARE(int) g711_encode(g711_state_t *s, + uint8_t g711_data[], + const int16_t amp[], + int len) +{ + int i; + + if (s->mode == G711_ALAW) + { + for (i = 0; i < len; i++) + g711_data[i] = linear_to_alaw(amp[i]); + /*endfor*/ + } + else + { + for (i = 0; i < len; i++) + g711_data[i] = linear_to_ulaw(amp[i]); + /*endfor*/ + } + /*endif*/ + return len; +} +/*- End of function --------------------------------------------------------*/ + +SPAN_DECLARE(int) g711_transcode(g711_state_t *s, + uint8_t g711_out[], + const uint8_t g711_in[], + int g711_bytes) +{ + int i; + + if (s->mode == G711_ALAW) + { + for (i = 0; i < g711_bytes; i++) + g711_out[i] = alaw_to_ulaw_table[g711_in[i]]; + /*endfor*/ + } + else + { + for (i = 0; i < g711_bytes; i++) + g711_out[i] = ulaw_to_alaw_table[g711_in[i]]; + /*endfor*/ + } + /*endif*/ + return g711_bytes; +} +/*- End of function --------------------------------------------------------*/ + +SPAN_DECLARE(g711_state_t *) g711_init(g711_state_t *s, int mode) +{ + if (s == NULL) + { + if ((s = (g711_state_t *) malloc(sizeof(*s))) == NULL) + return NULL; + } + s->mode = mode; + return s; +} +/*- End of function --------------------------------------------------------*/ + +SPAN_DECLARE(int) g711_release(g711_state_t *s) +{ + return 0; +} +/*- End of function --------------------------------------------------------*/ + +SPAN_DECLARE(int) g711_free(g711_state_t *s) +{ + free(s); + return 0; +} +/*- End of function --------------------------------------------------------*/ +/*- End of file ------------------------------------------------------------*/