579 lines
12 KiB
C
Executable File
579 lines
12 KiB
C
Executable File
/* codec_adpcm.c - translate between signed linear and Dialogic ADPCM
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*
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* Asterisk -- A telephony toolkit for Linux.
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*
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* Based on frompcm.c and topcm.c from the Emiliano MIPL browser/
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* interpreter. See http://www.bsdtelephony.com.mx
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*
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* Copyright (c) 2001 Linux Support Services, Inc. All rights reserved.
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*
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* Karl Sackett <krs@linux-support.net>, 2001-3-21
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*
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* This program is free software, distributed under the terms of
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* the GNU General Public License
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*/
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#include <asterisk/lock.h>
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#include <asterisk/logger.h>
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#include <asterisk/module.h>
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#include <asterisk/translate.h>
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#include <asterisk/channel.h>
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#include <fcntl.h>
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#include <netinet/in.h>
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#include <pthread.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#define BUFFER_SIZE 8096 /* size for the translation buffers */
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#define BUF_SHIFT 5
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static ast_mutex_t localuser_lock = AST_MUTEX_INITIALIZER;
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static int localusecnt = 0;
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static char *tdesc = "Adaptive Differential PCM Coder/Decoder";
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/* Sample frame data */
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#include "slin_adpcm_ex.h"
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#include "adpcm_slin_ex.h"
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/*
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* Step size index shift table
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*/
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static short indsft[8] = { -1, -1, -1, -1, 2, 4, 6, 8 };
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/*
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* Step size table, where stpsz[i]=floor[16*(11/10)^i]
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*/
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static short stpsz[49] = {
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16, 17, 19, 21, 23, 25, 28, 31, 34, 37, 41, 45, 50, 55, 60, 66, 73,
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80, 88, 97, 107, 118, 130, 143, 157, 173, 190, 209, 230, 253, 279,
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307, 337, 371, 408, 449, 494, 544, 598, 658, 724, 796, 876, 963,
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1060, 1166, 1282, 1411, 1552
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};
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/*
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* Nibble to bit map
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*/
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static short nbl2bit[16][4] = {
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{1, 0, 0, 0}, {1, 0, 0, 1}, {1, 0, 1, 0}, {1, 0, 1, 1},
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{1, 1, 0, 0}, {1, 1, 0, 1}, {1, 1, 1, 0}, {1, 1, 1, 1},
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{-1, 0, 0, 0}, {-1, 0, 0, 1}, {-1, 0, 1, 0}, {-1, 0, 1, 1},
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{-1, 1, 0, 0}, {-1, 1, 0, 1}, {-1, 1, 1, 0}, {-1, 1, 1, 1}
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};
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/*
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* Decode(encoded)
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* Decodes the encoded nibble from the adpcm file.
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*
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* Results:
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* Returns the encoded difference.
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*
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* Side effects:
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* Sets the index to the step size table for the next encode.
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*/
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static inline void
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decode (unsigned char encoded, short *ssindex, short *signal, unsigned char *rkey, unsigned char *next)
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{
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short diff, step;
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step = stpsz[*ssindex];
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diff = step * nbl2bit[encoded][1] +
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(step >> 1) * nbl2bit[encoded][2] +
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(step >> 2) * nbl2bit[encoded][3] +
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(step >> 3);
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if (nbl2bit[encoded][2] && (step & 0x1))
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diff++;
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diff *= nbl2bit[encoded][0];
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if ( *next & 0x1 )
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*signal -= 8;
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else if ( *next & 0x2 )
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*signal += 8;
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*signal += diff;
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if (*signal > 2047)
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*signal = 2047;
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else if (*signal < -2047)
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*signal = -2047;
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*next = 0;
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if( encoded & 0x7 )
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*rkey = 0;
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else if ( ++(*rkey) == 24 ) {
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*rkey = 0;
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if (*signal > 0)
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*next = 0x1;
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else if (*signal < 0)
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*next = 0x2;
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}
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*ssindex = *ssindex + indsft[(encoded & 7)];
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if (*ssindex < 0)
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*ssindex = 0;
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else if (*ssindex > 48)
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*ssindex = 48;
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}
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/*
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* Adpcm
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* Takes a signed linear signal and encodes it as ADPCM
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* For more information see http://support.dialogic.com/appnotes/adpcm.pdf
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*
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* Results:
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* Foo.
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*
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* Side effects:
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* signal gets updated with each pass.
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*/
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static inline unsigned char
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adpcm (short csig, short *ssindex, short *signal, unsigned char *rkey, unsigned char *next)
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{
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short diff, step;
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unsigned char encoded;
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step = stpsz[*ssindex];
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/*
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* Clip csig if too large or too small
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*/
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csig >>= 4;
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diff = csig - *signal;
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if (diff < 0)
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{
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encoded = 8;
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diff = -diff;
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}
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else
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encoded = 0;
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if (diff >= step)
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{
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encoded |= 4;
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diff -= step;
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}
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step >>= 1;
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if (diff >= step)
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{
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encoded |= 2;
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diff -= step;
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}
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step >>= 1;
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if (diff >= step)
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encoded |= 1;
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decode (encoded, ssindex, signal, rkey, next);
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return (encoded);
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}
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/*
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* Private workspace for translating signed linear signals to ADPCM.
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*/
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struct adpcm_encoder_pvt
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{
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struct ast_frame f;
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char offset[AST_FRIENDLY_OFFSET]; /* Space to build offset */
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short inbuf[BUFFER_SIZE]; /* Unencoded signed linear values */
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unsigned char outbuf[BUFFER_SIZE]; /* Encoded ADPCM, two nibbles to a word */
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short ssindex;
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short signal;
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unsigned char zero_count;
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unsigned char next_flag;
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int tail;
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};
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/*
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* Private workspace for translating ADPCM signals to signed linear.
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*/
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struct adpcm_decoder_pvt
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{
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struct ast_frame f;
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char offset[AST_FRIENDLY_OFFSET]; /* Space to build offset */
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short outbuf[BUFFER_SIZE]; /* Decoded signed linear values */
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int tail;
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};
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/*
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* AdpcmToLin_New
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* Create a new instance of adpcm_decoder_pvt.
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*
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* Results:
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* Returns a pointer to the new instance.
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*
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* Side effects:
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* None.
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*/
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static struct ast_translator_pvt *
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adpcmtolin_new (void)
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{
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struct adpcm_decoder_pvt *tmp;
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tmp = malloc (sizeof (struct adpcm_decoder_pvt));
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if (tmp)
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{
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memset(tmp, 0, sizeof(*tmp));
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tmp->tail = 0;
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localusecnt++;
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ast_update_use_count ();
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}
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return (struct ast_translator_pvt *) tmp;
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}
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/*
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* LinToAdpcm_New
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* Create a new instance of adpcm_encoder_pvt.
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*
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* Results:
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* Returns a pointer to the new instance.
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*
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* Side effects:
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* None.
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*/
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static struct ast_translator_pvt *
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lintoadpcm_new (void)
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{
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struct adpcm_encoder_pvt *tmp;
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tmp = malloc (sizeof (struct adpcm_encoder_pvt));
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if (tmp)
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{
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memset(tmp, 0, sizeof(*tmp));
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localusecnt++;
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ast_update_use_count ();
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tmp->tail = 0;
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}
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return (struct ast_translator_pvt *) tmp;
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}
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/*
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* AdpcmToLin_FrameIn
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* Fill an input buffer with packed 4-bit ADPCM values if there is room
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* left.
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*
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* Results:
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* Foo
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*
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* Side effects:
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* tmp->tail is the number of packed values in the buffer.
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*/
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static int
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adpcmtolin_framein (struct ast_translator_pvt *pvt, struct ast_frame *f)
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{
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struct adpcm_decoder_pvt *tmp = (struct adpcm_decoder_pvt *) pvt;
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int x;
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short signal;
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short ssindex;
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unsigned char *b;
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unsigned char zero_count;
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unsigned char next_flag;
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if (f->datalen < BUF_SHIFT) {
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ast_log(LOG_WARNING, "Didn't have at least %d bytes of input\n", BUF_SHIFT);
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return -1;
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}
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if ((f->datalen - BUF_SHIFT) * 4 > sizeof(tmp->outbuf)) {
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ast_log(LOG_WARNING, "Out of buffer space\n");
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return -1;
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}
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/* Reset ssindex and signal to frame's specified values */
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b = f->data;
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ssindex = b[0];
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if (ssindex < 0)
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ssindex = 0;
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if (ssindex > 48)
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ssindex = 48;
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signal = (b[1] << 8) | b[2];
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zero_count = b[3];
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next_flag = b[4];
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for (x=BUF_SHIFT;x<f->datalen;x++) {
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decode((b[x] >> 4) & 0xf, &ssindex, &signal, &zero_count, &next_flag);
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tmp->outbuf[tmp->tail++] = signal << 4;
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decode(b[x] & 0x0f, &ssindex, &signal, &zero_count, &next_flag);
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tmp->outbuf[tmp->tail++] = signal << 4;
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}
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return 0;
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}
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/*
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* AdpcmToLin_FrameOut
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* Convert 4-bit ADPCM encoded signals to 16-bit signed linear.
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*
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* Results:
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* Converted signals are placed in tmp->f.data, tmp->f.datalen
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* and tmp->f.samples are calculated.
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*
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* Side effects:
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* None.
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*/
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static struct ast_frame *
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adpcmtolin_frameout (struct ast_translator_pvt *pvt)
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{
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struct adpcm_decoder_pvt *tmp = (struct adpcm_decoder_pvt *) pvt;
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if (!tmp->tail)
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return NULL;
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tmp->f.frametype = AST_FRAME_VOICE;
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tmp->f.subclass = AST_FORMAT_SLINEAR;
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tmp->f.datalen = tmp->tail *2;
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tmp->f.samples = tmp->tail;
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tmp->f.mallocd = 0;
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tmp->f.offset = AST_FRIENDLY_OFFSET;
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tmp->f.src = __PRETTY_FUNCTION__;
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tmp->f.data = tmp->outbuf;
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tmp->tail = 0;
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return &tmp->f;
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}
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/*
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* LinToAdpcm_FrameIn
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* Fill an input buffer with 16-bit signed linear PCM values.
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*
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* Results:
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* None.
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*
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* Side effects:
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* tmp->tail is number of signal values in the input buffer.
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*/
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static int
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lintoadpcm_framein (struct ast_translator_pvt *pvt, struct ast_frame *f)
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{
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struct adpcm_encoder_pvt *tmp = (struct adpcm_encoder_pvt *) pvt;
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if ((tmp->tail + f->datalen / 2) < (sizeof (tmp->inbuf) / 2))
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{
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memcpy (&tmp->inbuf[tmp->tail], f->data, f->datalen);
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tmp->tail += f->datalen / 2;
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}
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else
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{
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ast_log (LOG_WARNING, "Out of buffer space\n");
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return -1;
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}
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return 0;
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}
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/*
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* LinToAdpcm_FrameOut
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* Convert a buffer of raw 16-bit signed linear PCM to a buffer
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* of 4-bit ADPCM packed two to a byte (Big Endian).
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*
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* Results:
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* Foo
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*
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* Side effects:
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* Leftover inbuf data gets packed, tail gets updated.
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*/
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static struct ast_frame *
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lintoadpcm_frameout (struct ast_translator_pvt *pvt)
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{
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struct adpcm_encoder_pvt *tmp = (struct adpcm_encoder_pvt *) pvt;
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unsigned char adpcm0, adpcm1;
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int i_max, i;
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if (tmp->tail < 2) return NULL;
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i_max = (tmp->tail / 2) * 2;
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tmp->outbuf[0] = tmp->ssindex & 0xff;
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tmp->outbuf[1] = (tmp->signal >> 8) & 0xff;
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tmp->outbuf[2] = (tmp->signal & 0xff);
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tmp->outbuf[3] = tmp->zero_count;
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tmp->outbuf[4] = tmp->next_flag;
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for (i = 0; i < i_max; i+=2)
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{
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adpcm0 = adpcm (tmp->inbuf[i], &tmp->ssindex, &tmp->signal, &tmp->zero_count, &tmp->next_flag);
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adpcm1 = adpcm (tmp->inbuf[i+1], &tmp->ssindex, &tmp->signal, &tmp->zero_count, &tmp->next_flag);
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tmp->outbuf[i/2 + BUF_SHIFT] = (adpcm0 << 4) | adpcm1;
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};
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tmp->f.frametype = AST_FRAME_VOICE;
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tmp->f.subclass = AST_FORMAT_ADPCM;
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tmp->f.samples = i_max;
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tmp->f.mallocd = 0;
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tmp->f.offset = AST_FRIENDLY_OFFSET;
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tmp->f.src = __PRETTY_FUNCTION__;
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tmp->f.data = tmp->outbuf;
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tmp->f.datalen = i_max / 2 + BUF_SHIFT;
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/*
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* If there is a signal left over (there should be no more than
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* one) move it to the beginning of the input buffer.
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*/
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if (tmp->tail == i_max)
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tmp->tail = 0;
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else
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{
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tmp->inbuf[0] = tmp->inbuf[tmp->tail];
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tmp->tail = 1;
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}
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return &tmp->f;
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}
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/*
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* AdpcmToLin_Sample
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*/
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static struct ast_frame *
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adpcmtolin_sample (void)
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{
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static struct ast_frame f;
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f.frametype = AST_FRAME_VOICE;
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f.subclass = AST_FORMAT_ADPCM;
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f.datalen = sizeof (adpcm_slin_ex);
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f.samples = sizeof(adpcm_slin_ex) * 2;
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f.mallocd = 0;
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f.offset = 0;
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f.src = __PRETTY_FUNCTION__;
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f.data = adpcm_slin_ex;
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return &f;
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}
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/*
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* LinToAdpcm_Sample
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*/
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static struct ast_frame *
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lintoadpcm_sample (void)
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{
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static struct ast_frame f;
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f.frametype = AST_FRAME_VOICE;
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f.subclass = AST_FORMAT_SLINEAR;
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f.datalen = sizeof (slin_adpcm_ex);
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/* Assume 8000 Hz */
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f.samples = sizeof (slin_adpcm_ex) / 2;
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f.mallocd = 0;
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f.offset = 0;
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f.src = __PRETTY_FUNCTION__;
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f.data = slin_adpcm_ex;
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return &f;
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}
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|
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/*
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* Adpcm_Destroy
|
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* Destroys a private workspace.
|
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*
|
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* Results:
|
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* It's gone!
|
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*
|
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* Side effects:
|
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* None.
|
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*/
|
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|
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static void
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adpcm_destroy (struct ast_translator_pvt *pvt)
|
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{
|
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free (pvt);
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localusecnt--;
|
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ast_update_use_count ();
|
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}
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|
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/*
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* The complete translator for ADPCMToLin.
|
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*/
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|
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static struct ast_translator adpcmtolin = {
|
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"adpcmtolin",
|
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AST_FORMAT_ADPCM,
|
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AST_FORMAT_SLINEAR,
|
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adpcmtolin_new,
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adpcmtolin_framein,
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adpcmtolin_frameout,
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adpcm_destroy,
|
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/* NULL */
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adpcmtolin_sample
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};
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|
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/*
|
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* The complete translator for LinToADPCM.
|
|
*/
|
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|
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static struct ast_translator lintoadpcm = {
|
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"lintoadpcm",
|
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AST_FORMAT_SLINEAR,
|
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AST_FORMAT_ADPCM,
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lintoadpcm_new,
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lintoadpcm_framein,
|
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lintoadpcm_frameout,
|
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adpcm_destroy,
|
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/* NULL */
|
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lintoadpcm_sample
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};
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|
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int
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unload_module (void)
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{
|
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int res;
|
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ast_mutex_lock (&localuser_lock);
|
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res = ast_unregister_translator (&lintoadpcm);
|
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if (!res)
|
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res = ast_unregister_translator (&adpcmtolin);
|
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if (localusecnt)
|
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res = -1;
|
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ast_mutex_unlock (&localuser_lock);
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return res;
|
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}
|
|
|
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int
|
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load_module (void)
|
|
{
|
|
int res;
|
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res = ast_register_translator (&adpcmtolin);
|
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if (!res)
|
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res = ast_register_translator (&lintoadpcm);
|
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else
|
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ast_unregister_translator (&adpcmtolin);
|
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return res;
|
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}
|
|
|
|
/*
|
|
* Return a description of this module.
|
|
*/
|
|
|
|
char *
|
|
description (void)
|
|
{
|
|
return tdesc;
|
|
}
|
|
|
|
int
|
|
usecount (void)
|
|
{
|
|
int res;
|
|
STANDARD_USECOUNT (res);
|
|
return res;
|
|
}
|
|
|
|
char *
|
|
key ()
|
|
{
|
|
return ASTERISK_GPL_KEY;
|
|
}
|