diff options
author | markster <markster@f38db490-d61c-443f-a65b-d21fe96a405b> | 2001-03-22 22:25:06 +0000 |
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committer | markster <markster@f38db490-d61c-443f-a65b-d21fe96a405b> | 2001-03-22 22:25:06 +0000 |
commit | f7f902ae13273469d523bb80c3f1e107ca0f1789 (patch) | |
tree | c967274e7368f940e08151d1815e6cf9d10a37ab /codecs/codec_adpcm.c | |
parent | ec2340452e7bf4f3a20cf964758b3e035606adbb (diff) |
Version 0.1.7 from FTP
git-svn-id: http://svn.digium.com/svn/asterisk/trunk@254 f38db490-d61c-443f-a65b-d21fe96a405b
Diffstat (limited to 'codecs/codec_adpcm.c')
-rwxr-xr-x | codecs/codec_adpcm.c | 545 |
1 files changed, 545 insertions, 0 deletions
diff --git a/codecs/codec_adpcm.c b/codecs/codec_adpcm.c new file mode 100755 index 000000000..cd1dfe83d --- /dev/null +++ b/codecs/codec_adpcm.c @@ -0,0 +1,545 @@ +/* codec_adpcm.c - translate between signed linear and Dialogic ADPCM + * + * Asterisk -- A telephony toolkit for Linux. + * + * Based on frompcm.c and topcm.c from the Emiliano MIPL browser/ + * interpreter. See http://www.bsdtelephony.com.mx + * + * Copyright (c) 2001 Linux Support Services, Inc. All rights reserved. + * + * Karl Sackett <krs@linux-support.net>, 2001-3-21 + * + * This program is free software, distributed under the terms of + * the GNU General Public License + */ + +#include <asterisk/logger.h> +#include <asterisk/module.h> +#include <asterisk/translate.h> +#include <fcntl.h> +#include <netinet/in.h> +#include <pthread.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +#define BUFFER_SIZE 8096 /* size for the translation buffers */ + +static pthread_mutex_t localuser_lock = PTHREAD_MUTEX_INITIALIZER; +static int localusecnt = 0; + +static char *tdesc = "Adaptive Differential PCM Coder/Decoder"; + +/* Sample frame data */ + +#include "slin_adpcm_ex.h" +#include "adpcm_slin_ex.h" + +/* + * Step size index shift table + */ + +static short indsft[8] = { -1, -1, -1, -1, 2, 4, 6, 8 }; + +/* + * Step size table, where stpsz[i]=floor[16*(11/10)^i] + */ + +static short stpsz[49] = { + 16, 17, 19, 21, 23, 25, 28, 31, 34, 37, 41, 45, 50, 55, 60, 66, 73, + 80, 88, 97, 107, 118, 130, 143, 157, 173, 190, 209, 230, 253, 279, + 307, 337, 371, 408, 449, 494, 544, 598, 658, 724, 796, 876, 963, + 1060, 1166, 1282, 1411, 1552 +}; + +/* + * Nibble to bit map + */ + +static short nbl2bit[16][4] = { + {1, 0, 0, 0}, {1, 0, 0, 1}, {1, 0, 1, 0}, {1, 0, 1, 1}, + {1, 1, 0, 0}, {1, 1, 0, 1}, {1, 1, 1, 0}, {1, 1, 1, 1}, + {-1, 0, 0, 0}, {-1, 0, 0, 1}, {-1, 0, 1, 0}, {-1, 0, 1, 1}, + {-1, 1, 0, 0}, {-1, 1, 0, 1}, {-1, 1, 1, 0}, {-1, 1, 1, 1} +}; + +/* + * Decode(encoded) + * Decodes the encoded nibble from the adpcm file. + * + * Results: + * Returns the encoded difference. + * + * Side effects: + * Sets the index to the step size table for the next encode. + */ + +static inline short +decode (unsigned char encoded, short *ssindex) +{ + short diff, step; + step = stpsz[*ssindex]; + diff = nbl2bit[encoded][0] * (step * nbl2bit[encoded][1] + + (step >> 1) * nbl2bit[encoded][2] + + (step >> 2) * nbl2bit[encoded][3] + + (step >> 3)); + *ssindex = *ssindex + indsft[(encoded & 7)]; + if (*ssindex < 0) + *ssindex = 0; + else if (*ssindex > 48) + *ssindex = 48; + return (diff); +} + +/* + * Adpcm + * Takes a signed linear signal and encodes it as ADPCM + * For more information see http://support.dialogic.com/appnotes/adpcm.pdf + * + * Results: + * Foo. + * + * Side effects: + * signal gets updated with each pass. + */ + +static inline unsigned char +adpcm (short csig, short *ssindex, short *signal) +{ + short diff, step; + unsigned char encoded; + step = stpsz[*ssindex]; + /* + * Clip csig if too large or too small + */ + + csig >>= 4; + + diff = csig - *signal; + + if (diff < 0) + { + encoded = 8; + diff = -diff; + } + else + encoded = 0; + if (diff >= step) + { + encoded |= 4; + diff -= step; + } + step >>= 1; + if (diff >= step) + { + encoded |= 2; + diff -= step; + } + step >>= 1; + if (diff >= step) + encoded |= 1; + + *signal += decode (encoded, ssindex); + return (encoded); +} + +/* + * Private workspace for translating signed linear signals to ADPCM. + */ + +struct adpcm_encoder_pvt +{ + struct ast_frame f; + char offset[AST_FRIENDLY_OFFSET]; /* Space to build offset */ + short inbuf[BUFFER_SIZE]; /* Unencoded signed linear values */ + unsigned char outbuf[BUFFER_SIZE]; /* Encoded ADPCM, two nibbles to a word */ + short ssindex; + short signal; + int tail; +}; + +/* + * Private workspace for translating ADPCM signals to signed linear. + */ + +struct adpcm_decoder_pvt +{ + struct ast_frame f; + char offset[AST_FRIENDLY_OFFSET]; /* Space to build offset */ + short outbuf[BUFFER_SIZE]; /* Decoded signed linear values */ + int tail; +}; + +/* + * AdpcmToLin_New + * Create a new instance of adpcm_decoder_pvt. + * + * Results: + * Returns a pointer to the new instance. + * + * Side effects: + * None. + */ + +static struct ast_translator_pvt * +adpcmtolin_new () +{ + struct adpcm_decoder_pvt *tmp; + tmp = malloc (sizeof (struct adpcm_decoder_pvt)); + if (tmp) + { + memset(tmp, 0, sizeof(*tmp)); + tmp->tail = 0; + localusecnt++; + ast_update_use_count (); + } + return (struct ast_translator_pvt *) tmp; +} + +/* + * LinToAdpcm_New + * Create a new instance of adpcm_encoder_pvt. + * + * Results: + * Returns a pointer to the new instance. + * + * Side effects: + * None. + */ + +static struct ast_translator_pvt * +lintoadpcm_new () +{ + struct adpcm_encoder_pvt *tmp; + tmp = malloc (sizeof (struct adpcm_encoder_pvt)); + if (tmp) + { + memset(tmp, 0, sizeof(*tmp)); + localusecnt++; + ast_update_use_count (); + tmp->tail = 0; + } + return (struct ast_translator_pvt *) tmp; +} + +/* + * AdpcmToLin_FrameIn + * Fill an input buffer with packed 4-bit ADPCM values if there is room + * left. + * + * Results: + * Foo + * + * Side effects: + * tmp->tail is the number of packed values in the buffer. + */ + +static int +adpcmtolin_framein (struct ast_translator_pvt *pvt, struct ast_frame *f) +{ + struct adpcm_decoder_pvt *tmp = (struct adpcm_decoder_pvt *) pvt; + int x; + short signal; + short ssindex; + unsigned char *b; + + if (f->datalen < 3) { + ast_log(LOG_WARNING, "Didn't have at least three bytes of input\n"); + return -1; + } + + if ((f->datalen - 3) * 4 > sizeof(tmp->outbuf)) { + ast_log(LOG_WARNING, "Out of buffer space\n"); + return -1; + } + + /* Reset ssindex and signal to frame's specified values */ + b = f->data; + ssindex = b[0]; + if (ssindex < 0) + ssindex = 0; + if (ssindex > 48) + ssindex = 48; + + signal = (b[1] << 8) | b[2]; + + for (x=3;x<f->datalen;x++) { + signal += decode(b[x] >> 4, &ssindex); + if (signal > 2047) + signal = 2047; + if (signal < -2048) + signal = -2048; + tmp->outbuf[tmp->tail++] = signal << 4; + signal += decode(b[x] & 0x0f, &ssindex); + if (signal > 2047) + signal = 2047; + if (signal < -2048) + signal = -2048; + tmp->outbuf[tmp->tail++] = signal << 4; + } + + return 0; +} + +/* + * AdpcmToLin_FrameOut + * Convert 4-bit ADPCM encoded signals to 16-bit signed linear. + * + * Results: + * Converted signals are placed in tmp->f.data, tmp->f.datalen + * and tmp->f.timelen are calculated. + * + * Side effects: + * None. + */ + +static struct ast_frame * +adpcmtolin_frameout (struct ast_translator_pvt *pvt) +{ + struct adpcm_decoder_pvt *tmp = (struct adpcm_decoder_pvt *) pvt; + + if (!tmp->tail) + return NULL; + + tmp->f.frametype = AST_FRAME_VOICE; + tmp->f.subclass = AST_FORMAT_SLINEAR; + tmp->f.datalen = tmp->tail *2; + tmp->f.timelen = tmp->tail / 8; + tmp->f.mallocd = 0; + tmp->f.offset = AST_FRIENDLY_OFFSET; + tmp->f.src = __PRETTY_FUNCTION__; + tmp->f.data = tmp->outbuf; + tmp->tail = 0; + return &tmp->f; +} + +/* + * LinToAdpcm_FrameIn + * Fill an input buffer with 16-bit signed linear PCM values. + * + * Results: + * None. + * + * Side effects: + * tmp->tail is number of signal values in the input buffer. + */ + +static int +lintoadpcm_framein (struct ast_translator_pvt *pvt, struct ast_frame *f) +{ + struct adpcm_encoder_pvt *tmp = (struct adpcm_encoder_pvt *) pvt; + + if ((tmp->tail + f->datalen / 2) < (sizeof (tmp->inbuf) / 2)) + { + memcpy (&tmp->inbuf[tmp->tail], f->data, f->datalen); + tmp->tail += f->datalen / 2; + } + else + { + ast_log (LOG_WARNING, "Out of buffer space\n"); + return -1; + } + return 0; +} + +/* + * LinToAdpcm_FrameOut + * Convert a buffer of raw 16-bit signed linear PCM to a buffer + * of 4-bit ADPCM packed two to a byte (Big Endian). + * + * Results: + * Foo + * + * Side effects: + * Leftover inbuf data gets packed, tail gets updated. + */ + +static struct ast_frame * +lintoadpcm_frameout (struct ast_translator_pvt *pvt) +{ + struct adpcm_encoder_pvt *tmp = (struct adpcm_encoder_pvt *) pvt; + unsigned char adpcm0, adpcm1; + int i_max, i; + + if (tmp->tail < 2) return NULL; + + + i_max = (tmp->tail / 2) * 2; + + tmp->outbuf[0] = tmp->ssindex & 0xff; + tmp->outbuf[1] = (tmp->signal >> 8) & 0xff; + tmp->outbuf[2] = (tmp->signal & 0xff); + + for (i = 0; i < i_max; i+=2) + { + adpcm0 = adpcm(tmp->inbuf[i], &tmp->ssindex, &tmp->signal); + adpcm1 = adpcm(tmp->inbuf[i+1], &tmp->ssindex, &tmp->signal); + tmp->outbuf[i/2 + 3] = (adpcm0 << 4) | adpcm1; + }; + + + tmp->f.frametype = AST_FRAME_VOICE; + tmp->f.subclass = AST_FORMAT_ADPCM; + tmp->f.timelen = i_max / 8; + tmp->f.mallocd = 0; + tmp->f.offset = AST_FRIENDLY_OFFSET; + tmp->f.src = __PRETTY_FUNCTION__; + tmp->f.data = tmp->outbuf; + tmp->f.datalen = i_max / 2 + 3; + + /* + * If there is a signal left over (there should be no more than + * one) move it to the beginning of the input buffer. + */ + + if (tmp->tail == i_max) + tmp->tail = 0; + else + { + tmp->inbuf[0] = tmp->inbuf[tmp->tail]; + tmp->tail = 1; + } + return &tmp->f; +} + + +/* + * AdpcmToLin_Sample + */ + +static struct ast_frame * +adpcmtolin_sample () +{ + static struct ast_frame f; + f.frametype = AST_FRAME_VOICE; + f.subclass = AST_FORMAT_ADPCM; + f.datalen = sizeof (adpcm_slin_ex); + f.timelen = sizeof(adpcm_slin_ex) / 4; + f.mallocd = 0; + f.offset = 0; + f.src = __PRETTY_FUNCTION__; + f.data = adpcm_slin_ex; + return &f; +} + +/* + * LinToAdpcm_Sample + */ + +static struct ast_frame * +lintoadpcm_sample () +{ + static struct ast_frame f; + f.frametype = AST_FRAME_VOICE; + f.subclass = AST_FORMAT_SLINEAR; + f.datalen = sizeof (slin_adpcm_ex); + /* Assume 8000 Hz */ + f.timelen = sizeof (slin_adpcm_ex) / 16; + f.mallocd = 0; + f.offset = 0; + f.src = __PRETTY_FUNCTION__; + f.data = slin_adpcm_ex; + return &f; +} + +/* + * Adpcm_Destroy + * Destroys a private workspace. + * + * Results: + * It's gone! + * + * Side effects: + * None. + */ + +static void +adpcm_destroy (struct ast_translator_pvt *pvt) +{ + free (pvt); + localusecnt--; + ast_update_use_count (); +} + +/* + * The complete translator for ADPCMToLin. + */ + +static struct ast_translator adpcmtolin = { + "adpcmtolin", + AST_FORMAT_ADPCM, + AST_FORMAT_SLINEAR, + adpcmtolin_new, + adpcmtolin_framein, + adpcmtolin_frameout, + adpcm_destroy, + /* NULL */ + adpcmtolin_sample +}; + +/* + * The complete translator for LinToADPCM. + */ + +static struct ast_translator lintoadpcm = { + "lintoadpcm", + AST_FORMAT_SLINEAR, + AST_FORMAT_ADPCM, + lintoadpcm_new, + lintoadpcm_framein, + lintoadpcm_frameout, + adpcm_destroy, + /* NULL */ + lintoadpcm_sample +}; + +int +unload_module (void) +{ + int res; + pthread_mutex_lock (&localuser_lock); + res = ast_unregister_translator (&lintoadpcm); + if (!res) + res = ast_unregister_translator (&adpcmtolin); + if (localusecnt) + res = -1; + pthread_mutex_unlock (&localuser_lock); + return res; +} + +int +load_module (void) +{ + int res; + res = ast_register_translator (&adpcmtolin); + if (!res) + res = ast_register_translator (&lintoadpcm); + else + ast_unregister_translator (&adpcmtolin); + return res; +} + +/* + * 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; +} |