diff options
Diffstat (limited to 'trunk/codecs/codec_alaw.c')
| -rw-r--r-- | trunk/codecs/codec_alaw.c | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/trunk/codecs/codec_alaw.c b/trunk/codecs/codec_alaw.c new file mode 100644 index 000000000..ba5808f78 --- /dev/null +++ b/trunk/codecs/codec_alaw.c @@ -0,0 +1,184 @@ +/* + * Asterisk -- An open source telephony toolkit. + * + * Copyright (C) 1999 - 2005, Digium, Inc. + * + * Mark Spencer <markster@digium.com> + * + * See http://www.asterisk.org for more information about + * the Asterisk project. Please do not directly contact + * any of the maintainers of this project for assistance; + * the project provides a web site, mailing lists and IRC + * channels for your use. + * + * This program is free software, distributed under the terms of + * the GNU General Public License Version 2. See the LICENSE file + * at the top of the source tree. + */ + +/*! \file + * + * \brief codec_alaw.c - translate between signed linear and alaw + * + * \ingroup codecs + */ + +#include "asterisk.h" + +ASTERISK_FILE_VERSION(__FILE__, "$Revision$") + +#include "asterisk/module.h" +#include "asterisk/config.h" +#include "asterisk/translate.h" +#include "asterisk/alaw.h" +#include "asterisk/utils.h" + +#define BUFFER_SAMPLES 8096 /* size for the translation buffers */ + +/* Sample frame data (Mu data is okay) */ + +#include "slin_ulaw_ex.h" +#include "ulaw_slin_ex.h" + +/*! \brief decode frame into lin and fill output buffer. */ +static int alawtolin_framein(struct ast_trans_pvt *pvt, struct ast_frame *f) +{ + int i = f->samples; + unsigned char *src = f->data; + int16_t *dst = (int16_t *)pvt->outbuf + pvt->samples; + + pvt->samples += i; + pvt->datalen += i * 2; /* 2 bytes/sample */ + + while (i--) + *dst++ = AST_ALAW(*src++); + + return 0; +} + +/*! \brief convert and store input samples in output buffer */ +static int lintoalaw_framein(struct ast_trans_pvt *pvt, struct ast_frame *f) +{ + int i = f->samples; + char *dst = pvt->outbuf + pvt->samples; + int16_t *src = f->data; + + pvt->samples += i; + pvt->datalen += i; /* 1 byte/sample */ + + while (i--) + *dst++ = AST_LIN2A(*src++); + + return 0; +} + +/*! \brief alawToLin_Sample */ +static struct ast_frame *alawtolin_sample(void) +{ + static struct ast_frame f; + f.frametype = AST_FRAME_VOICE; + f.subclass = AST_FORMAT_ALAW; + f.datalen = sizeof(ulaw_slin_ex); + f.samples = sizeof(ulaw_slin_ex); + f.mallocd = 0; + f.offset = 0; + f.src = __PRETTY_FUNCTION__; + f.data = ulaw_slin_ex; + return &f; +} + +/*! \brief LinToalaw_Sample */ +static struct ast_frame *lintoalaw_sample(void) +{ + static struct ast_frame f; + f.frametype = AST_FRAME_VOICE; + f.subclass = AST_FORMAT_SLINEAR; + f.datalen = sizeof(slin_ulaw_ex); + f.samples = sizeof(slin_ulaw_ex) / 2; + f.mallocd = 0; + f.offset = 0; + f.src = __PRETTY_FUNCTION__; + f.data = slin_ulaw_ex; + return &f; +} + +static struct ast_translator alawtolin = { + .name = "alawtolin", + .srcfmt = AST_FORMAT_ALAW, + .dstfmt = AST_FORMAT_SLINEAR, + .framein = alawtolin_framein, + .sample = alawtolin_sample, + .buffer_samples = BUFFER_SAMPLES, + .buf_size = BUFFER_SAMPLES * 2, + .plc_samples = 160, +}; + +static struct ast_translator lintoalaw = { + "lintoalaw", + .srcfmt = AST_FORMAT_SLINEAR, + .dstfmt = AST_FORMAT_ALAW, + .framein = lintoalaw_framein, + .sample = lintoalaw_sample, + .buffer_samples = BUFFER_SAMPLES, + .buf_size = BUFFER_SAMPLES, +}; + +static int parse_config(int reload) +{ + struct ast_variable *var; + struct ast_flags config_flags = { reload ? CONFIG_FLAG_FILEUNCHANGED : 0 }; + struct ast_config *cfg = ast_config_load("codecs.conf", config_flags); + if (cfg == NULL) + return 0; + if (cfg == CONFIG_STATUS_FILEUNCHANGED) + return 0; + for (var = ast_variable_browse(cfg, "plc"); var; var = var->next) { + if (!strcasecmp(var->name, "genericplc")) { + alawtolin.useplc = ast_true(var->value) ? 1 : 0; + ast_verb(3, "codec_alaw: %susing generic PLC\n", alawtolin.useplc ? "" : "not "); + } + } + ast_config_destroy(cfg); + return 0; +} + +/*! \brief standard module stuff */ + +static int reload(void) +{ + if (parse_config(1)) + return AST_MODULE_LOAD_DECLINE; + return AST_MODULE_LOAD_SUCCESS; +} + +static int unload_module(void) +{ + int res; + + res = ast_unregister_translator(&lintoalaw); + res |= ast_unregister_translator(&alawtolin); + + return res; +} + +static int load_module(void) +{ + int res; + + if (parse_config(0)) + return AST_MODULE_LOAD_DECLINE; + res = ast_register_translator(&alawtolin); + if (!res) + res = ast_register_translator(&lintoalaw); + else + ast_unregister_translator(&alawtolin); + if (res) + return AST_MODULE_LOAD_FAILURE; + return AST_MODULE_LOAD_SUCCESS; +} + +AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_DEFAULT, "A-law Coder/Decoder", + .load = load_module, + .unload = unload_module, + .reload = reload, + ); |