134 lines
3.5 KiB
C
134 lines
3.5 KiB
C
/*
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* Asterisk -- An open source telephony toolkit.
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*
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* Copyright (C) 2014, Digium, Inc.
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*
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* Joshua Colp <jcolp@digium.com>
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*
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* See http://www.asterisk.org for more information about
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* the Asterisk project. Please do not directly contact
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* any of the maintainers of this project for assistance;
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* the project provides a web site, mailing lists and IRC
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* channels for your use.
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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 Version 2. See the LICENSE file
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* at the top of the source tree.
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*/
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/*! \file
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*
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* \brief Media Format Bitfield Compatibility API
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*
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* \author Joshua Colp <jcolp@digium.com>
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*/
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/*** MODULEINFO
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<support_level>core</support_level>
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***/
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#include "asterisk.h"
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#include "asterisk/logger.h"
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#include "asterisk/astobj2.h"
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#include "asterisk/codec.h"
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#include "asterisk/format.h"
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#include "asterisk/format_compatibility.h"
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#include "asterisk/format_cache.h"
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#include "asterisk/format_cap.h"
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#include "asterisk/utils.h"
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#include "include/format_compatibility.h"
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uint64_t iax2_format_compatibility_cap2bitfield(const struct ast_format_cap *cap)
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{
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uint64_t bitfield = 0;
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int x;
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for (x = 0; x < ast_format_cap_count(cap); x++) {
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struct ast_format *format = ast_format_cap_get_format(cap, x);
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bitfield |= ast_format_compatibility_format2bitfield(format);
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ao2_ref(format, -1);
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}
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return bitfield;
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}
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int iax2_format_compatibility_bitfield2cap(uint64_t bitfield, struct ast_format_cap *cap)
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{
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int bit;
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for (bit = 0; bit < 64; ++bit) {
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uint64_t mask = (1ULL << bit);
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if (mask & bitfield) {
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struct ast_format *format;
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format = ast_format_compatibility_bitfield2format(mask);
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if (format && ast_format_cap_append(cap, format, 0)) {
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return -1;
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}
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}
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}
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return 0;
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}
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uint64_t iax2_format_compatibility_best(uint64_t formats)
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{
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/*
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* This just our opinion, expressed in code. We are
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* asked to choose the best codec to use, given no
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* information.
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*/
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static const uint64_t best[] = {
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/*! Okay, ulaw is used by all telephony equipment, so start with it */
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AST_FORMAT_ULAW,
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/*! Unless of course, you're a silly European, so then prefer ALAW */
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AST_FORMAT_ALAW,
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AST_FORMAT_G719,
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AST_FORMAT_SIREN14,
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AST_FORMAT_SIREN7,
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/*! G.722 is better then all below, but not as common as the above... so give ulaw and alaw priority */
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AST_FORMAT_G722,
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/*! Okay, well, signed linear is easy to translate into other stuff */
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AST_FORMAT_SLIN16,
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AST_FORMAT_SLIN,
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/*! G.726 is standard ADPCM, in RFC3551 packing order */
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AST_FORMAT_G726,
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/*! G.726 is standard ADPCM, in AAL2 packing order */
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AST_FORMAT_G726_AAL2,
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/*! ADPCM has great sound quality and is still pretty easy to translate */
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AST_FORMAT_ADPCM,
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/*! Okay, we're down to vocoders now, so pick GSM because it's small and easier to
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translate and sounds pretty good */
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AST_FORMAT_GSM,
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/*! iLBC is not too bad */
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AST_FORMAT_ILBC,
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/*! Speex is free, but computationally more expensive than GSM */
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AST_FORMAT_SPEEX16,
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AST_FORMAT_SPEEX,
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/*! Opus */
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AST_FORMAT_OPUS,
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/*! Ick, LPC10 sounds terrible, but at least we have code for it, if you're tacky enough
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to use it */
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AST_FORMAT_LPC10,
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/*! G.729a is faster than 723 and slightly less expensive */
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AST_FORMAT_G729,
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/*! Down to G.723.1 which is proprietary but at least designed for voice */
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AST_FORMAT_G723,
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};
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int idx;
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/* Find the first preferred codec in the format given */
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for (idx = 0; idx < ARRAY_LEN(best); ++idx) {
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if (formats & best[idx]) {
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return best[idx];
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}
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}
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return 0;
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}
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