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Diffstat (limited to 'openbsc/src/libmgcp/g711common.h')
| -rw-r--r-- | openbsc/src/libmgcp/g711common.h | 187 |
1 files changed, 0 insertions, 187 deletions
diff --git a/openbsc/src/libmgcp/g711common.h b/openbsc/src/libmgcp/g711common.h deleted file mode 100644 index cb35fc651..000000000 --- a/openbsc/src/libmgcp/g711common.h +++ /dev/null @@ -1,187 +0,0 @@ -/* - * PCM - A-Law conversion - * Copyright (c) 2000 by Abramo Bagnara <abramo@alsa-project.org> - * - * Wrapper for linphone Codec class by Simon Morlat <simon.morlat@linphone.org> - * - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * 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 General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA - */ - -static inline int val_seg(int val) -{ - int r = 0; - val >>= 7; /*7 = 4 + 3*/ - if (val & 0xf0) { - val >>= 4; - r += 4; - } - if (val & 0x0c) { - val >>= 2; - r += 2; - } - if (val & 0x02) - r += 1; - return r; -} - -/* - * s16_to_alaw() - Convert a 16-bit linear PCM value to 8-bit A-law - * - * s16_to_alaw() accepts an 16-bit integer and encodes it as A-law data. - * - * Linear Input Code Compressed Code - * ------------------------ --------------- - * 0000000wxyza 000wxyz - * 0000001wxyza 001wxyz - * 000001wxyzab 010wxyz - * 00001wxyzabc 011wxyz - * 0001wxyzabcd 100wxyz - * 001wxyzabcde 101wxyz - * 01wxyzabcdef 110wxyz - * 1wxyzabcdefg 111wxyz - * - * For further information see John C. Bellamy's Digital Telephony, 1982, - * John Wiley & Sons, pps 98-111 and 472-476. - * G711 is designed for 13 bits input signal, this function add extra shifting to take this into account. - */ - -static inline unsigned char s16_to_alaw(int pcm_val) -{ - int mask; - int seg; - unsigned char aval; - - if (pcm_val >= 0) { - mask = 0xD5; - } else { - mask = 0x55; - pcm_val = -pcm_val; - if (pcm_val > 0x7fff) - pcm_val = 0x7fff; - } - - if (pcm_val < 256) /*256 = 32 << 3*/ - aval = pcm_val >> 4; /*4 = 1 + 3*/ - else { - /* Convert the scaled magnitude to segment number. */ - seg = val_seg(pcm_val); - aval = (seg << 4) | ((pcm_val >> (seg + 3)) & 0x0f); - } - return aval ^ mask; -} - -/* - * alaw_to_s16() - Convert an A-law value to 16-bit linear PCM - * - */ -static inline int alaw_to_s16(unsigned char a_val) -{ - int t; - int seg; - - a_val ^= 0x55; - t = a_val & 0x7f; - if (t < 16) - t = (t << 4) + 8; - else { - seg = (t >> 4) & 0x07; - t = ((t & 0x0f) << 4) + 0x108; - t <<= seg -1; - } - return ((a_val & 0x80) ? t : -t); -} -/* - * s16_to_ulaw() - Convert a linear PCM value to u-law - * - * In order to simplify the encoding process, the original linear magnitude - * is biased by adding 33 which shifts the encoding range from (0 - 8158) to - * (33 - 8191). The result can be seen in the following encoding table: - * - * Biased Linear Input Code Compressed Code - * ------------------------ --------------- - * 00000001wxyza 000wxyz - * 0000001wxyzab 001wxyz - * 000001wxyzabc 010wxyz - * 00001wxyzabcd 011wxyz - * 0001wxyzabcde 100wxyz - * 001wxyzabcdef 101wxyz - * 01wxyzabcdefg 110wxyz - * 1wxyzabcdefgh 111wxyz - * - * Each biased linear code has a leading 1 which identifies the segment - * number. The value of the segment number is equal to 7 minus the number - * of leading 0's. The quantization interval is directly available as the - * four bits wxyz. * The trailing bits (a - h) are ignored. - * - * Ordinarily the complement of the resulting code word is used for - * transmission, and so the code word is complemented before it is returned. - * - * For further information see John C. Bellamy's Digital Telephony, 1982, - * John Wiley & Sons, pps 98-111 and 472-476. - */ - -static inline unsigned char s16_to_ulaw(int pcm_val) /* 2's complement (16-bit range) */ -{ - int mask; - int seg; - unsigned char uval; - - if (pcm_val < 0) { - pcm_val = 0x84 - pcm_val; - mask = 0x7f; - } else { - pcm_val += 0x84; - mask = 0xff; - } - if (pcm_val > 0x7fff) - pcm_val = 0x7fff; - - /* Convert the scaled magnitude to segment number. */ - seg = val_seg(pcm_val); - - /* - * Combine the sign, segment, quantization bits; - * and complement the code word. - */ - uval = (seg << 4) | ((pcm_val >> (seg + 3)) & 0x0f); - return uval ^ mask; -} - -/* - * ulaw_to_s16() - Convert a u-law value to 16-bit linear PCM - * - * First, a biased linear code is derived from the code word. An unbiased - * output can then be obtained by subtracting 33 from the biased code. - * - * Note that this function expects to be passed the complement of the - * original code word. This is in keeping with ISDN conventions. - */ -static inline int ulaw_to_s16(unsigned char u_val) -{ - int t; - - /* Complement to obtain normal u-law value. */ - u_val = ~u_val; - - /* - * Extract and bias the quantization bits. Then - * shift up by the segment number and subtract out the bias. - */ - t = ((u_val & 0x0f) << 3) + 0x84; - t <<= (u_val & 0x70) >> 4; - - return ((u_val & 0x80) ? (0x84 - t) : (t - 0x84)); -} |