diff options
Diffstat (limited to 'drivers/isdn/mISDN/l1oip_codec.c')
| -rw-r--r-- | drivers/isdn/mISDN/l1oip_codec.c | 374 |
1 files changed, 374 insertions, 0 deletions
diff --git a/drivers/isdn/mISDN/l1oip_codec.c b/drivers/isdn/mISDN/l1oip_codec.c new file mode 100644 index 0000000..a2dc457 --- /dev/null +++ b/drivers/isdn/mISDN/l1oip_codec.c @@ -0,0 +1,374 @@ +/* + + * l1oip_codec.c generic codec using lookup table + * -> conversion from a-Law to u-Law + * -> conversion from u-Law to a-Law + * -> compression by reducing the number of sample resolution to 4 + * + * NOTE: It is not compatible with any standard codec like ADPCM. + * + * Author Andreas Eversberg (jolly@eversberg.eu) + * + * 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, 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., 675 Mass Ave, Cambridge, MA 02139, USA. + + */ + +/* + +How the codec works: +-------------------- + +The volume is increased to increase the dynamic range of the audio signal. +Each sample is converted to a-LAW with only 16 steps of level resolution. +A pair of two samples are stored in one byte. + +The first byte is stored in the upper bits, the second byte is stored in the +lower bits. + +To speed up compression and decompression, two lookup tables are formed: + +- 16 bits index for two samples (law encoded) with 8 bit compressed result. +- 8 bits index for one compressed data with 16 bits decompressed result. + +NOTE: The bytes are handled as they are law-encoded. + +*/ + +#include <linux/vmalloc.h> +#include <linux/mISDNif.h> +#include "core.h" + +/* definitions of codec. don't use calculations, code may run slower. */ + +static u8 *table_com; +static u16 *table_dec; + + +/* alaw -> ulaw */ +static u8 alaw_to_ulaw[256] = +{ + 0xab, 0x2b, 0xe3, 0x63, 0x8b, 0x0b, 0xc9, 0x49, + 0xba, 0x3a, 0xf6, 0x76, 0x9b, 0x1b, 0xd7, 0x57, + 0xa3, 0x23, 0xdd, 0x5d, 0x83, 0x03, 0xc1, 0x41, + 0xb2, 0x32, 0xeb, 0x6b, 0x93, 0x13, 0xcf, 0x4f, + 0xaf, 0x2f, 0xe7, 0x67, 0x8f, 0x0f, 0xcd, 0x4d, + 0xbe, 0x3e, 0xfe, 0x7e, 0x9f, 0x1f, 0xdb, 0x5b, + 0xa7, 0x27, 0xdf, 0x5f, 0x87, 0x07, 0xc5, 0x45, + 0xb6, 0x36, 0xef, 0x6f, 0x97, 0x17, 0xd3, 0x53, + 0xa9, 0x29, 0xe1, 0x61, 0x89, 0x09, 0xc7, 0x47, + 0xb8, 0x38, 0xf2, 0x72, 0x99, 0x19, 0xd5, 0x55, + 0xa1, 0x21, 0xdc, 0x5c, 0x81, 0x01, 0xbf, 0x3f, + 0xb0, 0x30, 0xe9, 0x69, 0x91, 0x11, 0xce, 0x4e, + 0xad, 0x2d, 0xe5, 0x65, 0x8d, 0x0d, 0xcb, 0x4b, + 0xbc, 0x3c, 0xfa, 0x7a, 0x9d, 0x1d, 0xd9, 0x59, + 0xa5, 0x25, 0xde, 0x5e, 0x85, 0x05, 0xc3, 0x43, + 0xb4, 0x34, 0xed, 0x6d, 0x95, 0x15, 0xd1, 0x51, + 0xac, 0x2c, 0xe4, 0x64, 0x8c, 0x0c, 0xca, 0x4a, + 0xbb, 0x3b, 0xf8, 0x78, 0x9c, 0x1c, 0xd8, 0x58, + 0xa4, 0x24, 0xde, 0x5e, 0x84, 0x04, 0xc2, 0x42, + 0xb3, 0x33, 0xec, 0x6c, 0x94, 0x14, 0xd0, 0x50, + 0xb0, 0x30, 0xe8, 0x68, 0x90, 0x10, 0xce, 0x4e, + 0xbf, 0x3f, 0xfe, 0x7e, 0xa0, 0x20, 0xdc, 0x5c, + 0xa8, 0x28, 0xe0, 0x60, 0x88, 0x08, 0xc6, 0x46, + 0xb7, 0x37, 0xf0, 0x70, 0x98, 0x18, 0xd4, 0x54, + 0xaa, 0x2a, 0xe2, 0x62, 0x8a, 0x0a, 0xc8, 0x48, + 0xb9, 0x39, 0xf4, 0x74, 0x9a, 0x1a, 0xd6, 0x56, + 0xa2, 0x22, 0xdd, 0x5d, 0x82, 0x02, 0xc0, 0x40, + 0xb1, 0x31, 0xea, 0x6a, 0x92, 0x12, 0xcf, 0x4f, + 0xae, 0x2e, 0xe6, 0x66, 0x8e, 0x0e, 0xcc, 0x4c, + 0xbd, 0x3d, 0xfc, 0x7c, 0x9e, 0x1e, 0xda, 0x5a, + 0xa6, 0x26, 0xdf, 0x5f, 0x86, 0x06, 0xc4, 0x44, + 0xb5, 0x35, 0xee, 0x6e, 0x96, 0x16, 0xd2, 0x52 +}; + +/* ulaw -> alaw */ +static u8 ulaw_to_alaw[256] = +{ + 0xab, 0x55, 0xd5, 0x15, 0x95, 0x75, 0xf5, 0x35, + 0xb5, 0x45, 0xc5, 0x05, 0x85, 0x65, 0xe5, 0x25, + 0xa5, 0x5d, 0xdd, 0x1d, 0x9d, 0x7d, 0xfd, 0x3d, + 0xbd, 0x4d, 0xcd, 0x0d, 0x8d, 0x6d, 0xed, 0x2d, + 0xad, 0x51, 0xd1, 0x11, 0x91, 0x71, 0xf1, 0x31, + 0xb1, 0x41, 0xc1, 0x01, 0x81, 0x61, 0xe1, 0x21, + 0x59, 0xd9, 0x19, 0x99, 0x79, 0xf9, 0x39, 0xb9, + 0x49, 0xc9, 0x09, 0x89, 0x69, 0xe9, 0x29, 0xa9, + 0xd7, 0x17, 0x97, 0x77, 0xf7, 0x37, 0xb7, 0x47, + 0xc7, 0x07, 0x87, 0x67, 0xe7, 0x27, 0xa7, 0xdf, + 0x9f, 0x7f, 0xff, 0x3f, 0xbf, 0x4f, 0xcf, 0x0f, + 0x8f, 0x6f, 0xef, 0x2f, 0x53, 0x13, 0x73, 0x33, + 0xb3, 0x43, 0xc3, 0x03, 0x83, 0x63, 0xe3, 0x23, + 0xa3, 0x5b, 0xdb, 0x1b, 0x9b, 0x7b, 0xfb, 0x3b, + 0xbb, 0xbb, 0x4b, 0x4b, 0xcb, 0xcb, 0x0b, 0x0b, + 0x8b, 0x8b, 0x6b, 0x6b, 0xeb, 0xeb, 0x2b, 0x2b, + 0xab, 0x54, 0xd4, 0x14, 0x94, 0x74, 0xf4, 0x34, + 0xb4, 0x44, 0xc4, 0x04, 0x84, 0x64, 0xe4, 0x24, + 0xa4, 0x5c, 0xdc, 0x1c, 0x9c, 0x7c, 0xfc, 0x3c, + 0xbc, 0x4c, 0xcc, 0x0c, 0x8c, 0x6c, 0xec, 0x2c, + 0xac, 0x50, 0xd0, 0x10, 0x90, 0x70, 0xf0, 0x30, + 0xb0, 0x40, 0xc0, 0x00, 0x80, 0x60, 0xe0, 0x20, + 0x58, 0xd8, 0x18, 0x98, 0x78, 0xf8, 0x38, 0xb8, + 0x48, 0xc8, 0x08, 0x88, 0x68, 0xe8, 0x28, 0xa8, + 0xd6, 0x16, 0x96, 0x76, 0xf6, 0x36, 0xb6, 0x46, + 0xc6, 0x06, 0x86, 0x66, 0xe6, 0x26, 0xa6, 0xde, + 0x9e, 0x7e, 0xfe, 0x3e, 0xbe, 0x4e, 0xce, 0x0e, + 0x8e, 0x6e, 0xee, 0x2e, 0x52, 0x12, 0x72, 0x32, + 0xb2, 0x42, 0xc2, 0x02, 0x82, 0x62, 0xe2, 0x22, + 0xa2, 0x5a, 0xda, 0x1a, 0x9a, 0x7a, 0xfa, 0x3a, + 0xba, 0xba, 0x4a, 0x4a, 0xca, 0xca, 0x0a, 0x0a, + 0x8a, 0x8a, 0x6a, 0x6a, 0xea, 0xea, 0x2a, 0x2a +}; + +/* alaw -> 4bit compression */ +static u8 alaw_to_4bit[256] = { + 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, + 0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04, + 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, + 0x0d, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04, + 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, + 0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04, + 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, + 0x0d, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04, + 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, + 0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04, + 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0d, 0x02, + 0x0e, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04, + 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, + 0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04, + 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, + 0x0d, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04, + 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, + 0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04, + 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, + 0x0d, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04, + 0x0e, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04, + 0x0d, 0x02, 0x08, 0x07, 0x0f, 0x01, 0x0a, 0x05, + 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, + 0x0d, 0x02, 0x09, 0x07, 0x0f, 0x00, 0x0b, 0x04, + 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, + 0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04, + 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, + 0x0d, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04, + 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, + 0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04, + 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, + 0x0d, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04, +}; + +/* 4bit -> alaw decompression */ +static u8 _4bit_to_alaw[16] = { + 0x5d, 0x51, 0xd9, 0xd7, 0x5f, 0x53, 0xa3, 0x4b, + 0x2a, 0x3a, 0x22, 0x2e, 0x26, 0x56, 0x20, 0x2c, +}; + +/* ulaw -> 4bit compression */ +static u8 ulaw_to_4bit[256] = { + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, + 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, + 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, + 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, + 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, + 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x04, 0x04, + 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, + 0x04, 0x04, 0x04, 0x04, 0x05, 0x05, 0x05, 0x05, + 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, + 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, + 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, + 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x08, + 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, + 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, + 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, + 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, + 0x0f, 0x0e, 0x0e, 0x0e, 0x0e, 0x0e, 0x0e, 0x0e, + 0x0e, 0x0e, 0x0e, 0x0e, 0x0e, 0x0e, 0x0e, 0x0e, + 0x0e, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, + 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, + 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, + 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0b, 0x0b, + 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, + 0x0b, 0x0b, 0x0b, 0x0b, 0x0a, 0x0a, 0x0a, 0x0a, + 0x0a, 0x0a, 0x0a, 0x0a, 0x0a, 0x0a, 0x0a, 0x0a, + 0x09, 0x09, 0x09, 0x09, 0x09, 0x09, 0x09, 0x09, + 0x09, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, + 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, +}; + +/* 4bit -> ulaw decompression */ +static u8 _4bit_to_ulaw[16] = { + 0x11, 0x21, 0x31, 0x40, 0x4e, 0x5c, 0x68, 0x71, + 0xfe, 0xef, 0xe7, 0xdb, 0xcd, 0xbf, 0xaf, 0x9f, +}; + + +/* + * Compresses data to the result buffer + * The result size must be at least half of the input buffer. + * The number of samples also must be even! + */ +int +l1oip_law_to_4bit(u8 *data, int len, u8 *result, u32 *state) +{ + int ii, i = 0, o = 0; + + if (!len) + return 0; + + /* send saved byte and first input byte */ + if (*state) { + *result++ = table_com[(((*state)<<8)&0xff00) | (*data++)]; + len--; + o++; + } + + ii = len >> 1; + + while (i < ii) { + *result++ = table_com[(data[0]<<8) | (data[1])]; + data += 2; + i++; + o++; + } + + /* if len has an odd number, we save byte for next call */ + if (len & 1) + *state = 0x100 + *data; + else + *state = 0; + + return o; +} + +/* Decompress data to the result buffer + * The result size must be the number of sample in packet. (2 * input data) + * The number of samples in the result are even! + */ +int +l1oip_4bit_to_law(u8 *data, int len, u8 *result) +{ + int i = 0; + u16 r; + + while (i < len) { + r = table_dec[*data++]; + *result++ = r>>8; + *result++ = r; + i++; + } + + return len << 1; +} + + +/* + * law conversion + */ +int +l1oip_alaw_to_ulaw(u8 *data, int len, u8 *result) +{ + int i = 0; + + while (i < len) { + *result++ = alaw_to_ulaw[*data++]; + i++; + } + + return len; +} + +int +l1oip_ulaw_to_alaw(u8 *data, int len, u8 *result) +{ + int i = 0; + + while (i < len) { + *result++ = ulaw_to_alaw[*data++]; + i++; + } + + return len; +} + + +/* + * generate/free compression and decompression table + */ +void +l1oip_4bit_free(void) +{ + if (table_dec) + vfree(table_dec); + if (table_com) + vfree(table_com); + table_com = NULL; + table_dec = NULL; +} + +int +l1oip_4bit_alloc(int ulaw) +{ + int i1, i2, c, sample; + + /* in case, it is called again */ + if (table_dec) + return 0; + + /* alloc conversion tables */ + table_com = vmalloc(65536); + table_dec = vmalloc(512); + if (!table_com | !table_dec) { + l1oip_4bit_free(); + return -ENOMEM; + } + memset(table_com, 0, 65536); + memset(table_dec, 0, 512); + /* generate compression table */ + i1 = 0; + while (i1 < 256) { + if (ulaw) + c = ulaw_to_4bit[i1]; + else + c = alaw_to_4bit[i1]; + i2 = 0; + while (i2 < 256) { + table_com[(i1<<8) | i2] |= (c<<4); + table_com[(i2<<8) | i1] |= c; + i2++; + } + i1++; + } + + /* generate decompression table */ + i1 = 0; + while (i1 < 16) { + if (ulaw) + sample = _4bit_to_ulaw[i1]; + else + sample = _4bit_to_alaw[i1]; + i2 = 0; + while (i2 < 16) { + table_dec[(i1<<4) | i2] |= (sample<<8); + table_dec[(i2<<4) | i1] |= sample; + i2++; + } + i1++; + } + + return 0; +} + + |
