yading@10: /*
yading@10:  * Header file for hardcoded PCM tables
yading@10:  *
yading@10:  * Copyright (c) 2010 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: #ifndef AVCODEC_PCM_TABLEGEN_H
yading@10: #define AVCODEC_PCM_TABLEGEN_H
yading@10: 
yading@10: #include <stdint.h>
yading@10: #include "libavutil/attributes.h"
yading@10: 
yading@10: /* from g711.c by SUN microsystems (unrestricted use) */
yading@10: 
yading@10: #define         SIGN_BIT        (0x80)      /* Sign bit for a A-law byte. */
yading@10: #define         QUANT_MASK      (0xf)       /* Quantization field mask. */
yading@10: #define         NSEGS           (8)         /* Number of A-law segments. */
yading@10: #define         SEG_SHIFT       (4)         /* Left shift for segment number. */
yading@10: #define         SEG_MASK        (0x70)      /* Segment field mask. */
yading@10: 
yading@10: #define         BIAS            (0x84)      /* Bias for linear code. */
yading@10: 
yading@10: /*
yading@10:  * alaw2linear() - Convert an A-law value to 16-bit linear PCM
yading@10:  *
yading@10:  */
yading@10: static av_cold int alaw2linear(unsigned char a_val)
yading@10: {
yading@10:         int t;
yading@10:         int seg;
yading@10: 
yading@10:         a_val ^= 0x55;
yading@10: 
yading@10:         t = a_val & QUANT_MASK;
yading@10:         seg = ((unsigned)a_val & SEG_MASK) >> SEG_SHIFT;
yading@10:         if(seg) t= (t + t + 1 + 32) << (seg + 2);
yading@10:         else    t= (t + t + 1     ) << 3;
yading@10: 
yading@10:         return (a_val & SIGN_BIT) ? t : -t;
yading@10: }
yading@10: 
yading@10: static av_cold int ulaw2linear(unsigned char u_val)
yading@10: {
yading@10:         int t;
yading@10: 
yading@10:         /* Complement to obtain normal u-law value. */
yading@10:         u_val = ~u_val;
yading@10: 
yading@10:         /*
yading@10:          * Extract and bias the quantization bits. Then
yading@10:          * shift up by the segment number and subtract out the bias.
yading@10:          */
yading@10:         t = ((u_val & QUANT_MASK) << 3) + BIAS;
yading@10:         t <<= ((unsigned)u_val & SEG_MASK) >> SEG_SHIFT;
yading@10: 
yading@10:         return (u_val & SIGN_BIT) ? (BIAS - t) : (t - BIAS);
yading@10: }
yading@10: 
yading@10: #if CONFIG_HARDCODED_TABLES
yading@10: #define pcm_alaw_tableinit()
yading@10: #define pcm_ulaw_tableinit()
yading@10: #include "libavcodec/pcm_tables.h"
yading@10: #else
yading@10: /* 16384 entries per table */
yading@10: static uint8_t linear_to_alaw[16384];
yading@10: static uint8_t linear_to_ulaw[16384];
yading@10: 
yading@10: static av_cold void build_xlaw_table(uint8_t *linear_to_xlaw,
yading@10:                              int (*xlaw2linear)(unsigned char),
yading@10:                              int mask)
yading@10: {
yading@10:     int i, j, v, v1, v2;
yading@10: 
yading@10:     j = 0;
yading@10:     for(i=0;i<128;i++) {
yading@10:         if (i != 127) {
yading@10:             v1 = xlaw2linear(i ^ mask);
yading@10:             v2 = xlaw2linear((i + 1) ^ mask);
yading@10:             v = (v1 + v2 + 4) >> 3;
yading@10:         } else {
yading@10:             v = 8192;
yading@10:         }
yading@10:         for(;j<v;j++) {
yading@10:             linear_to_xlaw[8192 + j] = (i ^ mask);
yading@10:             if (j > 0)
yading@10:                 linear_to_xlaw[8192 - j] = (i ^ (mask ^ 0x80));
yading@10:         }
yading@10:     }
yading@10:     linear_to_xlaw[0] = linear_to_xlaw[1];
yading@10: }
yading@10: 
yading@10: static void pcm_alaw_tableinit(void)
yading@10: {
yading@10:     build_xlaw_table(linear_to_alaw, alaw2linear, 0xd5);
yading@10: }
yading@10: 
yading@10: static void pcm_ulaw_tableinit(void)
yading@10: {
yading@10:     build_xlaw_table(linear_to_ulaw, ulaw2linear, 0xff);
yading@10: }
yading@10: #endif /* CONFIG_HARDCODED_TABLES */
yading@10: 
yading@10: #endif /* AVCODEC_PCM_TABLEGEN_H */