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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 4349 | Serge | 1 | /* |
| 2 | * Header file for hardcoded PCM tables |
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| 3 | * |
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| 4 | * Copyright (c) 2010 Reimar Döffinger |
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| 5 | * |
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| 6 | * This file is part of FFmpeg. |
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| 7 | * |
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| 8 | * FFmpeg is free software; you can redistribute it and/or |
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| 9 | * modify it under the terms of the GNU Lesser General Public |
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| 10 | * License as published by the Free Software Foundation; either |
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| 11 | * version 2.1 of the License, or (at your option) any later version. |
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| 12 | * |
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| 13 | * FFmpeg is distributed in the hope that it will be useful, |
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| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 16 | * Lesser General Public License for more details. |
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| 17 | * |
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| 18 | * You should have received a copy of the GNU Lesser General Public |
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| 19 | * License along with FFmpeg; if not, write to the Free Software |
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| 20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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| 21 | */ |
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| 22 | |||
| 23 | #ifndef AVCODEC_PCM_TABLEGEN_H |
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| 24 | #define AVCODEC_PCM_TABLEGEN_H |
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| 25 | |||
| 26 | #include |
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| 27 | #include "libavutil/attributes.h" |
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| 28 | |||
| 29 | /* from g711.c by SUN microsystems (unrestricted use) */ |
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| 30 | |||
| 31 | #define SIGN_BIT (0x80) /* Sign bit for a A-law byte. */ |
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| 32 | #define QUANT_MASK (0xf) /* Quantization field mask. */ |
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| 33 | #define NSEGS (8) /* Number of A-law segments. */ |
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| 34 | #define SEG_SHIFT (4) /* Left shift for segment number. */ |
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| 35 | #define SEG_MASK (0x70) /* Segment field mask. */ |
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| 36 | |||
| 37 | #define BIAS (0x84) /* Bias for linear code. */ |
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| 38 | |||
| 39 | /* |
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| 40 | * alaw2linear() - Convert an A-law value to 16-bit linear PCM |
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| 41 | * |
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| 42 | */ |
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| 43 | static av_cold int alaw2linear(unsigned char a_val) |
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| 44 | { |
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| 45 | int t; |
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| 46 | int seg; |
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| 47 | |||
| 48 | a_val ^= 0x55; |
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| 49 | |||
| 50 | t = a_val & QUANT_MASK; |
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| 51 | seg = ((unsigned)a_val & SEG_MASK) >> SEG_SHIFT; |
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| 52 | if(seg) t= (t + t + 1 + 32) << (seg + 2); |
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| 53 | else t= (t + t + 1 ) << 3; |
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| 54 | |||
| 55 | return (a_val & SIGN_BIT) ? t : -t; |
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| 56 | } |
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| 57 | |||
| 58 | static av_cold int ulaw2linear(unsigned char u_val) |
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| 59 | { |
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| 60 | int t; |
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| 61 | |||
| 62 | /* Complement to obtain normal u-law value. */ |
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| 63 | u_val = ~u_val; |
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| 64 | |||
| 65 | /* |
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| 66 | * Extract and bias the quantization bits. Then |
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| 67 | * shift up by the segment number and subtract out the bias. |
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| 68 | */ |
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| 69 | t = ((u_val & QUANT_MASK) << 3) + BIAS; |
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| 70 | t <<= ((unsigned)u_val & SEG_MASK) >> SEG_SHIFT; |
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| 71 | |||
| 72 | return (u_val & SIGN_BIT) ? (BIAS - t) : (t - BIAS); |
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| 73 | } |
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| 74 | |||
| 75 | #if CONFIG_HARDCODED_TABLES |
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| 76 | #define pcm_alaw_tableinit() |
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| 77 | #define pcm_ulaw_tableinit() |
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| 78 | #include "libavcodec/pcm_tables.h" |
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| 79 | #else |
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| 80 | /* 16384 entries per table */ |
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| 81 | static uint8_t linear_to_alaw[16384]; |
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| 82 | static uint8_t linear_to_ulaw[16384]; |
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| 83 | |||
| 84 | static av_cold void build_xlaw_table(uint8_t *linear_to_xlaw, |
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| 85 | int (*xlaw2linear)(unsigned char), |
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| 86 | int mask) |
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| 87 | { |
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| 88 | int i, j, v, v1, v2; |
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| 89 | |||
| 90 | j = 0; |
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| 91 | for(i=0;i<128;i++) { |
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| 92 | if (i != 127) { |
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| 93 | v1 = xlaw2linear(i ^ mask); |
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| 94 | v2 = xlaw2linear((i + 1) ^ mask); |
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| 95 | v = (v1 + v2 + 4) >> 3; |
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| 96 | } else { |
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| 97 | v = 8192; |
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| 98 | } |
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| 99 | for(;j |
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| 100 | linear_to_xlaw[8192 + j] = (i ^ mask); |
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| 101 | if (j > 0) |
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| 102 | linear_to_xlaw[8192 - j] = (i ^ (mask ^ 0x80)); |
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| 103 | } |
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| 104 | } |
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| 105 | linear_to_xlaw[0] = linear_to_xlaw[1]; |
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| 106 | } |
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| 107 | |||
| 108 | static void pcm_alaw_tableinit(void) |
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| 109 | { |
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| 110 | build_xlaw_table(linear_to_alaw, alaw2linear, 0xd5); |
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| 111 | } |
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| 112 | |||
| 113 | static void pcm_ulaw_tableinit(void) |
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| 114 | { |
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| 115 | build_xlaw_table(linear_to_ulaw, ulaw2linear, 0xff); |
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| 116 | } |
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| 117 | #endif /* CONFIG_HARDCODED_TABLES */ |
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| 118 | |||
| 119 | #endif /* AVCODEC_PCM_TABLEGEN_H */ |