mirror of https://github.com/FFmpeg/FFmpeg.git
Originally committed as revision 22762 to svn://svn.ffmpeg.org/ffmpeg/trunkrelease/0.6
Reimar Döffinger
15 years ago
parent
8eaa6e0e04
commit
fa034b4427
4 changed files with 168 additions and 76 deletions
@ -0,0 +1,45 @@ |
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/*
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* Generate a header file for hardcoded PCM tables |
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* |
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* Copyright (c) 2010 Reimar Döffinger <Reimar.Doeffinger@gmx.de> |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#include <stdlib.h> |
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#define CONFIG_HARDCODED_TABLES 0 |
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#include "pcm_tablegen.h" |
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#include "tableprint.h" |
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int main(void) |
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{ |
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pcm_alaw_tableinit(); |
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pcm_ulaw_tableinit(); |
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write_fileheader(); |
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printf("static const uint8_t linear_to_alaw[1 << 14] = {\n"); |
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write_uint8_array(linear_to_alaw, 1 << 14); |
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printf("};\n"); |
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printf("static const uint8_t linear_to_ulaw[1 << 14] = {\n"); |
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write_uint8_array(linear_to_ulaw, 1 << 14); |
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printf("};\n"); |
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return 0; |
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} |
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@ -0,0 +1,119 @@ |
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/*
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* Header file for hardcoded PCM tables |
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* |
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* Copyright (c) 2010 Reimar Döffinger <Reimar.Doeffinger@gmx.de> |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#ifndef PCM_TABLEGEN_H |
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#define PCM_TABLEGEN_H |
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#include <stdint.h> |
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#include "../libavutil/attributes.h" |
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/* from g711.c by SUN microsystems (unrestricted use) */ |
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#define SIGN_BIT (0x80) /* Sign bit for a A-law byte. */ |
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#define QUANT_MASK (0xf) /* Quantization field mask. */ |
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#define NSEGS (8) /* Number of A-law segments. */ |
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#define SEG_SHIFT (4) /* Left shift for segment number. */ |
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#define SEG_MASK (0x70) /* Segment field mask. */ |
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#define BIAS (0x84) /* Bias for linear code. */ |
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/*
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* alaw2linear() - Convert an A-law value to 16-bit linear PCM |
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* |
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*/ |
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static av_cold int alaw2linear(unsigned char a_val) |
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{ |
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int t; |
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int seg; |
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a_val ^= 0x55; |
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t = a_val & QUANT_MASK; |
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seg = ((unsigned)a_val & SEG_MASK) >> SEG_SHIFT; |
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if(seg) t= (t + t + 1 + 32) << (seg + 2); |
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else t= (t + t + 1 ) << 3; |
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return (a_val & SIGN_BIT) ? t : -t; |
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} |
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static av_cold int ulaw2linear(unsigned char u_val) |
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{ |
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int t; |
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/* Complement to obtain normal u-law value. */ |
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u_val = ~u_val; |
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/*
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* Extract and bias the quantization bits. Then |
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* shift up by the segment number and subtract out the bias. |
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*/ |
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t = ((u_val & QUANT_MASK) << 3) + BIAS; |
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t <<= ((unsigned)u_val & SEG_MASK) >> SEG_SHIFT; |
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return (u_val & SIGN_BIT) ? (BIAS - t) : (t - BIAS); |
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} |
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#if CONFIG_HARDCODED_TABLES |
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#define pcm_alaw_tableinit() |
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#define pcm_ulaw_tableinit() |
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#include "libavcodec/pcm_tables.h" |
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#else |
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/* 16384 entries per table */ |
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static uint8_t linear_to_alaw[16384]; |
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static uint8_t linear_to_ulaw[16384]; |
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static av_cold void build_xlaw_table(uint8_t *linear_to_xlaw, |
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int (*xlaw2linear)(unsigned char), |
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int mask) |
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{ |
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int i, j, v, v1, v2; |
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j = 0; |
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for(i=0;i<128;i++) { |
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if (i != 127) { |
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v1 = xlaw2linear(i ^ mask); |
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v2 = xlaw2linear((i + 1) ^ mask); |
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v = (v1 + v2 + 4) >> 3; |
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} else { |
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v = 8192; |
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} |
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for(;j<v;j++) { |
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linear_to_xlaw[8192 + j] = (i ^ mask); |
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if (j > 0) |
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linear_to_xlaw[8192 - j] = (i ^ (mask ^ 0x80)); |
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} |
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} |
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linear_to_xlaw[0] = linear_to_xlaw[1]; |
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} |
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static void pcm_alaw_tableinit(void) |
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{ |
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build_xlaw_table(linear_to_alaw, alaw2linear, 0xd5); |
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} |
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static void pcm_ulaw_tableinit(void) |
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{ |
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build_xlaw_table(linear_to_ulaw, ulaw2linear, 0xff); |
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} |
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#endif /* CONFIG_HARDCODED_TABLES */ |
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#endif /* PCM_TABLEGEN_H */ |
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