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Allow hardcoding of ulaw and alaw tables. 

Originally committed as revision 22762 to svn://svn.ffmpeg.org/ffmpeg/trunk
tags/v0.6
Reimar Döffinger 15 years ago
parent
8eaa6e0e04
commit
fa034b4427
4 changed files with 168 additions and 76 deletions
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  1. +1
    -0
      libavcodec/Makefile
  2. +3
    -76
      libavcodec/pcm.c
  3. +45
    -0
      libavcodec/pcm_tablegen.c
  4. +119
    -0
      libavcodec/pcm_tablegen.h

+ 1
- 0
libavcodec/Makefile View File

@@ -645,5 +645,6 @@ $(SUBDIR)dv.o: $(SUBDIR)dv_tables.h
$(SUBDIR)mdct.o: $(SUBDIR)mdct_tables.h
$(SUBDIR)mpegaudiodec.o: $(SUBDIR)mpegaudio_tables.h
$(SUBDIR)motionpixels.o: $(SUBDIR)motionpixels_tables.h
$(SUBDIR)pcm.o: $(SUBDIR)pcm_tables.h
$(SUBDIR)qdm2.o: $(SUBDIR)qdm2_tables.h
endif

+ 3
- 76
libavcodec/pcm.c View File

@@ -27,92 +27,19 @@
#include "avcodec.h"
#include "libavutil/common.h" /* for av_reverse */
#include "bytestream.h"
#include "pcm_tablegen.h"

#define MAX_CHANNELS 64

/* from g711.c by SUN microsystems (unrestricted use) */

#define SIGN_BIT (0x80) /* Sign bit for a A-law byte. */
#define QUANT_MASK (0xf) /* Quantization field mask. */
#define NSEGS (8) /* Number of A-law segments. */
#define SEG_SHIFT (4) /* Left shift for segment number. */
#define SEG_MASK (0x70) /* Segment field mask. */

#define BIAS (0x84) /* Bias for linear code. */

/*
* alaw2linear() - Convert an A-law value to 16-bit linear PCM
*
*/
static av_cold int alaw2linear(unsigned char a_val)
{
int t;
int seg;

a_val ^= 0x55;

t = a_val & QUANT_MASK;
seg = ((unsigned)a_val & SEG_MASK) >> SEG_SHIFT;
if(seg) t= (t + t + 1 + 32) << (seg + 2);
else t= (t + t + 1 ) << 3;

return (a_val & SIGN_BIT) ? t : -t;
}

static av_cold int ulaw2linear(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 & QUANT_MASK) << 3) + BIAS;
t <<= ((unsigned)u_val & SEG_MASK) >> SEG_SHIFT;

return (u_val & SIGN_BIT) ? (BIAS - t) : (t - BIAS);
}

/* 16384 entries per table */
static uint8_t linear_to_alaw[16384];
static uint8_t linear_to_ulaw[16384];

static av_cold void build_xlaw_table(uint8_t *linear_to_xlaw,
int (*xlaw2linear)(unsigned char),
int mask)
{
int i, j, v, v1, v2;

j = 0;
for(i=0;i<128;i++) {
if (i != 127) {
v1 = xlaw2linear(i ^ mask);
v2 = xlaw2linear((i + 1) ^ mask);
v = (v1 + v2 + 4) >> 3;
} else {
v = 8192;
}
for(;j<v;j++) {
linear_to_xlaw[8192 + j] = (i ^ mask);
if (j > 0)
linear_to_xlaw[8192 - j] = (i ^ (mask ^ 0x80));
}
}
linear_to_xlaw[0] = linear_to_xlaw[1];
}

static av_cold int pcm_encode_init(AVCodecContext *avctx)
{
avctx->frame_size = 1;
switch(avctx->codec->id) {
case CODEC_ID_PCM_ALAW:
build_xlaw_table(linear_to_alaw, alaw2linear, 0xd5);
pcm_alaw_tableinit();
break;
case CODEC_ID_PCM_MULAW:
build_xlaw_table(linear_to_ulaw, ulaw2linear, 0xff);
pcm_ulaw_tableinit();
break;
default:
break;


+ 45
- 0
libavcodec/pcm_tablegen.c View File

@@ -0,0 +1,45 @@
/*
* Generate a header file for hardcoded PCM tables
*
* Copyright (c) 2010 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/

#include <stdlib.h>
#define CONFIG_HARDCODED_TABLES 0
#include "pcm_tablegen.h"
#include "tableprint.h"

int main(void)
{
pcm_alaw_tableinit();
pcm_ulaw_tableinit();

write_fileheader();

printf("static const uint8_t linear_to_alaw[1 << 14] = {\n");
write_uint8_array(linear_to_alaw, 1 << 14);
printf("};\n");

printf("static const uint8_t linear_to_ulaw[1 << 14] = {\n");
write_uint8_array(linear_to_ulaw, 1 << 14);
printf("};\n");

return 0;
}


+ 119
- 0
libavcodec/pcm_tablegen.h View File

@@ -0,0 +1,119 @@
/*
* Header file for hardcoded PCM tables
*
* Copyright (c) 2010 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/

#ifndef PCM_TABLEGEN_H
#define PCM_TABLEGEN_H

#include <stdint.h>
#include "../libavutil/attributes.h"

/* from g711.c by SUN microsystems (unrestricted use) */

#define SIGN_BIT (0x80) /* Sign bit for a A-law byte. */
#define QUANT_MASK (0xf) /* Quantization field mask. */
#define NSEGS (8) /* Number of A-law segments. */
#define SEG_SHIFT (4) /* Left shift for segment number. */
#define SEG_MASK (0x70) /* Segment field mask. */

#define BIAS (0x84) /* Bias for linear code. */

/*
* alaw2linear() - Convert an A-law value to 16-bit linear PCM
*
*/
static av_cold int alaw2linear(unsigned char a_val)
{
int t;
int seg;

a_val ^= 0x55;

t = a_val & QUANT_MASK;
seg = ((unsigned)a_val & SEG_MASK) >> SEG_SHIFT;
if(seg) t= (t + t + 1 + 32) << (seg + 2);
else t= (t + t + 1 ) << 3;

return (a_val & SIGN_BIT) ? t : -t;
}

static av_cold int ulaw2linear(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 & QUANT_MASK) << 3) + BIAS;
t <<= ((unsigned)u_val & SEG_MASK) >> SEG_SHIFT;

return (u_val & SIGN_BIT) ? (BIAS - t) : (t - BIAS);
}

#if CONFIG_HARDCODED_TABLES
#define pcm_alaw_tableinit()
#define pcm_ulaw_tableinit()
#include "libavcodec/pcm_tables.h"
#else
/* 16384 entries per table */
static uint8_t linear_to_alaw[16384];
static uint8_t linear_to_ulaw[16384];

static av_cold void build_xlaw_table(uint8_t *linear_to_xlaw,
int (*xlaw2linear)(unsigned char),
int mask)
{
int i, j, v, v1, v2;

j = 0;
for(i=0;i<128;i++) {
if (i != 127) {
v1 = xlaw2linear(i ^ mask);
v2 = xlaw2linear((i + 1) ^ mask);
v = (v1 + v2 + 4) >> 3;
} else {
v = 8192;
}
for(;j<v;j++) {
linear_to_xlaw[8192 + j] = (i ^ mask);
if (j > 0)
linear_to_xlaw[8192 - j] = (i ^ (mask ^ 0x80));
}
}
linear_to_xlaw[0] = linear_to_xlaw[1];
}

static void pcm_alaw_tableinit(void)
{
build_xlaw_table(linear_to_alaw, alaw2linear, 0xd5);
}

static void pcm_ulaw_tableinit(void)
{
build_xlaw_table(linear_to_ulaw, ulaw2linear, 0xff);
}
#endif /* CONFIG_HARDCODED_TABLES */

#endif /* PCM_TABLEGEN_H */

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