mirror of
https://github.com/FFmpeg/FFmpeg.git
synced 2024-11-21 10:55:51 +02:00
86 lines
2.1 KiB
C
86 lines
2.1 KiB
C
/*
|
|
* G.729 decoder
|
|
* Copyright (c) 2008 Vladimir Voroshilov
|
|
*
|
|
* 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>
|
|
#include <inttypes.h>
|
|
#include <limits.h>
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
#include <math.h>
|
|
#include <assert.h>
|
|
|
|
#include "avcodec.h"
|
|
#include "libavutil/avutil.h"
|
|
#include "bitstream.h"
|
|
|
|
/**
|
|
* minimum quantized LSF value (3.2.4)
|
|
* 0.005 in Q13
|
|
*/
|
|
#define LSFQ_MIN 40
|
|
|
|
/**
|
|
* maximum quantized LSF value (3.2.4)
|
|
* 3.135 in Q13
|
|
*/
|
|
#define LSFQ_MAX 25681
|
|
|
|
/**
|
|
* minimum LSF distance (3.2.4)
|
|
* 0.0391 in Q13
|
|
*/
|
|
#define LSFQ_DIFF_MIN 321
|
|
|
|
/**
|
|
* minimum gain pitch value (3.8, Equation 47)
|
|
* 0.2 in (1.14)
|
|
*/
|
|
#define SHARP_MIN 3277
|
|
|
|
/**
|
|
* maximum gain pitch value (3.8, Equation 47)
|
|
* (EE) This does not comply with the specification.
|
|
* Specification says about 0.8, which should be
|
|
* 13107 in (1.14), but reference C code uses
|
|
* 13017 (equals to 0.7945) instead of it.
|
|
*/
|
|
#define SHARP_MAX 13017
|
|
|
|
/**
|
|
* \brief pseudo random number generator
|
|
*/
|
|
static inline uint16_t g729_random(uint16_t value)
|
|
{
|
|
return 31821 * value + 13849;
|
|
}
|
|
|
|
AVCodec g729_decoder =
|
|
{
|
|
"g729",
|
|
CODEC_TYPE_AUDIO,
|
|
CODEC_ID_G729,
|
|
sizeof(G729_Context),
|
|
ff_g729_decoder_init,
|
|
NULL,
|
|
NULL,
|
|
ff_g729_decode_frame,
|
|
.long_name = NULL_IF_CONFIG_SMALL("G.729"),
|
|
};
|