FFmpeg/libavcodec/g729dec.c
Vladimir Voroshilov bc165ee392 Another set of approved G.729 chunks (from decoder core)
Originally committed as revision 15168 to svn://svn.ffmpeg.org/ffmpeg/trunk
2008-09-03 01:07:03 +00:00

137 lines
3.9 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;
}
/**
* Get parity bit of bit 2..7
*/
static inline int g729_get_parity(uint8_t value)
{
return (0x6996966996696996ULL >> (value >> 2)) & 1;
}
/*
This filter enhances harmonic components of the fixed-codebook vector to
improve the quality of the reconstructed speech.
/ fc_v[i], i < pitch_delay
fc_v[i] = <
\ fc_v[i] + gain_pitch * fc_v[i-pitch_delay], i >= pitch_delay
*/
ff_acelp_weighted_vector_sum(
fc + pitch_delay_int[i],
fc + pitch_delay_int[i],
fc,
1 << 14,
av_clip(ctx->gain_pitch, SHARP_MIN, SHARP_MAX),
0,
14,
ctx->subframe_size - pitch_delay_int[i]);
ctx->gain_pitch = cb_gain_1st_8k[parm->gc_1st_index[i]][0] +
cb_gain_2nd_8k[parm->gc_2nd_index[i]][0];
gain_corr_factor = cb_gain_1st_8k[parm->gc_1st_index[i]][1] +
cb_gain_2nd_8k[parm->gc_2nd_index[i]][1];
/* Routine requires rounding to lowest. */
ff_acelp_interpolate(
ctx->exc + i*ctx->subframe_size,
ctx->exc + i*ctx->subframe_size - pitch_delay_3x/3,
ff_acelp_interp_filter,
6,
(pitch_delay_3x%3)<<1,
10,
ctx->subframe_size);
ff_acelp_weighted_vector_sum(
ctx->exc + i * ctx->subframe_size,
ctx->exc + i * ctx->subframe_size,
fc,
(!voicing && ctx->frame_erasure) ? 0 : ctx->gain_pitch,
( voicing && ctx->frame_erasure) ? 0 : ctx->gain_code,
1<<13,
14,
ctx->subframe_size);
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"),
};