libavcodec/g729dec.c

   1 /*
   2  * G.729 decoder
   3  * Copyright (c) 2008 Vladimir Voroshilov
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21 #include <stdlib.h>
  22 #include <inttypes.h>
  23 #include <limits.h>
  24 #include <stdio.h>
  25 #include <string.h>
  26 #include <math.h>
  27 #include <assert.h>
  28
  29 #include "avcodec.h"
  30 #include "libavutil/avutil.h"
  31 #include "get_bits.h"
  32
  33 #include "g729.h"
  34 #include "lsp.h"
  35 #include "celp_math.h"
  36 #include "acelp_filters.h"
  37 #include "acelp_pitch_delay.h"
  38 #include "acelp_vectors.h"
  39 #include "g729data.h"
  40
  41 /**
  42  * minimum quantized LSF value (3.2.4)
  43  * 0.005 in Q13
  44  */
  45 #define LSFQ_MIN                   40
  46
  47 /**
  48  * maximum quantized LSF value (3.2.4)
  49  * 3.135 in Q13
  50  */
  51 #define LSFQ_MAX                   25681
  52
  53 /**
  54  * minimum LSF distance (3.2.4)
  55  * 0.0391 in Q13
  56  */
  57 #define LSFQ_DIFF_MIN              321
  58
  59 /**
  60  * minimum gain pitch value (3.8, Equation 47)
  61  * 0.2 in (1.14)
  62  */
  63 #define SHARP_MIN                  3277
  64
  65 /**
  66  * maximum gain pitch value (3.8, Equation 47)
  67  * (EE) This does not comply with the specification.
  68  * Specification says about 0.8, which should be
  69  * 13107 in (1.14), but reference C code uses
  70  * 13017 (equals to 0.7945) instead of it.
  71  */
  72 #define SHARP_MAX                  13017
  73
  74 typedef struct
  75 {
  76     int sample_rate;
  77     uint8_t packed_frame_size;  ///< input frame size(in bytes)
  78     uint8_t unpacked_frame_size;///< output frame size (in bytes)
  79     uint8_t fc_indexes_bits;    ///< size (in bits) of fixed-codebook index entry
  80
  81     /// mr_energy = mean_energy + 10 * log10(2^26  * subframe_size) in (7.13)
  82     int mr_energy;
  83 } G729_format_description;
  84
  85 /**
  86  * \brief pseudo random number generator
  87  */
  88 static inline uint16_t g729_random(uint16_t value)
  89 {
  90     return 31821 * value + 13849;
  91 }
  92
  93 /**
  94  * Get parity bit of bit 2..7
  95  */
  96 static inline int g729_get_parity(uint8_t value)
  97 {
  98    return (0x6996966996696996ULL >> (value >> 2)) & 1;
  99 }
 100
 101     if(avctx->channels != 1)
 102     {
 103         av_log(avctx, AV_LOG_ERROR, "Only mono sound is supported (requested channels: %d).\n", avctx->channels);
 104         return AVERROR_NOFMT;
 105     }
 106
 107         ff_acelp_weighted_vector_sum(
 108                 fc + pitch_delay_int[i],
 109                 fc + pitch_delay_int[i],
 110                 fc,
 111                 1 << 14,
 112                 av_clip(ctx->gain_pitch, SHARP_MIN, SHARP_MAX),
 113                 0,
 114                 14,
 115                 ctx->subframe_size - pitch_delay_int[i]);
 116
 117         if(ctx->frame_erasure)
 118         {
 119             ctx->gain_pitch = (29491 * ctx->gain_pitch) >> 15; // 0.9 (0.15)
 120             ctx->gain_code  = (2007 * ctx->gain_code) >> 11;   // 0.98 in (0.11)
 121
 122             gain_corr_factor = 0;
 123         }
 124         else
 125         {
 126             ctx->gain_pitch  = cb_gain_1st_8k[parm->gc_1st_index[i]][0] +
 127                                cb_gain_2nd_8k[parm->gc_2nd_index[i]][0];
 128             gain_corr_factor = cb_gain_1st_8k[parm->gc_1st_index[i]][1] +
 129                                cb_gain_2nd_8k[parm->gc_2nd_index[i]][1];
 130
 131         ff_acelp_weighted_vector_sum(
 132                 ctx->exc + i * ctx->subframe_size,
 133                 ctx->exc + i * ctx->subframe_size,
 134                 fc,
 135                 (!voicing && ctx->frame_erasure) ? 0 : ctx->gain_pitch,
 136                 ( voicing && ctx->frame_erasure) ? 0 : ctx->gain_code,
 137                 1<<13,
 138                 14,
 139                 ctx->subframe_size);
 140
 141     if (buf_size<packed_frame_size)
 142     {
 143         av_log(avctx, AV_LOG_ERROR, "Error processing packet: packet size too small\n");
 144         return AVERROR(EIO);
 145     }
 146     if (*data_size<unpacked_frame_size)
 147     {
 148         av_log(avctx, AV_LOG_ERROR, "Error processing packet: output buffer too small\n");
 149         return AVERROR(EIO);
 150     }
 151
 152 AVCodec g729_decoder =
 153 {
 154     "g729",
 155     CODEC_TYPE_AUDIO,
 156     CODEC_ID_G729,
 157     sizeof(G729_Context),
 158     ff_g729_decoder_init,
 159     NULL,
 160     NULL,
 161     ff_g729_decode_frame,
 162     .long_name = NULL_IF_CONFIG_SMALL("G.729"),
 163 };