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| Rev | Author | Line No. | Line |
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| 4349 | Serge | 1 | /* |
| 2 | * The simplest AC-3 encoder |
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| 3 | * Copyright (c) 2000 Fabrice Bellard |
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| 4 | * Copyright (c) 2006-2010 Justin Ruggles |
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| 5 | * Copyright (c) 2006-2010 Prakash Punnoor |
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| 6 | * |
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| 7 | * This file is part of FFmpeg. |
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| 8 | * |
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| 9 | * FFmpeg is free software; you can redistribute it and/or |
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| 10 | * modify it under the terms of the GNU Lesser General Public |
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| 11 | * License as published by the Free Software Foundation; either |
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| 12 | * version 2.1 of the License, or (at your option) any later version. |
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| 13 | * |
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| 14 | * FFmpeg is distributed in the hope that it will be useful, |
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| 15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 17 | * Lesser General Public License for more details. |
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| 18 | * |
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| 19 | * You should have received a copy of the GNU Lesser General Public |
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| 20 | * License along with FFmpeg; if not, write to the Free Software |
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| 21 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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| 22 | */ |
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| 23 | |||
| 24 | /** |
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| 25 | * @file |
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| 26 | * fixed-point AC-3 encoder. |
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| 27 | */ |
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| 28 | |||
| 29 | #define CONFIG_FFT_FLOAT 0 |
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| 30 | #undef CONFIG_AC3ENC_FLOAT |
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| 31 | #include "internal.h" |
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| 32 | #include "ac3enc.h" |
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| 33 | #include "eac3enc.h" |
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| 34 | |||
| 35 | #define AC3ENC_TYPE AC3ENC_TYPE_AC3_FIXED |
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| 36 | #include "ac3enc_opts_template.c" |
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| 37 | |||
| 38 | static const AVClass ac3enc_class = { |
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| 39 | .class_name = "Fixed-Point AC-3 Encoder", |
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| 40 | .item_name = av_default_item_name, |
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| 41 | .option = ac3_options, |
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| 42 | .version = LIBAVUTIL_VERSION_INT, |
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| 43 | }; |
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| 44 | |||
| 45 | #include "ac3enc_template.c" |
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| 46 | |||
| 47 | |||
| 48 | /** |
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| 49 | * Finalize MDCT and free allocated memory. |
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| 50 | * |
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| 51 | * @param s AC-3 encoder private context |
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| 52 | */ |
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| 53 | av_cold void AC3_NAME(mdct_end)(AC3EncodeContext *s) |
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| 54 | { |
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| 55 | ff_mdct_end(&s->mdct); |
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| 56 | } |
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| 57 | |||
| 58 | |||
| 59 | /** |
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| 60 | * Initialize MDCT tables. |
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| 61 | * |
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| 62 | * @param s AC-3 encoder private context |
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| 63 | * @return 0 on success, negative error code on failure |
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| 64 | */ |
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| 65 | av_cold int AC3_NAME(mdct_init)(AC3EncodeContext *s) |
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| 66 | { |
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| 67 | int ret = ff_mdct_init(&s->mdct, 9, 0, -1.0); |
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| 68 | s->mdct_window = ff_ac3_window; |
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| 69 | return ret; |
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| 70 | } |
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| 71 | |||
| 72 | |||
| 73 | /* |
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| 74 | * Apply KBD window to input samples prior to MDCT. |
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| 75 | */ |
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| 76 | static void apply_window(void *dsp, int16_t *output, const int16_t *input, |
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| 77 | const int16_t *window, unsigned int len) |
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| 78 | { |
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| 79 | DSPContext *dsp0 = dsp; |
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| 80 | dsp0->apply_window_int16(output, input, window, len); |
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| 81 | } |
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| 82 | |||
| 83 | |||
| 84 | /* |
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| 85 | * Normalize the input samples to use the maximum available precision. |
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| 86 | * This assumes signed 16-bit input samples. |
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| 87 | */ |
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| 88 | static int normalize_samples(AC3EncodeContext *s) |
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| 89 | { |
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| 90 | int v = s->ac3dsp.ac3_max_msb_abs_int16(s->windowed_samples, AC3_WINDOW_SIZE); |
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| 91 | v = 14 - av_log2(v); |
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| 92 | if (v > 0) |
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| 93 | s->ac3dsp.ac3_lshift_int16(s->windowed_samples, AC3_WINDOW_SIZE, v); |
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| 94 | /* +6 to right-shift from 31-bit to 25-bit */ |
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| 95 | return v + 6; |
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| 96 | } |
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| 97 | |||
| 98 | |||
| 99 | /* |
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| 100 | * Scale MDCT coefficients to 25-bit signed fixed-point. |
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| 101 | */ |
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| 102 | static void scale_coefficients(AC3EncodeContext *s) |
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| 103 | { |
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| 104 | int blk, ch; |
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| 105 | |||
| 106 | for (blk = 0; blk < s->num_blocks; blk++) { |
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| 107 | AC3Block *block = &s->blocks[blk]; |
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| 108 | for (ch = 1; ch <= s->channels; ch++) { |
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| 109 | s->ac3dsp.ac3_rshift_int32(block->mdct_coef[ch], AC3_MAX_COEFS, |
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| 110 | block->coeff_shift[ch]); |
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| 111 | } |
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| 112 | } |
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| 113 | } |
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| 114 | |||
| 115 | static void sum_square_butterfly(AC3EncodeContext *s, int64_t sum[4], |
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| 116 | const int32_t *coef0, const int32_t *coef1, |
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| 117 | int len) |
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| 118 | { |
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| 119 | s->ac3dsp.sum_square_butterfly_int32(sum, coef0, coef1, len); |
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| 120 | } |
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| 121 | |||
| 122 | /* |
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| 123 | * Clip MDCT coefficients to allowable range. |
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| 124 | */ |
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| 125 | static void clip_coefficients(DSPContext *dsp, int32_t *coef, unsigned int len) |
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| 126 | { |
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| 127 | dsp->vector_clip_int32(coef, coef, COEF_MIN, COEF_MAX, len); |
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| 128 | } |
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| 129 | |||
| 130 | |||
| 131 | /* |
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| 132 | * Calculate a single coupling coordinate. |
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| 133 | */ |
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| 134 | static CoefType calc_cpl_coord(CoefSumType energy_ch, CoefSumType energy_cpl) |
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| 135 | { |
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| 136 | if (energy_cpl <= COEF_MAX) { |
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| 137 | return 1048576; |
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| 138 | } else { |
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| 139 | uint64_t coord = energy_ch / (energy_cpl >> 24); |
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| 140 | uint32_t coord32 = FFMIN(coord, 1073741824); |
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| 141 | coord32 = ff_sqrt(coord32) << 9; |
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| 142 | return FFMIN(coord32, COEF_MAX); |
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| 143 | } |
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| 144 | } |
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| 145 | |||
| 146 | |||
| 147 | static av_cold int ac3_fixed_encode_init(AVCodecContext *avctx) |
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| 148 | { |
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| 149 | AC3EncodeContext *s = avctx->priv_data; |
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| 150 | s->fixed_point = 1; |
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| 151 | return ff_ac3_encode_init(avctx); |
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| 152 | } |
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| 153 | |||
| 154 | |||
| 155 | AVCodec ff_ac3_fixed_encoder = { |
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| 156 | .name = "ac3_fixed", |
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| 157 | .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52A (AC-3)"), |
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| 158 | .type = AVMEDIA_TYPE_AUDIO, |
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| 159 | .id = AV_CODEC_ID_AC3, |
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| 160 | .priv_data_size = sizeof(AC3EncodeContext), |
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| 161 | .init = ac3_fixed_encode_init, |
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| 162 | .encode2 = ff_ac3_fixed_encode_frame, |
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| 163 | .close = ff_ac3_encode_close, |
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| 164 | .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16P, |
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| 165 | AV_SAMPLE_FMT_NONE }, |
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| 166 | .priv_class = &ac3enc_class, |
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| 167 | .channel_layouts = ff_ac3_channel_layouts, |
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| 168 | .defaults = ac3_defaults, |
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| 169 | }; |