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1 | /* | ||
2 | * The simplest AC-3 encoder | ||
3 | * Copyright (c) 2000 Fabrice Bellard | ||
4 | * Copyright (c) 2006-2010 Justin Ruggles <justin.ruggles@gmail.com> | ||
5 | * Copyright (c) 2006-2010 Prakash Punnoor <prakash@punnoor.de> | ||
6 | * | ||
7 | * This file is part of FFmpeg. | ||
8 | * | ||
9 | * FFmpeg is free software; you can redistribute it and/or | ||
10 | * modify it under the terms of the GNU Lesser General Public | ||
11 | * License as published by the Free Software Foundation; either | ||
12 | * version 2.1 of the License, or (at your option) any later version. | ||
13 | * | ||
14 | * FFmpeg is distributed in the hope that it will be useful, | ||
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | ||
17 | * Lesser General Public License for more details. | ||
18 | * | ||
19 | * You should have received a copy of the GNU Lesser General Public | ||
20 | * License along with FFmpeg; if not, write to the Free Software | ||
21 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | ||
22 | */ | ||
23 | |||
24 | /** | ||
25 | * @file | ||
26 | * floating-point AC-3 encoder. | ||
27 | */ | ||
28 | |||
29 | #define AC3ENC_FLOAT 1 | ||
30 | #include "audiodsp.h" | ||
31 | #include "ac3enc.h" | ||
32 | #include "codec_internal.h" | ||
33 | #include "eac3enc.h" | ||
34 | #include "kbdwin.h" | ||
35 | |||
36 | |||
37 | /* | ||
38 | * Scale MDCT coefficients from float to 24-bit fixed-point. | ||
39 | */ | ||
40 | 546 | static void scale_coefficients(AC3EncodeContext *s) | |
41 | { | ||
42 | 546 | int chan_size = AC3_MAX_COEFS * s->num_blocks; | |
43 | 546 | int cpl = s->cpl_on; | |
44 | 546 | s->ac3dsp.float_to_fixed24(s->fixed_coef_buffer + (chan_size * !cpl), | |
45 | 546 | s->mdct_coef_buffer + (chan_size * !cpl), | |
46 | 546 | chan_size * (s->channels + cpl)); | |
47 | 546 | } | |
48 | |||
49 | |||
50 | /* | ||
51 | * Clip MDCT coefficients to allowable range. | ||
52 | */ | ||
53 | 3276 | static void clip_coefficients(AudioDSPContext *adsp, float *coef, | |
54 | unsigned int len) | ||
55 | { | ||
56 | 3276 | adsp->vector_clipf(coef, coef, len, COEF_MIN, COEF_MAX); | |
57 | 3276 | } | |
58 | |||
59 | |||
60 | /* | ||
61 | * Calculate a single coupling coordinate. | ||
62 | */ | ||
63 | 30736 | static CoefType calc_cpl_coord(CoefSumType energy_ch, CoefSumType energy_cpl) | |
64 | { | ||
65 | 30736 | float coord = 0.125; | |
66 |
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30736 | if (energy_cpl > 0) |
67 | 30736 | coord *= sqrtf(energy_ch / energy_cpl); | |
68 |
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30736 | return FFMIN(coord, COEF_MAX); |
69 | } | ||
70 | |||
71 | 13104 | static void sum_square_butterfly(AC3EncodeContext *s, float sum[4], | |
72 | const float *coef0, const float *coef1, | ||
73 | int len) | ||
74 | { | ||
75 | 13104 | s->ac3dsp.sum_square_butterfly_float(sum, coef0, coef1, len); | |
76 | 13104 | } | |
77 | |||
78 | #include "ac3enc_template.c" | ||
79 | |||
80 | /** | ||
81 | * Initialize MDCT tables. | ||
82 | * | ||
83 | * @param s AC-3 encoder private context | ||
84 | * @return 0 on success, negative error code on failure | ||
85 | */ | ||
86 | 2 | static av_cold int ac3_float_mdct_init(AC3EncodeContext *s) | |
87 | { | ||
88 | 2 | const float scale = -2.0 / AC3_WINDOW_SIZE; | |
89 | 2 | float *window = av_malloc_array(AC3_BLOCK_SIZE, sizeof(*window)); | |
90 |
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2 | if (!window) { |
91 | ✗ | av_log(s->avctx, AV_LOG_ERROR, "Cannot allocate memory.\n"); | |
92 | ✗ | return AVERROR(ENOMEM); | |
93 | } | ||
94 | |||
95 | 2 | avpriv_kbd_window_init(window, 5.0, AC3_BLOCK_SIZE); | |
96 | 2 | s->mdct_window = window; | |
97 | |||
98 | 2 | return av_tx_init(&s->tx, &s->tx_fn, AV_TX_FLOAT_MDCT, 0, | |
99 | AC3_BLOCK_SIZE, &scale, 0); | ||
100 | } | ||
101 | |||
102 | |||
103 | 2 | av_cold int ff_ac3_float_encode_init(AVCodecContext *avctx) | |
104 | { | ||
105 | 2 | AC3EncodeContext *s = avctx->priv_data; | |
106 | 2 | s->mdct_init = ac3_float_mdct_init; | |
107 | 2 | s->allocate_sample_buffers = allocate_sample_buffers; | |
108 | 2 | s->fdsp = avpriv_float_dsp_alloc(avctx->flags & AV_CODEC_FLAG_BITEXACT); | |
109 |
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2 | if (!s->fdsp) |
110 | ✗ | return AVERROR(ENOMEM); | |
111 | 2 | return ff_ac3_encode_init(avctx); | |
112 | } | ||
113 | |||
114 | const FFCodec ff_ac3_encoder = { | ||
115 | .p.name = "ac3", | ||
116 | CODEC_LONG_NAME("ATSC A/52A (AC-3)"), | ||
117 | .p.type = AVMEDIA_TYPE_AUDIO, | ||
118 | .p.id = AV_CODEC_ID_AC3, | ||
119 | .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE, | ||
120 | .priv_data_size = sizeof(AC3EncodeContext), | ||
121 | .init = ff_ac3_float_encode_init, | ||
122 | FF_CODEC_ENCODE_CB(ff_ac3_float_encode_frame), | ||
123 | .close = ff_ac3_encode_close, | ||
124 | .p.sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_FLTP, | ||
125 | AV_SAMPLE_FMT_NONE }, | ||
126 | .p.priv_class = &ff_ac3enc_class, | ||
127 | .p.supported_samplerates = ff_ac3_sample_rate_tab, | ||
128 | CODEC_OLD_CHANNEL_LAYOUTS_ARRAY(ff_ac3_channel_layouts) | ||
129 | .p.ch_layouts = ff_ac3_ch_layouts, | ||
130 | .defaults = ff_ac3_enc_defaults, | ||
131 | .caps_internal = FF_CODEC_CAP_INIT_CLEANUP, | ||
132 | }; | ||
133 |