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1 | /* |
2 | * ADX ADPCM codecs | |
3 | * Copyright (c) 2001,2003 BERO | |
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 | ||
22 | #include "avcodec.h" | |
23 | #include "adx.h" | |
24 | #include "bytestream.h" | |
25 | #include "internal.h" | |
26 | #include "put_bits.h" | |
27 | ||
28 | /** | |
29 | * @file | |
30 | * SEGA CRI adx codecs. | |
31 | * | |
32 | * Reference documents: | |
33 | * http://ku-www.ss.titech.ac.jp/~yatsushi/adx.html | |
34 | * adx2wav & wav2adx http://www.geocities.co.jp/Playtown/2004/ | |
35 | */ | |
36 | ||
37 | static void adx_encode(ADXContext *c, uint8_t *adx, const int16_t *wav, | |
38 | ADXChannelState *prev, int channels) | |
39 | { | |
40 | PutBitContext pb; | |
41 | int scale; | |
42 | int i, j; | |
43 | int s0, s1, s2, d; | |
44 | int max = 0; | |
45 | int min = 0; | |
46 | int data[BLOCK_SAMPLES]; | |
47 | ||
48 | s1 = prev->s1; | |
49 | s2 = prev->s2; | |
50 | for (i = 0, j = 0; j < 32; i += channels, j++) { | |
51 | s0 = wav[i]; | |
52 | d = ((s0 << COEFF_BITS) - c->coeff[0] * s1 - c->coeff[1] * s2) >> COEFF_BITS; | |
53 | data[j] = d; | |
54 | if (max < d) | |
55 | max = d; | |
56 | if (min > d) | |
57 | min = d; | |
58 | s2 = s1; | |
59 | s1 = s0; | |
60 | } | |
61 | prev->s1 = s1; | |
62 | prev->s2 = s2; | |
63 | ||
64 | if (max == 0 && min == 0) { | |
65 | memset(adx, 0, BLOCK_SIZE); | |
66 | return; | |
67 | } | |
68 | ||
69 | if (max / 7 > -min / 8) | |
70 | scale = max / 7; | |
71 | else | |
72 | scale = -min / 8; | |
73 | ||
74 | if (scale == 0) | |
75 | scale = 1; | |
76 | ||
77 | AV_WB16(adx, scale); | |
78 | ||
79 | init_put_bits(&pb, adx + 2, 16); | |
80 | for (i = 0; i < BLOCK_SAMPLES; i++) | |
81 | put_sbits(&pb, 4, av_clip(data[i] / scale, -8, 7)); | |
82 | flush_put_bits(&pb); | |
83 | } | |
84 | ||
85 | #define HEADER_SIZE 36 | |
86 | ||
87 | static int adx_encode_header(AVCodecContext *avctx, uint8_t *buf, int bufsize) | |
88 | { | |
89 | ADXContext *c = avctx->priv_data; | |
90 | ||
91 | bytestream_put_be16(&buf, 0x8000); /* header signature */ | |
92 | bytestream_put_be16(&buf, HEADER_SIZE - 4); /* copyright offset */ | |
93 | bytestream_put_byte(&buf, 3); /* encoding */ | |
94 | bytestream_put_byte(&buf, BLOCK_SIZE); /* block size */ | |
95 | bytestream_put_byte(&buf, 4); /* sample size */ | |
96 | bytestream_put_byte(&buf, avctx->channels); /* channels */ | |
97 | bytestream_put_be32(&buf, avctx->sample_rate); /* sample rate */ | |
98 | bytestream_put_be32(&buf, 0); /* total sample count */ | |
99 | bytestream_put_be16(&buf, c->cutoff); /* cutoff frequency */ | |
100 | bytestream_put_byte(&buf, 3); /* version */ | |
101 | bytestream_put_byte(&buf, 0); /* flags */ | |
102 | bytestream_put_be32(&buf, 0); /* unknown */ | |
103 | bytestream_put_be32(&buf, 0); /* loop enabled */ | |
104 | bytestream_put_be16(&buf, 0); /* padding */ | |
105 | bytestream_put_buffer(&buf, "(c)CRI", 6); /* copyright signature */ | |
106 | ||
107 | return HEADER_SIZE; | |
108 | } | |
109 | ||
110 | static av_cold int adx_encode_init(AVCodecContext *avctx) | |
111 | { | |
112 | ADXContext *c = avctx->priv_data; | |
113 | ||
114 | if (avctx->channels > 2) { | |
115 | av_log(avctx, AV_LOG_ERROR, "Invalid number of channels\n"); | |
116 | return AVERROR(EINVAL); | |
117 | } | |
118 | avctx->frame_size = BLOCK_SAMPLES; | |
119 | ||
120 | /* the cutoff can be adjusted, but this seems to work pretty well */ | |
121 | c->cutoff = 500; | |
122 | ff_adx_calculate_coeffs(c->cutoff, avctx->sample_rate, COEFF_BITS, c->coeff); | |
123 | ||
124 | return 0; | |
125 | } | |
126 | ||
127 | static int adx_encode_frame(AVCodecContext *avctx, AVPacket *avpkt, | |
128 | const AVFrame *frame, int *got_packet_ptr) | |
129 | { | |
130 | ADXContext *c = avctx->priv_data; | |
131 | const int16_t *samples = (const int16_t *)frame->data[0]; | |
132 | uint8_t *dst; | |
133 | int ch, out_size, ret; | |
134 | ||
135 | out_size = BLOCK_SIZE * avctx->channels + !c->header_parsed * HEADER_SIZE; | |
136 | if ((ret = ff_alloc_packet2(avctx, avpkt, out_size)) < 0) | |
137 | return ret; | |
138 | dst = avpkt->data; | |
139 | ||
140 | if (!c->header_parsed) { | |
141 | int hdrsize; | |
142 | if ((hdrsize = adx_encode_header(avctx, dst, avpkt->size)) < 0) { | |
143 | av_log(avctx, AV_LOG_ERROR, "output buffer is too small\n"); | |
144 | return AVERROR(EINVAL); | |
145 | } | |
146 | dst += hdrsize; | |
147 | c->header_parsed = 1; | |
148 | } | |
149 | ||
150 | for (ch = 0; ch < avctx->channels; ch++) { | |
151 | adx_encode(c, dst, samples + ch, &c->prev[ch], avctx->channels); | |
152 | dst += BLOCK_SIZE; | |
153 | } | |
154 | ||
155 | *got_packet_ptr = 1; | |
156 | return 0; | |
157 | } | |
158 | ||
159 | AVCodec ff_adpcm_adx_encoder = { | |
160 | .name = "adpcm_adx", | |
161 | .long_name = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"), | |
162 | .type = AVMEDIA_TYPE_AUDIO, | |
163 | .id = AV_CODEC_ID_ADPCM_ADX, | |
164 | .priv_data_size = sizeof(ADXContext), | |
165 | .init = adx_encode_init, | |
166 | .encode2 = adx_encode_frame, | |
167 | .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16, | |
168 | AV_SAMPLE_FMT_NONE }, | |
169 | }; |