1/*
2 * ADX ADPCM codecs
3 * Copyright (c) 2001,2003 BERO
4 *
5 * This file is part of Libav.
6 *
7 * Libav 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 * Libav 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 Libav; 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 "put_bits.h"
26
27/**
28 * @file
29 * SEGA CRI adx codecs.
30 *
31 * Reference documents:
32 * http://ku-www.ss.titech.ac.jp/~yatsushi/adx.html
33 * adx2wav & wav2adx http://www.geocities.co.jp/Playtown/2004/
34 */
35
36static void adx_encode(ADXContext *c, uint8_t *adx, const int16_t *wav,
37                       ADXChannelState *prev, int channels)
38{
39    PutBitContext pb;
40    int scale;
41    int i, j;
42    int s0, s1, s2, d;
43    int max = 0;
44    int min = 0;
45    int data[BLOCK_SAMPLES];
46
47    s1 = prev->s1;
48    s2 = prev->s2;
49    for (i = 0, j = 0; j < 32; i += channels, j++) {
50        s0 = wav[i];
51        d = ((s0 << COEFF_BITS) - c->coeff[0] * s1 - c->coeff[1] * s2) >> COEFF_BITS;
52        data[j] = d;
53        if (max < d)
54            max = d;
55        if (min > d)
56            min = d;
57        s2 = s1;
58        s1 = s0;
59    }
60    prev->s1 = s1;
61    prev->s2 = s2;
62
63    if (max == 0 && min == 0) {
64        memset(adx, 0, BLOCK_SIZE);
65        return;
66    }
67
68    if (max / 7 > -min / 8)
69        scale = max / 7;
70    else
71        scale = -min / 8;
72
73    if (scale == 0)
74        scale = 1;
75
76    AV_WB16(adx, scale);
77
78    init_put_bits(&pb, adx + 2, 16);
79    for (i = 0; i < BLOCK_SAMPLES; i++)
80        put_sbits(&pb, 4, av_clip(data[i] / scale, -8, 7));
81    flush_put_bits(&pb);
82}
83
84#define HEADER_SIZE 36
85
86static int adx_encode_header(AVCodecContext *avctx, uint8_t *buf, int bufsize)
87{
88    ADXContext *c = avctx->priv_data;
89
90    if (bufsize < HEADER_SIZE)
91        return AVERROR(EINVAL);
92
93    bytestream_put_be16(&buf, 0x8000);              /* header signature */
94    bytestream_put_be16(&buf, HEADER_SIZE - 4);     /* copyright offset */
95    bytestream_put_byte(&buf, 3);                   /* encoding */
96    bytestream_put_byte(&buf, BLOCK_SIZE);          /* block size */
97    bytestream_put_byte(&buf, 4);                   /* sample size */
98    bytestream_put_byte(&buf, avctx->channels);     /* channels */
99    bytestream_put_be32(&buf, avctx->sample_rate);  /* sample rate */
100    bytestream_put_be32(&buf, 0);                   /* total sample count */
101    bytestream_put_be16(&buf, c->cutoff);           /* cutoff frequency */
102    bytestream_put_byte(&buf, 3);                   /* version */
103    bytestream_put_byte(&buf, 0);                   /* flags */
104    bytestream_put_be32(&buf, 0);                   /* unknown */
105    bytestream_put_be32(&buf, 0);                   /* loop enabled */
106    bytestream_put_be16(&buf, 0);                   /* padding */
107    bytestream_put_buffer(&buf, "(c)CRI", 6);       /* copyright signature */
108
109    return HEADER_SIZE;
110}
111
112static av_cold int adx_encode_init(AVCodecContext *avctx)
113{
114    ADXContext *c = avctx->priv_data;
115
116    if (avctx->channels > 2) {
117        av_log(avctx, AV_LOG_ERROR, "Invalid number of channels\n");
118        return AVERROR(EINVAL);
119    }
120    avctx->frame_size = BLOCK_SAMPLES;
121
122    avctx->coded_frame = avcodec_alloc_frame();
123
124    /* the cutoff can be adjusted, but this seems to work pretty well */
125    c->cutoff = 500;
126    ff_adx_calculate_coeffs(c->cutoff, avctx->sample_rate, COEFF_BITS, c->coeff);
127
128    return 0;
129}
130
131static av_cold int adx_encode_close(AVCodecContext *avctx)
132{
133    av_freep(&avctx->coded_frame);
134    return 0;
135}
136
137static int adx_encode_frame(AVCodecContext *avctx, uint8_t *frame,
138                            int buf_size, void *data)
139{
140    ADXContext *c          = avctx->priv_data;
141    const int16_t *samples = data;
142    uint8_t *dst           = frame;
143    int ch;
144
145    if (!c->header_parsed) {
146        int hdrsize;
147        if ((hdrsize = adx_encode_header(avctx, dst, buf_size)) < 0) {
148            av_log(avctx, AV_LOG_ERROR, "output buffer is too small\n");
149            return AVERROR(EINVAL);
150        }
151        dst      += hdrsize;
152        buf_size -= hdrsize;
153        c->header_parsed = 1;
154    }
155    if (buf_size < BLOCK_SIZE * avctx->channels) {
156        av_log(avctx, AV_LOG_ERROR, "output buffer is too small\n");
157        return AVERROR(EINVAL);
158    }
159
160    for (ch = 0; ch < avctx->channels; ch++) {
161        adx_encode(c, dst, samples + ch, &c->prev[ch], avctx->channels);
162        dst += BLOCK_SIZE;
163    }
164    return dst - frame;
165}
166
167AVCodec ff_adpcm_adx_encoder = {
168    .name           = "adpcm_adx",
169    .type           = AVMEDIA_TYPE_AUDIO,
170    .id             = CODEC_ID_ADPCM_ADX,
171    .priv_data_size = sizeof(ADXContext),
172    .init           = adx_encode_init,
173    .encode         = adx_encode_frame,
174    .close          = adx_encode_close,
175    .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16,
176                                                      AV_SAMPLE_FMT_NONE },
177    .long_name      = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"),
178};
179