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 "libavutil/intreadwrite.h"
23#include "avcodec.h"
24#include "adx.h"
25#include "get_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 av_cold int adx_decode_init(AVCodecContext *avctx)
37{
38    ADXContext *c = avctx->priv_data;
39    int ret, header_size;
40
41    if (avctx->extradata_size >= 24) {
42        if ((ret = avpriv_adx_decode_header(avctx, avctx->extradata,
43                                            avctx->extradata_size, &header_size,
44                                            c->coeff)) < 0) {
45            av_log(avctx, AV_LOG_ERROR, "error parsing ADX header\n");
46            return AVERROR_INVALIDDATA;
47        }
48        c->channels      = avctx->channels;
49        c->header_parsed = 1;
50    }
51
52    avctx->sample_fmt = AV_SAMPLE_FMT_S16;
53
54    avcodec_get_frame_defaults(&c->frame);
55    avctx->coded_frame = &c->frame;
56
57    return 0;
58}
59
60/**
61 * Decode 32 samples from 18 bytes.
62 *
63 * A 16-bit scalar value is applied to 32 residuals, which then have a
64 * 2nd-order LPC filter applied to it to form the output signal for a single
65 * channel.
66 */
67static int adx_decode(ADXContext *c, int16_t *out, const uint8_t *in, int ch)
68{
69    ADXChannelState *prev = &c->prev[ch];
70    GetBitContext gb;
71    int scale = AV_RB16(in);
72    int i;
73    int s0, s1, s2, d;
74
75    /* check if this is an EOF packet */
76    if (scale & 0x8000)
77        return -1;
78
79    init_get_bits(&gb, in + 2, (BLOCK_SIZE - 2) * 8);
80    s1 = prev->s1;
81    s2 = prev->s2;
82    for (i = 0; i < BLOCK_SAMPLES; i++) {
83        d  = get_sbits(&gb, 4);
84        s0 = ((d << COEFF_BITS) * scale + c->coeff[0] * s1 + c->coeff[1] * s2) >> COEFF_BITS;
85        s2 = s1;
86        s1 = av_clip_int16(s0);
87        *out = s1;
88        out += c->channels;
89    }
90    prev->s1 = s1;
91    prev->s2 = s2;
92
93    return 0;
94}
95
96static int adx_decode_frame(AVCodecContext *avctx, void *data,
97                            int *got_frame_ptr, AVPacket *avpkt)
98{
99    int buf_size        = avpkt->size;
100    ADXContext *c       = avctx->priv_data;
101    int16_t *samples;
102    const uint8_t *buf  = avpkt->data;
103    int num_blocks, ch, ret;
104
105    if (c->eof) {
106        *got_frame_ptr = 0;
107        return buf_size;
108    }
109
110    if (!c->header_parsed && buf_size >= 2 && AV_RB16(buf) == 0x8000) {
111        int header_size;
112        if ((ret = avpriv_adx_decode_header(avctx, buf, buf_size, &header_size,
113                                            c->coeff)) < 0) {
114            av_log(avctx, AV_LOG_ERROR, "error parsing ADX header\n");
115            return AVERROR_INVALIDDATA;
116        }
117        c->channels      = avctx->channels;
118        c->header_parsed = 1;
119        if (buf_size < header_size)
120            return AVERROR_INVALIDDATA;
121        buf      += header_size;
122        buf_size -= header_size;
123    }
124    if (!c->header_parsed)
125        return AVERROR_INVALIDDATA;
126
127    /* calculate number of blocks in the packet */
128    num_blocks = buf_size / (BLOCK_SIZE * c->channels);
129
130    /* if the packet is not an even multiple of BLOCK_SIZE, check for an EOF
131       packet */
132    if (!num_blocks || buf_size % (BLOCK_SIZE * avctx->channels)) {
133        if (buf_size >= 4 && (AV_RB16(buf) & 0x8000)) {
134            c->eof = 1;
135            *got_frame_ptr = 0;
136            return avpkt->size;
137        }
138        return AVERROR_INVALIDDATA;
139    }
140
141    /* get output buffer */
142    c->frame.nb_samples = num_blocks * BLOCK_SAMPLES;
143    if ((ret = avctx->get_buffer(avctx, &c->frame)) < 0) {
144        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
145        return ret;
146    }
147    samples = (int16_t *)c->frame.data[0];
148
149    while (num_blocks--) {
150        for (ch = 0; ch < c->channels; ch++) {
151            if (adx_decode(c, samples + ch, buf, ch)) {
152                c->eof = 1;
153                buf = avpkt->data + avpkt->size;
154                break;
155            }
156            buf_size -= BLOCK_SIZE;
157            buf      += BLOCK_SIZE;
158        }
159        samples += BLOCK_SAMPLES * c->channels;
160    }
161
162    *got_frame_ptr   = 1;
163    *(AVFrame *)data = c->frame;
164
165    return buf - avpkt->data;
166}
167
168static void adx_decode_flush(AVCodecContext *avctx)
169{
170    ADXContext *c = avctx->priv_data;
171    memset(c->prev, 0, sizeof(c->prev));
172    c->eof = 0;
173}
174
175AVCodec ff_adpcm_adx_decoder = {
176    .name           = "adpcm_adx",
177    .type           = AVMEDIA_TYPE_AUDIO,
178    .id             = CODEC_ID_ADPCM_ADX,
179    .priv_data_size = sizeof(ADXContext),
180    .init           = adx_decode_init,
181    .decode         = adx_decode_frame,
182    .flush          = adx_decode_flush,
183    .capabilities   = CODEC_CAP_DR1,
184    .long_name      = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"),
185};
186