3 * Copyright (c) 2001,2003 BERO
5 * This file is part of Libav.
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.
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.
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
22 #include "libavutil/intreadwrite.h"
29 * SEGA CRI adx codecs.
31 * Reference documents:
32 * http://ku-www.ss.titech.ac.jp/~yatsushi/adx.html
33 * adx2wav & wav2adx http://www.geocities.co.jp/Playtown/2004/
36 static av_cold int adx_decode_init(AVCodecContext *avctx)
38 avctx->sample_fmt = AV_SAMPLE_FMT_S16;
43 * Decode 32 samples from 18 bytes.
45 * A 16-bit scalar value is applied to 32 residuals, which then have a
46 * 2nd-order LPC filter applied to it to form the output signal for a single
49 static void adx_decode(ADXContext *c, int16_t *out, const uint8_t *in, int ch)
51 ADXChannelState *prev = &c->prev[ch];
53 int scale = AV_RB16(in);
57 init_get_bits(&gb, in + 2, (18 - 2) * 8);
60 for (i = 0; i < 32; i++) {
61 d = get_sbits(&gb, 4);
62 s0 = (BASEVOL * d * scale + SCALE1 * s1 - SCALE2 * s2) >> 14;
64 s1 = av_clip_int16(s0);
73 * Decode stream header.
75 * @param avctx codec context
76 * @param buf packet data
77 * @param bufsize packet size
78 * @return data offset or negative error code if header is invalid
80 static int adx_decode_header(AVCodecContext *avctx, const uint8_t *buf,
83 ADXContext *c = avctx->priv_data;
86 if (AV_RB16(buf) != 0x8000)
87 return AVERROR_INVALIDDATA;
88 offset = AV_RB16(buf + 2) + 4;
89 if (bufsize < offset || memcmp(buf + offset - 6, "(c)CRI", 6))
90 return AVERROR_INVALIDDATA;
92 c->channels = avctx->channels = buf[7];
93 if (avctx->channels > 2)
94 return AVERROR_INVALIDDATA;
95 avctx->sample_rate = AV_RB32(buf + 8);
96 if (avctx->sample_rate < 1 ||
97 avctx->sample_rate > INT_MAX / (avctx->channels * 18 * 8))
98 return AVERROR_INVALIDDATA;
99 avctx->bit_rate = avctx->sample_rate * avctx->channels * 18 * 8 / 32;
104 static int adx_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
107 const uint8_t *buf0 = avpkt->data;
108 int buf_size = avpkt->size;
109 ADXContext *c = avctx->priv_data;
110 int16_t *samples = data;
111 const uint8_t *buf = buf0;
114 if (!c->header_parsed) {
115 int hdrsize = adx_decode_header(avctx, buf, rest);
117 av_log(avctx, AV_LOG_ERROR, "invalid stream header\n");
120 c->header_parsed = 1;
125 /* 18 bytes of data are expanded into 32*2 bytes of audio,
126 so guard against buffer overflows */
127 if (rest / 18 > *data_size / 64)
128 rest = (*data_size / 64) * 18;
131 int copysize = 18 * avctx->channels - c->in_temp;
132 memcpy(c->dec_temp + c->in_temp, buf, copysize);
135 adx_decode(c, samples, c->dec_temp, 0);
136 if (avctx->channels == 2)
137 adx_decode(c, samples + 1, c->dec_temp + 18, 1);
138 samples += 32 * c->channels;
141 while (rest >= 18 * c->channels) {
142 adx_decode(c, samples, buf, 0);
143 if (c->channels == 2)
144 adx_decode(c, samples + 1, buf + 18, 1);
145 rest -= 18 * c->channels;
146 buf += 18 * c->channels;
147 samples += 32 * c->channels;
152 memcpy(c->dec_temp, buf, rest);
155 *data_size = (uint8_t*)samples - (uint8_t*)data;
159 AVCodec ff_adpcm_adx_decoder = {
161 .type = AVMEDIA_TYPE_AUDIO,
162 .id = CODEC_ID_ADPCM_ADX,
163 .priv_data_size = sizeof(ADXContext),
164 .init = adx_decode_init,
165 .decode = adx_decode_frame,
166 .long_name = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"),