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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 "libavutil/intreadwrite.h" | |
23 | #include "avcodec.h" | |
24 | #include "adx.h" | |
25 | #include "get_bits.h" | |
26 | #include "internal.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 av_cold int adx_decode_init(AVCodecContext *avctx) | |
38 | { | |
39 | ADXContext *c = avctx->priv_data; | |
40 | int ret, header_size; | |
41 | ||
42 | if (avctx->extradata_size >= 24) { | |
43 | if ((ret = ff_adx_decode_header(avctx, avctx->extradata, | |
44 | avctx->extradata_size, &header_size, | |
45 | c->coeff)) < 0) { | |
46 | av_log(avctx, AV_LOG_ERROR, "error parsing ADX header\n"); | |
47 | return AVERROR_INVALIDDATA; | |
48 | } | |
49 | c->channels = avctx->channels; | |
50 | c->header_parsed = 1; | |
51 | } | |
52 | ||
53 | avctx->sample_fmt = AV_SAMPLE_FMT_S16P; | |
54 | ||
55 | return 0; | |
56 | } | |
57 | ||
58 | /** | |
59 | * Decode 32 samples from 18 bytes. | |
60 | * | |
61 | * A 16-bit scalar value is applied to 32 residuals, which then have a | |
62 | * 2nd-order LPC filter applied to it to form the output signal for a single | |
63 | * channel. | |
64 | */ | |
65 | static int adx_decode(ADXContext *c, int16_t *out, int offset, | |
66 | const uint8_t *in, int ch) | |
67 | { | |
68 | ADXChannelState *prev = &c->prev[ch]; | |
69 | GetBitContext gb; | |
70 | int scale = AV_RB16(in); | |
71 | int i; | |
72 | int s0, s1, s2, d; | |
73 | ||
74 | /* check if this is an EOF packet */ | |
75 | if (scale & 0x8000) | |
76 | return -1; | |
77 | ||
78 | init_get_bits(&gb, in + 2, (BLOCK_SIZE - 2) * 8); | |
79 | out += offset; | |
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 | } | |
89 | prev->s1 = s1; | |
90 | prev->s2 = s2; | |
91 | ||
92 | return 0; | |
93 | } | |
94 | ||
95 | static int adx_decode_frame(AVCodecContext *avctx, void *data, | |
96 | int *got_frame_ptr, AVPacket *avpkt) | |
97 | { | |
98 | AVFrame *frame = data; | |
99 | int buf_size = avpkt->size; | |
100 | ADXContext *c = avctx->priv_data; | |
101 | int16_t **samples; | |
102 | int samples_offset; | |
103 | const uint8_t *buf = avpkt->data; | |
104 | const uint8_t *buf_end = buf + avpkt->size; | |
105 | int num_blocks, ch, ret; | |
106 | ||
107 | if (c->eof) { | |
108 | *got_frame_ptr = 0; | |
109 | return buf_size; | |
110 | } | |
111 | ||
112 | if (!c->header_parsed && buf_size >= 2 && AV_RB16(buf) == 0x8000) { | |
113 | int header_size; | |
114 | if ((ret = ff_adx_decode_header(avctx, buf, buf_size, &header_size, | |
115 | c->coeff)) < 0) { | |
116 | av_log(avctx, AV_LOG_ERROR, "error parsing ADX header\n"); | |
117 | return AVERROR_INVALIDDATA; | |
118 | } | |
119 | c->channels = avctx->channels; | |
120 | c->header_parsed = 1; | |
121 | if (buf_size < header_size) | |
122 | return AVERROR_INVALIDDATA; | |
123 | buf += header_size; | |
124 | buf_size -= header_size; | |
125 | } | |
126 | if (!c->header_parsed) | |
127 | return AVERROR_INVALIDDATA; | |
128 | ||
129 | /* calculate number of blocks in the packet */ | |
130 | num_blocks = buf_size / (BLOCK_SIZE * c->channels); | |
131 | ||
132 | /* if the packet is not an even multiple of BLOCK_SIZE, check for an EOF | |
133 | packet */ | |
134 | if (!num_blocks || buf_size % (BLOCK_SIZE * avctx->channels)) { | |
135 | if (buf_size >= 4 && (AV_RB16(buf) & 0x8000)) { | |
136 | c->eof = 1; | |
137 | *got_frame_ptr = 0; | |
138 | return avpkt->size; | |
139 | } | |
140 | return AVERROR_INVALIDDATA; | |
141 | } | |
142 | ||
143 | /* get output buffer */ | |
144 | frame->nb_samples = num_blocks * BLOCK_SAMPLES; | |
145 | if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) | |
146 | return ret; | |
147 | samples = (int16_t **)frame->extended_data; | |
148 | samples_offset = 0; | |
149 | ||
150 | while (num_blocks--) { | |
151 | for (ch = 0; ch < c->channels; ch++) { | |
152 | if (buf_end - buf < BLOCK_SIZE || adx_decode(c, samples[ch], samples_offset, buf, ch)) { | |
153 | c->eof = 1; | |
154 | buf = avpkt->data + avpkt->size; | |
155 | break; | |
156 | } | |
157 | buf_size -= BLOCK_SIZE; | |
158 | buf += BLOCK_SIZE; | |
159 | } | |
160 | if (!c->eof) | |
161 | samples_offset += BLOCK_SAMPLES; | |
162 | } | |
163 | ||
164 | frame->nb_samples = samples_offset; | |
165 | *got_frame_ptr = 1; | |
166 | ||
167 | return buf - avpkt->data; | |
168 | } | |
169 | ||
170 | static void adx_decode_flush(AVCodecContext *avctx) | |
171 | { | |
172 | ADXContext *c = avctx->priv_data; | |
173 | memset(c->prev, 0, sizeof(c->prev)); | |
174 | c->eof = 0; | |
175 | } | |
176 | ||
177 | AVCodec ff_adpcm_adx_decoder = { | |
178 | .name = "adpcm_adx", | |
179 | .long_name = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"), | |
180 | .type = AVMEDIA_TYPE_AUDIO, | |
181 | .id = AV_CODEC_ID_ADPCM_ADX, | |
182 | .priv_data_size = sizeof(ADXContext), | |
183 | .init = adx_decode_init, | |
184 | .decode = adx_decode_frame, | |
185 | .flush = adx_decode_flush, | |
186 | .capabilities = CODEC_CAP_DR1, | |
187 | .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P, | |
188 | AV_SAMPLE_FMT_NONE }, | |
189 | }; |