blob: 178ea99dcfc8f2e49d1722d63ea6e8764bae1ee1
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 * (1 << 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 = AV_CODEC_CAP_DR1, |
187 | .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P, |
188 | AV_SAMPLE_FMT_NONE }, |
189 | }; |
190 |