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 "avcodec.h"
23 #include "adx.h"
24 #include "bytestream.h"
25 #include "internal.h"
26 #include "put_bits.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
adx_encode(ADXContext * c,uint8_t * adx,const int16_t * wav,ADXChannelState * prev,int channels)37 static void adx_encode(ADXContext *c, uint8_t *adx, const int16_t *wav,
38 ADXChannelState *prev, int channels)
39 {
40 PutBitContext pb;
41 int scale;
42 int i, j;
43 int s0, s1, s2, d;
44 int max = 0;
45 int min = 0;
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 + ((-c->coeff[0] * s1 - c->coeff[1] * s2) >> COEFF_BITS);
52 if (max < d)
53 max = d;
54 if (min > d)
55 min = d;
56 s2 = s1;
57 s1 = s0;
58 }
59
60 if (max == 0 && min == 0) {
61 prev->s1 = s1;
62 prev->s2 = s2;
63 memset(adx, 0, BLOCK_SIZE);
64 return;
65 }
66
67 if (max / 7 > -min / 8)
68 scale = max / 7;
69 else
70 scale = -min / 8;
71
72 if (scale == 0)
73 scale = 1;
74
75 AV_WB16(adx, scale);
76
77 init_put_bits(&pb, adx + 2, 16);
78
79 s1 = prev->s1;
80 s2 = prev->s2;
81 for (i = 0, j = 0; j < 32; i += channels, j++) {
82 d = wav[i] + ((-c->coeff[0] * s1 - c->coeff[1] * s2) >> COEFF_BITS);
83
84 d = av_clip_intp2(ROUNDED_DIV(d, scale), 3);
85
86 put_sbits(&pb, 4, d);
87
88 s0 = d * scale + ((c->coeff[0] * s1 + c->coeff[1] * s2) >> COEFF_BITS);
89 s2 = s1;
90 s1 = s0;
91 }
92 prev->s1 = s1;
93 prev->s2 = s2;
94
95 flush_put_bits(&pb);
96 }
97
98 #define HEADER_SIZE 36
99
adx_encode_header(AVCodecContext * avctx,uint8_t * buf,int bufsize)100 static int adx_encode_header(AVCodecContext *avctx, uint8_t *buf, int bufsize)
101 {
102 ADXContext *c = avctx->priv_data;
103
104 bytestream_put_be16(&buf, 0x8000); /* header signature */
105 bytestream_put_be16(&buf, HEADER_SIZE - 4); /* copyright offset */
106 bytestream_put_byte(&buf, 3); /* encoding */
107 bytestream_put_byte(&buf, BLOCK_SIZE); /* block size */
108 bytestream_put_byte(&buf, 4); /* sample size */
109 bytestream_put_byte(&buf, avctx->channels); /* channels */
110 bytestream_put_be32(&buf, avctx->sample_rate); /* sample rate */
111 bytestream_put_be32(&buf, 0); /* total sample count */
112 bytestream_put_be16(&buf, c->cutoff); /* cutoff frequency */
113 bytestream_put_byte(&buf, 3); /* version */
114 bytestream_put_byte(&buf, 0); /* flags */
115 bytestream_put_be32(&buf, 0); /* unknown */
116 bytestream_put_be32(&buf, 0); /* loop enabled */
117 bytestream_put_be16(&buf, 0); /* padding */
118 bytestream_put_buffer(&buf, "(c)CRI", 6); /* copyright signature */
119
120 return HEADER_SIZE;
121 }
122
adx_encode_init(AVCodecContext * avctx)123 static av_cold int adx_encode_init(AVCodecContext *avctx)
124 {
125 ADXContext *c = avctx->priv_data;
126
127 if (avctx->channels > 2) {
128 av_log(avctx, AV_LOG_ERROR, "Invalid number of channels\n");
129 return AVERROR(EINVAL);
130 }
131 avctx->frame_size = BLOCK_SAMPLES;
132
133 /* the cutoff can be adjusted, but this seems to work pretty well */
134 c->cutoff = 500;
135 ff_adx_calculate_coeffs(c->cutoff, avctx->sample_rate, COEFF_BITS, c->coeff);
136
137 return 0;
138 }
139
adx_encode_frame(AVCodecContext * avctx,AVPacket * avpkt,const AVFrame * frame,int * got_packet_ptr)140 static int adx_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
141 const AVFrame *frame, int *got_packet_ptr)
142 {
143 ADXContext *c = avctx->priv_data;
144 const int16_t *samples = frame ? (const int16_t *)frame->data[0] : NULL;
145 uint8_t *dst;
146 int ch, out_size, ret;
147
148 if (!samples) {
149 if (c->eof)
150 return 0;
151 if ((ret = ff_alloc_packet2(avctx, avpkt, 18, 0)) < 0)
152 return ret;
153 c->eof = 1;
154 dst = avpkt->data;
155 bytestream_put_be16(&dst, 0x8001);
156 bytestream_put_be16(&dst, 0x000E);
157 bytestream_put_be64(&dst, 0x0);
158 bytestream_put_be32(&dst, 0x0);
159 bytestream_put_be16(&dst, 0x0);
160 *got_packet_ptr = 1;
161 return 0;
162 }
163
164 out_size = BLOCK_SIZE * avctx->channels + !c->header_parsed * HEADER_SIZE;
165 if ((ret = ff_alloc_packet2(avctx, avpkt, out_size, 0)) < 0)
166 return ret;
167 dst = avpkt->data;
168
169 if (!c->header_parsed) {
170 int hdrsize;
171 if ((hdrsize = adx_encode_header(avctx, dst, avpkt->size)) < 0) {
172 av_log(avctx, AV_LOG_ERROR, "output buffer is too small\n");
173 return AVERROR(EINVAL);
174 }
175 dst += hdrsize;
176 c->header_parsed = 1;
177 }
178
179 for (ch = 0; ch < avctx->channels; ch++) {
180 adx_encode(c, dst, samples + ch, &c->prev[ch], avctx->channels);
181 dst += BLOCK_SIZE;
182 }
183
184 avpkt->pts = frame->pts;
185 avpkt->duration = frame->nb_samples;
186 *got_packet_ptr = 1;
187 return 0;
188 }
189
190 AVCodec ff_adpcm_adx_encoder = {
191 .name = "adpcm_adx",
192 .long_name = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"),
193 .type = AVMEDIA_TYPE_AUDIO,
194 .id = AV_CODEC_ID_ADPCM_ADX,
195 .priv_data_size = sizeof(ADXContext),
196 .init = adx_encode_init,
197 .encode2 = adx_encode_frame,
198 .capabilities = AV_CODEC_CAP_DELAY,
199 .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16,
200 AV_SAMPLE_FMT_NONE },
201 };
202