adxenc: use bytestream functions for header writing.
[libav.git] / libavcodec / adxenc.c
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 "avcodec.h"
23 #include "adx.h"
24 #include "bytestream.h"
25 #include "put_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
36 static void adx_encode(ADXContext *c, uint8_t *adx, const int16_t *wav,
37 ADXChannelState *prev, int channels)
38 {
39 PutBitContext pb;
40 int scale;
41 int i, j;
42 int s0, s1, s2, d;
43 int max = 0;
44 int min = 0;
45 int data[BLOCK_SAMPLES];
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 << COEFF_BITS) - c->coeff[0] * s1 - c->coeff[1] * s2) >> COEFF_BITS;
52 data[j] = d;
53 if (max < d)
54 max = d;
55 if (min > d)
56 min = d;
57 s2 = s1;
58 s1 = s0;
59 }
60 prev->s1 = s1;
61 prev->s2 = s2;
62
63 if (max == 0 && min == 0) {
64 memset(adx, 0, BLOCK_SIZE);
65 return;
66 }
67
68 if (max / 7 > -min / 8)
69 scale = max / 7;
70 else
71 scale = -min / 8;
72
73 if (scale == 0)
74 scale = 1;
75
76 AV_WB16(adx, scale);
77
78 init_put_bits(&pb, adx + 2, 16);
79 for (i = 0; i < BLOCK_SAMPLES; i++)
80 put_sbits(&pb, 4, av_clip(data[i] / scale, -8, 7));
81 flush_put_bits(&pb);
82 }
83
84 #define HEADER_SIZE 36
85
86 static int adx_encode_header(AVCodecContext *avctx, uint8_t *buf, int bufsize)
87 {
88 ADXContext *c = avctx->priv_data;
89
90 bytestream_put_be16(&buf, 0x8000); /* header signature */
91 bytestream_put_be16(&buf, HEADER_SIZE - 4); /* copyright offset */
92 bytestream_put_byte(&buf, 3); /* encoding */
93 bytestream_put_byte(&buf, BLOCK_SIZE); /* block size */
94 bytestream_put_byte(&buf, 4); /* sample size */
95 bytestream_put_byte(&buf, avctx->channels); /* channels */
96 bytestream_put_be32(&buf, avctx->sample_rate); /* sample rate */
97 bytestream_put_be32(&buf, 0); /* total sample count */
98 bytestream_put_be16(&buf, c->cutoff); /* cutoff frequency */
99 bytestream_put_byte(&buf, 3); /* version */
100 bytestream_put_byte(&buf, 0); /* flags */
101 bytestream_put_be32(&buf, 0); /* unknown */
102 bytestream_put_be32(&buf, 0); /* loop enabled */
103 bytestream_put_be16(&buf, 0); /* padding */
104 bytestream_put_buffer(&buf, "(c)CRI", 6); /* copyright signature */
105
106 return HEADER_SIZE;
107 }
108
109 static av_cold int adx_encode_init(AVCodecContext *avctx)
110 {
111 ADXContext *c = avctx->priv_data;
112
113 if (avctx->channels > 2) {
114 av_log(avctx, AV_LOG_ERROR, "Invalid number of channels\n");
115 return AVERROR(EINVAL);
116 }
117 avctx->frame_size = BLOCK_SAMPLES;
118
119 avctx->coded_frame = avcodec_alloc_frame();
120
121 /* the cutoff can be adjusted, but this seems to work pretty well */
122 c->cutoff = 500;
123 ff_adx_calculate_coeffs(c->cutoff, avctx->sample_rate, COEFF_BITS, c->coeff);
124
125 return 0;
126 }
127
128 static av_cold int adx_encode_close(AVCodecContext *avctx)
129 {
130 av_freep(&avctx->coded_frame);
131 return 0;
132 }
133
134 static int adx_encode_frame(AVCodecContext *avctx, uint8_t *frame,
135 int buf_size, void *data)
136 {
137 ADXContext *c = avctx->priv_data;
138 const int16_t *samples = data;
139 uint8_t *dst = frame;
140 int ch;
141
142 if (!c->header_parsed) {
143 int hdrsize = adx_encode_header(avctx, dst, buf_size);
144 dst += hdrsize;
145 c->header_parsed = 1;
146 }
147
148 for (ch = 0; ch < avctx->channels; ch++) {
149 adx_encode(c, dst, samples + ch, &c->prev[ch], avctx->channels);
150 dst += BLOCK_SIZE;
151 }
152 return dst - frame;
153 }
154
155 AVCodec ff_adpcm_adx_encoder = {
156 .name = "adpcm_adx",
157 .type = AVMEDIA_TYPE_AUDIO,
158 .id = CODEC_ID_ADPCM_ADX,
159 .priv_data_size = sizeof(ADXContext),
160 .init = adx_encode_init,
161 .encode = adx_encode_frame,
162 .close = adx_encode_close,
163 .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16,
164 AV_SAMPLE_FMT_NONE },
165 .long_name = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"),
166 };