Use bitstream_init8() where appropriate
[libav.git] / libavcodec / adxdec.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 "libavutil/intreadwrite.h"
23
24 #include "avcodec.h"
25 #include "adx.h"
26 #include "bitstream.h"
27 #include "internal.h"
28
29 /**
30 * @file
31 * SEGA CRI adx codecs.
32 *
33 * Reference documents:
34 * http://ku-www.ss.titech.ac.jp/~yatsushi/adx.html
35 * adx2wav & wav2adx http://www.geocities.co.jp/Playtown/2004/
36 */
37
38 static av_cold int adx_decode_init(AVCodecContext *avctx)
39 {
40 ADXContext *c = avctx->priv_data;
41 int ret, header_size;
42
43 if (avctx->extradata_size >= 24) {
44 if ((ret = ff_adx_decode_header(avctx, avctx->extradata,
45 avctx->extradata_size, &header_size,
46 c->coeff)) < 0) {
47 av_log(avctx, AV_LOG_ERROR, "error parsing ADX header\n");
48 return AVERROR_INVALIDDATA;
49 }
50 c->channels = avctx->channels;
51 c->header_parsed = 1;
52 }
53
54 avctx->sample_fmt = AV_SAMPLE_FMT_S16P;
55
56 return 0;
57 }
58
59 /**
60 * Decode 32 samples from 18 bytes.
61 *
62 * A 16-bit scalar value is applied to 32 residuals, which then have a
63 * 2nd-order LPC filter applied to it to form the output signal for a single
64 * channel.
65 */
66 static int adx_decode(ADXContext *c, int16_t *out, int offset,
67 const uint8_t *in, int ch)
68 {
69 ADXChannelState *prev = &c->prev[ch];
70 BitstreamContext bc;
71 int scale = AV_RB16(in);
72 int i;
73 int s0, s1, s2, d;
74
75 /* check if this is an EOF packet */
76 if (scale & 0x8000)
77 return -1;
78
79 bitstream_init8(&bc, in + 2, BLOCK_SIZE - 2);
80 out += offset;
81 s1 = prev->s1;
82 s2 = prev->s2;
83 for (i = 0; i < BLOCK_SAMPLES; i++) {
84 d = bitstream_read_signed(&bc, 4);
85 s0 = ((d << COEFF_BITS) * scale + c->coeff[0] * s1 + c->coeff[1] * s2) >> COEFF_BITS;
86 s2 = s1;
87 s1 = av_clip_int16(s0);
88 *out++ = s1;
89 }
90 prev->s1 = s1;
91 prev->s2 = s2;
92
93 return 0;
94 }
95
96 static int adx_decode_frame(AVCodecContext *avctx, void *data,
97 int *got_frame_ptr, AVPacket *avpkt)
98 {
99 AVFrame *frame = data;
100 int buf_size = avpkt->size;
101 ADXContext *c = avctx->priv_data;
102 int16_t **samples;
103 int samples_offset;
104 const uint8_t *buf = avpkt->data;
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 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
147 return ret;
148 }
149 samples = (int16_t **)frame->extended_data;
150 samples_offset = 0;
151
152 while (num_blocks--) {
153 for (ch = 0; ch < c->channels; ch++) {
154 if (adx_decode(c, samples[ch], samples_offset, buf, ch)) {
155 c->eof = 1;
156 buf = avpkt->data + avpkt->size;
157 break;
158 }
159 buf_size -= BLOCK_SIZE;
160 buf += BLOCK_SIZE;
161 }
162 samples_offset += BLOCK_SAMPLES;
163 }
164
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 };