adxdec.c
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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 #include "avcodec.h"
24 #include "adx.h"
25 #include "get_bits.h"
26 #include "internal.h"
27 
38 {
39  ADXContext *c = avctx->priv_data;
40  int ret, header_size;
41 
42  if (avctx->extradata_size >= 24) {
43  if ((ret = avpriv_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 
54 
56  avctx->coded_frame = &c->frame;
57 
58  return 0;
59 }
60 
68 static int adx_decode(ADXContext *c, int16_t *out, int offset,
69  const uint8_t *in, int ch)
70 {
71  ADXChannelState *prev = &c->prev[ch];
72  GetBitContext gb;
73  int scale = AV_RB16(in);
74  int i;
75  int s0, s1, s2, d;
76 
77  /* check if this is an EOF packet */
78  if (scale & 0x8000)
79  return -1;
80 
81  init_get_bits(&gb, in + 2, (BLOCK_SIZE - 2) * 8);
82  out += offset;
83  s1 = prev->s1;
84  s2 = prev->s2;
85  for (i = 0; i < BLOCK_SAMPLES; i++) {
86  d = get_sbits(&gb, 4);
87  s0 = ((d << COEFF_BITS) * scale + c->coeff[0] * s1 + c->coeff[1] * s2) >> COEFF_BITS;
88  s2 = s1;
89  s1 = av_clip_int16(s0);
90  *out++ = s1;
91  }
92  prev->s1 = s1;
93  prev->s2 = s2;
94 
95  return 0;
96 }
97 
98 static int adx_decode_frame(AVCodecContext *avctx, void *data,
99  int *got_frame_ptr, AVPacket *avpkt)
100 {
101  int buf_size = avpkt->size;
102  ADXContext *c = avctx->priv_data;
103  int16_t **samples;
104  int samples_offset;
105  const uint8_t *buf = avpkt->data;
106  int num_blocks, ch, ret;
107 
108  if (c->eof) {
109  *got_frame_ptr = 0;
110  return buf_size;
111  }
112 
113  if (!c->header_parsed && buf_size >= 2 && AV_RB16(buf) == 0x8000) {
114  int header_size;
115  if ((ret = avpriv_adx_decode_header(avctx, buf, buf_size, &header_size,
116  c->coeff)) < 0) {
117  av_log(avctx, AV_LOG_ERROR, "error parsing ADX header\n");
118  return AVERROR_INVALIDDATA;
119  }
120  c->channels = avctx->channels;
121  c->header_parsed = 1;
122  if (buf_size < header_size)
123  return AVERROR_INVALIDDATA;
124  buf += header_size;
125  buf_size -= header_size;
126  }
127  if (!c->header_parsed)
128  return AVERROR_INVALIDDATA;
129 
130  /* calculate number of blocks in the packet */
131  num_blocks = buf_size / (BLOCK_SIZE * c->channels);
132 
133  /* if the packet is not an even multiple of BLOCK_SIZE, check for an EOF
134  packet */
135  if (!num_blocks || buf_size % (BLOCK_SIZE * avctx->channels)) {
136  if (buf_size >= 4 && (AV_RB16(buf) & 0x8000)) {
137  c->eof = 1;
138  *got_frame_ptr = 0;
139  return avpkt->size;
140  }
141  return AVERROR_INVALIDDATA;
142  }
143 
144  /* get output buffer */
145  c->frame.nb_samples = num_blocks * BLOCK_SAMPLES;
146  if ((ret = ff_get_buffer(avctx, &c->frame)) < 0) {
147  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
148  return ret;
149  }
150  samples = (int16_t **)c->frame.extended_data;
151  samples_offset = 0;
152 
153  while (num_blocks--) {
154  for (ch = 0; ch < c->channels; ch++) {
155  if (adx_decode(c, samples[ch], samples_offset, buf, ch)) {
156  c->eof = 1;
157  buf = avpkt->data + avpkt->size;
158  break;
159  }
160  buf_size -= BLOCK_SIZE;
161  buf += BLOCK_SIZE;
162  }
163  samples_offset += BLOCK_SAMPLES;
164  }
165 
166  *got_frame_ptr = 1;
167  *(AVFrame *)data = c->frame;
168 
169  return buf - avpkt->data;
170 }
171 
172 static void adx_decode_flush(AVCodecContext *avctx)
173 {
174  ADXContext *c = avctx->priv_data;
175  memset(c->prev, 0, sizeof(c->prev));
176  c->eof = 0;
177 }
178 
180  .name = "adpcm_adx",
181  .type = AVMEDIA_TYPE_AUDIO,
182  .id = AV_CODEC_ID_ADPCM_ADX,
183  .priv_data_size = sizeof(ADXContext),
187  .capabilities = CODEC_CAP_DR1,
188  .long_name = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"),
189  .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P,
191 };