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vima.c
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1 /*
2  * LucasArts VIMA decoder
3  * Copyright (c) 2012 Paul B Mahol
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 /**
23  * @file
24  * LucasArts VIMA audio decoder
25  * @author Paul B Mahol
26  */
27 
28 #include "libavutil/channel_layout.h"
29 #include "avcodec.h"
30 #include "get_bits.h"
31 #include "internal.h"
32 #include "adpcm_data.h"
33 
34 static int predict_table_init = 0;
35 static uint16_t predict_table[5786 * 2];
36 
37 static const uint8_t size_table[] =
38 {
39  4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
40  4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
41  4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
42  5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
43  6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
44  7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7
45 };
46 
47 static const int8_t index_table1[] =
48 {
49  -1, 4, -1, 4
50 };
51 
52 static const int8_t index_table2[] =
53 {
54  -1, -1, 2, 6, -1, -1, 2, 6
55 };
56 
57 static const int8_t index_table3[] =
58 {
59  -1, -1, -1, -1, 1, 2, 4, 6,
60  -1, -1, -1, -1, 1, 2, 4, 6
61 };
62 
63 static const int8_t index_table4[] =
64 {
65  -1, -1, -1, -1, -1, -1, -1, -1,
66  1, 1, 1, 2, 2, 4, 5, 6,
67  -1, -1, -1, -1, -1, -1, -1, -1,
68  1, 1, 1, 2, 2, 4, 5, 6
69 };
70 
71 static const int8_t index_table5[] =
72 {
73  -1, -1, -1, -1, -1, -1, -1, -1,
74  -1, -1, -1, -1, -1, -1, -1, -1,
75  1, 1, 1, 1, 1, 2, 2, 2,
76  2, 4, 4, 4, 5, 5, 6, 6,
77  -1, -1, -1, -1, -1, -1, -1, -1,
78  -1, -1, -1, -1, -1, -1, -1, -1,
79  1, 1, 1, 1, 1, 2, 2, 2,
80  2, 4, 4, 4, 5, 5, 6, 6
81 };
82 
83 static const int8_t index_table6[] =
84 {
85  -1, -1, -1, -1, -1, -1, -1, -1,
86  -1, -1, -1, -1, -1, -1, -1, -1,
87  -1, -1, -1, -1, -1, -1, -1, -1,
88  -1, -1, -1, -1, -1, -1, -1, -1,
89  1, 1, 1, 1, 1, 1, 1, 1,
90  1, 1, 2, 2, 2, 2, 2, 2,
91  2, 2, 4, 4, 4, 4, 4, 4,
92  5, 5, 5, 5, 6, 6, 6, 6,
93  -1, -1, -1, -1, -1, -1, -1, -1,
94  -1, -1, -1, -1, -1, -1, -1, -1,
95  -1, -1, -1, -1, -1, -1, -1, -1,
96  -1, -1, -1, -1, -1, -1, -1, -1,
97  1, 1, 1, 1, 1, 1, 1, 1,
98  1, 1, 2, 2, 2, 2, 2, 2,
99  2, 2, 4, 4, 4, 4, 4, 4,
100  5, 5, 5, 5, 6, 6, 6, 6
101 };
102 
103 static const int8_t* const step_index_tables[] =
104 {
105  index_table1, index_table2, index_table3,
106  index_table4, index_table5, index_table6
107 };
108 
109 static av_cold int decode_init(AVCodecContext *avctx)
110 {
111  int start_pos;
112 
113  avctx->sample_fmt = AV_SAMPLE_FMT_S16;
114 
115  if (predict_table_init)
116  return 0;
117 
118  for (start_pos = 0; start_pos < 64; start_pos++) {
119  unsigned int dest_pos, table_pos;
120 
121  for (table_pos = 0, dest_pos = start_pos;
122  table_pos < FF_ARRAY_ELEMS(ff_adpcm_step_table);
123  table_pos++, dest_pos += 64) {
124  int put = 0, count, table_value;
125 
126  table_value = ff_adpcm_step_table[table_pos];
127  for (count = 32; count != 0; count >>= 1) {
128  if (start_pos & count)
129  put += table_value;
130  table_value >>= 1;
131  }
132  predict_table[dest_pos] = put;
133  }
134  }
135  predict_table_init = 1;
136 
137  return 0;
138 }
139 
140 static int decode_frame(AVCodecContext *avctx, void *data,
141  int *got_frame_ptr, AVPacket *pkt)
142 {
143  GetBitContext gb;
144  AVFrame *frame = data;
145  int16_t pcm_data[2];
146  uint32_t samples;
147  int8_t channel_hint[2];
148  int ret, chan, channels = 1;
149 
150  if (pkt->size < 13)
151  return AVERROR_INVALIDDATA;
152 
153  if ((ret = init_get_bits8(&gb, pkt->data, pkt->size)) < 0)
154  return ret;
155 
156  samples = get_bits_long(&gb, 32);
157  if (samples == 0xffffffff) {
158  skip_bits_long(&gb, 32);
159  samples = get_bits_long(&gb, 32);
160  }
161 
162  if (samples > pkt->size * 2)
163  return AVERROR_INVALIDDATA;
164 
165  channel_hint[0] = get_sbits(&gb, 8);
166  if (channel_hint[0] & 0x80) {
167  channel_hint[0] = ~channel_hint[0];
168  channels = 2;
169  }
170  avctx->channels = channels;
171  avctx->channel_layout = (channels == 2) ? AV_CH_LAYOUT_STEREO :
172  AV_CH_LAYOUT_MONO;
173  pcm_data[0] = get_sbits(&gb, 16);
174  if (channels > 1) {
175  channel_hint[1] = get_sbits(&gb, 8);
176  pcm_data[1] = get_sbits(&gb, 16);
177  }
178 
179  frame->nb_samples = samples;
180  if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
181  return ret;
182 
183  for (chan = 0; chan < channels; chan++) {
184  uint16_t *dest = (uint16_t*)frame->data[0] + chan;
185  int step_index = channel_hint[chan];
186  int output = pcm_data[chan];
187  int sample;
188 
189  for (sample = 0; sample < samples; sample++) {
190  int lookup_size, lookup, highbit, lowbits;
191 
192  step_index = av_clip(step_index, 0, 88);
193  lookup_size = size_table[step_index];
194  lookup = get_bits(&gb, lookup_size);
195  highbit = 1 << (lookup_size - 1);
196  lowbits = highbit - 1;
197 
198  if (lookup & highbit)
199  lookup ^= highbit;
200  else
201  highbit = 0;
202 
203  if (lookup == lowbits) {
204  output = get_sbits(&gb, 16);
205  } else {
206  int predict_index, diff;
207 
208  predict_index = (lookup << (7 - lookup_size)) | (step_index << 6);
209  predict_index = av_clip(predict_index, 0, 5785);
210  diff = predict_table[predict_index];
211  if (lookup)
212  diff += ff_adpcm_step_table[step_index] >> (lookup_size - 1);
213  if (highbit)
214  diff = -diff;
215 
216  output = av_clip_int16(output + diff);
217  }
218 
219  *dest = output;
220  dest += channels;
221 
222  step_index += step_index_tables[lookup_size - 2][lookup];
223  }
224  }
225 
226  *got_frame_ptr = 1;
227 
228  return pkt->size;
229 }
230 
231 AVCodec ff_vima_decoder = {
232  .name = "vima",
233  .long_name = NULL_IF_CONFIG_SMALL("LucasArts VIMA audio"),
234  .type = AVMEDIA_TYPE_AUDIO,
235  .id = AV_CODEC_ID_VIMA,
236  .init = decode_init,
237  .decode = decode_frame,
238  .capabilities = CODEC_CAP_DR1,
239 };
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