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