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