FFmpeg: libavcodec/vima.c Source File

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