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avs.c
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1 /*
2  * AVS video decoder.
3  * Copyright (c) 2006 Aurelien Jacobs <aurel@gnuage.org>
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 "avcodec.h"
23 #include "get_bits.h"
24 
25 
26 typedef struct {
28 } AvsContext;
29 
30 typedef enum {
31  AVS_VIDEO = 0x01,
32  AVS_AUDIO = 0x02,
33  AVS_PALETTE = 0x03,
34  AVS_GAME_DATA = 0x04,
35 } AvsBlockType;
36 
37 typedef enum {
38  AVS_I_FRAME = 0x00,
43 
44 
45 static int
47  void *data, int *got_frame, AVPacket *avpkt)
48 {
49  const uint8_t *buf = avpkt->data;
50  const uint8_t *buf_end = avpkt->data + avpkt->size;
51  int buf_size = avpkt->size;
52  AvsContext *const avs = avctx->priv_data;
53  AVFrame *picture = data;
54  AVFrame *const p = &avs->picture;
55  const uint8_t *table, *vect;
56  uint8_t *out;
57  int i, j, x, y, stride, ret, vect_w = 3, vect_h = 3;
58  AvsVideoSubType sub_type;
59  AvsBlockType type;
60  GetBitContext change_map = {0}; //init to silence warning
61 
62  if ((ret = avctx->reget_buffer(avctx, p)) < 0) {
63  av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
64  return ret;
65  }
66  p->reference = 3;
68  p->key_frame = 0;
69 
70  out = avs->picture.data[0];
71  stride = avs->picture.linesize[0];
72 
73  if (buf_end - buf < 4)
74  return AVERROR_INVALIDDATA;
75  sub_type = buf[0];
76  type = buf[1];
77  buf += 4;
78 
79  if (type == AVS_PALETTE) {
80  int first, last;
81  uint32_t *pal = (uint32_t *) avs->picture.data[1];
82 
83  first = AV_RL16(buf);
84  last = first + AV_RL16(buf + 2);
85  if (first >= 256 || last > 256 || buf_end - buf < 4 + 4 + 3 * (last - first))
86  return AVERROR_INVALIDDATA;
87  buf += 4;
88  for (i=first; i<last; i++, buf+=3) {
89  pal[i] = (buf[0] << 18) | (buf[1] << 10) | (buf[2] << 2);
90  pal[i] |= 0xFFU << 24 | (pal[i] >> 6) & 0x30303;
91  }
92 
93  sub_type = buf[0];
94  type = buf[1];
95  buf += 4;
96  }
97 
98  if (type != AVS_VIDEO)
99  return AVERROR_INVALIDDATA;
100 
101  switch (sub_type) {
102  case AVS_I_FRAME:
104  p->key_frame = 1;
105  case AVS_P_FRAME_3X3:
106  vect_w = 3;
107  vect_h = 3;
108  break;
109 
110  case AVS_P_FRAME_2X2:
111  vect_w = 2;
112  vect_h = 2;
113  break;
114 
115  case AVS_P_FRAME_2X3:
116  vect_w = 2;
117  vect_h = 3;
118  break;
119 
120  default:
121  return AVERROR_INVALIDDATA;
122  }
123 
124  if (buf_end - buf < 256 * vect_w * vect_h)
125  return AVERROR_INVALIDDATA;
126  table = buf + (256 * vect_w * vect_h);
127  if (sub_type != AVS_I_FRAME) {
128  int map_size = ((318 / vect_w + 7) / 8) * (198 / vect_h);
129  if (buf_end - table < map_size)
130  return AVERROR_INVALIDDATA;
131  init_get_bits(&change_map, table, map_size * 8);
132  table += map_size;
133  }
134 
135  for (y=0; y<198; y+=vect_h) {
136  for (x=0; x<318; x+=vect_w) {
137  if (sub_type == AVS_I_FRAME || get_bits1(&change_map)) {
138  if (buf_end - table < 1)
139  return AVERROR_INVALIDDATA;
140  vect = &buf[*table++ * (vect_w * vect_h)];
141  for (j=0; j<vect_w; j++) {
142  out[(y + 0) * stride + x + j] = vect[(0 * vect_w) + j];
143  out[(y + 1) * stride + x + j] = vect[(1 * vect_w) + j];
144  if (vect_h == 3)
145  out[(y + 2) * stride + x + j] =
146  vect[(2 * vect_w) + j];
147  }
148  }
149  }
150  if (sub_type != AVS_I_FRAME)
151  align_get_bits(&change_map);
152  }
153 
154  *picture = avs->picture;
155  *got_frame = 1;
156 
157  return buf_size;
158 }
159 
161 {
162  AvsContext *const avs = avctx->priv_data;
163  avctx->pix_fmt = AV_PIX_FMT_PAL8;
165  avcodec_set_dimensions(avctx, 318, 198);
166  return 0;
167 }
168 
170 {
171  AvsContext *s = avctx->priv_data;
172  if (s->picture.data[0])
173  avctx->release_buffer(avctx, &s->picture);
174  return 0;
175 }
176 
177 
179  .name = "avs",
180  .type = AVMEDIA_TYPE_VIDEO,
181  .id = AV_CODEC_ID_AVS,
182  .priv_data_size = sizeof(AvsContext),
186  .capabilities = CODEC_CAP_DR1,
187  .long_name = NULL_IF_CONFIG_SMALL("AVS (Audio Video Standard) video"),
188 };