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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 #include "internal.h"
25 
26 
27 typedef struct {
29 } AvsContext;
30 
31 typedef enum {
32  AVS_VIDEO = 0x01,
33  AVS_AUDIO = 0x02,
34  AVS_PALETTE = 0x03,
35  AVS_GAME_DATA = 0x04,
36 } AvsBlockType;
37 
38 typedef enum {
39  AVS_I_FRAME = 0x00,
44 
45 
46 static int
48  void *data, int *got_frame, AVPacket *avpkt)
49 {
50  const uint8_t *buf = avpkt->data;
51  const uint8_t *buf_end = avpkt->data + avpkt->size;
52  int buf_size = avpkt->size;
53  AvsContext *const avs = avctx->priv_data;
54  AVFrame *picture = data;
55  AVFrame *const p = avs->frame;
56  const uint8_t *table, *vect;
57  uint8_t *out;
58  int i, j, x, y, stride, ret, vect_w = 3, vect_h = 3;
59  AvsVideoSubType sub_type;
61  GetBitContext change_map = {0}; //init to silence warning
62 
63  if ((ret = ff_reget_buffer(avctx, p)) < 0)
64  return ret;
66  p->key_frame = 0;
67 
68  out = p->data[0];
69  stride = p->linesize[0];
70 
71  if (buf_end - buf < 4)
72  return AVERROR_INVALIDDATA;
73  sub_type = buf[0];
74  type = buf[1];
75  buf += 4;
76 
77  if (type == AVS_PALETTE) {
78  int first, last;
79  uint32_t *pal = (uint32_t *) p->data[1];
80 
81  first = AV_RL16(buf);
82  last = first + AV_RL16(buf + 2);
83  if (first >= 256 || last > 256 || buf_end - buf < 4 + 4 + 3 * (last - first))
84  return AVERROR_INVALIDDATA;
85  buf += 4;
86  for (i=first; i<last; i++, buf+=3) {
87  pal[i] = (buf[0] << 18) | (buf[1] << 10) | (buf[2] << 2);
88  pal[i] |= 0xFFU << 24 | (pal[i] >> 6) & 0x30303;
89  }
90 
91  sub_type = buf[0];
92  type = buf[1];
93  buf += 4;
94  }
95 
96  if (type != AVS_VIDEO)
97  return AVERROR_INVALIDDATA;
98 
99  switch (sub_type) {
100  case AVS_I_FRAME:
102  p->key_frame = 1;
103  case AVS_P_FRAME_3X3:
104  vect_w = 3;
105  vect_h = 3;
106  break;
107 
108  case AVS_P_FRAME_2X2:
109  vect_w = 2;
110  vect_h = 2;
111  break;
112 
113  case AVS_P_FRAME_2X3:
114  vect_w = 2;
115  vect_h = 3;
116  break;
117 
118  default:
119  return AVERROR_INVALIDDATA;
120  }
121 
122  if (buf_end - buf < 256 * vect_w * vect_h)
123  return AVERROR_INVALIDDATA;
124  table = buf + (256 * vect_w * vect_h);
125  if (sub_type != AVS_I_FRAME) {
126  int map_size = ((318 / vect_w + 7) / 8) * (198 / vect_h);
127  if (buf_end - table < map_size)
128  return AVERROR_INVALIDDATA;
129  init_get_bits(&change_map, table, map_size * 8);
130  table += map_size;
131  }
132 
133  for (y=0; y<198; y+=vect_h) {
134  for (x=0; x<318; x+=vect_w) {
135  if (sub_type == AVS_I_FRAME || get_bits1(&change_map)) {
136  if (buf_end - table < 1)
137  return AVERROR_INVALIDDATA;
138  vect = &buf[*table++ * (vect_w * vect_h)];
139  for (j=0; j<vect_w; j++) {
140  out[(y + 0) * stride + x + j] = vect[(0 * vect_w) + j];
141  out[(y + 1) * stride + x + j] = vect[(1 * vect_w) + j];
142  if (vect_h == 3)
143  out[(y + 2) * stride + x + j] =
144  vect[(2 * vect_w) + j];
145  }
146  }
147  }
148  if (sub_type != AVS_I_FRAME)
149  align_get_bits(&change_map);
150  }
151 
152  if ((ret = av_frame_ref(picture, p)) < 0)
153  return ret;
154  *got_frame = 1;
155 
156  return buf_size;
157 }
158 
160 {
161  AvsContext *s = avctx->priv_data;
162 
163  s->frame = av_frame_alloc();
164  if (!s->frame)
165  return AVERROR(ENOMEM);
166 
167  avctx->pix_fmt = AV_PIX_FMT_PAL8;
168 
169  return ff_set_dimensions(avctx, 318, 198);
170 }
171 
173 {
174  AvsContext *s = avctx->priv_data;
175  av_frame_free(&s->frame);
176  return 0;
177 }
178 
179 
181  .name = "avs",
182  .long_name = NULL_IF_CONFIG_SMALL("AVS (Audio Video Standard) video"),
183  .type = AVMEDIA_TYPE_VIDEO,
184  .id = AV_CODEC_ID_AVS,
185  .priv_data_size = sizeof(AvsContext),
188  .close = avs_decode_end,
189  .capabilities = CODEC_CAP_DR1,
190 };