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mmvideo.c
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1 /*
2  * American Laser Games MM Video Decoder
3  * Copyright (c) 2006,2008 Peter Ross
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  * American Laser Games MM Video Decoder
25  * by Peter Ross (pross@xvid.org)
26  *
27  * The MM format was used by IBM-PC ports of ALG's "arcade shooter" games,
28  * including Mad Dog McCree and Crime Patrol.
29  *
30  * Technical details here:
31  * http://wiki.multimedia.cx/index.php?title=American_Laser_Games_MM
32  */
33 
34 #include "libavutil/intreadwrite.h"
35 #include "avcodec.h"
36 #include "bytestream.h"
37 #include "internal.h"
38 
39 #define MM_PREAMBLE_SIZE 6
40 
41 #define MM_TYPE_INTER 0x5
42 #define MM_TYPE_INTRA 0x8
43 #define MM_TYPE_INTRA_HH 0xc
44 #define MM_TYPE_INTER_HH 0xd
45 #define MM_TYPE_INTRA_HHV 0xe
46 #define MM_TYPE_INTER_HHV 0xf
47 #define MM_TYPE_PALETTE 0x31
48 
49 typedef struct MmContext {
54 } MmContext;
55 
57 {
58  MmContext *s = avctx->priv_data;
59 
60  s->avctx = avctx;
61 
62  avctx->pix_fmt = AV_PIX_FMT_PAL8;
63 
64  s->frame = av_frame_alloc();
65  if (!s->frame)
66  return AVERROR(ENOMEM);
67 
68  return 0;
69 }
70 
72 {
73  int i;
74 
75  bytestream2_skip(&s->gb, 4);
76  for (i = 0; i < 128; i++) {
77  s->palette[i] = 0xFFU << 24 | bytestream2_get_be24(&s->gb);
78  s->palette[i+128] = s->palette[i]<<2;
79  }
80 
81  return 0;
82 }
83 
84 /**
85  * @param half_horiz Half horizontal resolution (0 or 1)
86  * @param half_vert Half vertical resolution (0 or 1)
87  */
88 static int mm_decode_intra(MmContext * s, int half_horiz, int half_vert)
89 {
90  int x = 0, y = 0;
91 
92  while (bytestream2_get_bytes_left(&s->gb) > 0) {
93  int run_length, color;
94 
95  if (y >= s->avctx->height)
96  return 0;
97 
98  color = bytestream2_get_byte(&s->gb);
99  if (color & 0x80) {
100  run_length = 1;
101  }else{
102  run_length = (color & 0x7f) + 2;
103  color = bytestream2_get_byte(&s->gb);
104  }
105 
106  if (half_horiz)
107  run_length *=2;
108 
109  if (run_length > s->avctx->width - x)
110  return AVERROR_INVALIDDATA;
111 
112  if (color) {
113  memset(s->frame->data[0] + y*s->frame->linesize[0] + x, color, run_length);
114  if (half_vert)
115  memset(s->frame->data[0] + (y+1)*s->frame->linesize[0] + x, color, run_length);
116  }
117  x+= run_length;
118 
119  if (x >= s->avctx->width) {
120  x=0;
121  y += 1 + half_vert;
122  }
123  }
124 
125  return 0;
126 }
127 
128 /**
129  * @param half_horiz Half horizontal resolution (0 or 1)
130  * @param half_vert Half vertical resolution (0 or 1)
131  */
132 static int mm_decode_inter(MmContext * s, int half_horiz, int half_vert)
133 {
134  int data_off = bytestream2_get_le16(&s->gb);
135  int y = 0;
136  GetByteContext data_ptr;
137 
138  if (bytestream2_get_bytes_left(&s->gb) < data_off)
139  return AVERROR_INVALIDDATA;
140 
141  bytestream2_init(&data_ptr, s->gb.buffer + data_off, bytestream2_get_bytes_left(&s->gb) - data_off);
142  while (s->gb.buffer < data_ptr.buffer_start) {
143  int i, j;
144  int length = bytestream2_get_byte(&s->gb);
145  int x = bytestream2_get_byte(&s->gb) + ((length & 0x80) << 1);
146  length &= 0x7F;
147 
148  if (length==0) {
149  y += x;
150  continue;
151  }
152 
153  if (y + half_vert >= s->avctx->height)
154  return 0;
155 
156  for(i=0; i<length; i++) {
157  int replace_array = bytestream2_get_byte(&s->gb);
158  for(j=0; j<8; j++) {
159  int replace = (replace_array >> (7-j)) & 1;
160  if (x + half_horiz >= s->avctx->width)
161  return AVERROR_INVALIDDATA;
162  if (replace) {
163  int color = bytestream2_get_byte(&data_ptr);
164  s->frame->data[0][y*s->frame->linesize[0] + x] = color;
165  if (half_horiz)
166  s->frame->data[0][y*s->frame->linesize[0] + x + 1] = color;
167  if (half_vert) {
168  s->frame->data[0][(y+1)*s->frame->linesize[0] + x] = color;
169  if (half_horiz)
170  s->frame->data[0][(y+1)*s->frame->linesize[0] + x + 1] = color;
171  }
172  }
173  x += 1 + half_horiz;
174  }
175  }
176 
177  y += 1 + half_vert;
178  }
179 
180  return 0;
181 }
182 
183 static int mm_decode_frame(AVCodecContext *avctx,
184  void *data, int *got_frame,
185  AVPacket *avpkt)
186 {
187  const uint8_t *buf = avpkt->data;
188  int buf_size = avpkt->size;
189  MmContext *s = avctx->priv_data;
190  int type, res;
191 
192  if (buf_size < MM_PREAMBLE_SIZE)
193  return AVERROR_INVALIDDATA;
194  type = AV_RL16(&buf[0]);
195  buf += MM_PREAMBLE_SIZE;
196  buf_size -= MM_PREAMBLE_SIZE;
197  bytestream2_init(&s->gb, buf, buf_size);
198 
199  if ((res = ff_reget_buffer(avctx, s->frame)) < 0)
200  return res;
201 
202  switch(type) {
203  case MM_TYPE_PALETTE : res = mm_decode_pal(s); return avpkt->size;
204  case MM_TYPE_INTRA : res = mm_decode_intra(s, 0, 0); break;
205  case MM_TYPE_INTRA_HH : res = mm_decode_intra(s, 1, 0); break;
206  case MM_TYPE_INTRA_HHV : res = mm_decode_intra(s, 1, 1); break;
207  case MM_TYPE_INTER : res = mm_decode_inter(s, 0, 0); break;
208  case MM_TYPE_INTER_HH : res = mm_decode_inter(s, 1, 0); break;
209  case MM_TYPE_INTER_HHV : res = mm_decode_inter(s, 1, 1); break;
210  default:
211  res = AVERROR_INVALIDDATA;
212  break;
213  }
214  if (res < 0)
215  return res;
216 
217  memcpy(s->frame->data[1], s->palette, AVPALETTE_SIZE);
218 
219  if ((res = av_frame_ref(data, s->frame)) < 0)
220  return res;
221 
222  *got_frame = 1;
223 
224  return avpkt->size;
225 }
226 
228 {
229  MmContext *s = avctx->priv_data;
230 
231  av_frame_free(&s->frame);
232 
233  return 0;
234 }
235 
237  .name = "mmvideo",
238  .long_name = NULL_IF_CONFIG_SMALL("American Laser Games MM Video"),
239  .type = AVMEDIA_TYPE_VIDEO,
240  .id = AV_CODEC_ID_MMVIDEO,
241  .priv_data_size = sizeof(MmContext),
242  .init = mm_decode_init,
243  .close = mm_decode_end,
245  .capabilities = CODEC_CAP_DR1,
246 };