Libav
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 Libav.
6  *
7  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
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  if (!avctx->width || !avctx->height ||
65  (avctx->width & 1) || (avctx->height & 1)) {
66  av_log(avctx, AV_LOG_ERROR, "Invalid video dimensions: %dx%d\n",
67  avctx->width, avctx->height);
68  return AVERROR(EINVAL);
69  }
70 
71  s->frame = av_frame_alloc();
72  if (!s->frame)
73  return AVERROR(ENOMEM);
74 
75  return 0;
76 }
77 
78 static int mm_decode_pal(MmContext *s)
79 {
80  int i;
81 
82  bytestream2_skip(&s->gb, 4);
83  for (i = 0; i < 128; i++) {
84  s->palette[i] = bytestream2_get_be24(&s->gb);
85  s->palette[i+128] = s->palette[i]<<2;
86  }
87 
88  return 0;
89 }
90 
95 static int mm_decode_intra(MmContext * s, int half_horiz, int half_vert)
96 {
97  int x = 0, y = 0;
98 
99  while (bytestream2_get_bytes_left(&s->gb) > 0) {
100  int run_length, color;
101 
102  if (y >= s->avctx->height)
103  return 0;
104 
105  color = bytestream2_get_byte(&s->gb);
106  if (color & 0x80) {
107  run_length = 1;
108  }else{
109  run_length = (color & 0x7f) + 2;
110  color = bytestream2_get_byte(&s->gb);
111  }
112 
113  if (half_horiz)
114  run_length *=2;
115 
116  if (color) {
117  memset(s->frame->data[0] + y*s->frame->linesize[0] + x, color, run_length);
118  if (half_vert)
119  memset(s->frame->data[0] + (y+1)*s->frame->linesize[0] + x, color, run_length);
120  }
121  x+= run_length;
122 
123  if (x >= s->avctx->width) {
124  x=0;
125  y += 1 + half_vert;
126  }
127  }
128 
129  return 0;
130 }
131 
132 /*
133  * @param half_horiz Half horizontal resolution (0 or 1)
134  * @param half_vert Half vertical resolution (0 or 1)
135  */
136 static int mm_decode_inter(MmContext * s, int half_horiz, int half_vert)
137 {
138  int data_off = bytestream2_get_le16(&s->gb);
139  int y = 0;
140  GetByteContext data_ptr;
141 
142  if (bytestream2_get_bytes_left(&s->gb) < data_off)
143  return AVERROR_INVALIDDATA;
144 
145  bytestream2_init(&data_ptr, s->gb.buffer + data_off, bytestream2_get_bytes_left(&s->gb) - data_off);
146  while (s->gb.buffer < data_ptr.buffer_start) {
147  int i, j;
148  int length = bytestream2_get_byte(&s->gb);
149  int x = bytestream2_get_byte(&s->gb) + ((length & 0x80) << 1);
150  length &= 0x7F;
151 
152  if (length==0) {
153  y += x;
154  continue;
155  }
156 
157  if (y + half_vert >= s->avctx->height)
158  return 0;
159 
160  for(i=0; i<length; i++) {
161  int replace_array = bytestream2_get_byte(&s->gb);
162  for(j=0; j<8; j++) {
163  int replace = (replace_array >> (7-j)) & 1;
164  if (x + half_horiz >= s->avctx->width)
165  return AVERROR_INVALIDDATA;
166  if (replace) {
167  int color = bytestream2_get_byte(&data_ptr);
168  s->frame->data[0][y*s->frame->linesize[0] + x] = color;
169  if (half_horiz)
170  s->frame->data[0][y*s->frame->linesize[0] + x + 1] = color;
171  if (half_vert) {
172  s->frame->data[0][(y+1)*s->frame->linesize[0] + x] = color;
173  if (half_horiz)
174  s->frame->data[0][(y+1)*s->frame->linesize[0] + x + 1] = color;
175  }
176  }
177  x += 1 + half_horiz;
178  }
179  }
180 
181  y += 1 + half_vert;
182  }
183 
184  return 0;
185 }
186 
187 static int mm_decode_frame(AVCodecContext *avctx,
188  void *data, int *got_frame,
189  AVPacket *avpkt)
190 {
191  const uint8_t *buf = avpkt->data;
192  int buf_size = avpkt->size;
193  MmContext *s = avctx->priv_data;
194  int type, res;
195 
196  if (buf_size < MM_PREAMBLE_SIZE)
197  return AVERROR_INVALIDDATA;
198  type = AV_RL16(&buf[0]);
199  buf += MM_PREAMBLE_SIZE;
200  buf_size -= MM_PREAMBLE_SIZE;
201  bytestream2_init(&s->gb, buf, buf_size);
202 
203  if ((res = ff_reget_buffer(avctx, s->frame)) < 0) {
204  av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
205  return res;
206  }
207 
208  switch(type) {
209  case MM_TYPE_PALETTE : res = mm_decode_pal(s); return buf_size;
210  case MM_TYPE_INTRA : res = mm_decode_intra(s, 0, 0); break;
211  case MM_TYPE_INTRA_HH : res = mm_decode_intra(s, 1, 0); break;
212  case MM_TYPE_INTRA_HHV : res = mm_decode_intra(s, 1, 1); break;
213  case MM_TYPE_INTER : res = mm_decode_inter(s, 0, 0); break;
214  case MM_TYPE_INTER_HH : res = mm_decode_inter(s, 1, 0); break;
215  case MM_TYPE_INTER_HHV : res = mm_decode_inter(s, 1, 1); break;
216  default:
217  res = AVERROR_INVALIDDATA;
218  break;
219  }
220  if (res < 0)
221  return res;
222 
223  memcpy(s->frame->data[1], s->palette, AVPALETTE_SIZE);
224 
225  if ((res = av_frame_ref(data, s->frame)) < 0)
226  return res;
227 
228  *got_frame = 1;
229 
230  return buf_size;
231 }
232 
234 {
235  MmContext *s = avctx->priv_data;
236 
237  av_frame_free(&s->frame);
238 
239  return 0;
240 }
241 
243  .name = "mmvideo",
244  .long_name = NULL_IF_CONFIG_SMALL("American Laser Games MM Video"),
245  .type = AVMEDIA_TYPE_VIDEO,
246  .id = AV_CODEC_ID_MMVIDEO,
247  .priv_data_size = sizeof(MmContext),
248  .init = mm_decode_init,
249  .close = mm_decode_end,
251  .capabilities = CODEC_CAP_DR1,
252 };