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  s->frame = av_frame_alloc();
65  if (!s->frame)
66  return AVERROR(ENOMEM);
67 
68  return 0;
69 }
70 
71 static int mm_decode_pal(MmContext *s)
72 {
73  int i;
74 
75  bytestream2_skip(&s->gb, 4);
76  for (i = 0; i < 128; i++) {
77  s->palette[i] = bytestream2_get_be24(&s->gb);
78  s->palette[i+128] = s->palette[i]<<2;
79  }
80 
81  return 0;
82 }
83 
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 (color) {
110  memset(s->frame->data[0] + y*s->frame->linesize[0] + x, color, run_length);
111  if (half_vert)
112  memset(s->frame->data[0] + (y+1)*s->frame->linesize[0] + x, color, run_length);
113  }
114  x+= run_length;
115 
116  if (x >= s->avctx->width) {
117  x=0;
118  y += 1 + half_vert;
119  }
120  }
121 
122  return 0;
123 }
124 
125 /*
126  * @param half_horiz Half horizontal resolution (0 or 1)
127  * @param half_vert Half vertical resolution (0 or 1)
128  */
129 static int mm_decode_inter(MmContext * s, int half_horiz, int half_vert)
130 {
131  int data_off = bytestream2_get_le16(&s->gb);
132  int y = 0;
133  GetByteContext data_ptr;
134 
135  if (bytestream2_get_bytes_left(&s->gb) < data_off)
136  return AVERROR_INVALIDDATA;
137 
138  bytestream2_init(&data_ptr, s->gb.buffer + data_off, bytestream2_get_bytes_left(&s->gb) - data_off);
139  while (s->gb.buffer < data_ptr.buffer_start) {
140  int i, j;
141  int length = bytestream2_get_byte(&s->gb);
142  int x = bytestream2_get_byte(&s->gb) + ((length & 0x80) << 1);
143  length &= 0x7F;
144 
145  if (length==0) {
146  y += x;
147  continue;
148  }
149 
150  if (y + half_vert >= s->avctx->height)
151  return 0;
152 
153  for(i=0; i<length; i++) {
154  int replace_array = bytestream2_get_byte(&s->gb);
155  for(j=0; j<8; j++) {
156  int replace = (replace_array >> (7-j)) & 1;
157  if (replace) {
158  int color = bytestream2_get_byte(&data_ptr);
159  s->frame->data[0][y*s->frame->linesize[0] + x] = color;
160  if (half_horiz)
161  s->frame->data[0][y*s->frame->linesize[0] + x + 1] = color;
162  if (half_vert) {
163  s->frame->data[0][(y+1)*s->frame->linesize[0] + x] = color;
164  if (half_horiz)
165  s->frame->data[0][(y+1)*s->frame->linesize[0] + x + 1] = color;
166  }
167  }
168  x += 1 + half_horiz;
169  }
170  }
171 
172  y += 1 + half_vert;
173  }
174 
175  return 0;
176 }
177 
178 static int mm_decode_frame(AVCodecContext *avctx,
179  void *data, int *got_frame,
180  AVPacket *avpkt)
181 {
182  const uint8_t *buf = avpkt->data;
183  int buf_size = avpkt->size;
184  MmContext *s = avctx->priv_data;
185  int type, res;
186 
187  if (buf_size < MM_PREAMBLE_SIZE)
188  return AVERROR_INVALIDDATA;
189  type = AV_RL16(&buf[0]);
190  buf += MM_PREAMBLE_SIZE;
191  buf_size -= MM_PREAMBLE_SIZE;
192  bytestream2_init(&s->gb, buf, buf_size);
193 
194  if ((res = ff_reget_buffer(avctx, s->frame)) < 0) {
195  av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
196  return res;
197  }
198 
199  switch(type) {
200  case MM_TYPE_PALETTE : res = mm_decode_pal(s); return buf_size;
201  case MM_TYPE_INTRA : res = mm_decode_intra(s, 0, 0); break;
202  case MM_TYPE_INTRA_HH : res = mm_decode_intra(s, 1, 0); break;
203  case MM_TYPE_INTRA_HHV : res = mm_decode_intra(s, 1, 1); break;
204  case MM_TYPE_INTER : res = mm_decode_inter(s, 0, 0); break;
205  case MM_TYPE_INTER_HH : res = mm_decode_inter(s, 1, 0); break;
206  case MM_TYPE_INTER_HHV : res = mm_decode_inter(s, 1, 1); break;
207  default:
208  res = AVERROR_INVALIDDATA;
209  break;
210  }
211  if (res < 0)
212  return res;
213 
214  memcpy(s->frame->data[1], s->palette, AVPALETTE_SIZE);
215 
216  if ((res = av_frame_ref(data, s->frame)) < 0)
217  return res;
218 
219  *got_frame = 1;
220 
221  return buf_size;
222 }
223 
225 {
226  MmContext *s = avctx->priv_data;
227 
228  av_frame_free(&s->frame);
229 
230  return 0;
231 }
232 
234  .name = "mmvideo",
235  .long_name = NULL_IF_CONFIG_SMALL("American Laser Games MM Video"),
236  .type = AVMEDIA_TYPE_VIDEO,
237  .id = AV_CODEC_ID_MMVIDEO,
238  .priv_data_size = sizeof(MmContext),
239  .init = mm_decode_init,
240  .close = mm_decode_end,
242  .capabilities = CODEC_CAP_DR1,
243 };