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 
38 #define MM_PREAMBLE_SIZE 6
39 
40 #define MM_TYPE_INTER 0x5
41 #define MM_TYPE_INTRA 0x8
42 #define MM_TYPE_INTRA_HH 0xc
43 #define MM_TYPE_INTER_HH 0xd
44 #define MM_TYPE_INTRA_HHV 0xe
45 #define MM_TYPE_INTER_HHV 0xf
46 #define MM_TYPE_PALETTE 0x31
47 
48 typedef struct MmContext {
53 } MmContext;
54 
56 {
57  MmContext *s = avctx->priv_data;
58 
59  s->avctx = avctx;
60 
61  avctx->pix_fmt = AV_PIX_FMT_PAL8;
62 
63  s->frame.reference = 1;
64 
65  return 0;
66 }
67 
68 static int mm_decode_pal(MmContext *s)
69 {
70  int i;
71 
72  bytestream2_skip(&s->gb, 4);
73  for (i = 0; i < 128; i++) {
74  s->palette[i] = bytestream2_get_be24(&s->gb);
75  s->palette[i+128] = s->palette[i]<<2;
76  }
77 
78  return 0;
79 }
80 
85 static int mm_decode_intra(MmContext * s, int half_horiz, int half_vert)
86 {
87  int x = 0, y = 0;
88 
89  while (bytestream2_get_bytes_left(&s->gb) > 0) {
90  int run_length, color;
91 
92  if (y >= s->avctx->height)
93  return 0;
94 
95  color = bytestream2_get_byte(&s->gb);
96  if (color & 0x80) {
97  run_length = 1;
98  }else{
99  run_length = (color & 0x7f) + 2;
100  color = bytestream2_get_byte(&s->gb);
101  }
102 
103  if (half_horiz)
104  run_length *=2;
105 
106  if (color) {
107  memset(s->frame.data[0] + y*s->frame.linesize[0] + x, color, run_length);
108  if (half_vert)
109  memset(s->frame.data[0] + (y+1)*s->frame.linesize[0] + x, color, run_length);
110  }
111  x+= run_length;
112 
113  if (x >= s->avctx->width) {
114  x=0;
115  y += 1 + half_vert;
116  }
117  }
118 
119  return 0;
120 }
121 
122 /*
123  * @param half_horiz Half horizontal resolution (0 or 1)
124  * @param half_vert Half vertical resolution (0 or 1)
125  */
126 static int mm_decode_inter(MmContext * s, int half_horiz, int half_vert)
127 {
128  int data_off = bytestream2_get_le16(&s->gb), y;
129  GetByteContext data_ptr;
130 
131  if (bytestream2_get_bytes_left(&s->gb) < data_off)
132  return AVERROR_INVALIDDATA;
133 
134  bytestream2_init(&data_ptr, s->gb.buffer + data_off, bytestream2_get_bytes_left(&s->gb) - data_off);
135  while (s->gb.buffer < data_ptr.buffer_start) {
136  int i, j;
137  int length = bytestream2_get_byte(&s->gb);
138  int x = bytestream2_get_byte(&s->gb) + ((length & 0x80) << 1);
139  length &= 0x7F;
140 
141  if (length==0) {
142  y += x;
143  continue;
144  }
145 
146  if (y + half_vert >= s->avctx->height)
147  return 0;
148 
149  for(i=0; i<length; i++) {
150  int replace_array = bytestream2_get_byte(&s->gb);
151  for(j=0; j<8; j++) {
152  int replace = (replace_array >> (7-j)) & 1;
153  if (replace) {
154  int color = bytestream2_get_byte(&data_ptr);
155  s->frame.data[0][y*s->frame.linesize[0] + x] = color;
156  if (half_horiz)
157  s->frame.data[0][y*s->frame.linesize[0] + x + 1] = color;
158  if (half_vert) {
159  s->frame.data[0][(y+1)*s->frame.linesize[0] + x] = color;
160  if (half_horiz)
161  s->frame.data[0][(y+1)*s->frame.linesize[0] + x + 1] = color;
162  }
163  }
164  x += 1 + half_horiz;
165  }
166  }
167 
168  y += 1 + half_vert;
169  }
170 
171  return 0;
172 }
173 
174 static int mm_decode_frame(AVCodecContext *avctx,
175  void *data, int *got_frame,
176  AVPacket *avpkt)
177 {
178  const uint8_t *buf = avpkt->data;
179  int buf_size = avpkt->size;
180  MmContext *s = avctx->priv_data;
181  int type, res;
182 
183  if (buf_size < MM_PREAMBLE_SIZE)
184  return AVERROR_INVALIDDATA;
185  type = AV_RL16(&buf[0]);
186  buf += MM_PREAMBLE_SIZE;
187  buf_size -= MM_PREAMBLE_SIZE;
188  bytestream2_init(&s->gb, buf, buf_size);
189 
190  if (avctx->reget_buffer(avctx, &s->frame) < 0) {
191  av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
192  return -1;
193  }
194 
195  switch(type) {
196  case MM_TYPE_PALETTE : res = mm_decode_pal(s); return buf_size;
197  case MM_TYPE_INTRA : res = mm_decode_intra(s, 0, 0); break;
198  case MM_TYPE_INTRA_HH : res = mm_decode_intra(s, 1, 0); break;
199  case MM_TYPE_INTRA_HHV : res = mm_decode_intra(s, 1, 1); break;
200  case MM_TYPE_INTER : res = mm_decode_inter(s, 0, 0); break;
201  case MM_TYPE_INTER_HH : res = mm_decode_inter(s, 1, 0); break;
202  case MM_TYPE_INTER_HHV : res = mm_decode_inter(s, 1, 1); break;
203  default:
204  res = AVERROR_INVALIDDATA;
205  break;
206  }
207  if (res < 0)
208  return res;
209 
210  memcpy(s->frame.data[1], s->palette, AVPALETTE_SIZE);
211 
212  *got_frame = 1;
213  *(AVFrame*)data = s->frame;
214 
215  return buf_size;
216 }
217 
219 {
220  MmContext *s = avctx->priv_data;
221 
222  if(s->frame.data[0])
223  avctx->release_buffer(avctx, &s->frame);
224 
225  return 0;
226 }
227 
229  .name = "mmvideo",
230  .type = AVMEDIA_TYPE_VIDEO,
231  .id = AV_CODEC_ID_MMVIDEO,
232  .priv_data_size = sizeof(MmContext),
233  .init = mm_decode_init,
234  .close = mm_decode_end,
236  .capabilities = CODEC_CAP_DR1,
237  .long_name = NULL_IF_CONFIG_SMALL("American Laser Games MM Video"),
238 };