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 = 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 i, x, y;
88  i=0; x=0; y=0;
89 
90  while (bytestream2_get_bytes_left(&s->gb) > 0) {
91  int run_length, color;
92 
93  if (y >= s->avctx->height)
94  return 0;
95 
96  color = bytestream2_get_byte(&s->gb);
97  if (color & 0x80) {
98  run_length = 1;
99  }else{
100  run_length = (color & 0x7f) + 2;
101  color = bytestream2_get_byte(&s->gb);
102  }
103 
104  if (half_horiz)
105  run_length *=2;
106 
107  if (color) {
108  memset(s->frame.data[0] + y*s->frame.linesize[0] + x, color, run_length);
109  if (half_vert)
110  memset(s->frame.data[0] + (y+1)*s->frame.linesize[0] + x, color, run_length);
111  }
112  x+= run_length;
113 
114  if (x >= s->avctx->width) {
115  x=0;
116  y += 1 + half_vert;
117  }
118  }
119 
120  return 0;
121 }
122 
123 /*
124  * @param half_horiz Half horizontal resolution (0 or 1)
125  * @param half_vert Half vertical resolution (0 or 1)
126  */
127 static int mm_decode_inter(MmContext * s, int half_horiz, int half_vert)
128 {
129  int data_off = bytestream2_get_le16(&s->gb), y;
130  GetByteContext data_ptr;
131 
132  if (bytestream2_get_bytes_left(&s->gb) < data_off)
133  return AVERROR_INVALIDDATA;
134 
135  bytestream2_init(&data_ptr, s->gb.buffer + data_off, bytestream2_get_bytes_left(&s->gb) - data_off);
136  while (s->gb.buffer < data_ptr.buffer_start) {
137  int i, j;
138  int length = bytestream2_get_byte(&s->gb);
139  int x = bytestream2_get_byte(&s->gb) + ((length & 0x80) << 1);
140  length &= 0x7F;
141 
142  if (length==0) {
143  y += x;
144  continue;
145  }
146 
147  if (y + half_vert >= s->avctx->height)
148  return 0;
149 
150  for(i=0; i<length; i++) {
151  int replace_array = bytestream2_get_byte(&s->gb);
152  for(j=0; j<8; j++) {
153  int replace = (replace_array >> (7-j)) & 1;
154  if (replace) {
155  int color = bytestream2_get_byte(&data_ptr);
156  s->frame.data[0][y*s->frame.linesize[0] + x] = color;
157  if (half_horiz)
158  s->frame.data[0][y*s->frame.linesize[0] + x + 1] = color;
159  if (half_vert) {
160  s->frame.data[0][(y+1)*s->frame.linesize[0] + x] = color;
161  if (half_horiz)
162  s->frame.data[0][(y+1)*s->frame.linesize[0] + x + 1] = color;
163  }
164  }
165  x += 1 + half_horiz;
166  }
167  }
168 
169  y += 1 + half_vert;
170  }
171 
172  return 0;
173 }
174 
175 static int mm_decode_frame(AVCodecContext *avctx,
176  void *data, int *data_size,
177  AVPacket *avpkt)
178 {
179  const uint8_t *buf = avpkt->data;
180  int buf_size = avpkt->size;
181  MmContext *s = avctx->priv_data;
182  int type, res;
183 
184  if (buf_size < MM_PREAMBLE_SIZE)
185  return AVERROR_INVALIDDATA;
186  type = AV_RL16(&buf[0]);
187  buf += MM_PREAMBLE_SIZE;
188  buf_size -= MM_PREAMBLE_SIZE;
189  bytestream2_init(&s->gb, buf, buf_size);
190 
191  if (avctx->reget_buffer(avctx, &s->frame) < 0) {
192  av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
193  return -1;
194  }
195 
196  switch(type) {
197  case MM_TYPE_PALETTE : res = mm_decode_pal(s); return buf_size;
198  case MM_TYPE_INTRA : res = mm_decode_intra(s, 0, 0); break;
199  case MM_TYPE_INTRA_HH : res = mm_decode_intra(s, 1, 0); break;
200  case MM_TYPE_INTRA_HHV : res = mm_decode_intra(s, 1, 1); break;
201  case MM_TYPE_INTER : res = mm_decode_inter(s, 0, 0); break;
202  case MM_TYPE_INTER_HH : res = mm_decode_inter(s, 1, 0); break;
203  case MM_TYPE_INTER_HHV : res = mm_decode_inter(s, 1, 1); break;
204  default:
205  res = AVERROR_INVALIDDATA;
206  break;
207  }
208  if (res < 0)
209  return res;
210 
211  memcpy(s->frame.data[1], s->palette, AVPALETTE_SIZE);
212 
213  *data_size = sizeof(AVFrame);
214  *(AVFrame*)data = s->frame;
215 
216  return buf_size;
217 }
218 
220 {
221  MmContext *s = avctx->priv_data;
222 
223  if(s->frame.data[0])
224  avctx->release_buffer(avctx, &s->frame);
225 
226  return 0;
227 }
228 
230  .name = "mmvideo",
231  .type = AVMEDIA_TYPE_VIDEO,
232  .id = CODEC_ID_MMVIDEO,
233  .priv_data_size = sizeof(MmContext),
234  .init = mm_decode_init,
235  .close = mm_decode_end,
237  .capabilities = CODEC_CAP_DR1,
238  .long_name = NULL_IF_CONFIG_SMALL("American Laser Games MM Video"),
239 };