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msvideo1.c
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1 /*
2  * Microsoft Video-1 Decoder
3  * Copyright (C) 2003 the ffmpeg project
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  * Microsoft Video-1 Decoder by Mike Melanson (melanson@pcisys.net)
25  * For more information about the MS Video-1 format, visit:
26  * http://www.pcisys.net/~melanson/codecs/
27  *
28  */
29 
30 #include <stdio.h>
31 #include <stdlib.h>
32 #include <string.h>
33 
34 #include "libavutil/internal.h"
35 #include "libavutil/intreadwrite.h"
36 #include "avcodec.h"
37 #include "internal.h"
38 
39 #define PALETTE_COUNT 256
40 #define CHECK_STREAM_PTR(n) \
41  if ((stream_ptr + n) > s->size ) { \
42  av_log(s->avctx, AV_LOG_ERROR, " MS Video-1 warning: stream_ptr out of bounds (%d >= %d)\n", \
43  stream_ptr + n, s->size); \
44  return; \
45  }
46 
47 typedef struct Msvideo1Context {
48 
51 
52  const unsigned char *buf;
53  int size;
54 
55  int mode_8bit; /* if it's not 8-bit, it's 16-bit */
56 
57  uint32_t pal[256];
59 
61 {
62  Msvideo1Context *s = avctx->priv_data;
63 
64  s->avctx = avctx;
65 
66  /* figure out the colorspace based on the presence of a palette */
67  if (s->avctx->bits_per_coded_sample == 8) {
68  s->mode_8bit = 1;
69  avctx->pix_fmt = AV_PIX_FMT_PAL8;
70  } else {
71  s->mode_8bit = 0;
72  avctx->pix_fmt = AV_PIX_FMT_RGB555;
73  }
74 
75  s->frame = av_frame_alloc();
76  if (!s->frame)
77  return AVERROR(ENOMEM);
78 
79  return 0;
80 }
81 
83 {
84  int block_ptr, pixel_ptr;
85  int total_blocks;
86  int pixel_x, pixel_y; /* pixel width and height iterators */
87  int block_x, block_y; /* block width and height iterators */
88  int blocks_wide, blocks_high; /* width and height in 4x4 blocks */
89  int block_inc;
90  int row_dec;
91 
92  /* decoding parameters */
93  int stream_ptr;
94  unsigned char byte_a, byte_b;
95  unsigned short flags;
96  int skip_blocks;
97  unsigned char colors[8];
98  unsigned char *pixels = s->frame->data[0];
99  int stride = s->frame->linesize[0];
100 
101  stream_ptr = 0;
102  skip_blocks = 0;
103  blocks_wide = s->avctx->width / 4;
104  blocks_high = s->avctx->height / 4;
105  total_blocks = blocks_wide * blocks_high;
106  block_inc = 4;
107  row_dec = stride + 4;
108 
109  for (block_y = blocks_high; block_y > 0; block_y--) {
110  block_ptr = ((block_y * 4) - 1) * stride;
111  for (block_x = blocks_wide; block_x > 0; block_x--) {
112  /* check if this block should be skipped */
113  if (skip_blocks) {
114  block_ptr += block_inc;
115  skip_blocks--;
116  total_blocks--;
117  continue;
118  }
119 
120  pixel_ptr = block_ptr;
121 
122  /* get the next two bytes in the encoded data stream */
123  CHECK_STREAM_PTR(2);
124  byte_a = s->buf[stream_ptr++];
125  byte_b = s->buf[stream_ptr++];
126 
127  /* check if the decode is finished */
128  if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0))
129  return;
130  else if ((byte_b & 0xFC) == 0x84) {
131  /* skip code, but don't count the current block */
132  skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
133  } else if (byte_b < 0x80) {
134  /* 2-color encoding */
135  flags = (byte_b << 8) | byte_a;
136 
137  CHECK_STREAM_PTR(2);
138  colors[0] = s->buf[stream_ptr++];
139  colors[1] = s->buf[stream_ptr++];
140 
141  for (pixel_y = 0; pixel_y < 4; pixel_y++) {
142  for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
143  pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
144  pixel_ptr -= row_dec;
145  }
146  } else if (byte_b >= 0x90) {
147  /* 8-color encoding */
148  flags = (byte_b << 8) | byte_a;
149 
150  CHECK_STREAM_PTR(8);
151  memcpy(colors, &s->buf[stream_ptr], 8);
152  stream_ptr += 8;
153 
154  for (pixel_y = 0; pixel_y < 4; pixel_y++) {
155  for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
156  pixels[pixel_ptr++] =
157  colors[((pixel_y & 0x2) << 1) +
158  (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
159  pixel_ptr -= row_dec;
160  }
161  } else {
162  /* 1-color encoding */
163  colors[0] = byte_a;
164 
165  for (pixel_y = 0; pixel_y < 4; pixel_y++) {
166  for (pixel_x = 0; pixel_x < 4; pixel_x++)
167  pixels[pixel_ptr++] = colors[0];
168  pixel_ptr -= row_dec;
169  }
170  }
171 
172  block_ptr += block_inc;
173  total_blocks--;
174  }
175  }
176 
177  /* make the palette available on the way out */
178  if (s->avctx->pix_fmt == AV_PIX_FMT_PAL8)
179  memcpy(s->frame->data[1], s->pal, AVPALETTE_SIZE);
180 }
181 
183 {
184  int block_ptr, pixel_ptr;
185  int total_blocks;
186  int pixel_x, pixel_y; /* pixel width and height iterators */
187  int block_x, block_y; /* block width and height iterators */
188  int blocks_wide, blocks_high; /* width and height in 4x4 blocks */
189  int block_inc;
190  int row_dec;
191 
192  /* decoding parameters */
193  int stream_ptr;
194  unsigned char byte_a, byte_b;
195  unsigned short flags;
196  int skip_blocks;
197  unsigned short colors[8];
198  unsigned short *pixels = (unsigned short *)s->frame->data[0];
199  int stride = s->frame->linesize[0] / 2;
200 
201  stream_ptr = 0;
202  skip_blocks = 0;
203  blocks_wide = s->avctx->width / 4;
204  blocks_high = s->avctx->height / 4;
205  total_blocks = blocks_wide * blocks_high;
206  block_inc = 4;
207  row_dec = stride + 4;
208 
209  for (block_y = blocks_high; block_y > 0; block_y--) {
210  block_ptr = ((block_y * 4) - 1) * stride;
211  for (block_x = blocks_wide; block_x > 0; block_x--) {
212  /* check if this block should be skipped */
213  if (skip_blocks) {
214  block_ptr += block_inc;
215  skip_blocks--;
216  total_blocks--;
217  continue;
218  }
219 
220  pixel_ptr = block_ptr;
221 
222  /* get the next two bytes in the encoded data stream */
223  CHECK_STREAM_PTR(2);
224  byte_a = s->buf[stream_ptr++];
225  byte_b = s->buf[stream_ptr++];
226 
227  /* check if the decode is finished */
228  if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0)) {
229  return;
230  } else if ((byte_b & 0xFC) == 0x84) {
231  /* skip code, but don't count the current block */
232  skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
233  } else if (byte_b < 0x80) {
234  /* 2- or 8-color encoding modes */
235  flags = (byte_b << 8) | byte_a;
236 
237  CHECK_STREAM_PTR(4);
238  colors[0] = AV_RL16(&s->buf[stream_ptr]);
239  stream_ptr += 2;
240  colors[1] = AV_RL16(&s->buf[stream_ptr]);
241  stream_ptr += 2;
242 
243  if (colors[0] & 0x8000) {
244  /* 8-color encoding */
245  CHECK_STREAM_PTR(12);
246  colors[2] = AV_RL16(&s->buf[stream_ptr]);
247  stream_ptr += 2;
248  colors[3] = AV_RL16(&s->buf[stream_ptr]);
249  stream_ptr += 2;
250  colors[4] = AV_RL16(&s->buf[stream_ptr]);
251  stream_ptr += 2;
252  colors[5] = AV_RL16(&s->buf[stream_ptr]);
253  stream_ptr += 2;
254  colors[6] = AV_RL16(&s->buf[stream_ptr]);
255  stream_ptr += 2;
256  colors[7] = AV_RL16(&s->buf[stream_ptr]);
257  stream_ptr += 2;
258 
259  for (pixel_y = 0; pixel_y < 4; pixel_y++) {
260  for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
261  pixels[pixel_ptr++] =
262  colors[((pixel_y & 0x2) << 1) +
263  (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
264  pixel_ptr -= row_dec;
265  }
266  } else {
267  /* 2-color encoding */
268  for (pixel_y = 0; pixel_y < 4; pixel_y++) {
269  for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
270  pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
271  pixel_ptr -= row_dec;
272  }
273  }
274  } else {
275  /* otherwise, it's a 1-color block */
276  colors[0] = (byte_b << 8) | byte_a;
277 
278  for (pixel_y = 0; pixel_y < 4; pixel_y++) {
279  for (pixel_x = 0; pixel_x < 4; pixel_x++)
280  pixels[pixel_ptr++] = colors[0];
281  pixel_ptr -= row_dec;
282  }
283  }
284 
285  block_ptr += block_inc;
286  total_blocks--;
287  }
288  }
289 }
290 
292  void *data, int *got_frame,
293  AVPacket *avpkt)
294 {
295  const uint8_t *buf = avpkt->data;
296  int buf_size = avpkt->size;
297  Msvideo1Context *s = avctx->priv_data;
298  int ret;
299 
300  s->buf = buf;
301  s->size = buf_size;
302 
303  if ((ret = ff_reget_buffer(avctx, s->frame)) < 0)
304  return ret;
305 
306  if (s->mode_8bit) {
307  const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
308 
309  if (pal) {
310  memcpy(s->pal, pal, AVPALETTE_SIZE);
311  s->frame->palette_has_changed = 1;
312  }
313  }
314 
315  if (s->mode_8bit)
317  else
319 
320  if ((ret = av_frame_ref(data, s->frame)) < 0)
321  return ret;
322 
323  *got_frame = 1;
324 
325  /* report that the buffer was completely consumed */
326  return buf_size;
327 }
328 
330 {
331  Msvideo1Context *s = avctx->priv_data;
332 
333  av_frame_free(&s->frame);
334 
335  return 0;
336 }
337 
339  .name = "msvideo1",
340  .long_name = NULL_IF_CONFIG_SMALL("Microsoft Video 1"),
341  .type = AVMEDIA_TYPE_VIDEO,
342  .id = AV_CODEC_ID_MSVIDEO1,
343  .priv_data_size = sizeof(Msvideo1Context),
347  .capabilities = CODEC_CAP_DR1,
348 };