FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
pictordec.c
Go to the documentation of this file.
1 /*
2  * Pictor/PC Paint decoder
3  * Copyright (c) 2010 Peter Ross <pross@xvid.org>
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  * Pictor/PC Paint decoder
25  */
26 
27 #include "libavutil/imgutils.h"
28 #include "avcodec.h"
29 #include "bytestream.h"
30 #include "cga_data.h"
31 #include "internal.h"
32 
33 typedef struct PicContext {
34  int width, height;
35  int nb_planes;
37 } PicContext;
38 
39 static void picmemset_8bpp(PicContext *s, AVFrame *frame, int value, int run,
40  int *x, int *y)
41 {
42  while (run > 0) {
43  uint8_t *d = frame->data[0] + *y * frame->linesize[0];
44  if (*x + run >= s->width) {
45  int n = s->width - *x;
46  memset(d + *x, value, n);
47  run -= n;
48  *x = 0;
49  *y -= 1;
50  if (*y < 0)
51  break;
52  } else {
53  memset(d + *x, value, run);
54  *x += run;
55  break;
56  }
57  }
58 }
59 
60 static void picmemset(PicContext *s, AVFrame *frame, int value, int run,
61  int *x, int *y, int *plane, int bits_per_plane)
62 {
63  uint8_t *d;
64  int shift = *plane * bits_per_plane;
65  int mask = ((1 << bits_per_plane) - 1) << shift;
66  value <<= shift;
67 
68  while (run > 0) {
69  int j;
70  for (j = 8-bits_per_plane; j >= 0; j -= bits_per_plane) {
71  d = frame->data[0] + *y * frame->linesize[0];
72  d[*x] |= (value >> j) & mask;
73  *x += 1;
74  if (*x == s->width) {
75  *y -= 1;
76  *x = 0;
77  if (*y < 0) {
78  *y = s->height - 1;
79  *plane += 1;
80  value <<= bits_per_plane;
81  mask <<= bits_per_plane;
82  if (*plane >= s->nb_planes)
83  break;
84  }
85  }
86  }
87  run--;
88  }
89 }
90 
91 static const uint8_t cga_mode45_index[6][4] = {
92  [0] = { 0, 3, 5, 7 }, // mode4, palette#1, low intensity
93  [1] = { 0, 2, 4, 6 }, // mode4, palette#2, low intensity
94  [2] = { 0, 3, 4, 7 }, // mode5, low intensity
95  [3] = { 0, 11, 13, 15 }, // mode4, palette#1, high intensity
96  [4] = { 0, 10, 12, 14 }, // mode4, palette#2, high intensity
97  [5] = { 0, 11, 12, 15 }, // mode5, high intensity
98 };
99 
100 static int decode_frame(AVCodecContext *avctx,
101  void *data, int *got_frame,
102  AVPacket *avpkt)
103 {
104  PicContext *s = avctx->priv_data;
105  AVFrame *frame = data;
106  uint32_t *palette;
107  int bits_per_plane, bpp, etype, esize, npal, pos_after_pal;
108  int i, x, y, plane, tmp, ret, val;
109 
110  bytestream2_init(&s->g, avpkt->data, avpkt->size);
111 
112  if (bytestream2_get_bytes_left(&s->g) < 11)
113  return AVERROR_INVALIDDATA;
114 
115  if (bytestream2_get_le16u(&s->g) != 0x1234)
116  return AVERROR_INVALIDDATA;
117 
118  s->width = bytestream2_get_le16u(&s->g);
119  s->height = bytestream2_get_le16u(&s->g);
120  bytestream2_skip(&s->g, 4);
121  tmp = bytestream2_get_byteu(&s->g);
122  bits_per_plane = tmp & 0xF;
123  s->nb_planes = (tmp >> 4) + 1;
124  bpp = bits_per_plane * s->nb_planes;
125  if (bits_per_plane > 8 || bpp < 1 || bpp > 32) {
126  avpriv_request_sample(avctx, "Unsupported bit depth");
127  return AVERROR_PATCHWELCOME;
128  }
129 
130  if (bytestream2_peek_byte(&s->g) == 0xFF || bpp == 1 || bpp == 4 || bpp == 8) {
131  bytestream2_skip(&s->g, 2);
132  etype = bytestream2_get_le16(&s->g);
133  esize = bytestream2_get_le16(&s->g);
134  if (bytestream2_get_bytes_left(&s->g) < esize)
135  return AVERROR_INVALIDDATA;
136  } else {
137  etype = -1;
138  esize = 0;
139  }
140 
141  avctx->pix_fmt = AV_PIX_FMT_PAL8;
142 
143  if (av_image_check_size(s->width, s->height, 0, avctx) < 0)
144  return -1;
145  if (s->width != avctx->width && s->height != avctx->height) {
146  avcodec_set_dimensions(avctx, s->width, s->height);
147  }
148 
149  if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
150  return ret;
151  memset(frame->data[0], 0, s->height * frame->linesize[0]);
152  frame->pict_type = AV_PICTURE_TYPE_I;
153  frame->palette_has_changed = 1;
154 
155  pos_after_pal = bytestream2_tell(&s->g) + esize;
156  palette = (uint32_t*)frame->data[1];
157  if (etype == 1 && esize > 1 && bytestream2_peek_byte(&s->g) < 6) {
158  int idx = bytestream2_get_byte(&s->g);
159  npal = 4;
160  for (i = 0; i < npal; i++)
161  palette[i] = ff_cga_palette[ cga_mode45_index[idx][i] ];
162  } else if (etype == 2) {
163  npal = FFMIN(esize, 16);
164  for (i = 0; i < npal; i++) {
165  int pal_idx = bytestream2_get_byte(&s->g);
166  palette[i] = ff_cga_palette[FFMIN(pal_idx, 15)];
167  }
168  } else if (etype == 3) {
169  npal = FFMIN(esize, 16);
170  for (i = 0; i < npal; i++) {
171  int pal_idx = bytestream2_get_byte(&s->g);
172  palette[i] = ff_ega_palette[FFMIN(pal_idx, 63)];
173  }
174  } else if (etype == 4 || etype == 5) {
175  npal = FFMIN(esize / 3, 256);
176  for (i = 0; i < npal; i++) {
177  palette[i] = bytestream2_get_be24(&s->g) << 2;
178  palette[i] |= 0xFFU << 24 | palette[i] >> 6 & 0x30303;
179  }
180  } else {
181  if (bpp == 1) {
182  npal = 2;
183  palette[0] = 0xFF000000;
184  palette[1] = 0xFFFFFFFF;
185  } else if (bpp == 2) {
186  npal = 4;
187  for (i = 0; i < npal; i++)
188  palette[i] = ff_cga_palette[ cga_mode45_index[0][i] ];
189  } else {
190  npal = 16;
191  memcpy(palette, ff_cga_palette, npal * 4);
192  }
193  }
194  // fill remaining palette entries
195  memset(palette + npal, 0, AVPALETTE_SIZE - npal * 4);
196  // skip remaining palette bytes
197  bytestream2_seek(&s->g, pos_after_pal, SEEK_SET);
198 
199  val = 0;
200  y = s->height - 1;
201  if (bytestream2_get_le16(&s->g)) {
202  x = 0;
203  plane = 0;
204  while (bytestream2_get_bytes_left(&s->g) >= 6) {
205  int stop_size, marker, t1, t2;
206 
207  t1 = bytestream2_get_bytes_left(&s->g);
208  t2 = bytestream2_get_le16(&s->g);
209  stop_size = t1 - FFMIN(t1, t2);
210  // ignore uncompressed block size
211  bytestream2_skip(&s->g, 2);
212  marker = bytestream2_get_byte(&s->g);
213 
214  while (plane < s->nb_planes &&
215  bytestream2_get_bytes_left(&s->g) > stop_size) {
216  int run = 1;
217  val = bytestream2_get_byte(&s->g);
218  if (val == marker) {
219  run = bytestream2_get_byte(&s->g);
220  if (run == 0)
221  run = bytestream2_get_le16(&s->g);
222  val = bytestream2_get_byte(&s->g);
223  }
224  if (!bytestream2_get_bytes_left(&s->g))
225  break;
226 
227  if (bits_per_plane == 8) {
228  picmemset_8bpp(s, frame, val, run, &x, &y);
229  if (y < 0)
230  goto finish;
231  } else {
232  picmemset(s, frame, val, run, &x, &y, &plane, bits_per_plane);
233  }
234  }
235  }
236 
237  if (x < avctx->width) {
238  int run = (y + 1) * avctx->width - x;
239  if (bits_per_plane == 8)
240  picmemset_8bpp(s, frame, val, run, &x, &y);
241  else
242  picmemset(s, frame, val, run / (8 / bits_per_plane), &x, &y, &plane, bits_per_plane);
243  }
244  } else {
245  while (y >= 0 && bytestream2_get_bytes_left(&s->g) > 0) {
246  memcpy(frame->data[0] + y * frame->linesize[0], s->g.buffer, FFMIN(avctx->width, bytestream2_get_bytes_left(&s->g)));
247  bytestream2_skip(&s->g, avctx->width);
248  y--;
249  }
250  }
251 finish:
252 
253  *got_frame = 1;
254  return avpkt->size;
255 }
256 
258  .name = "pictor",
259  .long_name = NULL_IF_CONFIG_SMALL("Pictor/PC Paint"),
260  .type = AVMEDIA_TYPE_VIDEO,
261  .id = AV_CODEC_ID_PICTOR,
262  .priv_data_size = sizeof(PicContext),
263  .decode = decode_frame,
264  .capabilities = CODEC_CAP_DR1,
265 };