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yop.c
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1 /*
2  * Psygnosis YOP decoder
3  *
4  * Copyright (C) 2010 Mohamed Naufal Basheer <naufal11@gmail.com>
5  * derived from the code by
6  * Copyright (C) 2009 Thomas P. Higdon <thomas.p.higdon@gmail.com>
7  *
8  * This file is part of FFmpeg.
9  *
10  * FFmpeg is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU Lesser General Public
12  * License as published by the Free Software Foundation; either
13  * version 2.1 of the License, or (at your option) any later version.
14  *
15  * FFmpeg is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18  * Lesser General Public License for more details.
19  *
20  * You should have received a copy of the GNU Lesser General Public
21  * License along with FFmpeg; if not, write to the Free Software
22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23  */
24 
25 #include "libavutil/intreadwrite.h"
26 #include "libavutil/imgutils.h"
27 
28 #include "avcodec.h"
29 #include "get_bits.h"
30 #include "internal.h"
31 
32 typedef struct YopDecContext {
35 
37  int first_color[2];
39 
46 
47 // These tables are taken directly from:
48 // http://wiki.multimedia.cx/index.php?title=Psygnosis_YOP
49 
50 /**
51  * Lookup table for painting macroblocks. Bytes 0-2 of each entry contain
52  * the macroblock positions to be painted (taken as (0, B0, B1, B2)).
53  * Byte 3 contains the number of bytes consumed on the input,
54  * equal to max(bytes 0-2) + 1.
55  */
56 static const uint8_t paint_lut[15][4] =
57  {{1, 2, 3, 4}, {1, 2, 0, 3},
58  {1, 2, 1, 3}, {1, 2, 2, 3},
59  {1, 0, 2, 3}, {1, 0, 0, 2},
60  {1, 0, 1, 2}, {1, 1, 2, 3},
61  {0, 1, 2, 3}, {0, 1, 0, 2},
62  {1, 1, 0, 2}, {0, 1, 1, 2},
63  {0, 0, 1, 2}, {0, 0, 0, 1},
64  {1, 1, 1, 2},
65  };
66 
67 /**
68  * Lookup table for copying macroblocks. Each entry contains the respective
69  * x and y pixel offset for the copy source.
70  */
71 static const int8_t motion_vector[16][2] =
72  {{-4, -4}, {-2, -4},
73  { 0, -4}, { 2, -4},
74  {-4, -2}, {-4, 0},
75  {-3, -3}, {-1, -3},
76  { 1, -3}, { 3, -3},
77  {-3, -1}, {-2, -2},
78  { 0, -2}, { 2, -2},
79  { 4, -2}, {-2, 0},
80  };
81 
83 {
84  YopDecContext *s = avctx->priv_data;
85 
86  av_frame_free(&s->frame);
87 
88  return 0;
89 }
90 
92 {
93  YopDecContext *s = avctx->priv_data;
94  s->avctx = avctx;
95 
96  if (avctx->width & 1 || avctx->height & 1 ||
97  av_image_check_size(avctx->width, avctx->height, 0, avctx) < 0) {
98  av_log(avctx, AV_LOG_ERROR, "YOP has invalid dimensions\n");
99  return AVERROR_INVALIDDATA;
100  }
101 
102  if (avctx->extradata_size < 3) {
103  av_log(avctx, AV_LOG_ERROR, "Missing or incomplete extradata.\n");
104  return AVERROR_INVALIDDATA;
105  }
106 
107  avctx->pix_fmt = AV_PIX_FMT_PAL8;
108 
109  s->num_pal_colors = avctx->extradata[0];
110  s->first_color[0] = avctx->extradata[1];
111  s->first_color[1] = avctx->extradata[2];
112 
113  if (s->num_pal_colors + s->first_color[0] > 256 ||
114  s->num_pal_colors + s->first_color[1] > 256) {
115  av_log(avctx, AV_LOG_ERROR,
116  "Palette parameters invalid, header probably corrupt\n");
117  return AVERROR_INVALIDDATA;
118  }
119 
120  s->frame = av_frame_alloc();
121 
122  return 0;
123 }
124 
125 /**
126  * Paint a macroblock using the pattern in paint_lut.
127  * @param s codec context
128  * @param tag the tag that was in the nibble
129  */
130 static int yop_paint_block(YopDecContext *s, int linesize, int tag)
131 {
132  if (s->src_end - s->srcptr < paint_lut[tag][3]) {
133  av_log(s->avctx, AV_LOG_ERROR, "Packet too small.\n");
134  return AVERROR_INVALIDDATA;
135  }
136 
137  s->dstptr[0] = s->srcptr[0];
138  s->dstptr[1] = s->srcptr[paint_lut[tag][0]];
139  s->dstptr[linesize] = s->srcptr[paint_lut[tag][1]];
140  s->dstptr[linesize + 1] = s->srcptr[paint_lut[tag][2]];
141 
142  // The number of src bytes consumed is in the last part of the lut entry.
143  s->srcptr += paint_lut[tag][3];
144  return 0;
145 }
146 
147 /**
148  * Copy a previously painted macroblock to the current_block.
149  * @param copy_tag the tag that was in the nibble
150  */
151 static int yop_copy_previous_block(YopDecContext *s, int linesize, int copy_tag)
152 {
153  uint8_t *bufptr;
154 
155  // Calculate position for the copy source
156  bufptr = s->dstptr + motion_vector[copy_tag][0] +
157  linesize * motion_vector[copy_tag][1];
158  if (bufptr < s->dstbuf) {
159  av_log(s->avctx, AV_LOG_ERROR, "File probably corrupt\n");
160  return AVERROR_INVALIDDATA;
161  }
162 
163  s->dstptr[0] = bufptr[0];
164  s->dstptr[1] = bufptr[1];
165  s->dstptr[linesize] = bufptr[linesize];
166  s->dstptr[linesize + 1] = bufptr[linesize + 1];
167 
168  return 0;
169 }
170 
171 /**
172  * Return the next nibble in sequence, consuming a new byte on the input
173  * only if necessary.
174  */
176 {
177  int ret;
178 
179  if (s->low_nibble) {
180  ret = *s->low_nibble & 0xf;
181  s->low_nibble = NULL;
182  }else {
183  s->low_nibble = s->srcptr++;
184  ret = *s->low_nibble >> 4;
185  }
186  return ret;
187 }
188 
189 static int yop_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
190  AVPacket *avpkt)
191 {
192  YopDecContext *s = avctx->priv_data;
193  AVFrame *frame = s->frame;
194  int tag, firstcolor, is_odd_frame;
195  int ret, i, x, y;
196  uint32_t *palette;
197 
198  if (avpkt->size < 4 + 3 * s->num_pal_colors) {
199  av_log(avctx, AV_LOG_ERROR, "Packet too small.\n");
200  return AVERROR_INVALIDDATA;
201  }
202 
203  if ((ret = ff_reget_buffer(avctx, frame)) < 0)
204  return ret;
205 
206  if (!avctx->frame_number)
207  memset(frame->data[1], 0, AVPALETTE_SIZE);
208 
209  s->dstbuf = frame->data[0];
210  s->dstptr = frame->data[0];
211  s->srcptr = avpkt->data + 4;
212  s->src_end = avpkt->data + avpkt->size;
213  s->low_nibble = NULL;
214 
215  is_odd_frame = avpkt->data[0];
216  if(is_odd_frame>1){
217  av_log(avctx, AV_LOG_ERROR, "frame is too odd %d\n", is_odd_frame);
218  return AVERROR_INVALIDDATA;
219  }
220  firstcolor = s->first_color[is_odd_frame];
221  palette = (uint32_t *)frame->data[1];
222 
223  for (i = 0; i < s->num_pal_colors; i++, s->srcptr += 3) {
224  palette[i + firstcolor] = (s->srcptr[0] << 18) |
225  (s->srcptr[1] << 10) |
226  (s->srcptr[2] << 2);
227  palette[i + firstcolor] |= 0xFFU << 24 |
228  (palette[i + firstcolor] >> 6) & 0x30303;
229  }
230 
231  frame->palette_has_changed = 1;
232 
233  for (y = 0; y < avctx->height; y += 2) {
234  for (x = 0; x < avctx->width; x += 2) {
235  if (s->srcptr - avpkt->data >= avpkt->size) {
236  av_log(avctx, AV_LOG_ERROR, "Packet too small.\n");
237  return AVERROR_INVALIDDATA;
238  }
239 
240  tag = yop_get_next_nibble(s);
241 
242  if (tag != 0xf) {
243  ret = yop_paint_block(s, frame->linesize[0], tag);
244  if (ret < 0)
245  return ret;
246  } else {
247  tag = yop_get_next_nibble(s);
248  ret = yop_copy_previous_block(s, frame->linesize[0], tag);
249  if (ret < 0)
250  return ret;
251  }
252  s->dstptr += 2;
253  }
254  s->dstptr += 2*frame->linesize[0] - x;
255  }
256 
257  if ((ret = av_frame_ref(data, s->frame)) < 0)
258  return ret;
259 
260  *got_frame = 1;
261  return avpkt->size;
262 }
263 
265  .name = "yop",
266  .type = AVMEDIA_TYPE_VIDEO,
267  .id = AV_CODEC_ID_YOP,
268  .priv_data_size = sizeof(YopDecContext),
272  .long_name = NULL_IF_CONFIG_SMALL("Psygnosis YOP Video"),
273 };