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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  s->avctx = avctx;
86 
87  if (avctx->width & 1 || avctx->height & 1 ||
88  av_image_check_size(avctx->width, avctx->height, 0, avctx) < 0) {
89  return -1;
90  }
91 
92  if (avctx->extradata_size < 3) {
93  av_log(avctx, AV_LOG_ERROR, "Missing or incomplete extradata.\n");
94  return AVERROR_INVALIDDATA;
95  }
96 
97  avctx->pix_fmt = AV_PIX_FMT_PAL8;
98 
100  s->num_pal_colors = avctx->extradata[0];
101  s->first_color[0] = avctx->extradata[1];
102  s->first_color[1] = avctx->extradata[2];
103 
104  if (s->num_pal_colors + s->first_color[0] > 256 ||
105  s->num_pal_colors + s->first_color[1] > 256) {
106  av_log(avctx, AV_LOG_ERROR,
107  "Palette parameters invalid, header probably corrupt\n");
108  return AVERROR_INVALIDDATA;
109  }
110 
111  return 0;
112 }
113 
115 {
116  YopDecContext *s = avctx->priv_data;
117  if (s->frame.data[0])
118  avctx->release_buffer(avctx, &s->frame);
119  return 0;
120 }
121 
122 /**
123  * Paint a macroblock using the pattern in paint_lut.
124  * @param s codec context
125  * @param tag the tag that was in the nibble
126  */
127 static int yop_paint_block(YopDecContext *s, int tag)
128 {
129  if (s->src_end - s->srcptr < paint_lut[tag][3]) {
130  av_log(s->avctx, AV_LOG_ERROR, "Packet too small.\n");
131  return AVERROR_INVALIDDATA;
132  }
133 
134  s->dstptr[0] = s->srcptr[0];
135  s->dstptr[1] = s->srcptr[paint_lut[tag][0]];
136  s->dstptr[s->frame.linesize[0]] = s->srcptr[paint_lut[tag][1]];
137  s->dstptr[s->frame.linesize[0] + 1] = s->srcptr[paint_lut[tag][2]];
138 
139  // The number of src bytes consumed is in the last part of the lut entry.
140  s->srcptr += paint_lut[tag][3];
141  return 0;
142 }
143 
144 /**
145  * Copy a previously painted macroblock to the current_block.
146  * @param copy_tag the tag that was in the nibble
147  */
149 {
150  uint8_t *bufptr;
151 
152  // Calculate position for the copy source
153  bufptr = s->dstptr + motion_vector[copy_tag][0] +
154  s->frame.linesize[0] * motion_vector[copy_tag][1];
155  if (bufptr < s->dstbuf) {
156  av_log(s->avctx, AV_LOG_ERROR, "File probably corrupt\n");
157  return AVERROR_INVALIDDATA;
158  }
159 
160  s->dstptr[0] = bufptr[0];
161  s->dstptr[1] = bufptr[1];
162  s->dstptr[s->frame.linesize[0]] = bufptr[s->frame.linesize[0]];
163  s->dstptr[s->frame.linesize[0] + 1] = bufptr[s->frame.linesize[0] + 1];
164 
165  return 0;
166 }
167 
168 /**
169  * Return the next nibble in sequence, consuming a new byte on the input
170  * only if necessary.
171  */
173 {
174  int ret;
175 
176  if (s->low_nibble) {
177  ret = *s->low_nibble & 0xf;
178  s->low_nibble = NULL;
179  }else {
180  s->low_nibble = s->srcptr++;
181  ret = *s->low_nibble >> 4;
182  }
183  return ret;
184 }
185 
186 static int yop_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
187  AVPacket *avpkt)
188 {
189  YopDecContext *s = avctx->priv_data;
190  int tag, firstcolor, is_odd_frame;
191  int ret, i, x, y;
192  uint32_t *palette;
193 
194  if (avpkt->size < 4 + 3 * s->num_pal_colors) {
195  av_log(avctx, AV_LOG_ERROR, "Packet too small.\n");
196  return AVERROR_INVALIDDATA;
197  }
198 
199  if (s->frame.data[0])
200  avctx->release_buffer(avctx, &s->frame);
201 
202  if (avpkt->size < 4 + 3*s->num_pal_colors) {
203  av_log(avctx, AV_LOG_ERROR, "packet of size %d too small\n", avpkt->size);
204  return AVERROR_INVALIDDATA;
205  }
206 
207  ret = ff_get_buffer(avctx, &s->frame);
208  if (ret < 0) {
209  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
210  return ret;
211  }
212 
213  s->dstbuf = s->frame.data[0];
214  s->dstptr = s->frame.data[0];
215  s->srcptr = avpkt->data + 4;
216  s->src_end = avpkt->data + avpkt->size;
217  s->low_nibble = NULL;
218 
219  is_odd_frame = avpkt->data[0];
220  if(is_odd_frame>1){
221  av_log(avctx, AV_LOG_ERROR, "frame is too odd %d\n", is_odd_frame);
222  return AVERROR_INVALIDDATA;
223  }
224  firstcolor = s->first_color[is_odd_frame];
225  palette = (uint32_t *)s->frame.data[1];
226 
227  for (i = 0; i < s->num_pal_colors; i++, s->srcptr += 3) {
228  palette[i + firstcolor] = (s->srcptr[0] << 18) |
229  (s->srcptr[1] << 10) |
230  (s->srcptr[2] << 2);
231  palette[i + firstcolor] |= 0xFFU << 24 |
232  (palette[i + firstcolor] >> 6) & 0x30303;
233  }
234 
235  s->frame.palette_has_changed = 1;
236 
237  for (y = 0; y < avctx->height; y += 2) {
238  for (x = 0; x < avctx->width; x += 2) {
239  if (s->srcptr - avpkt->data >= avpkt->size) {
240  av_log(avctx, AV_LOG_ERROR, "Packet too small.\n");
241  return AVERROR_INVALIDDATA;
242  }
243 
244  tag = yop_get_next_nibble(s);
245 
246  if (tag != 0xf) {
247  ret = yop_paint_block(s, tag);
248  if (ret < 0)
249  return ret;
250  } else {
251  tag = yop_get_next_nibble(s);
252  ret = yop_copy_previous_block(s, tag);
253  if (ret < 0) {
254  avctx->release_buffer(avctx, &s->frame);
255  return ret;
256  }
257  }
258  s->dstptr += 2;
259  }
260  s->dstptr += 2*s->frame.linesize[0] - x;
261  }
262 
263  *got_frame = 1;
264  *(AVFrame *) data = s->frame;
265  return avpkt->size;
266 }
267 
269  .name = "yop",
270  .type = AVMEDIA_TYPE_VIDEO,
271  .id = AV_CODEC_ID_YOP,
272  .priv_data_size = sizeof(YopDecContext),
276  .long_name = NULL_IF_CONFIG_SMALL("Psygnosis YOP Video"),
277 };