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eamad.c
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1 /*
2  * Electronic Arts Madcow Video Decoder
3  * Copyright (c) 2007-2009 Peter Ross
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 St, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 /**
23  * @file
24  * Electronic Arts Madcow Video Decoder
25  * @author Peter Ross <pross@xvid.org>
26  *
27  * @see technical details at
28  * http://wiki.multimedia.cx/index.php?title=Electronic_Arts_MAD
29  */
30 
31 #include "avcodec.h"
32 #include "bswapdsp.h"
33 #include "get_bits.h"
34 #include "aandcttab.h"
35 #include "eaidct.h"
36 #include "idctdsp.h"
37 #include "internal.h"
38 #include "mpeg12.h"
39 #include "mpeg12data.h"
40 #include "libavutil/imgutils.h"
41 
42 #define EA_PREAMBLE_SIZE 8
43 #define MADk_TAG MKTAG('M', 'A', 'D', 'k') /* MAD i-frame */
44 #define MADm_TAG MKTAG('M', 'A', 'D', 'm') /* MAD p-frame */
45 #define MADe_TAG MKTAG('M', 'A', 'D', 'e') /* MAD lqp-frame */
46 
47 typedef struct MadContext {
55  unsigned int bitstream_buf_size;
56  DECLARE_ALIGNED(16, int16_t, block)[64];
58  uint16_t quant_matrix[64];
59  int mb_x;
60  int mb_y;
61 } MadContext;
62 
64 {
65  MadContext *s = avctx->priv_data;
66  s->avctx = avctx;
67  avctx->pix_fmt = AV_PIX_FMT_YUV420P;
68  ff_blockdsp_init(&s->bdsp, avctx);
70  ff_idctdsp_init(&s->idsp, avctx);
74 
76  if (!s->last_frame)
77  return AVERROR(ENOMEM);
78 
79  return 0;
80 }
81 
82 static inline void comp(unsigned char *dst, int dst_stride,
83  unsigned char *src, int src_stride, int add)
84 {
85  int j, i;
86  for (j=0; j<8; j++)
87  for (i=0; i<8; i++)
88  dst[j*dst_stride + i] = av_clip_uint8(src[j*src_stride + i] + add);
89 }
90 
91 static inline void comp_block(MadContext *t, AVFrame *frame,
92  int mb_x, int mb_y,
93  int j, int mv_x, int mv_y, int add)
94 {
95  if (j < 4) {
96  unsigned offset = (mb_y*16 + ((j&2)<<2) + mv_y)*t->last_frame->linesize[0] + mb_x*16 + ((j&1)<<3) + mv_x;
97  if (offset >= (t->avctx->height - 7) * t->last_frame->linesize[0] - 7)
98  return;
99  comp(frame->data[0] + (mb_y*16 + ((j&2)<<2))*frame->linesize[0] + mb_x*16 + ((j&1)<<3),
100  frame->linesize[0],
101  t->last_frame->data[0] + offset,
102  t->last_frame->linesize[0], add);
103  } else if (!(t->avctx->flags & CODEC_FLAG_GRAY)) {
104  int index = j - 3;
105  unsigned offset = (mb_y * 8 + (mv_y/2))*t->last_frame->linesize[index] + mb_x * 8 + (mv_x/2);
106  if (offset >= (t->avctx->height/2 - 7) * t->last_frame->linesize[index] - 7)
107  return;
108  comp(frame->data[index] + (mb_y*8)*frame->linesize[index] + mb_x * 8,
109  frame->linesize[index],
110  t->last_frame->data[index] + offset,
111  t->last_frame->linesize[index], add);
112  }
113 }
114 
115 static inline void idct_put(MadContext *t, AVFrame *frame, int16_t *block,
116  int mb_x, int mb_y, int j)
117 {
118  if (j < 4) {
120  frame->data[0] + (mb_y*16 + ((j&2)<<2))*frame->linesize[0] + mb_x*16 + ((j&1)<<3),
121  frame->linesize[0], block);
122  } else if (!(t->avctx->flags & CODEC_FLAG_GRAY)) {
123  int index = j - 3;
125  frame->data[index] + (mb_y*8)*frame->linesize[index] + mb_x*8,
126  frame->linesize[index], block);
127  }
128 }
129 
130 static inline int decode_block_intra(MadContext *s, int16_t * block)
131 {
132  int level, i, j, run;
133  RLTable *rl = &ff_rl_mpeg1;
134  const uint8_t *scantable = s->scantable.permutated;
135  int16_t *quant_matrix = s->quant_matrix;
136 
137  block[0] = (128 + get_sbits(&s->gb, 8)) * quant_matrix[0];
138 
139  /* The RL decoder is derived from mpeg1_decode_block_intra;
140  Escaped level and run values a decoded differently */
141  i = 0;
142  {
143  OPEN_READER(re, &s->gb);
144  /* now quantify & encode AC coefficients */
145  for (;;) {
146  UPDATE_CACHE(re, &s->gb);
147  GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
148 
149  if (level == 127) {
150  break;
151  } else if (level != 0) {
152  i += run;
153  j = scantable[i];
154  level = (level*quant_matrix[j]) >> 4;
155  level = (level-1)|1;
156  level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
157  LAST_SKIP_BITS(re, &s->gb, 1);
158  } else {
159  /* escape */
160  UPDATE_CACHE(re, &s->gb);
161  level = SHOW_SBITS(re, &s->gb, 10); SKIP_BITS(re, &s->gb, 10);
162 
163  UPDATE_CACHE(re, &s->gb);
164  run = SHOW_UBITS(re, &s->gb, 6)+1; LAST_SKIP_BITS(re, &s->gb, 6);
165 
166  i += run;
167  j = scantable[i];
168  if (level < 0) {
169  level = -level;
170  level = (level*quant_matrix[j]) >> 4;
171  level = (level-1)|1;
172  level = -level;
173  } else {
174  level = (level*quant_matrix[j]) >> 4;
175  level = (level-1)|1;
176  }
177  }
178  if (i > 63) {
179  av_log(s->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
180  return -1;
181  }
182 
183  block[j] = level;
184  }
185  CLOSE_READER(re, &s->gb);
186  }
187  return 0;
188 }
189 
191 {
192  int value = 0;
193  if (get_bits1(gb)) {
194  if (get_bits1(gb))
195  value = -17;
196  value += get_bits(gb, 4) + 1;
197  }
198  return value;
199 }
200 
201 static int decode_mb(MadContext *s, AVFrame *frame, int inter)
202 {
203  int mv_map = 0;
204  int av_uninit(mv_x), av_uninit(mv_y);
205  int j;
206 
207  if (inter) {
208  int v = decode210(&s->gb);
209  if (v < 2) {
210  mv_map = v ? get_bits(&s->gb, 6) : 63;
211  mv_x = decode_motion(&s->gb);
212  mv_y = decode_motion(&s->gb);
213  }
214  }
215 
216  for (j=0; j<6; j++) {
217  if (mv_map & (1<<j)) { // mv_x and mv_y are guarded by mv_map
218  int add = 2*decode_motion(&s->gb);
219  if (s->last_frame->data[0])
220  comp_block(s, frame, s->mb_x, s->mb_y, j, mv_x, mv_y, add);
221  } else {
222  s->bdsp.clear_block(s->block);
223  if(decode_block_intra(s, s->block) < 0)
224  return -1;
225  idct_put(s, frame, s->block, s->mb_x, s->mb_y, j);
226  }
227  }
228  return 0;
229 }
230 
231 static void calc_quant_matrix(MadContext *s, int qscale)
232 {
233  int i;
234 
236  for (i=1; i<64; i++)
237  s->quant_matrix[i] = (ff_inv_aanscales[i]*ff_mpeg1_default_intra_matrix[i]*qscale + 32) >> 10;
238 }
239 
240 static int decode_frame(AVCodecContext *avctx,
241  void *data, int *got_frame,
242  AVPacket *avpkt)
243 {
244  const uint8_t *buf = avpkt->data;
245  int buf_size = avpkt->size;
246  const uint8_t *buf_end = buf+buf_size;
247  MadContext *s = avctx->priv_data;
248  AVFrame *frame = data;
249  int width, height;
250  int chunk_type;
251  int inter, ret;
252 
253  if (buf_size < 26) {
254  av_log(avctx, AV_LOG_ERROR, "Input buffer too small\n");
255  *got_frame = 0;
256  return AVERROR_INVALIDDATA;
257  }
258 
259  chunk_type = AV_RL32(&buf[0]);
260  inter = (chunk_type == MADm_TAG || chunk_type == MADe_TAG);
261  buf += 8;
262 
263  av_reduce(&avctx->time_base.num, &avctx->time_base.den,
264  AV_RL16(&buf[6]), 1000, 1<<30);
265 
266  width = AV_RL16(&buf[8]);
267  height = AV_RL16(&buf[10]);
268  calc_quant_matrix(s, buf[13]);
269  buf += 16;
270 
271  if (width < 16 || height < 16) {
272  av_log(avctx, AV_LOG_ERROR, "Dimensions too small\n");
273  return AVERROR_INVALIDDATA;
274  }
275 
276  if (avctx->width != width || avctx->height != height) {
278  if((width * height)/2048*7 > buf_end-buf)
279  return AVERROR_INVALIDDATA;
280  if ((ret = ff_set_dimensions(avctx, width, height)) < 0)
281  return ret;
282  }
283 
284  if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)
285  return ret;
286 
287  if (inter && !s->last_frame->data[0]) {
288  av_log(avctx, AV_LOG_WARNING, "Missing reference frame.\n");
290  if (ret < 0)
291  return ret;
292  memset(s->last_frame->data[0], 0, s->last_frame->height *
293  s->last_frame->linesize[0]);
294  memset(s->last_frame->data[1], 0x80, s->last_frame->height / 2 *
295  s->last_frame->linesize[1]);
296  memset(s->last_frame->data[2], 0x80, s->last_frame->height / 2 *
297  s->last_frame->linesize[2]);
298  }
299 
301  buf_end - buf);
302  if (!s->bitstream_buf)
303  return AVERROR(ENOMEM);
304  s->bbdsp.bswap16_buf(s->bitstream_buf, (const uint16_t *) buf,
305  (buf_end - buf) / 2);
306  memset((uint8_t*)s->bitstream_buf + (buf_end-buf), 0, FF_INPUT_BUFFER_PADDING_SIZE);
307  init_get_bits(&s->gb, s->bitstream_buf, 8*(buf_end-buf));
308 
309  for (s->mb_y=0; s->mb_y < (avctx->height+15)/16; s->mb_y++)
310  for (s->mb_x=0; s->mb_x < (avctx->width +15)/16; s->mb_x++)
311  if(decode_mb(s, frame, inter) < 0)
312  return AVERROR_INVALIDDATA;
313 
314  *got_frame = 1;
315 
316  if (chunk_type != MADe_TAG) {
318  if ((ret = av_frame_ref(s->last_frame, frame)) < 0)
319  return ret;
320  }
321 
322  return buf_size;
323 }
324 
326 {
327  MadContext *t = avctx->priv_data;
330  return 0;
331 }
332 
334  .name = "eamad",
335  .long_name = NULL_IF_CONFIG_SMALL("Electronic Arts Madcow Video"),
336  .type = AVMEDIA_TYPE_VIDEO,
337  .id = AV_CODEC_ID_MAD,
338  .priv_data_size = sizeof(MadContext),
339  .init = decode_init,
340  .close = decode_end,
341  .decode = decode_frame,
342  .capabilities = CODEC_CAP_DR1,
343 };