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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 "get_bits.h"
33 #include "aandcttab.h"
34 #include "eaidct.h"
35 #include "internal.h"
36 #include "mpeg12.h"
37 #include "mpeg12data.h"
38 #include "libavutil/imgutils.h"
39 
40 #define EA_PREAMBLE_SIZE 8
41 #define MADk_TAG MKTAG('M', 'A', 'D', 'k') /* MAD i-frame */
42 #define MADm_TAG MKTAG('M', 'A', 'D', 'm') /* MAD p-frame */
43 #define MADe_TAG MKTAG('M', 'A', 'D', 'e') /* MAD lqp-frame */
44 
45 typedef struct MadContext {
51  unsigned int bitstream_buf_size;
52  DECLARE_ALIGNED(16, int16_t, block)[64];
54  uint16_t quant_matrix[64];
55  int mb_x;
56  int mb_y;
57 } MadContext;
58 
60 {
61  MadContext *s = avctx->priv_data;
62  s->avctx = avctx;
63  avctx->pix_fmt = AV_PIX_FMT_YUV420P;
64  ff_dsputil_init(&s->dsp, avctx);
68 
70  if (!s->last_frame)
71  return AVERROR(ENOMEM);
72 
73  return 0;
74 }
75 
76 static inline void comp(unsigned char *dst, int dst_stride,
77  unsigned char *src, int src_stride, int add)
78 {
79  int j, i;
80  for (j=0; j<8; j++)
81  for (i=0; i<8; i++)
82  dst[j*dst_stride + i] = av_clip_uint8(src[j*src_stride + i] + add);
83 }
84 
85 static inline void comp_block(MadContext *t, AVFrame *frame,
86  int mb_x, int mb_y,
87  int j, int mv_x, int mv_y, int add)
88 {
89  if (j < 4) {
90  unsigned offset = (mb_y*16 + ((j&2)<<2) + mv_y)*t->last_frame->linesize[0] + mb_x*16 + ((j&1)<<3) + mv_x;
91  if (offset >= (t->avctx->height - 7) * t->last_frame->linesize[0] - 7)
92  return;
93  comp(frame->data[0] + (mb_y*16 + ((j&2)<<2))*frame->linesize[0] + mb_x*16 + ((j&1)<<3),
94  frame->linesize[0],
95  t->last_frame->data[0] + offset,
96  t->last_frame->linesize[0], add);
97  } else if (!(t->avctx->flags & CODEC_FLAG_GRAY)) {
98  int index = j - 3;
99  unsigned offset = (mb_y * 8 + (mv_y/2))*t->last_frame->linesize[index] + mb_x * 8 + (mv_x/2);
100  if (offset >= (t->avctx->height/2 - 7) * t->last_frame->linesize[index] - 7)
101  return;
102  comp(frame->data[index] + (mb_y*8)*frame->linesize[index] + mb_x * 8,
103  frame->linesize[index],
104  t->last_frame->data[index] + offset,
105  t->last_frame->linesize[index], add);
106  }
107 }
108 
109 static inline void idct_put(MadContext *t, AVFrame *frame, int16_t *block,
110  int mb_x, int mb_y, int j)
111 {
112  if (j < 4) {
114  frame->data[0] + (mb_y*16 + ((j&2)<<2))*frame->linesize[0] + mb_x*16 + ((j&1)<<3),
115  frame->linesize[0], block);
116  } else if (!(t->avctx->flags & CODEC_FLAG_GRAY)) {
117  int index = j - 3;
119  frame->data[index] + (mb_y*8)*frame->linesize[index] + mb_x*8,
120  frame->linesize[index], block);
121  }
122 }
123 
124 static inline int decode_block_intra(MadContext *s, int16_t * block)
125 {
126  int level, i, j, run;
127  RLTable *rl = &ff_rl_mpeg1;
128  const uint8_t *scantable = s->scantable.permutated;
129  int16_t *quant_matrix = s->quant_matrix;
130 
131  block[0] = (128 + get_sbits(&s->gb, 8)) * quant_matrix[0];
132 
133  /* The RL decoder is derived from mpeg1_decode_block_intra;
134  Escaped level and run values a decoded differently */
135  i = 0;
136  {
137  OPEN_READER(re, &s->gb);
138  /* now quantify & encode AC coefficients */
139  for (;;) {
140  UPDATE_CACHE(re, &s->gb);
141  GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
142 
143  if (level == 127) {
144  break;
145  } else if (level != 0) {
146  i += run;
147  j = scantable[i];
148  level = (level*quant_matrix[j]) >> 4;
149  level = (level-1)|1;
150  level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
151  LAST_SKIP_BITS(re, &s->gb, 1);
152  } else {
153  /* escape */
154  UPDATE_CACHE(re, &s->gb);
155  level = SHOW_SBITS(re, &s->gb, 10); SKIP_BITS(re, &s->gb, 10);
156 
157  UPDATE_CACHE(re, &s->gb);
158  run = SHOW_UBITS(re, &s->gb, 6)+1; LAST_SKIP_BITS(re, &s->gb, 6);
159 
160  i += run;
161  j = scantable[i];
162  if (level < 0) {
163  level = -level;
164  level = (level*quant_matrix[j]) >> 4;
165  level = (level-1)|1;
166  level = -level;
167  } else {
168  level = (level*quant_matrix[j]) >> 4;
169  level = (level-1)|1;
170  }
171  }
172  if (i > 63) {
173  av_log(s->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
174  return -1;
175  }
176 
177  block[j] = level;
178  }
179  CLOSE_READER(re, &s->gb);
180  }
181  return 0;
182 }
183 
185 {
186  int value = 0;
187  if (get_bits1(gb)) {
188  if (get_bits1(gb))
189  value = -17;
190  value += get_bits(gb, 4) + 1;
191  }
192  return value;
193 }
194 
195 static int decode_mb(MadContext *s, AVFrame *frame, int inter)
196 {
197  int mv_map = 0;
198  int mv_x, mv_y;
199  int j;
200 
201  if (inter) {
202  int v = decode210(&s->gb);
203  if (v < 2) {
204  mv_map = v ? get_bits(&s->gb, 6) : 63;
205  mv_x = decode_motion(&s->gb);
206  mv_y = decode_motion(&s->gb);
207  }
208  }
209 
210  for (j=0; j<6; j++) {
211  if (mv_map & (1<<j)) { // mv_x and mv_y are guarded by mv_map
212  int add = 2*decode_motion(&s->gb);
213  if (s->last_frame->data[0])
214  comp_block(s, frame, s->mb_x, s->mb_y, j, mv_x, mv_y, add);
215  } else {
216  s->dsp.clear_block(s->block);
217  if(decode_block_intra(s, s->block) < 0)
218  return -1;
219  idct_put(s, frame, s->block, s->mb_x, s->mb_y, j);
220  }
221  }
222  return 0;
223 }
224 
225 static void calc_quant_matrix(MadContext *s, int qscale)
226 {
227  int i;
228 
230  for (i=1; i<64; i++)
231  s->quant_matrix[i] = (ff_inv_aanscales[i]*ff_mpeg1_default_intra_matrix[i]*qscale + 32) >> 10;
232 }
233 
234 static int decode_frame(AVCodecContext *avctx,
235  void *data, int *got_frame,
236  AVPacket *avpkt)
237 {
238  const uint8_t *buf = avpkt->data;
239  int buf_size = avpkt->size;
240  const uint8_t *buf_end = buf+buf_size;
241  MadContext *s = avctx->priv_data;
242  AVFrame *frame = data;
243  int width, height;
244  int chunk_type;
245  int inter, ret;
246 
247  if (buf_size < 26) {
248  av_log(avctx, AV_LOG_ERROR, "Input buffer too small\n");
249  *got_frame = 0;
250  return AVERROR_INVALIDDATA;
251  }
252 
253  chunk_type = AV_RL32(&buf[0]);
254  inter = (chunk_type == MADm_TAG || chunk_type == MADe_TAG);
255  buf += 8;
256 
257  av_reduce(&avctx->time_base.num, &avctx->time_base.den,
258  AV_RL16(&buf[6]), 1000, 1<<30);
259 
260  width = AV_RL16(&buf[8]);
261  height = AV_RL16(&buf[10]);
262  calc_quant_matrix(s, buf[13]);
263  buf += 16;
264 
265  if (width < 16 || height < 16) {
266  av_log(avctx, AV_LOG_ERROR, "Dimensions too small\n");
267  return AVERROR_INVALIDDATA;
268  }
269 
270  if (avctx->width != width || avctx->height != height) {
272  if((width * height)/2048*7 > buf_end-buf)
273  return AVERROR_INVALIDDATA;
274  if ((ret = ff_set_dimensions(avctx, width, height)) < 0)
275  return ret;
276  }
277 
278  if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)
279  return ret;
280 
281  if (inter && !s->last_frame->data[0]) {
282  av_log(avctx, AV_LOG_WARNING, "Missing reference frame.\n");
284  if (ret < 0)
285  return ret;
286  memset(s->last_frame->data[0], 0, s->last_frame->height *
287  s->last_frame->linesize[0]);
288  memset(s->last_frame->data[1], 0x80, s->last_frame->height / 2 *
289  s->last_frame->linesize[1]);
290  memset(s->last_frame->data[2], 0x80, s->last_frame->height / 2 *
291  s->last_frame->linesize[2]);
292  }
293 
295  buf_end - buf);
296  if (!s->bitstream_buf)
297  return AVERROR(ENOMEM);
298  s->dsp.bswap16_buf(s->bitstream_buf, (const uint16_t*)buf, (buf_end-buf)/2);
299  memset((uint8_t*)s->bitstream_buf + (buf_end-buf), 0, FF_INPUT_BUFFER_PADDING_SIZE);
300  init_get_bits(&s->gb, s->bitstream_buf, 8*(buf_end-buf));
301 
302  for (s->mb_y=0; s->mb_y < (avctx->height+15)/16; s->mb_y++)
303  for (s->mb_x=0; s->mb_x < (avctx->width +15)/16; s->mb_x++)
304  if(decode_mb(s, frame, inter) < 0)
305  return AVERROR_INVALIDDATA;
306 
307  *got_frame = 1;
308 
309  if (chunk_type != MADe_TAG) {
311  if ((ret = av_frame_ref(s->last_frame, frame)) < 0)
312  return ret;
313  }
314 
315  return buf_size;
316 }
317 
319 {
320  MadContext *t = avctx->priv_data;
323  return 0;
324 }
325 
327  .name = "eamad",
328  .long_name = NULL_IF_CONFIG_SMALL("Electronic Arts Madcow Video"),
329  .type = AVMEDIA_TYPE_VIDEO,
330  .id = AV_CODEC_ID_MAD,
331  .priv_data_size = sizeof(MadContext),
332  .init = decode_init,
333  .close = decode_end,
334  .decode = decode_frame,
335  .capabilities = CODEC_CAP_DR1,
336 };