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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  return 0;
69 }
70 
71 static inline void comp(unsigned char *dst, int dst_stride,
72  unsigned char *src, int src_stride, int add)
73 {
74  int j, i;
75  for (j=0; j<8; j++)
76  for (i=0; i<8; i++)
77  dst[j*dst_stride + i] = av_clip_uint8(src[j*src_stride + i] + add);
78 }
79 
80 static inline void comp_block(MadContext *t, AVFrame *frame,
81  int mb_x, int mb_y,
82  int j, int mv_x, int mv_y, int add)
83 {
84  if (j < 4) {
85  unsigned offset = (mb_y*16 + ((j&2)<<2) + mv_y)*t->last_frame.linesize[0] + mb_x*16 + ((j&1)<<3) + mv_x;
86  if (offset >= (t->avctx->height - 7) * t->last_frame.linesize[0] - 7)
87  return;
88  comp(frame->data[0] + (mb_y*16 + ((j&2)<<2))*frame->linesize[0] + mb_x*16 + ((j&1)<<3),
89  frame->linesize[0],
90  t->last_frame.data[0] + offset,
91  t->last_frame.linesize[0], add);
92  } else if (!(t->avctx->flags & CODEC_FLAG_GRAY)) {
93  int index = j - 3;
94  unsigned offset = (mb_y * 8 + (mv_y/2))*t->last_frame.linesize[index] + mb_x * 8 + (mv_x/2);
95  if (offset >= (t->avctx->height/2 - 7) * t->last_frame.linesize[index] - 7)
96  return;
97  comp(frame->data[index] + (mb_y*8)*frame->linesize[index] + mb_x * 8,
98  frame->linesize[index],
99  t->last_frame.data[index] + offset,
100  t->last_frame.linesize[index], add);
101  }
102 }
103 
104 static inline void idct_put(MadContext *t, AVFrame *frame, int16_t *block,
105  int mb_x, int mb_y, int j)
106 {
107  if (j < 4) {
109  frame->data[0] + (mb_y*16 + ((j&2)<<2))*frame->linesize[0] + mb_x*16 + ((j&1)<<3),
110  frame->linesize[0], block);
111  } else if (!(t->avctx->flags & CODEC_FLAG_GRAY)) {
112  int index = j - 3;
114  frame->data[index] + (mb_y*8)*frame->linesize[index] + mb_x*8,
115  frame->linesize[index], block);
116  }
117 }
118 
119 static inline int decode_block_intra(MadContext *s, int16_t * block)
120 {
121  int level, i, j, run;
122  RLTable *rl = &ff_rl_mpeg1;
123  const uint8_t *scantable = s->scantable.permutated;
124  int16_t *quant_matrix = s->quant_matrix;
125 
126  block[0] = (128 + get_sbits(&s->gb, 8)) * quant_matrix[0];
127 
128  /* The RL decoder is derived from mpeg1_decode_block_intra;
129  Escaped level and run values a decoded differently */
130  i = 0;
131  {
132  OPEN_READER(re, &s->gb);
133  /* now quantify & encode AC coefficients */
134  for (;;) {
135  UPDATE_CACHE(re, &s->gb);
136  GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
137 
138  if (level == 127) {
139  break;
140  } else if (level != 0) {
141  i += run;
142  j = scantable[i];
143  level = (level*quant_matrix[j]) >> 4;
144  level = (level-1)|1;
145  level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
146  LAST_SKIP_BITS(re, &s->gb, 1);
147  } else {
148  /* escape */
149  UPDATE_CACHE(re, &s->gb);
150  level = SHOW_SBITS(re, &s->gb, 10); SKIP_BITS(re, &s->gb, 10);
151 
152  UPDATE_CACHE(re, &s->gb);
153  run = SHOW_UBITS(re, &s->gb, 6)+1; LAST_SKIP_BITS(re, &s->gb, 6);
154 
155  i += run;
156  j = scantable[i];
157  if (level < 0) {
158  level = -level;
159  level = (level*quant_matrix[j]) >> 4;
160  level = (level-1)|1;
161  level = -level;
162  } else {
163  level = (level*quant_matrix[j]) >> 4;
164  level = (level-1)|1;
165  }
166  }
167  if (i > 63) {
168  av_log(s->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
169  return -1;
170  }
171 
172  block[j] = level;
173  }
174  CLOSE_READER(re, &s->gb);
175  }
176  return 0;
177 }
178 
180 {
181  int value = 0;
182  if (get_bits1(gb)) {
183  if (get_bits1(gb))
184  value = -17;
185  value += get_bits(gb, 4) + 1;
186  }
187  return value;
188 }
189 
190 static int decode_mb(MadContext *s, AVFrame *frame, int inter)
191 {
192  int mv_map = 0;
193  int mv_x, mv_y;
194  int j;
195 
196  if (inter) {
197  int v = decode210(&s->gb);
198  if (v < 2) {
199  mv_map = v ? get_bits(&s->gb, 6) : 63;
200  mv_x = decode_motion(&s->gb);
201  mv_y = decode_motion(&s->gb);
202  }
203  }
204 
205  for (j=0; j<6; j++) {
206  if (mv_map & (1<<j)) { // mv_x and mv_y are guarded by mv_map
207  int add = 2*decode_motion(&s->gb);
208  if (s->last_frame.data[0])
209  comp_block(s, frame, s->mb_x, s->mb_y, j, mv_x, mv_y, add);
210  } else {
211  s->dsp.clear_block(s->block);
212  if(decode_block_intra(s, s->block) < 0)
213  return -1;
214  idct_put(s, frame, s->block, s->mb_x, s->mb_y, j);
215  }
216  }
217  return 0;
218 }
219 
220 static void calc_quant_matrix(MadContext *s, int qscale)
221 {
222  int i;
223 
225  for (i=1; i<64; i++)
226  s->quant_matrix[i] = (ff_inv_aanscales[i]*ff_mpeg1_default_intra_matrix[i]*qscale + 32) >> 10;
227 }
228 
229 static int decode_frame(AVCodecContext *avctx,
230  void *data, int *got_frame,
231  AVPacket *avpkt)
232 {
233  const uint8_t *buf = avpkt->data;
234  int buf_size = avpkt->size;
235  const uint8_t *buf_end = buf+buf_size;
236  MadContext *s = avctx->priv_data;
237  AVFrame *frame = data;
238  int width, height;
239  int chunk_type;
240  int inter, ret;
241 
242  if (buf_size < 26) {
243  av_log(avctx, AV_LOG_ERROR, "Input buffer too small\n");
244  *got_frame = 0;
245  return AVERROR_INVALIDDATA;
246  }
247 
248  chunk_type = AV_RL32(&buf[0]);
249  inter = (chunk_type == MADm_TAG || chunk_type == MADe_TAG);
250  buf += 8;
251 
252  av_reduce(&avctx->time_base.num, &avctx->time_base.den,
253  AV_RL16(&buf[6]), 1000, 1<<30);
254 
255  width = AV_RL16(&buf[8]);
256  height = AV_RL16(&buf[10]);
257  calc_quant_matrix(s, buf[13]);
258  buf += 16;
259 
260  if (width < 16 || height < 16) {
261  av_log(avctx, AV_LOG_ERROR, "Dimensions too small\n");
262  return AVERROR_INVALIDDATA;
263  }
264 
265  if (avctx->width != width || avctx->height != height) {
266  if((width * height)/2048*7 > buf_end-buf)
267  return AVERROR_INVALIDDATA;
268  if ((ret = av_image_check_size(width, height, 0, avctx)) < 0)
269  return ret;
270  avcodec_set_dimensions(avctx, width, height);
272  }
273 
274  if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)
275  return ret;
276 
277  if (inter && !s->last_frame.data[0]) {
278  av_log(avctx, AV_LOG_WARNING, "Missing reference frame.\n");
280  if (ret < 0)
281  return ret;
282  memset(s->last_frame.data[0], 0, s->last_frame.height *
283  s->last_frame.linesize[0]);
284  memset(s->last_frame.data[1], 0x80, s->last_frame.height / 2 *
285  s->last_frame.linesize[1]);
286  memset(s->last_frame.data[2], 0x80, s->last_frame.height / 2 *
287  s->last_frame.linesize[2]);
288  }
289 
291  buf_end - buf);
292  if (!s->bitstream_buf)
293  return AVERROR(ENOMEM);
294  s->dsp.bswap16_buf(s->bitstream_buf, (const uint16_t*)buf, (buf_end-buf)/2);
295  memset((uint8_t*)s->bitstream_buf + (buf_end-buf), 0, FF_INPUT_BUFFER_PADDING_SIZE);
296  init_get_bits(&s->gb, s->bitstream_buf, 8*(buf_end-buf));
297 
298  for (s->mb_y=0; s->mb_y < (avctx->height+15)/16; s->mb_y++)
299  for (s->mb_x=0; s->mb_x < (avctx->width +15)/16; s->mb_x++)
300  if(decode_mb(s, frame, inter) < 0)
301  return AVERROR_INVALIDDATA;
302 
303  *got_frame = 1;
304 
305  if (chunk_type != MADe_TAG) {
307  if ((ret = av_frame_ref(&s->last_frame, frame)) < 0)
308  return ret;
309  }
310 
311  return buf_size;
312 }
313 
315 {
316  MadContext *t = avctx->priv_data;
319  return 0;
320 }
321 
323  .name = "eamad",
324  .type = AVMEDIA_TYPE_VIDEO,
325  .id = AV_CODEC_ID_MAD,
326  .priv_data_size = sizeof(MadContext),
327  .init = decode_init,
328  .close = decode_end,
329  .decode = decode_frame,
330  .capabilities = CODEC_CAP_DR1,
331  .long_name = NULL_IF_CONFIG_SMALL("Electronic Arts Madcow Video")
332 };