FFmpeg
 All Data Structures Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
eamad.c
Go to the documentation of this file.
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 {
46  AVCodecContext *avctx;
47  DSPContext dsp;
48  AVFrame frame;
49  AVFrame last_frame;
50  GetBitContext gb;
51  void *bitstream_buf;
52  unsigned int bitstream_buf_size;
53  DECLARE_ALIGNED(16, int16_t, block)[64];
54  ScanTable scantable;
55  uint16_t quant_matrix[64];
56  int mb_x;
57  int mb_y;
58 } MadContext;
59 
60 static av_cold int decode_init(AVCodecContext *avctx)
61 {
62  MadContext *s = avctx->priv_data;
63  s->avctx = avctx;
64  avctx->pix_fmt = AV_PIX_FMT_YUV420P;
65  ff_dsputil_init(&s->dsp, avctx);
66  ff_init_scantable_permutation(s->dsp.idct_permutation, FF_NO_IDCT_PERM);
67  ff_init_scantable(s->dsp.idct_permutation, &s->scantable, ff_zigzag_direct);
68  ff_mpeg12_init_vlcs();
69  return 0;
70 }
71 
72 static inline void comp(unsigned char *dst, int dst_stride,
73  unsigned char *src, int src_stride, int add)
74 {
75  int j, i;
76  for (j=0; j<8; j++)
77  for (i=0; i<8; i++)
78  dst[j*dst_stride + i] = av_clip_uint8(src[j*src_stride + i] + add);
79 }
80 
81 static inline void comp_block(MadContext *t, 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(t->frame.data[0] + (mb_y*16 + ((j&2)<<2))*t->frame.linesize[0] + mb_x*16 + ((j&1)<<3),
89  t->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(t->frame.data[index] + (mb_y*8)*t->frame.linesize[index] + mb_x * 8,
98  t->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, int16_t *block, int mb_x, int mb_y, int j)
105 {
106  if (j < 4) {
107  ff_ea_idct_put_c(
108  t->frame.data[0] + (mb_y*16 + ((j&2)<<2))*t->frame.linesize[0] + mb_x*16 + ((j&1)<<3),
109  t->frame.linesize[0], block);
110  } else if (!(t->avctx->flags & CODEC_FLAG_GRAY)) {
111  int index = j - 3;
112  ff_ea_idct_put_c(
113  t->frame.data[index] + (mb_y*8)*t->frame.linesize[index] + mb_x*8,
114  t->frame.linesize[index], block);
115  }
116 }
117 
118 static inline int decode_block_intra(MadContext *s, int16_t * block)
119 {
120  int level, i, j, run;
121  RLTable *rl = &ff_rl_mpeg1;
122  const uint8_t *scantable = s->scantable.permutated;
123  int16_t *quant_matrix = s->quant_matrix;
124 
125  block[0] = (128 + get_sbits(&s->gb, 8)) * quant_matrix[0];
126 
127  /* The RL decoder is derived from mpeg1_decode_block_intra;
128  Escaped level and run values a decoded differently */
129  i = 0;
130  {
131  OPEN_READER(re, &s->gb);
132  /* now quantify & encode AC coefficients */
133  for (;;) {
134  UPDATE_CACHE(re, &s->gb);
135  GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
136 
137  if (level == 127) {
138  break;
139  } else if (level != 0) {
140  i += run;
141  j = scantable[i];
142  level = (level*quant_matrix[j]) >> 4;
143  level = (level-1)|1;
144  level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
145  LAST_SKIP_BITS(re, &s->gb, 1);
146  } else {
147  /* escape */
148  UPDATE_CACHE(re, &s->gb);
149  level = SHOW_SBITS(re, &s->gb, 10); SKIP_BITS(re, &s->gb, 10);
150 
151  UPDATE_CACHE(re, &s->gb);
152  run = SHOW_UBITS(re, &s->gb, 6)+1; LAST_SKIP_BITS(re, &s->gb, 6);
153 
154  i += run;
155  j = scantable[i];
156  if (level < 0) {
157  level = -level;
158  level = (level*quant_matrix[j]) >> 4;
159  level = (level-1)|1;
160  level = -level;
161  } else {
162  level = (level*quant_matrix[j]) >> 4;
163  level = (level-1)|1;
164  }
165  }
166  if (i > 63) {
167  av_log(s->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
168  return -1;
169  }
170 
171  block[j] = level;
172  }
173  CLOSE_READER(re, &s->gb);
174  }
175  return 0;
176 }
177 
178 static int decode_motion(GetBitContext *gb)
179 {
180  int value = 0;
181  if (get_bits1(gb)) {
182  if (get_bits1(gb))
183  value = -17;
184  value += get_bits(gb, 4) + 1;
185  }
186  return value;
187 }
188 
189 static int decode_mb(MadContext *s, int inter)
190 {
191  int mv_map = 0;
192  int mv_x, mv_y;
193  int j;
194 
195  if (inter) {
196  int v = decode210(&s->gb);
197  if (v < 2) {
198  mv_map = v ? get_bits(&s->gb, 6) : 63;
199  mv_x = decode_motion(&s->gb);
200  mv_y = decode_motion(&s->gb);
201  }
202  }
203 
204  for (j=0; j<6; j++) {
205  if (mv_map & (1<<j)) { // mv_x and mv_y are guarded by mv_map
206  int add = 2*decode_motion(&s->gb);
207  if (s->last_frame.data[0])
208  comp_block(s, s->mb_x, s->mb_y, j, mv_x, mv_y, add);
209  } else {
210  s->dsp.clear_block(s->block);
211  if(decode_block_intra(s, s->block) < 0)
212  return -1;
213  idct_put(s, s->block, s->mb_x, s->mb_y, j);
214  }
215  }
216  return 0;
217 }
218 
219 static void calc_quant_matrix(MadContext *s, int qscale)
220 {
221  int i;
222 
223  s->quant_matrix[0] = (ff_inv_aanscales[0]*ff_mpeg1_default_intra_matrix[0]) >> 11;
224  for (i=1; i<64; i++)
225  s->quant_matrix[i] = (ff_inv_aanscales[i]*ff_mpeg1_default_intra_matrix[i]*qscale + 32) >> 10;
226 }
227 
228 static int decode_frame(AVCodecContext *avctx,
229  void *data, int *got_frame,
230  AVPacket *avpkt)
231 {
232  const uint8_t *buf = avpkt->data;
233  int buf_size = avpkt->size;
234  const uint8_t *buf_end = buf+buf_size;
235  MadContext *s = avctx->priv_data;
236  int width, height, ret;
237  int chunk_type;
238  int inter;
239 
240  if (buf_size < 26) {
241  av_log(avctx, AV_LOG_ERROR, "Input buffer too small\n");
242  *got_frame = 0;
243  return AVERROR_INVALIDDATA;
244  }
245 
246  chunk_type = AV_RL32(&buf[0]);
247  inter = (chunk_type == MADm_TAG || chunk_type == MADe_TAG);
248  buf += 8;
249 
250  av_reduce(&avctx->time_base.num, &avctx->time_base.den,
251  AV_RL16(&buf[6]), 1000, 1<<30);
252 
253  width = AV_RL16(&buf[8]);
254  height = AV_RL16(&buf[10]);
255  calc_quant_matrix(s, buf[13]);
256  buf += 16;
257 
258  if (avctx->width != width || avctx->height != height) {
259  if((width * height)/2048*7 > buf_end-buf)
260  return AVERROR_INVALIDDATA;
261  if ((ret = av_image_check_size(width, height, 0, avctx)) < 0)
262  return ret;
263  avcodec_set_dimensions(avctx, width, height);
264  if (s->frame.data[0])
265  avctx->release_buffer(avctx, &s->frame);
266  if (s->last_frame.data[0])
267  avctx->release_buffer(avctx, &s->last_frame);
268  }
269 
270  s->frame.reference = 3;
271  if (!s->frame.data[0]) {
272  if ((ret = ff_get_buffer(avctx, &s->frame)) < 0) {
273  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
274  return ret;
275  }
276  }
277 
278  av_fast_padded_malloc(&s->bitstream_buf, &s->bitstream_buf_size,
279  buf_end - buf);
280  if (!s->bitstream_buf)
281  return AVERROR(ENOMEM);
282  s->dsp.bswap16_buf(s->bitstream_buf, (const uint16_t*)buf, (buf_end-buf)/2);
283  memset((uint8_t*)s->bitstream_buf + (buf_end-buf), 0, FF_INPUT_BUFFER_PADDING_SIZE);
284  init_get_bits(&s->gb, s->bitstream_buf, 8*(buf_end-buf));
285 
286  for (s->mb_y=0; s->mb_y < (avctx->height+15)/16; s->mb_y++)
287  for (s->mb_x=0; s->mb_x < (avctx->width +15)/16; s->mb_x++)
288  if(decode_mb(s, inter) < 0)
289  return AVERROR_INVALIDDATA;
290 
291  *got_frame = 1;
292  *(AVFrame*)data = s->frame;
293 
294  if (chunk_type != MADe_TAG)
295  FFSWAP(AVFrame, s->frame, s->last_frame);
296 
297  return buf_size;
298 }
299 
300 static av_cold int decode_end(AVCodecContext *avctx)
301 {
302  MadContext *t = avctx->priv_data;
303  if (t->frame.data[0])
304  avctx->release_buffer(avctx, &t->frame);
305  if (t->last_frame.data[0])
306  avctx->release_buffer(avctx, &t->last_frame);
307  av_free(t->bitstream_buf);
308  return 0;
309 }
310 
311 AVCodec ff_eamad_decoder = {
312  .name = "eamad",
313  .type = AVMEDIA_TYPE_VIDEO,
314  .id = AV_CODEC_ID_MAD,
315  .priv_data_size = sizeof(MadContext),
316  .init = decode_init,
317  .close = decode_end,
318  .decode = decode_frame,
319  .capabilities = CODEC_CAP_DR1,
320  .long_name = NULL_IF_CONFIG_SMALL("Electronic Arts Madcow Video")
321 };
Generated on Sat May 25 2013 04:01:03 for FFmpeg by   doxygen 1.8.2