Libav
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 Libav.
6  *
7  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
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  comp(frame->data[0] + (mb_y*16 + ((j&2)<<2))*frame->linesize[0] + mb_x*16 + ((j&1)<<3),
91  frame->linesize[0],
92  t->last_frame->data[0] + (mb_y*16 + ((j&2)<<2) + mv_y)*t->last_frame->linesize[0] + mb_x*16 + ((j&1)<<3) + mv_x,
93  t->last_frame->linesize[0], add);
94  } else if (!(t->avctx->flags & CODEC_FLAG_GRAY)) {
95  int index = j - 3;
96  comp(frame->data[index] + (mb_y*8)*frame->linesize[index] + mb_x * 8,
97  frame->linesize[index],
98  t->last_frame->data[index] + (mb_y * 8 + (mv_y/2))*t->last_frame->linesize[index] + mb_x * 8 + (mv_x/2),
99  t->last_frame->linesize[index], add);
100  }
101 }
102 
103 static inline void idct_put(MadContext *t, AVFrame *frame, int16_t *block,
104  int mb_x, int mb_y, int j)
105 {
106  if (j < 4) {
108  frame->data[0] + (mb_y*16 + ((j&2)<<2))*frame->linesize[0] + mb_x*16 + ((j&1)<<3),
109  frame->linesize[0], block);
110  } else if (!(t->avctx->flags & CODEC_FLAG_GRAY)) {
111  int index = j - 3;
113  frame->data[index] + (mb_y*8)*frame->linesize[index] + mb_x*8,
114  frame->linesize[index], block);
115  }
116 }
117 
118 static inline void 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;
169  }
170 
171  block[j] = level;
172  }
173  CLOSE_READER(re, &s->gb);
174  }
175 }
176 
178 {
179  int value = 0;
180  if (get_bits1(gb)) {
181  if (get_bits1(gb))
182  value = -17;
183  value += get_bits(gb, 4) + 1;
184  }
185  return value;
186 }
187 
188 static void decode_mb(MadContext *s, AVFrame *frame, int inter)
189 {
190  int mv_map = 0;
191  int mv_x, mv_y;
192  int j;
193 
194  if (inter) {
195  int v = decode210(&s->gb);
196  if (v < 2) {
197  mv_map = v ? get_bits(&s->gb, 6) : 63;
198  mv_x = decode_motion(&s->gb);
199  mv_y = decode_motion(&s->gb);
200  } else {
201  mv_map = 0;
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  comp_block(s, frame, s->mb_x, s->mb_y, j, mv_x, mv_y, add);
209  } else {
210  s->dsp.clear_block(s->block);
211  decode_block_intra(s, s->block);
212  idct_put(s, frame, s->block, s->mb_x, s->mb_y, j);
213  }
214  }
215 }
216 
217 static void calc_quant_matrix(MadContext *s, int qscale)
218 {
219  int i;
220 
222  for (i=1; i<64; i++)
223  s->quant_matrix[i] = (ff_inv_aanscales[i]*ff_mpeg1_default_intra_matrix[i]*qscale + 32) >> 10;
224 }
225 
226 static int decode_frame(AVCodecContext *avctx,
227  void *data, int *got_frame,
228  AVPacket *avpkt)
229 {
230  const uint8_t *buf = avpkt->data;
231  int buf_size = avpkt->size;
232  const uint8_t *buf_end = buf+buf_size;
233  MadContext *s = avctx->priv_data;
234  AVFrame *frame = data;
235  int width, height;
236  int chunk_type;
237  int inter, ret;
238 
239  if (buf_size < 17) {
240  av_log(avctx, AV_LOG_ERROR, "Input buffer too small\n");
241  *got_frame = 0;
242  return -1;
243  }
244 
245  chunk_type = AV_RL32(&buf[0]);
246  inter = (chunk_type == MADm_TAG || chunk_type == MADe_TAG);
247  buf += 8;
248 
249  av_reduce(&avctx->time_base.num, &avctx->time_base.den,
250  AV_RL16(&buf[6]), 1000, 1<<30);
251 
252  width = AV_RL16(&buf[8]);
253  height = AV_RL16(&buf[10]);
254  calc_quant_matrix(s, buf[13]);
255  buf += 16;
256 
257  if (avctx->width != width || avctx->height != height) {
259  if ((ret = ff_set_dimensions(avctx, width, height)) < 0)
260  return ret;
261  }
262 
263  if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0) {
264  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
265  return ret;
266  }
267 
268  if (inter && !s->last_frame->data[0]) {
269  av_log(avctx, AV_LOG_WARNING, "Missing reference frame.\n");
271  if (ret < 0)
272  return ret;
273  memset(s->last_frame->data[0], 0, s->last_frame->height *
274  s->last_frame->linesize[0]);
275  memset(s->last_frame->data[1], 0x80, s->last_frame->height / 2 *
276  s->last_frame->linesize[1]);
277  memset(s->last_frame->data[2], 0x80, s->last_frame->height / 2 *
278  s->last_frame->linesize[2]);
279  }
280 
282  buf_end - buf);
283  if (!s->bitstream_buf)
284  return AVERROR(ENOMEM);
285  s->dsp.bswap16_buf(s->bitstream_buf, (const uint16_t*)buf, (buf_end-buf)/2);
286  init_get_bits(&s->gb, s->bitstream_buf, 8*(buf_end-buf));
287 
288  for (s->mb_y=0; s->mb_y < (avctx->height+15)/16; s->mb_y++)
289  for (s->mb_x=0; s->mb_x < (avctx->width +15)/16; s->mb_x++)
290  decode_mb(s, frame, inter);
291 
292  *got_frame = 1;
293 
294  if (chunk_type != MADe_TAG) {
296  if ((ret = av_frame_ref(s->last_frame, frame)) < 0)
297  return ret;
298  }
299 
300  return buf_size;
301 }
302 
304 {
305  MadContext *t = avctx->priv_data;
308  return 0;
309 }
310 
312  .name = "eamad",
313  .long_name = NULL_IF_CONFIG_SMALL("Electronic Arts Madcow Video"),
314  .type = AVMEDIA_TYPE_VIDEO,
315  .id = AV_CODEC_ID_MAD,
316  .priv_data_size = sizeof(MadContext),
317  .init = decode_init,
318  .close = decode_end,
319  .decode = decode_frame,
320  .capabilities = CODEC_CAP_DR1,
321 };