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 "dsputil.h"
34 #include "aandcttab.h"
35 #include "mpeg12.h"
36 #include "mpeg12data.h"
37 #include "libavutil/imgutils.h"
38 
39 #define EA_PREAMBLE_SIZE 8
40 #define MADk_TAG MKTAG('M', 'A', 'D', 'k') /* MAD i-frame */
41 #define MADm_TAG MKTAG('M', 'A', 'D', 'm') /* MAD p-frame */
42 #define MADe_TAG MKTAG('M', 'A', 'D', 'e') /* MAD lqp-frame */
43 
44 typedef struct MadContext {
49  unsigned int bitstream_buf_size;
51 } MadContext;
52 
53 static void bswap16_buf(uint16_t *dst, const uint16_t *src, int count)
54 {
55  int i;
56  for (i=0; i<count; i++)
57  dst[i] = av_bswap16(src[i]);
58 }
59 
61 {
62  MadContext *t = avctx->priv_data;
63  MpegEncContext *s = &t->s;
64  s->avctx = avctx;
65  avctx->pix_fmt = PIX_FMT_YUV420P;
66  if (avctx->idct_algo == FF_IDCT_AUTO)
67  avctx->idct_algo = FF_IDCT_EA;
68  dsputil_init(&s->dsp, avctx);
71  return 0;
72 }
73 
74 static inline void comp(unsigned char *dst, int dst_stride,
75  unsigned char *src, int src_stride, int add)
76 {
77  int j, i;
78  for (j=0; j<8; j++)
79  for (i=0; i<8; i++)
80  dst[j*dst_stride + i] = av_clip_uint8(src[j*src_stride + i] + add);
81 }
82 
83 static inline void comp_block(MadContext *t, int mb_x, int mb_y,
84  int j, int mv_x, int mv_y, int add)
85 {
86  MpegEncContext *s = &t->s;
87  if (j < 4) {
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] + (mb_y*16 + ((j&2)<<2) + mv_y)*t->last_frame.linesize[0] + mb_x*16 + ((j&1)<<3) + mv_x,
91  t->last_frame.linesize[0], add);
92  } else if (!(s->avctx->flags & CODEC_FLAG_GRAY)) {
93  int index = j - 3;
94  comp(t->frame.data[index] + (mb_y*8)*t->frame.linesize[index] + mb_x * 8,
95  t->frame.linesize[index],
96  t->last_frame.data[index] + (mb_y * 8 + (mv_y/2))*t->last_frame.linesize[index] + mb_x * 8 + (mv_x/2),
97  t->last_frame.linesize[index], add);
98  }
99 }
100 
101 static inline void idct_put(MadContext *t, DCTELEM *block, int mb_x, int mb_y, int j)
102 {
103  MpegEncContext *s = &t->s;
104  if (j < 4) {
105  s->dsp.idct_put(
106  t->frame.data[0] + (mb_y*16 + ((j&2)<<2))*t->frame.linesize[0] + mb_x*16 + ((j&1)<<3),
107  t->frame.linesize[0], block);
108  } else if (!(s->avctx->flags & CODEC_FLAG_GRAY)) {
109  int index = j - 3;
110  s->dsp.idct_put(
111  t->frame.data[index] + (mb_y*8)*t->frame.linesize[index] + mb_x*8,
112  t->frame.linesize[index], block);
113  }
114 }
115 
116 static inline void decode_block_intra(MadContext * t, DCTELEM * block)
117 {
118  MpegEncContext *s = &t->s;
119  int level, i, j, run;
120  RLTable *rl = &ff_rl_mpeg1;
121  const uint8_t *scantable = s->intra_scantable.permutated;
122  int16_t *quant_matrix = s->intra_matrix;
123 
124  block[0] = (128 + get_sbits(&s->gb, 8)) * quant_matrix[0];
125 
126  /* The RL decoder is derived from mpeg1_decode_block_intra;
127  Escaped level and run values a decoded differently */
128  i = 0;
129  {
130  OPEN_READER(re, &s->gb);
131  /* now quantify & encode AC coefficients */
132  for (;;) {
133  UPDATE_CACHE(re, &s->gb);
134  GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
135 
136  if (level == 127) {
137  break;
138  } else if (level != 0) {
139  i += run;
140  j = scantable[i];
141  level = (level*quant_matrix[j]) >> 4;
142  level = (level-1)|1;
143  level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
144  LAST_SKIP_BITS(re, &s->gb, 1);
145  } else {
146  /* escape */
147  UPDATE_CACHE(re, &s->gb);
148  level = SHOW_SBITS(re, &s->gb, 10); SKIP_BITS(re, &s->gb, 10);
149 
150  UPDATE_CACHE(re, &s->gb);
151  run = SHOW_UBITS(re, &s->gb, 6)+1; LAST_SKIP_BITS(re, &s->gb, 6);
152 
153  i += run;
154  j = scantable[i];
155  if (level < 0) {
156  level = -level;
157  level = (level*quant_matrix[j]) >> 4;
158  level = (level-1)|1;
159  level = -level;
160  } else {
161  level = (level*quant_matrix[j]) >> 4;
162  level = (level-1)|1;
163  }
164  }
165  if (i > 63) {
166  av_log(s->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
167  return;
168  }
169 
170  block[j] = level;
171  }
172  CLOSE_READER(re, &s->gb);
173  }
174 }
175 
177 {
178  int value = 0;
179  if (get_bits1(gb)) {
180  if (get_bits1(gb))
181  value = -17;
182  value += get_bits(gb, 4) + 1;
183  }
184  return value;
185 }
186 
187 static void decode_mb(MadContext *t, int inter)
188 {
189  MpegEncContext *s = &t->s;
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(t, s->mb_x, s->mb_y, j, mv_x, mv_y, add);
209  } else {
210  s->dsp.clear_block(t->block);
211  decode_block_intra(t, t->block);
212  idct_put(t, t->block, s->mb_x, s->mb_y, j);
213  }
214  }
215 }
216 
217 static void calc_intra_matrix(MadContext *t, int qscale)
218 {
219  MpegEncContext *s = &t->s;
220  int i;
221 
222  if (s->avctx->idct_algo == FF_IDCT_EA) {
224  for (i=1; i<64; i++)
225  s->intra_matrix[i] = (ff_inv_aanscales[i]*ff_mpeg1_default_intra_matrix[i]*qscale + 32) >> 10;
226  } else {
228  for (i=1; i<64; i++)
229  s->intra_matrix[i] = (ff_mpeg1_default_intra_matrix[i]*qscale) << 1;
230  }
231 }
232 
233 static int decode_frame(AVCodecContext *avctx,
234  void *data, int *data_size,
235  AVPacket *avpkt)
236 {
237  const uint8_t *buf = avpkt->data;
238  int buf_size = avpkt->size;
239  const uint8_t *buf_end = buf+buf_size;
240  MadContext *t = avctx->priv_data;
241  MpegEncContext *s = &t->s;
242  int chunk_type;
243  int inter;
244 
245  if (buf_size < 17) {
246  av_log(avctx, AV_LOG_ERROR, "Input buffer too small\n");
247  *data_size = 0;
248  return -1;
249  }
250 
251  chunk_type = AV_RL32(&buf[0]);
252  inter = (chunk_type == MADm_TAG || chunk_type == MADe_TAG);
253  buf += 8;
254 
255  av_reduce(&avctx->time_base.num, &avctx->time_base.den,
256  AV_RL16(&buf[6]), 1000, 1<<30);
257 
258  s->width = AV_RL16(&buf[8]);
259  s->height = AV_RL16(&buf[10]);
260  calc_intra_matrix(t, buf[13]);
261  buf += 16;
262 
263  if (avctx->width != s->width || avctx->height != s->height) {
264  if (av_image_check_size(s->width, s->height, 0, avctx) < 0)
265  return -1;
266  avcodec_set_dimensions(avctx, s->width, s->height);
267  if (t->frame.data[0])
268  avctx->release_buffer(avctx, &t->frame);
269  }
270 
271  t->frame.reference = 1;
272  if (!t->frame.data[0]) {
273  if (avctx->get_buffer(avctx, &t->frame) < 0) {
274  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
275  return -1;
276  }
277  }
278 
280  if (!t->bitstream_buf)
281  return AVERROR(ENOMEM);
282  bswap16_buf(t->bitstream_buf, (const uint16_t*)buf, (buf_end-buf)/2);
283  init_get_bits(&s->gb, t->bitstream_buf, 8*(buf_end-buf));
284 
285  for (s->mb_y=0; s->mb_y < (avctx->height+15)/16; s->mb_y++)
286  for (s->mb_x=0; s->mb_x < (avctx->width +15)/16; s->mb_x++)
287  decode_mb(t, inter);
288 
289  *data_size = sizeof(AVFrame);
290  *(AVFrame*)data = t->frame;
291 
292  if (chunk_type != MADe_TAG)
293  FFSWAP(AVFrame, t->frame, t->last_frame);
294 
295  return buf_size;
296 }
297 
299 {
300  MadContext *t = avctx->priv_data;
301  if (t->frame.data[0])
302  avctx->release_buffer(avctx, &t->frame);
303  if (t->last_frame.data[0])
304  avctx->release_buffer(avctx, &t->last_frame);
306  return 0;
307 }
308 
310  .name = "eamad",
311  .type = AVMEDIA_TYPE_VIDEO,
312  .id = CODEC_ID_MAD,
313  .priv_data_size = sizeof(MadContext),
314  .init = decode_init,
315  .close = decode_end,
316  .decode = decode_frame,
317  .capabilities = CODEC_CAP_DR1,
318  .long_name = NULL_IF_CONFIG_SMALL("Electronic Arts Madcow Video")
319 };