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 "bytestream.h"
33 #include "get_bits.h"
34 #include "aandcttab.h"
35 #include "eaidct.h"
36 #include "internal.h"
37 #include "mpeg12.h"
38 #include "mpeg12data.h"
39 #include "libavutil/imgutils.h"
40 
41 #define EA_PREAMBLE_SIZE 8
42 #define MADk_TAG MKTAG('M', 'A', 'D', 'k') /* MAD i-frame */
43 #define MADm_TAG MKTAG('M', 'A', 'D', 'm') /* MAD p-frame */
44 #define MADe_TAG MKTAG('M', 'A', 'D', 'e') /* MAD lqp-frame */
45 
46 typedef struct MadContext {
52  unsigned int bitstream_buf_size;
53  DECLARE_ALIGNED(16, int16_t, block)[64];
55  uint16_t quant_matrix[64];
56  int mb_x;
57  int mb_y;
58 } MadContext;
59 
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);
69 
71  if (!s->last_frame)
72  return AVERROR(ENOMEM);
73 
74  return 0;
75 }
76 
77 static inline void comp(unsigned char *dst, int dst_stride,
78  unsigned char *src, int src_stride, int add)
79 {
80  int j, i;
81  for (j=0; j<8; j++)
82  for (i=0; i<8; i++)
83  dst[j*dst_stride + i] = av_clip_uint8(src[j*src_stride + i] + add);
84 }
85 
86 static inline void comp_block(MadContext *t, AVFrame *frame,
87  int mb_x, int mb_y,
88  int j, int mv_x, int mv_y, int add)
89 {
90  if (j < 4) {
91  comp(frame->data[0] + (mb_y*16 + ((j&2)<<2))*frame->linesize[0] + mb_x*16 + ((j&1)<<3),
92  frame->linesize[0],
93  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,
94  t->last_frame->linesize[0], add);
95  } else if (!(t->avctx->flags & CODEC_FLAG_GRAY)) {
96  int index = j - 3;
97  comp(frame->data[index] + (mb_y*8)*frame->linesize[index] + mb_x * 8,
98  frame->linesize[index],
99  t->last_frame->data[index] + (mb_y * 8 + (mv_y/2))*t->last_frame->linesize[index] + mb_x * 8 + (mv_x/2),
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 void 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  if (i > 63) {
144  "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
145  return;
146  }
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  if (i > 63) {
163  "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
164  return;
165  }
166  j = scantable[i];
167  if (level < 0) {
168  level = -level;
169  level = (level*quant_matrix[j]) >> 4;
170  level = (level-1)|1;
171  level = -level;
172  } else {
173  level = (level*quant_matrix[j]) >> 4;
174  level = (level-1)|1;
175  }
176  }
177 
178  block[j] = level;
179  }
180  CLOSE_READER(re, &s->gb);
181  }
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 void 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  } else {
208  mv_map = 0;
209  }
210  }
211 
212  for (j=0; j<6; j++) {
213  if (mv_map & (1<<j)) { // mv_x and mv_y are guarded by mv_map
214  int add = 2*decode_motion(&s->gb);
215  comp_block(s, frame, s->mb_x, s->mb_y, j, mv_x, mv_y, add);
216  } else {
217  s->dsp.clear_block(s->block);
218  decode_block_intra(s, s->block);
219  idct_put(s, frame, s->block, s->mb_x, s->mb_y, j);
220  }
221  }
222 }
223 
224 static void calc_quant_matrix(MadContext *s, int qscale)
225 {
226  int i;
227 
229  for (i=1; i<64; i++)
230  s->quant_matrix[i] = (ff_inv_aanscales[i]*ff_mpeg1_default_intra_matrix[i]*qscale + 32) >> 10;
231 }
232 
233 static int decode_frame(AVCodecContext *avctx,
234  void *data, int *got_frame,
235  AVPacket *avpkt)
236 {
237  const uint8_t *buf = avpkt->data;
238  int buf_size = avpkt->size;
239  MadContext *s = avctx->priv_data;
240  AVFrame *frame = data;
241  GetByteContext gb;
242  int width, height;
243  int chunk_type;
244  int inter, ret;
245 
246  bytestream2_init(&gb, buf, buf_size);
247 
248  chunk_type = bytestream2_get_le32(&gb);
249  inter = (chunk_type == MADm_TAG || chunk_type == MADe_TAG);
250  bytestream2_skip(&gb, 10);
251 
252  av_reduce(&avctx->time_base.num, &avctx->time_base.den,
253  bytestream2_get_le16(&gb), 1000, 1<<30);
254 
255  width = bytestream2_get_le16(&gb);
256  height = bytestream2_get_le16(&gb);
257  bytestream2_skip(&gb, 1);
258  calc_quant_matrix(s, bytestream2_get_byte(&gb));
259  bytestream2_skip(&gb, 2);
260 
261  if (bytestream2_get_bytes_left(&gb) < 2) {
262  av_log(avctx, AV_LOG_ERROR, "Input data too small\n");
263  return AVERROR_INVALIDDATA;
264  }
265 
266  if (avctx->width != width || avctx->height != height) {
268  if ((ret = ff_set_dimensions(avctx, width, height)) < 0)
269  return ret;
270  }
271 
272  if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0) {
273  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
274  return ret;
275  }
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 
292  if (!s->bitstream_buf)
293  return AVERROR(ENOMEM);
294  s->dsp.bswap16_buf(s->bitstream_buf, (const uint16_t *)(buf + bytestream2_tell(&gb)),
295  bytestream2_get_bytes_left(&gb) / 2);
297  for (s->mb_y=0; s->mb_y < (avctx->height+15)/16; s->mb_y++)
298  for (s->mb_x=0; s->mb_x < (avctx->width +15)/16; s->mb_x++)
299  decode_mb(s, frame, inter);
300 
301  *got_frame = 1;
302 
303  if (chunk_type != MADe_TAG) {
305  if ((ret = av_frame_ref(s->last_frame, frame)) < 0)
306  return ret;
307  }
308 
309  return buf_size;
310 }
311 
313 {
314  MadContext *t = avctx->priv_data;
317  return 0;
318 }
319 
321  .name = "eamad",
322  .long_name = NULL_IF_CONFIG_SMALL("Electronic Arts Madcow Video"),
323  .type = AVMEDIA_TYPE_VIDEO,
324  .id = AV_CODEC_ID_MAD,
325  .priv_data_size = sizeof(MadContext),
326  .init = decode_init,
327  .close = decode_end,
328  .decode = decode_frame,
329  .capabilities = CODEC_CAP_DR1,
330 };