mdec.c
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1 /*
2  * Sony PlayStation MDEC (Motion DECoder)
3  * Copyright (c) 2003 Michael Niedermayer
4  *
5  * based upon code from Sebastian Jedruszkiewicz <elf@frogger.rules.pl>
6  *
7  * This file is part of Libav.
8  *
9  * Libav is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU Lesser General Public
11  * License as published by the Free Software Foundation; either
12  * version 2.1 of the License, or (at your option) any later version.
13  *
14  * Libav is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17  * Lesser General Public License for more details.
18  *
19  * You should have received a copy of the GNU Lesser General Public
20  * License along with Libav; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22  */
23 
30 #include "avcodec.h"
31 #include "dsputil.h"
32 #include "mpegvideo.h"
33 #include "mpeg12.h"
34 #include "thread.h"
35 
36 typedef struct MDECContext{
42  int version;
43  int qscale;
44  int last_dc[3];
45  int mb_width;
46  int mb_height;
47  int mb_x, mb_y;
49  uint8_t *bitstream_buffer;
50  unsigned int bitstream_buffer_size;
52 } MDECContext;
53 
54 //very similar to MPEG-1
55 static inline int mdec_decode_block_intra(MDECContext *a, DCTELEM *block, int n)
56 {
57  int level, diff, i, j, run;
58  int component;
59  RLTable *rl = &ff_rl_mpeg1;
60  uint8_t * const scantable= a->scantable.permutated;
61  const uint16_t *quant_matrix= ff_mpeg1_default_intra_matrix;
62  const int qscale= a->qscale;
63 
64  /* DC coefficient */
65  if(a->version==2){
66  block[0]= 2*get_sbits(&a->gb, 10) + 1024;
67  }else{
68  component = (n <= 3 ? 0 : n - 4 + 1);
69  diff = decode_dc(&a->gb, component);
70  if (diff >= 0xffff)
71  return -1;
72  a->last_dc[component]+= diff;
73  block[0] = a->last_dc[component]<<3;
74  }
75 
76  i = 0;
77  {
78  OPEN_READER(re, &a->gb);
79  /* now quantify & encode AC coefficients */
80  for(;;) {
81  UPDATE_CACHE(re, &a->gb);
82  GET_RL_VLC(level, run, re, &a->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
83 
84  if(level == 127){
85  break;
86  } else if(level != 0) {
87  i += run;
88  j = scantable[i];
89  level= (level*qscale*quant_matrix[j])>>3;
90  level = (level ^ SHOW_SBITS(re, &a->gb, 1)) - SHOW_SBITS(re, &a->gb, 1);
91  LAST_SKIP_BITS(re, &a->gb, 1);
92  } else {
93  /* escape */
94  run = SHOW_UBITS(re, &a->gb, 6)+1; LAST_SKIP_BITS(re, &a->gb, 6);
95  UPDATE_CACHE(re, &a->gb);
96  level = SHOW_SBITS(re, &a->gb, 10); SKIP_BITS(re, &a->gb, 10);
97  i += run;
98  j = scantable[i];
99  if(level<0){
100  level= -level;
101  level= (level*qscale*quant_matrix[j])>>3;
102  level= (level-1)|1;
103  level= -level;
104  }else{
105  level= (level*qscale*quant_matrix[j])>>3;
106  level= (level-1)|1;
107  }
108  }
109  if (i > 63){
110  av_log(a->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", a->mb_x, a->mb_y);
111  return -1;
112  }
113 
114  block[j] = level;
115  }
116  CLOSE_READER(re, &a->gb);
117  }
118  a->block_last_index[n] = i;
119  return 0;
120 }
121 
122 static inline int decode_mb(MDECContext *a, DCTELEM block[6][64]){
123  int i;
124  const int block_index[6]= {5,4,0,1,2,3};
125 
126  a->dsp.clear_blocks(block[0]);
127 
128  for(i=0; i<6; i++){
129  if( mdec_decode_block_intra(a, block[ block_index[i] ], block_index[i]) < 0 ||
130  get_bits_left(&a->gb) < 0)
131  return -1;
132  }
133  return 0;
134 }
135 
136 static inline void idct_put(MDECContext *a, int mb_x, int mb_y){
137  DCTELEM (*block)[64]= a->block;
138  int linesize= a->picture.linesize[0];
139 
140  uint8_t *dest_y = a->picture.data[0] + (mb_y * 16* linesize ) + mb_x * 16;
141  uint8_t *dest_cb = a->picture.data[1] + (mb_y * 8 * a->picture.linesize[1]) + mb_x * 8;
142  uint8_t *dest_cr = a->picture.data[2] + (mb_y * 8 * a->picture.linesize[2]) + mb_x * 8;
143 
144  a->dsp.idct_put(dest_y , linesize, block[0]);
145  a->dsp.idct_put(dest_y + 8, linesize, block[1]);
146  a->dsp.idct_put(dest_y + 8*linesize , linesize, block[2]);
147  a->dsp.idct_put(dest_y + 8*linesize + 8, linesize, block[3]);
148 
149  if(!(a->avctx->flags&CODEC_FLAG_GRAY)){
150  a->dsp.idct_put(dest_cb, a->picture.linesize[1], block[4]);
151  a->dsp.idct_put(dest_cr, a->picture.linesize[2], block[5]);
152  }
153 }
154 
155 static int decode_frame(AVCodecContext *avctx,
156  void *data, int *data_size,
157  AVPacket *avpkt)
158 {
159  const uint8_t *buf = avpkt->data;
160  int buf_size = avpkt->size;
161  MDECContext * const a = avctx->priv_data;
162  AVFrame *picture = data;
163  AVFrame * const p= &a->picture;
164  int i;
165 
166  if(p->data[0])
167  ff_thread_release_buffer(avctx, p);
168 
169  p->reference= 0;
170  if(ff_thread_get_buffer(avctx, p) < 0){
171  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
172  return -1;
173  }
175  p->key_frame= 1;
176 
178  if (!a->bitstream_buffer)
179  return AVERROR(ENOMEM);
180  for(i=0; i<buf_size; i+=2){
181  a->bitstream_buffer[i] = buf[i+1];
182  a->bitstream_buffer[i+1]= buf[i ];
183  }
184  init_get_bits(&a->gb, a->bitstream_buffer, buf_size*8);
185 
186  /* skip over 4 preamble bytes in stream (typically 0xXX 0xXX 0x00 0x38) */
187  skip_bits(&a->gb, 32);
188 
189  a->qscale= get_bits(&a->gb, 16);
190  a->version= get_bits(&a->gb, 16);
191 
192  a->last_dc[0]=
193  a->last_dc[1]=
194  a->last_dc[2]= 128;
195 
196  for(a->mb_x=0; a->mb_x<a->mb_width; a->mb_x++){
197  for(a->mb_y=0; a->mb_y<a->mb_height; a->mb_y++){
198  if( decode_mb(a, a->block) <0)
199  return -1;
200 
201  idct_put(a, a->mb_x, a->mb_y);
202  }
203  }
204 
205  p->quality= a->qscale * FF_QP2LAMBDA;
206  memset(p->qscale_table, a->qscale, a->mb_width);
207 
208  *picture = a->picture;
209  *data_size = sizeof(AVPicture);
210 
211  return (get_bits_count(&a->gb)+31)/32*4;
212 }
213 
215  MDECContext * const a = avctx->priv_data;
216 
217  dsputil_init(&a->dsp, avctx);
218 
219  a->mb_width = (avctx->coded_width + 15) / 16;
220  a->mb_height = (avctx->coded_height + 15) / 16;
221 
222  avctx->coded_frame= &a->picture;
223  a->avctx= avctx;
224 }
225 
226 static av_cold int decode_init(AVCodecContext *avctx){
227  MDECContext * const a = avctx->priv_data;
228  AVFrame *p= &a->picture;
229 
230  mdec_common_init(avctx);
233 
234  if( avctx->idct_algo == FF_IDCT_AUTO )
235  avctx->idct_algo = FF_IDCT_SIMPLE;
236  p->qstride= 0;
238  avctx->pix_fmt= PIX_FMT_YUVJ420P;
239 
240  return 0;
241 }
242 
244  MDECContext * const a = avctx->priv_data;
245  AVFrame *p = (AVFrame*)&a->picture;
246 
247  avctx->coded_frame = p;
248  a->avctx= avctx;
249 
250  p->qscale_table = av_mallocz( a->mb_width);
251 
252  return 0;
253 }
254 
255 static av_cold int decode_end(AVCodecContext *avctx){
256  MDECContext * const a = avctx->priv_data;
257 
258  if(a->picture.data[0])
259  avctx->release_buffer(avctx, &a->picture);
263 
264  return 0;
265 }
266 
268  .name = "mdec",
269  .type = AVMEDIA_TYPE_VIDEO,
270  .id = CODEC_ID_MDEC,
271  .priv_data_size = sizeof(MDECContext),
272  .init = decode_init,
273  .close = decode_end,
274  .decode = decode_frame,
275  .capabilities = CODEC_CAP_DR1 | CODEC_CAP_FRAME_THREADS,
276  .long_name= NULL_IF_CONFIG_SMALL("Sony PlayStation MDEC (Motion DECoder)"),
278 };
279