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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 FFmpeg.
8  *
9  * FFmpeg 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  * FFmpeg 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 FFmpeg; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22  */
23 
24 /**
25  * @file
26  * Sony PlayStation MDEC (Motion DECoder)
27  * This is very similar to intra-only MPEG-1.
28  */
29 
30 #include "avcodec.h"
31 #include "blockdsp.h"
32 #include "bswapdsp.h"
33 #include "idctdsp.h"
34 #include "mpegvideo.h"
35 #include "mpeg12.h"
36 #include "thread.h"
37 
38 typedef struct MDECContext {
46  int version;
47  int qscale;
48  int last_dc[3];
49  int mb_width;
50  int mb_height;
51  int mb_x, mb_y;
52  DECLARE_ALIGNED(16, int16_t, block)[6][64];
54  unsigned int bitstream_buffer_size;
56 } MDECContext;
57 
58 //very similar to MPEG-1
59 static inline int mdec_decode_block_intra(MDECContext *a, int16_t *block, int n)
60 {
61  int level, diff, i, j, run;
62  int component;
63  RLTable *rl = &ff_rl_mpeg1;
64  uint8_t * const scantable = a->scantable.permutated;
65  const uint16_t *quant_matrix = ff_mpeg1_default_intra_matrix;
66  const int qscale = a->qscale;
67 
68  /* DC coefficient */
69  if (a->version == 2) {
70  block[0] = 2 * get_sbits(&a->gb, 10) + 1024;
71  } else {
72  component = (n <= 3 ? 0 : n - 4 + 1);
73  diff = decode_dc(&a->gb, component);
74  if (diff >= 0xffff)
75  return AVERROR_INVALIDDATA;
76  a->last_dc[component] += diff;
77  block[0] = a->last_dc[component] << 3;
78  }
79 
80  i = 0;
81  {
82  OPEN_READER(re, &a->gb);
83  /* now quantify & encode AC coefficients */
84  for (;;) {
85  UPDATE_CACHE(re, &a->gb);
86  GET_RL_VLC(level, run, re, &a->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
87 
88  if (level == 127) {
89  break;
90  } else if (level != 0) {
91  i += run;
92  j = scantable[i];
93  level = (level * qscale * quant_matrix[j]) >> 3;
94  level = (level ^ SHOW_SBITS(re, &a->gb, 1)) - SHOW_SBITS(re, &a->gb, 1);
95  LAST_SKIP_BITS(re, &a->gb, 1);
96  } else {
97  /* escape */
98  run = SHOW_UBITS(re, &a->gb, 6)+1; LAST_SKIP_BITS(re, &a->gb, 6);
99  UPDATE_CACHE(re, &a->gb);
100  level = SHOW_SBITS(re, &a->gb, 10); SKIP_BITS(re, &a->gb, 10);
101  i += run;
102  j = scantable[i];
103  if (level < 0) {
104  level = -level;
105  level = (level * qscale * quant_matrix[j]) >> 3;
106  level = (level - 1) | 1;
107  level = -level;
108  } else {
109  level = (level * qscale * quant_matrix[j]) >> 3;
110  level = (level - 1) | 1;
111  }
112  }
113  if (i > 63) {
114  av_log(a->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", a->mb_x, a->mb_y);
115  return AVERROR_INVALIDDATA;
116  }
117 
118  block[j] = level;
119  }
120  CLOSE_READER(re, &a->gb);
121  }
122  a->block_last_index[n] = i;
123  return 0;
124 }
125 
126 static inline int decode_mb(MDECContext *a, int16_t block[6][64])
127 {
128  int i, ret;
129  static const int block_index[6] = { 5, 4, 0, 1, 2, 3 };
130 
131  a->bdsp.clear_blocks(block[0]);
132 
133  for (i = 0; i < 6; i++) {
134  if ((ret = mdec_decode_block_intra(a, block[block_index[i]],
135  block_index[i])) < 0)
136  return ret;
137  if (get_bits_left(&a->gb) < 0)
138  return AVERROR_INVALIDDATA;
139  }
140  return 0;
141 }
142 
143 static inline void idct_put(MDECContext *a, AVFrame *frame, int mb_x, int mb_y)
144 {
145  int16_t (*block)[64] = a->block;
146  int linesize = frame->linesize[0];
147 
148  uint8_t *dest_y = frame->data[0] + (mb_y * 16* linesize ) + mb_x * 16;
149  uint8_t *dest_cb = frame->data[1] + (mb_y * 8 * frame->linesize[1]) + mb_x * 8;
150  uint8_t *dest_cr = frame->data[2] + (mb_y * 8 * frame->linesize[2]) + mb_x * 8;
151 
152  a->idsp.idct_put(dest_y, linesize, block[0]);
153  a->idsp.idct_put(dest_y + 8, linesize, block[1]);
154  a->idsp.idct_put(dest_y + 8 * linesize, linesize, block[2]);
155  a->idsp.idct_put(dest_y + 8 * linesize + 8, linesize, block[3]);
156 
157  if (!(a->avctx->flags & CODEC_FLAG_GRAY)) {
158  a->idsp.idct_put(dest_cb, frame->linesize[1], block[4]);
159  a->idsp.idct_put(dest_cr, frame->linesize[2], block[5]);
160  }
161 }
162 
163 static int decode_frame(AVCodecContext *avctx,
164  void *data, int *got_frame,
165  AVPacket *avpkt)
166 {
167  MDECContext * const a = avctx->priv_data;
168  const uint8_t *buf = avpkt->data;
169  int buf_size = avpkt->size;
170  ThreadFrame frame = { .f = data };
171  int ret;
172 
173  if ((ret = ff_thread_get_buffer(avctx, &frame, 0)) < 0)
174  return ret;
175  frame.f->pict_type = AV_PICTURE_TYPE_I;
176  frame.f->key_frame = 1;
177 
179  if (!a->bitstream_buffer)
180  return AVERROR(ENOMEM);
181  a->bbdsp.bswap16_buf((uint16_t *)a->bitstream_buffer, (uint16_t *)buf, (buf_size + 1) / 2);
182  if ((ret = init_get_bits8(&a->gb, a->bitstream_buffer, buf_size)) < 0)
183  return ret;
184 
185  /* skip over 4 preamble bytes in stream (typically 0xXX 0xXX 0x00 0x38) */
186  skip_bits(&a->gb, 32);
187 
188  a->qscale = get_bits(&a->gb, 16);
189  a->version = get_bits(&a->gb, 16);
190 
191  a->last_dc[0] = a->last_dc[1] = a->last_dc[2] = 128;
192 
193  for (a->mb_x = 0; a->mb_x < a->mb_width; a->mb_x++) {
194  for (a->mb_y = 0; a->mb_y < a->mb_height; a->mb_y++) {
195  if ((ret = decode_mb(a, a->block)) < 0)
196  return ret;
197 
198  idct_put(a, frame.f, a->mb_x, a->mb_y);
199  }
200  }
201 
202  *got_frame = 1;
203 
204  return (get_bits_count(&a->gb) + 31) / 32 * 4;
205 }
206 
208 {
209  MDECContext * const a = avctx->priv_data;
210 
211  a->mb_width = (avctx->coded_width + 15) / 16;
212  a->mb_height = (avctx->coded_height + 15) / 16;
213 
214  a->avctx = avctx;
215 
216  ff_blockdsp_init(&a->bdsp, avctx);
217  ff_bswapdsp_init(&a->bbdsp);
218  ff_idctdsp_init(&a->idsp, avctx);
222 
223  if (avctx->idct_algo == FF_IDCT_AUTO)
224  avctx->idct_algo = FF_IDCT_SIMPLE;
225  avctx->pix_fmt = AV_PIX_FMT_YUVJ420P;
226  avctx->color_range = AVCOL_RANGE_JPEG;
227 
228  return 0;
229 }
230 
232 {
233  MDECContext * const a = avctx->priv_data;
234 
235  a->avctx = avctx;
236 
237  return 0;
238 }
239 
241 {
242  MDECContext * const a = avctx->priv_data;
243 
245  a->bitstream_buffer_size = 0;
246 
247  return 0;
248 }
249 
251  .name = "mdec",
252  .long_name = NULL_IF_CONFIG_SMALL("Sony PlayStation MDEC (Motion DECoder)"),
253  .type = AVMEDIA_TYPE_VIDEO,
254  .id = AV_CODEC_ID_MDEC,
255  .priv_data_size = sizeof(MDECContext),
256  .init = decode_init,
257  .close = decode_end,
258  .decode = decode_frame,
259  .capabilities = CODEC_CAP_DR1 | CODEC_CAP_FRAME_THREADS,
261 };