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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 "mpegvideo.h"
32 #include "mpeg12.h"
33 #include "thread.h"
34 
35 typedef struct MDECContext {
41  int version;
42  int qscale;
43  int last_dc[3];
44  int mb_width;
45  int mb_height;
46  int mb_x, mb_y;
47  DECLARE_ALIGNED(16, int16_t, block)[6][64];
49  unsigned int bitstream_buffer_size;
51 } MDECContext;
52 
53 //very similar to MPEG-1
54 static inline int mdec_decode_block_intra(MDECContext *a, int16_t *block, int n)
55 {
56  int level, diff, i, j, run;
57  int component;
58  RLTable *rl = &ff_rl_mpeg1;
59  uint8_t * const scantable = a->scantable.permutated;
60  const uint16_t *quant_matrix = ff_mpeg1_default_intra_matrix;
61  const int qscale = a->qscale;
62 
63  /* DC coefficient */
64  if (a->version == 2) {
65  block[0] = 2 * get_sbits(&a->gb, 10) + 1024;
66  } else {
67  component = (n <= 3 ? 0 : n - 4 + 1);
68  diff = decode_dc(&a->gb, component);
69  if (diff >= 0xffff)
70  return AVERROR_INVALIDDATA;
71  a->last_dc[component] += diff;
72  block[0] = a->last_dc[component] << 3;
73  }
74 
75  i = 0;
76  {
77  OPEN_READER(re, &a->gb);
78  /* now quantify & encode AC coefficients */
79  for (;;) {
80  UPDATE_CACHE(re, &a->gb);
81  GET_RL_VLC(level, run, re, &a->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
82 
83  if (level == 127) {
84  break;
85  } else if (level != 0) {
86  i += run;
87  j = scantable[i];
88  level = (level * qscale * quant_matrix[j]) >> 3;
89  level = (level ^ SHOW_SBITS(re, &a->gb, 1)) - SHOW_SBITS(re, &a->gb, 1);
90  LAST_SKIP_BITS(re, &a->gb, 1);
91  } else {
92  /* escape */
93  run = SHOW_UBITS(re, &a->gb, 6)+1; LAST_SKIP_BITS(re, &a->gb, 6);
94  UPDATE_CACHE(re, &a->gb);
95  level = SHOW_SBITS(re, &a->gb, 10); SKIP_BITS(re, &a->gb, 10);
96  i += run;
97  j = scantable[i];
98  if (level < 0) {
99  level = -level;
100  level = (level * qscale * quant_matrix[j]) >> 3;
101  level = (level - 1) | 1;
102  level = -level;
103  } else {
104  level = (level * qscale * quant_matrix[j]) >> 3;
105  level = (level - 1) | 1;
106  }
107  }
108  if (i > 63) {
109  av_log(a->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", a->mb_x, a->mb_y);
110  return AVERROR_INVALIDDATA;
111  }
112 
113  block[j] = level;
114  }
115  CLOSE_READER(re, &a->gb);
116  }
117  a->block_last_index[n] = i;
118  return 0;
119 }
120 
121 static inline int decode_mb(MDECContext *a, int16_t block[6][64])
122 {
123  int i, ret;
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 ((ret = mdec_decode_block_intra(a, block[block_index[i]],
130  block_index[i])) < 0)
131  return ret;
132  if (get_bits_left(&a->gb) < 0)
133  return AVERROR_INVALIDDATA;
134  }
135  return 0;
136 }
137 
138 static inline void idct_put(MDECContext *a, AVFrame *frame, int mb_x, int mb_y)
139 {
140  int16_t (*block)[64] = a->block;
141  int linesize = frame->linesize[0];
142 
143  uint8_t *dest_y = frame->data[0] + (mb_y * 16* linesize ) + mb_x * 16;
144  uint8_t *dest_cb = frame->data[1] + (mb_y * 8 * frame->linesize[1]) + mb_x * 8;
145  uint8_t *dest_cr = frame->data[2] + (mb_y * 8 * frame->linesize[2]) + mb_x * 8;
146 
147  a->dsp.idct_put(dest_y, linesize, block[0]);
148  a->dsp.idct_put(dest_y + 8, linesize, block[1]);
149  a->dsp.idct_put(dest_y + 8 * linesize, linesize, block[2]);
150  a->dsp.idct_put(dest_y + 8 * linesize + 8, linesize, block[3]);
151 
152  if (!(a->avctx->flags & CODEC_FLAG_GRAY)) {
153  a->dsp.idct_put(dest_cb, frame->linesize[1], block[4]);
154  a->dsp.idct_put(dest_cr, frame->linesize[2], block[5]);
155  }
156 }
157 
158 static int decode_frame(AVCodecContext *avctx,
159  void *data, int *got_frame,
160  AVPacket *avpkt)
161 {
162  MDECContext * const a = avctx->priv_data;
163  const uint8_t *buf = avpkt->data;
164  int buf_size = avpkt->size;
165  ThreadFrame frame = { .f = data };
166  int i, ret;
167 
168  if ((ret = ff_thread_get_buffer(avctx, &frame, 0)) < 0)
169  return ret;
170  frame.f->pict_type = AV_PICTURE_TYPE_I;
171  frame.f->key_frame = 1;
172 
174  if (!a->bitstream_buffer)
175  return AVERROR(ENOMEM);
176  for (i = 0; i < buf_size; i += 2) {
177  a->bitstream_buffer[i] = buf[i + 1];
178  a->bitstream_buffer[i + 1] = buf[i];
179  }
180  init_get_bits(&a->gb, a->bitstream_buffer, buf_size * 8);
181 
182  /* skip over 4 preamble bytes in stream (typically 0xXX 0xXX 0x00 0x38) */
183  skip_bits(&a->gb, 32);
184 
185  a->qscale = get_bits(&a->gb, 16);
186  a->version = get_bits(&a->gb, 16);
187 
188  a->last_dc[0] = a->last_dc[1] = a->last_dc[2] = 128;
189 
190  for (a->mb_x = 0; a->mb_x < a->mb_width; a->mb_x++) {
191  for (a->mb_y = 0; a->mb_y < a->mb_height; a->mb_y++) {
192  if ((ret = decode_mb(a, a->block)) < 0)
193  return ret;
194 
195  idct_put(a, frame.f, a->mb_x, a->mb_y);
196  }
197  }
198 
199  *got_frame = 1;
200 
201  return (get_bits_count(&a->gb) + 31) / 32 * 4;
202 }
203 
205 {
206  MDECContext * const a = avctx->priv_data;
207 
208  a->mb_width = (avctx->coded_width + 15) / 16;
209  a->mb_height = (avctx->coded_height + 15) / 16;
210 
211  a->avctx = avctx;
212 
213  ff_dsputil_init(&a->dsp, avctx);
216 
217  if (avctx->idct_algo == FF_IDCT_AUTO)
218  avctx->idct_algo = FF_IDCT_SIMPLE;
219  avctx->pix_fmt = AV_PIX_FMT_YUVJ420P;
220 
221  return 0;
222 }
223 
225 {
226  MDECContext * const a = avctx->priv_data;
227 
228  a->avctx = avctx;
229 
230  return 0;
231 }
232 
234 {
235  MDECContext * const a = avctx->priv_data;
236 
238  a->bitstream_buffer_size = 0;
239 
240  return 0;
241 }
242 
244  .name = "mdec",
245  .type = AVMEDIA_TYPE_VIDEO,
246  .id = AV_CODEC_ID_MDEC,
247  .priv_data_size = sizeof(MDECContext),
248  .init = decode_init,
249  .close = decode_end,
250  .decode = decode_frame,
251  .capabilities = CODEC_CAP_DR1 | CODEC_CAP_FRAME_THREADS,
252  .long_name = NULL_IF_CONFIG_SMALL("Sony PlayStation MDEC (Motion DECoder)"),
254 };