Libav
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 "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  if (i > 63) {
89  "ac-tex damaged at %d %d\n", a->mb_x, a->mb_y);
90  return AVERROR_INVALIDDATA;
91  }
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  if (i > 63) {
104  "ac-tex damaged at %d %d\n", a->mb_x, a->mb_y);
105  return AVERROR_INVALIDDATA;
106  }
107  j = scantable[i];
108  if (level < 0) {
109  level = -level;
110  level = (level * qscale * quant_matrix[j]) >> 3;
111  level = (level - 1) | 1;
112  level = -level;
113  } else {
114  level = (level * qscale * quant_matrix[j]) >> 3;
115  level = (level - 1) | 1;
116  }
117  }
118 
119  block[j] = level;
120  }
121  CLOSE_READER(re, &a->gb);
122  }
123  a->block_last_index[n] = i;
124  return 0;
125 }
126 
127 static inline int decode_mb(MDECContext *a, int16_t block[6][64])
128 {
129  int i, ret;
130  const int block_index[6] = { 5, 4, 0, 1, 2, 3 };
131 
132  a->dsp.clear_blocks(block[0]);
133 
134  for (i = 0; i < 6; i++) {
135  if ((ret = mdec_decode_block_intra(a, block[block_index[i]],
136  block_index[i])) < 0)
137  return ret;
138  if (get_bits_left(&a->gb) < 0)
139  return AVERROR_INVALIDDATA;
140  }
141  return 0;
142 }
143 
144 static inline void idct_put(MDECContext *a, AVFrame *frame, int mb_x, int mb_y)
145 {
146  int16_t (*block)[64] = a->block;
147  int linesize = frame->linesize[0];
148 
149  uint8_t *dest_y = frame->data[0] + (mb_y * 16* linesize ) + mb_x * 16;
150  uint8_t *dest_cb = frame->data[1] + (mb_y * 8 * frame->linesize[1]) + mb_x * 8;
151  uint8_t *dest_cr = frame->data[2] + (mb_y * 8 * frame->linesize[2]) + mb_x * 8;
152 
153  a->dsp.idct_put(dest_y, linesize, block[0]);
154  a->dsp.idct_put(dest_y + 8, linesize, block[1]);
155  a->dsp.idct_put(dest_y + 8 * linesize, linesize, block[2]);
156  a->dsp.idct_put(dest_y + 8 * linesize + 8, linesize, block[3]);
157 
158  if (!(a->avctx->flags & CODEC_FLAG_GRAY)) {
159  a->dsp.idct_put(dest_cb, frame->linesize[1], block[4]);
160  a->dsp.idct_put(dest_cr, frame->linesize[2], block[5]);
161  }
162 }
163 
164 static int decode_frame(AVCodecContext *avctx,
165  void *data, int *got_frame,
166  AVPacket *avpkt)
167 {
168  MDECContext * const a = avctx->priv_data;
169  const uint8_t *buf = avpkt->data;
170  int buf_size = avpkt->size;
171  ThreadFrame frame = { .f = data };
172  int i, ret;
173 
174  if ((ret = ff_thread_get_buffer(avctx, &frame, 0)) < 0) {
175  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
176  return ret;
177  }
178  frame.f->pict_type = AV_PICTURE_TYPE_I;
179  frame.f->key_frame = 1;
180 
182  if (!a->bitstream_buffer)
183  return AVERROR(ENOMEM);
184  for (i = 0; i < buf_size; i += 2) {
185  a->bitstream_buffer[i] = buf[i + 1];
186  a->bitstream_buffer[i + 1] = buf[i];
187  }
188  init_get_bits(&a->gb, a->bitstream_buffer, buf_size * 8);
189 
190  /* skip over 4 preamble bytes in stream (typically 0xXX 0xXX 0x00 0x38) */
191  skip_bits(&a->gb, 32);
192 
193  a->qscale = get_bits(&a->gb, 16);
194  a->version = get_bits(&a->gb, 16);
195 
196  a->last_dc[0] = a->last_dc[1] = a->last_dc[2] = 128;
197 
198  for (a->mb_x = 0; a->mb_x < a->mb_width; a->mb_x++) {
199  for (a->mb_y = 0; a->mb_y < a->mb_height; a->mb_y++) {
200  if ((ret = decode_mb(a, a->block)) < 0)
201  return ret;
202 
203  idct_put(a, frame.f, a->mb_x, a->mb_y);
204  }
205  }
206 
207  *got_frame = 1;
208 
209  return (get_bits_count(&a->gb) + 31) / 32 * 4;
210 }
211 
213 {
214  MDECContext * const a = avctx->priv_data;
215 
216  a->mb_width = (avctx->coded_width + 15) / 16;
217  a->mb_height = (avctx->coded_height + 15) / 16;
218 
219  a->avctx = avctx;
220 
221  ff_dsputil_init(&a->dsp, avctx);
224 
225  if (avctx->idct_algo == FF_IDCT_AUTO)
226  avctx->idct_algo = FF_IDCT_SIMPLE;
227  avctx->pix_fmt = AV_PIX_FMT_YUVJ420P;
228 
229  return 0;
230 }
231 
233 {
234  MDECContext * const a = avctx->priv_data;
235 
236  a->avctx = avctx;
237 
238  return 0;
239 }
240 
242 {
243  MDECContext * const a = avctx->priv_data;
244 
246  a->bitstream_buffer_size = 0;
247 
248  return 0;
249 }
250 
252  .name = "mdec",
253  .long_name = NULL_IF_CONFIG_SMALL("Sony PlayStation MDEC (Motion DECoder)"),
254  .type = AVMEDIA_TYPE_VIDEO,
255  .id = AV_CODEC_ID_MDEC,
256  .priv_data_size = sizeof(MDECContext),
257  .init = decode_init,
258  .close = decode_end,
259  .decode = decode_frame,
260  .capabilities = CODEC_CAP_DR1 | CODEC_CAP_FRAME_THREADS,
262 };