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  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  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
170  return ret;
171  }
172  frame.f->pict_type = AV_PICTURE_TYPE_I;
173  frame.f->key_frame = 1;
174 
176  if (!a->bitstream_buffer)
177  return AVERROR(ENOMEM);
178  for (i = 0; i < buf_size; i += 2) {
179  a->bitstream_buffer[i] = buf[i + 1];
180  a->bitstream_buffer[i + 1] = buf[i];
181  }
182  init_get_bits(&a->gb, a->bitstream_buffer, buf_size * 8);
183 
184  /* skip over 4 preamble bytes in stream (typically 0xXX 0xXX 0x00 0x38) */
185  skip_bits(&a->gb, 32);
186 
187  a->qscale = get_bits(&a->gb, 16);
188  a->version = get_bits(&a->gb, 16);
189 
190  a->last_dc[0] = a->last_dc[1] = a->last_dc[2] = 128;
191 
192  for (a->mb_x = 0; a->mb_x < a->mb_width; a->mb_x++) {
193  for (a->mb_y = 0; a->mb_y < a->mb_height; a->mb_y++) {
194  if ((ret = decode_mb(a, a->block)) < 0)
195  return ret;
196 
197  idct_put(a, frame.f, a->mb_x, a->mb_y);
198  }
199  }
200 
201  *got_frame = 1;
202 
203  return (get_bits_count(&a->gb) + 31) / 32 * 4;
204 }
205 
207 {
208  MDECContext * const a = avctx->priv_data;
209 
210  a->mb_width = (avctx->coded_width + 15) / 16;
211  a->mb_height = (avctx->coded_height + 15) / 16;
212 
213  a->avctx = avctx;
214 
215  ff_dsputil_init(&a->dsp, avctx);
218 
219  if (avctx->idct_algo == FF_IDCT_AUTO)
220  avctx->idct_algo = FF_IDCT_SIMPLE;
221  avctx->pix_fmt = AV_PIX_FMT_YUVJ420P;
222 
223  return 0;
224 }
225 
227 {
228  MDECContext * const a = avctx->priv_data;
229 
230  a->avctx = avctx;
231 
232  return 0;
233 }
234 
236 {
237  MDECContext * const a = avctx->priv_data;
238 
240  a->bitstream_buffer_size = 0;
241 
242  return 0;
243 }
244 
246  .name = "mdec",
247  .long_name = NULL_IF_CONFIG_SMALL("Sony PlayStation MDEC (Motion DECoder)"),
248  .type = AVMEDIA_TYPE_VIDEO,
249  .id = AV_CODEC_ID_MDEC,
250  .priv_data_size = sizeof(MDECContext),
251  .init = decode_init,
252  .close = decode_end,
253  .decode = decode_frame,
254  .capabilities = CODEC_CAP_DR1 | CODEC_CAP_FRAME_THREADS,
256 };