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dvdec.c
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1 /*
2  * DV decoder
3  * Copyright (c) 2002 Fabrice Bellard
4  * Copyright (c) 2004 Roman Shaposhnik
5  *
6  * 50 Mbps (DVCPRO50) support
7  * Copyright (c) 2006 Daniel Maas <dmaas@maasdigital.com>
8  *
9  * 100 Mbps (DVCPRO HD) support
10  * Initial code by Daniel Maas <dmaas@maasdigital.com> (funded by BBC R&D)
11  * Final code by Roman Shaposhnik
12  *
13  * Many thanks to Dan Dennedy <dan@dennedy.org> for providing wealth
14  * of DV technical info.
15  *
16  * This file is part of FFmpeg.
17  *
18  * FFmpeg is free software; you can redistribute it and/or
19  * modify it under the terms of the GNU Lesser General Public
20  * License as published by the Free Software Foundation; either
21  * version 2.1 of the License, or (at your option) any later version.
22  *
23  * FFmpeg is distributed in the hope that it will be useful,
24  * but WITHOUT ANY WARRANTY; without even the implied warranty of
25  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
26  * Lesser General Public License for more details.
27  *
28  * You should have received a copy of the GNU Lesser General Public
29  * License along with FFmpeg; if not, write to the Free Software
30  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
31  */
32 
33 /**
34  * @file
35  * DV decoder
36  */
37 
38 #include "libavutil/avassert.h"
39 #include "libavutil/internal.h"
40 #include "libavutil/pixdesc.h"
41 #include "avcodec.h"
42 #include "internal.h"
43 #include "get_bits.h"
44 #include "put_bits.h"
45 #include "simple_idct.h"
46 #include "dvdata.h"
47 
48 typedef struct BlockInfo {
49  const uint32_t *factor_table;
51  uint8_t pos; /* position in block */
52  void (*idct_put)(uint8_t *dest, int line_size, int16_t *block);
56 } BlockInfo;
57 
58 static const int dv_iweight_bits = 14;
59 
60 /* decode AC coefficients */
61 static void dv_decode_ac(GetBitContext *gb, BlockInfo *mb, int16_t *block)
62 {
63  int last_index = gb->size_in_bits;
64  const uint8_t *scan_table = mb->scan_table;
65  const uint32_t *factor_table = mb->factor_table;
66  int pos = mb->pos;
67  int partial_bit_count = mb->partial_bit_count;
68  int level, run, vlc_len, index;
69 
70  OPEN_READER(re, gb);
71  UPDATE_CACHE(re, gb);
72 
73  /* if we must parse a partial VLC, we do it here */
74  if (partial_bit_count > 0) {
75  re_cache = re_cache >> partial_bit_count | mb->partial_bit_buffer;
76  re_index -= partial_bit_count;
77  mb->partial_bit_count = 0;
78  }
79 
80  /* get the AC coefficients until last_index is reached */
81  for (;;) {
82  av_dlog(NULL, "%2d: bits=%04x index=%d\n", pos, SHOW_UBITS(re, gb, 16),
83  re_index);
84  /* our own optimized GET_RL_VLC */
85  index = NEG_USR32(re_cache, TEX_VLC_BITS);
86  vlc_len = ff_dv_rl_vlc[index].len;
87  if (vlc_len < 0) {
88  index = NEG_USR32((unsigned)re_cache << TEX_VLC_BITS, -vlc_len) +
90  vlc_len = TEX_VLC_BITS - vlc_len;
91  }
92  level = ff_dv_rl_vlc[index].level;
93  run = ff_dv_rl_vlc[index].run;
94 
95  /* gotta check if we're still within gb boundaries */
96  if (re_index + vlc_len > last_index) {
97  /* should be < 16 bits otherwise a codeword could have been parsed */
98  mb->partial_bit_count = last_index - re_index;
99  mb->partial_bit_buffer = re_cache & ~(-1u >> mb->partial_bit_count);
100  re_index = last_index;
101  break;
102  }
103  re_index += vlc_len;
104 
105  av_dlog(NULL, "run=%d level=%d\n", run, level);
106  pos += run;
107  if (pos >= 64)
108  break;
109 
110  level = (level * factor_table[pos] + (1 << (dv_iweight_bits - 1))) >> dv_iweight_bits;
111  block[scan_table[pos]] = level;
112 
113  UPDATE_CACHE(re, gb);
114  }
115  CLOSE_READER(re, gb);
116  mb->pos = pos;
117 }
118 
119 static inline void bit_copy(PutBitContext *pb, GetBitContext *gb)
120 {
121  int bits_left = get_bits_left(gb);
122  while (bits_left >= MIN_CACHE_BITS) {
124  bits_left -= MIN_CACHE_BITS;
125  }
126  if (bits_left > 0) {
127  put_bits(pb, bits_left, get_bits(gb, bits_left));
128  }
129 }
130 
131 /* mb_x and mb_y are in units of 8 pixels */
132 static int dv_decode_video_segment(AVCodecContext *avctx, void *arg)
133 {
134  DVVideoContext *s = avctx->priv_data;
135  DVwork_chunk *work_chunk = arg;
136  int quant, dc, dct_mode, class1, j;
137  int mb_index, mb_x, mb_y, last_index;
138  int y_stride, linesize;
139  int16_t *block, *block1;
140  int c_offset;
141  uint8_t *y_ptr;
142  const uint8_t *buf_ptr;
143  PutBitContext pb, vs_pb;
144  GetBitContext gb;
145  BlockInfo mb_data[5 * DV_MAX_BPM], *mb, *mb1;
146  LOCAL_ALIGNED_16(int16_t, sblock, [5*DV_MAX_BPM], [64]);
147  LOCAL_ALIGNED_16(uint8_t, mb_bit_buffer, [ 80 + FF_INPUT_BUFFER_PADDING_SIZE]); /* allow some slack */
148  LOCAL_ALIGNED_16(uint8_t, vs_bit_buffer, [5*80 + FF_INPUT_BUFFER_PADDING_SIZE]); /* allow some slack */
149  const int log2_blocksize = 3-s->avctx->lowres;
150  int is_field_mode[5];
151 
152  av_assert1((((int)mb_bit_buffer) & 7) == 0);
153  av_assert1((((int)vs_bit_buffer) & 7) == 0);
154 
155  memset(sblock, 0, 5*DV_MAX_BPM*sizeof(*sblock));
156 
157  /* pass 1: read DC and AC coefficients in blocks */
158  buf_ptr = &s->buf[work_chunk->buf_offset*80];
159  block1 = &sblock[0][0];
160  mb1 = mb_data;
161  init_put_bits(&vs_pb, vs_bit_buffer, 5 * 80);
162  for (mb_index = 0; mb_index < 5; mb_index++, mb1 += s->sys->bpm, block1 += s->sys->bpm * 64) {
163  /* skip header */
164  quant = buf_ptr[3] & 0x0f;
165  buf_ptr += 4;
166  init_put_bits(&pb, mb_bit_buffer, 80);
167  mb = mb1;
168  block = block1;
169  is_field_mode[mb_index] = 0;
170  for (j = 0; j < s->sys->bpm; j++) {
171  last_index = s->sys->block_sizes[j];
172  init_get_bits(&gb, buf_ptr, last_index);
173 
174  /* get the DC */
175  dc = get_sbits(&gb, 9);
176  dct_mode = get_bits1(&gb);
177  class1 = get_bits(&gb, 2);
178  if (DV_PROFILE_IS_HD(s->sys)) {
179  mb->idct_put = s->idct_put[0];
180  mb->scan_table = s->dv_zigzag[0];
181  mb->factor_table = &s->sys->idct_factor[(j >= 4)*4*16*64 + class1*16*64 + quant*64];
182  is_field_mode[mb_index] |= !j && dct_mode;
183  } else {
184  mb->idct_put = s->idct_put[dct_mode && log2_blocksize == 3];
185  mb->scan_table = s->dv_zigzag[dct_mode];
186  mb->factor_table = &s->sys->idct_factor[(class1 == 3)*2*22*64 + dct_mode*22*64 +
187  (quant + ff_dv_quant_offset[class1])*64];
188  }
189  dc = dc << 2;
190  /* convert to unsigned because 128 is not added in the
191  standard IDCT */
192  dc += 1024;
193  block[0] = dc;
194  buf_ptr += last_index >> 3;
195  mb->pos = 0;
196  mb->partial_bit_count = 0;
197 
198  av_dlog(avctx, "MB block: %d, %d ", mb_index, j);
199  dv_decode_ac(&gb, mb, block);
200 
201  /* write the remaining bits in a new buffer only if the
202  block is finished */
203  if (mb->pos >= 64)
204  bit_copy(&pb, &gb);
205 
206  block += 64;
207  mb++;
208  }
209 
210  /* pass 2: we can do it just after */
211  av_dlog(avctx, "***pass 2 size=%d MB#=%d\n", put_bits_count(&pb), mb_index);
212  block = block1;
213  mb = mb1;
214  init_get_bits(&gb, mb_bit_buffer, put_bits_count(&pb));
215  put_bits32(&pb, 0); // padding must be zeroed
216  flush_put_bits(&pb);
217  for (j = 0; j < s->sys->bpm; j++, block += 64, mb++) {
218  if (mb->pos < 64 && get_bits_left(&gb) > 0) {
219  dv_decode_ac(&gb, mb, block);
220  /* if still not finished, no need to parse other blocks */
221  if (mb->pos < 64)
222  break;
223  }
224  }
225  /* all blocks are finished, so the extra bytes can be used at
226  the video segment level */
227  if (j >= s->sys->bpm)
228  bit_copy(&vs_pb, &gb);
229  }
230 
231  /* we need a pass over the whole video segment */
232  av_dlog(avctx, "***pass 3 size=%d\n", put_bits_count(&vs_pb));
233  block = &sblock[0][0];
234  mb = mb_data;
235  init_get_bits(&gb, vs_bit_buffer, put_bits_count(&vs_pb));
236  put_bits32(&vs_pb, 0); // padding must be zeroed
237  flush_put_bits(&vs_pb);
238  for (mb_index = 0; mb_index < 5; mb_index++) {
239  for (j = 0; j < s->sys->bpm; j++) {
240  if (mb->pos < 64) {
241  av_dlog(avctx, "start %d:%d\n", mb_index, j);
242  dv_decode_ac(&gb, mb, block);
243  }
244  if (mb->pos >= 64 && mb->pos < 127)
245  av_log(avctx, AV_LOG_ERROR, "AC EOB marker is absent pos=%d\n", mb->pos);
246  block += 64;
247  mb++;
248  }
249  }
250 
251  /* compute idct and place blocks */
252  block = &sblock[0][0];
253  mb = mb_data;
254  for (mb_index = 0; mb_index < 5; mb_index++) {
255  dv_calculate_mb_xy(s, work_chunk, mb_index, &mb_x, &mb_y);
256 
257  /* idct_put'ting luminance */
258  if ((s->sys->pix_fmt == AV_PIX_FMT_YUV420P) ||
259  (s->sys->pix_fmt == AV_PIX_FMT_YUV411P && mb_x >= (704 / 8)) ||
260  (s->sys->height >= 720 && mb_y != 134)) {
261  y_stride = (s->picture.linesize[0] << ((!is_field_mode[mb_index]) * log2_blocksize));
262  } else {
263  y_stride = (2 << log2_blocksize);
264  }
265  y_ptr = s->picture.data[0] + ((mb_y * s->picture.linesize[0] + mb_x) << log2_blocksize);
266  linesize = s->picture.linesize[0] << is_field_mode[mb_index];
267  mb[0] .idct_put(y_ptr , linesize, block + 0*64);
268  if (s->sys->video_stype == 4) { /* SD 422 */
269  mb[2].idct_put(y_ptr + (1 << log2_blocksize) , linesize, block + 2*64);
270  } else {
271  mb[1].idct_put(y_ptr + (1 << log2_blocksize) , linesize, block + 1*64);
272  mb[2].idct_put(y_ptr + y_stride, linesize, block + 2*64);
273  mb[3].idct_put(y_ptr + (1 << log2_blocksize) + y_stride, linesize, block + 3*64);
274  }
275  mb += 4;
276  block += 4*64;
277 
278  /* idct_put'ting chrominance */
279  c_offset = (((mb_y >> (s->sys->pix_fmt == AV_PIX_FMT_YUV420P)) * s->picture.linesize[1] +
280  (mb_x >> ((s->sys->pix_fmt == AV_PIX_FMT_YUV411P) ? 2 : 1))) << log2_blocksize);
281  for (j = 2; j; j--) {
282  uint8_t *c_ptr = s->picture.data[j] + c_offset;
283  if (s->sys->pix_fmt == AV_PIX_FMT_YUV411P && mb_x >= (704 / 8)) {
284  uint64_t aligned_pixels[64/8];
285  uint8_t *pixels = (uint8_t*)aligned_pixels;
286  uint8_t *c_ptr1, *ptr1;
287  int x, y;
288  mb->idct_put(pixels, 8, block);
289  for (y = 0; y < (1 << log2_blocksize); y++, c_ptr += s->picture.linesize[j], pixels += 8) {
290  ptr1 = pixels + ((1 << (log2_blocksize))>>1);
291  c_ptr1 = c_ptr + (s->picture.linesize[j] << log2_blocksize);
292  for (x = 0; x < (1 << FFMAX(log2_blocksize - 1, 0)); x++) {
293  c_ptr[x] = pixels[x];
294  c_ptr1[x] = ptr1[x];
295  }
296  }
297  block += 64; mb++;
298  } else {
299  y_stride = (mb_y == 134) ? (1 << log2_blocksize) :
300  s->picture.linesize[j] << ((!is_field_mode[mb_index]) * log2_blocksize);
301  linesize = s->picture.linesize[j] << is_field_mode[mb_index];
302  (mb++)-> idct_put(c_ptr , linesize, block); block += 64;
303  if (s->sys->bpm == 8) {
304  (mb++)->idct_put(c_ptr + y_stride, linesize, block); block += 64;
305  }
306  }
307  }
308  }
309  return 0;
310 }
311 
312 /* NOTE: exactly one frame must be given (120000 bytes for NTSC,
313  144000 bytes for PAL - or twice those for 50Mbps) */
315  void *data, int *got_frame,
316  AVPacket *avpkt)
317 {
318  uint8_t *buf = avpkt->data;
319  int buf_size = avpkt->size;
320  DVVideoContext *s = avctx->priv_data;
321  const uint8_t* vsc_pack;
322  int ret, apt, is16_9;
323 
324  s->sys = avpriv_dv_frame_profile2(avctx, s->sys, buf, buf_size);
325  if (!s->sys || buf_size < s->sys->frame_size || ff_dv_init_dynamic_tables(s->sys)) {
326  av_log(avctx, AV_LOG_ERROR, "could not find dv frame profile\n");
327  return -1; /* NOTE: we only accept several full frames */
328  }
329 
330  s->picture.key_frame = 1;
332  avctx->pix_fmt = s->sys->pix_fmt;
333  avctx->time_base = s->sys->time_base;
334  avcodec_set_dimensions(avctx, s->sys->width, s->sys->height);
335  if ((ret = ff_get_buffer(avctx, &s->picture, 0)) < 0)
336  return ret;
337  s->picture.interlaced_frame = 1;
338  s->picture.top_field_first = 0;
339 
340  /* Determine the codec's sample_aspect ratio and field order from the packet */
341  vsc_pack = buf + 80*5 + 48 + 5;
342  if ( *vsc_pack == dv_video_control ) {
343  apt = buf[4] & 0x07;
344  is16_9 = (vsc_pack[2] & 0x07) == 0x02 || (!apt && (vsc_pack[2] & 0x07) == 0x07);
345  avctx->sample_aspect_ratio = s->sys->sar[is16_9];
346  s->picture.top_field_first = !(vsc_pack[3] & 0x40);
347  }
348 
349  s->buf = buf;
350  avctx->execute(avctx, dv_decode_video_segment, s->sys->work_chunks, NULL,
351  dv_work_pool_size(s->sys), sizeof(DVwork_chunk));
352 
353  emms_c();
354 
355  /* return image */
356  *got_frame = 1;
357  av_frame_move_ref(data, &s->picture);
358 
359  return s->sys->frame_size;
360 }
361 
363 {
364  DVVideoContext *s = c->priv_data;
365 
366  av_frame_unref(&s->picture);
367 
368  return 0;
369 }
370 
372  .name = "dvvideo",
373  .type = AVMEDIA_TYPE_VIDEO,
374  .id = AV_CODEC_ID_DVVIDEO,
375  .priv_data_size = sizeof(DVVideoContext),
377  .close = dvvideo_close,
379  .capabilities = CODEC_CAP_DR1 | CODEC_CAP_SLICE_THREADS,
380  .max_lowres = 3,
381  .long_name = NULL_IF_CONFIG_SMALL("DV (Digital Video)"),
382 };