FFmpeg
 All Data Structures Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
kmvc.c
Go to the documentation of this file.
1 /*
2  * KMVC decoder
3  * Copyright (c) 2006 Konstantin Shishkov
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 /**
23  * @file
24  * Karl Morton's Video Codec decoder
25  */
26 
27 #include <stdio.h>
28 #include <stdlib.h>
29 
30 #include "avcodec.h"
31 #include "bytestream.h"
32 #include "internal.h"
33 
34 #define KMVC_KEYFRAME 0x80
35 #define KMVC_PALETTE 0x40
36 #define KMVC_METHOD 0x0F
37 #define MAX_PALSIZE 256
38 
39 /*
40  * Decoder context
41  */
42 typedef struct KmvcContext {
43  AVCodecContext *avctx;
44  AVFrame pic;
45 
46  int setpal;
47  int palsize;
48  uint32_t pal[MAX_PALSIZE];
49  uint8_t *cur, *prev;
50  uint8_t *frm0, *frm1;
51  GetByteContext g;
52 } KmvcContext;
53 
54 typedef struct BitBuf {
55  int bits;
56  int bitbuf;
57 } BitBuf;
58 
59 #define BLK(data, x, y) data[(x) + (y) * 320]
60 
61 #define kmvc_init_getbits(bb, g) bb.bits = 7; bb.bitbuf = bytestream2_get_byte(g);
62 
63 #define kmvc_getbit(bb, g, res) {\
64  res = 0; \
65  if (bb.bitbuf & (1 << bb.bits)) res = 1; \
66  bb.bits--; \
67  if(bb.bits == -1) { \
68  bb.bitbuf = bytestream2_get_byte(g); \
69  bb.bits = 7; \
70  } \
71 }
72 
73 static int kmvc_decode_intra_8x8(KmvcContext * ctx, int w, int h)
74 {
75  BitBuf bb;
76  int res, val;
77  int i, j;
78  int bx, by;
79  int l0x, l1x, l0y, l1y;
80  int mx, my;
81 
82  kmvc_init_getbits(bb, &ctx->g);
83 
84  for (by = 0; by < h; by += 8)
85  for (bx = 0; bx < w; bx += 8) {
86  if (!bytestream2_get_bytes_left(&ctx->g)) {
87  av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n");
88  return AVERROR_INVALIDDATA;
89  }
90  kmvc_getbit(bb, &ctx->g, res);
91  if (!res) { // fill whole 8x8 block
92  val = bytestream2_get_byte(&ctx->g);
93  for (i = 0; i < 64; i++)
94  BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) = val;
95  } else { // handle four 4x4 subblocks
96  for (i = 0; i < 4; i++) {
97  l0x = bx + (i & 1) * 4;
98  l0y = by + (i & 2) * 2;
99  kmvc_getbit(bb, &ctx->g, res);
100  if (!res) {
101  kmvc_getbit(bb, &ctx->g, res);
102  if (!res) { // fill whole 4x4 block
103  val = bytestream2_get_byte(&ctx->g);
104  for (j = 0; j < 16; j++)
105  BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) = val;
106  } else { // copy block from already decoded place
107  val = bytestream2_get_byte(&ctx->g);
108  mx = val & 0xF;
109  my = val >> 4;
110  if ((l0x-mx) + 320*(l0y-my) < 0 || (l0x-mx) + 320*(l0y-my) > 316*196) {
111  av_log(ctx->avctx, AV_LOG_ERROR, "Invalid MV\n");
112  return AVERROR_INVALIDDATA;
113  }
114  for (j = 0; j < 16; j++)
115  BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) =
116  BLK(ctx->cur, l0x + (j & 3) - mx, l0y + (j >> 2) - my);
117  }
118  } else { // descend to 2x2 sub-sub-blocks
119  for (j = 0; j < 4; j++) {
120  l1x = l0x + (j & 1) * 2;
121  l1y = l0y + (j & 2);
122  kmvc_getbit(bb, &ctx->g, res);
123  if (!res) {
124  kmvc_getbit(bb, &ctx->g, res);
125  if (!res) { // fill whole 2x2 block
126  val = bytestream2_get_byte(&ctx->g);
127  BLK(ctx->cur, l1x, l1y) = val;
128  BLK(ctx->cur, l1x + 1, l1y) = val;
129  BLK(ctx->cur, l1x, l1y + 1) = val;
130  BLK(ctx->cur, l1x + 1, l1y + 1) = val;
131  } else { // copy block from already decoded place
132  val = bytestream2_get_byte(&ctx->g);
133  mx = val & 0xF;
134  my = val >> 4;
135  if ((l1x-mx) + 320*(l1y-my) < 0 || (l1x-mx) + 320*(l1y-my) > 318*198) {
136  av_log(ctx->avctx, AV_LOG_ERROR, "Invalid MV\n");
137  return AVERROR_INVALIDDATA;
138  }
139  BLK(ctx->cur, l1x, l1y) = BLK(ctx->cur, l1x - mx, l1y - my);
140  BLK(ctx->cur, l1x + 1, l1y) =
141  BLK(ctx->cur, l1x + 1 - mx, l1y - my);
142  BLK(ctx->cur, l1x, l1y + 1) =
143  BLK(ctx->cur, l1x - mx, l1y + 1 - my);
144  BLK(ctx->cur, l1x + 1, l1y + 1) =
145  BLK(ctx->cur, l1x + 1 - mx, l1y + 1 - my);
146  }
147  } else { // read values for block
148  BLK(ctx->cur, l1x, l1y) = bytestream2_get_byte(&ctx->g);
149  BLK(ctx->cur, l1x + 1, l1y) = bytestream2_get_byte(&ctx->g);
150  BLK(ctx->cur, l1x, l1y + 1) = bytestream2_get_byte(&ctx->g);
151  BLK(ctx->cur, l1x + 1, l1y + 1) = bytestream2_get_byte(&ctx->g);
152  }
153  }
154  }
155  }
156  }
157  }
158 
159  return 0;
160 }
161 
162 static int kmvc_decode_inter_8x8(KmvcContext * ctx, int w, int h)
163 {
164  BitBuf bb;
165  int res, val;
166  int i, j;
167  int bx, by;
168  int l0x, l1x, l0y, l1y;
169  int mx, my;
170 
171  kmvc_init_getbits(bb, &ctx->g);
172 
173  for (by = 0; by < h; by += 8)
174  for (bx = 0; bx < w; bx += 8) {
175  kmvc_getbit(bb, &ctx->g, res);
176  if (!res) {
177  kmvc_getbit(bb, &ctx->g, res);
178  if (!res) { // fill whole 8x8 block
179  if (!bytestream2_get_bytes_left(&ctx->g)) {
180  av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n");
181  return AVERROR_INVALIDDATA;
182  }
183  val = bytestream2_get_byte(&ctx->g);
184  for (i = 0; i < 64; i++)
185  BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) = val;
186  } else { // copy block from previous frame
187  for (i = 0; i < 64; i++)
188  BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) =
189  BLK(ctx->prev, bx + (i & 0x7), by + (i >> 3));
190  }
191  } else { // handle four 4x4 subblocks
192  if (!bytestream2_get_bytes_left(&ctx->g)) {
193  av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n");
194  return AVERROR_INVALIDDATA;
195  }
196  for (i = 0; i < 4; i++) {
197  l0x = bx + (i & 1) * 4;
198  l0y = by + (i & 2) * 2;
199  kmvc_getbit(bb, &ctx->g, res);
200  if (!res) {
201  kmvc_getbit(bb, &ctx->g, res);
202  if (!res) { // fill whole 4x4 block
203  val = bytestream2_get_byte(&ctx->g);
204  for (j = 0; j < 16; j++)
205  BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) = val;
206  } else { // copy block
207  val = bytestream2_get_byte(&ctx->g);
208  mx = (val & 0xF) - 8;
209  my = (val >> 4) - 8;
210  if ((l0x+mx) + 320*(l0y+my) < 0 || (l0x+mx) + 320*(l0y+my) > 318*198) {
211  av_log(ctx->avctx, AV_LOG_ERROR, "Invalid MV\n");
212  return AVERROR_INVALIDDATA;
213  }
214  for (j = 0; j < 16; j++)
215  BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) =
216  BLK(ctx->prev, l0x + (j & 3) + mx, l0y + (j >> 2) + my);
217  }
218  } else { // descend to 2x2 sub-sub-blocks
219  for (j = 0; j < 4; j++) {
220  l1x = l0x + (j & 1) * 2;
221  l1y = l0y + (j & 2);
222  kmvc_getbit(bb, &ctx->g, res);
223  if (!res) {
224  kmvc_getbit(bb, &ctx->g, res);
225  if (!res) { // fill whole 2x2 block
226  val = bytestream2_get_byte(&ctx->g);
227  BLK(ctx->cur, l1x, l1y) = val;
228  BLK(ctx->cur, l1x + 1, l1y) = val;
229  BLK(ctx->cur, l1x, l1y + 1) = val;
230  BLK(ctx->cur, l1x + 1, l1y + 1) = val;
231  } else { // copy block
232  val = bytestream2_get_byte(&ctx->g);
233  mx = (val & 0xF) - 8;
234  my = (val >> 4) - 8;
235  if ((l1x+mx) + 320*(l1y+my) < 0 || (l1x+mx) + 320*(l1y+my) > 318*198) {
236  av_log(ctx->avctx, AV_LOG_ERROR, "Invalid MV\n");
237  return AVERROR_INVALIDDATA;
238  }
239  BLK(ctx->cur, l1x, l1y) = BLK(ctx->prev, l1x + mx, l1y + my);
240  BLK(ctx->cur, l1x + 1, l1y) =
241  BLK(ctx->prev, l1x + 1 + mx, l1y + my);
242  BLK(ctx->cur, l1x, l1y + 1) =
243  BLK(ctx->prev, l1x + mx, l1y + 1 + my);
244  BLK(ctx->cur, l1x + 1, l1y + 1) =
245  BLK(ctx->prev, l1x + 1 + mx, l1y + 1 + my);
246  }
247  } else { // read values for block
248  BLK(ctx->cur, l1x, l1y) = bytestream2_get_byte(&ctx->g);
249  BLK(ctx->cur, l1x + 1, l1y) = bytestream2_get_byte(&ctx->g);
250  BLK(ctx->cur, l1x, l1y + 1) = bytestream2_get_byte(&ctx->g);
251  BLK(ctx->cur, l1x + 1, l1y + 1) = bytestream2_get_byte(&ctx->g);
252  }
253  }
254  }
255  }
256  }
257  }
258 
259  return 0;
260 }
261 
262 static int decode_frame(AVCodecContext * avctx, void *data, int *got_frame,
263  AVPacket *avpkt)
264 {
265  KmvcContext *const ctx = avctx->priv_data;
266  uint8_t *out, *src;
267  int i;
268  int header;
269  int blocksize;
270  const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
271  int ret;
272 
273  bytestream2_init(&ctx->g, avpkt->data, avpkt->size);
274  if (ctx->pic.data[0])
275  avctx->release_buffer(avctx, &ctx->pic);
276 
277  ctx->pic.reference = 3;
278  ctx->pic.buffer_hints = FF_BUFFER_HINTS_VALID;
279  if ((ret = ff_get_buffer(avctx, &ctx->pic)) < 0) {
280  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
281  return ret;
282  }
283 
284  header = bytestream2_get_byte(&ctx->g);
285 
286  /* blocksize 127 is really palette change event */
287  if (bytestream2_peek_byte(&ctx->g) == 127) {
288  bytestream2_skip(&ctx->g, 3);
289  for (i = 0; i < 127; i++) {
290  ctx->pal[i + (header & 0x81)] = 0xFFU << 24 | bytestream2_get_be24(&ctx->g);
291  bytestream2_skip(&ctx->g, 1);
292  }
293  bytestream2_seek(&ctx->g, -127 * 4 - 3, SEEK_CUR);
294  }
295 
296  if (header & KMVC_KEYFRAME) {
297  ctx->pic.key_frame = 1;
298  ctx->pic.pict_type = AV_PICTURE_TYPE_I;
299  } else {
300  ctx->pic.key_frame = 0;
301  ctx->pic.pict_type = AV_PICTURE_TYPE_P;
302  }
303 
304  if (header & KMVC_PALETTE) {
305  ctx->pic.palette_has_changed = 1;
306  // palette starts from index 1 and has 127 entries
307  for (i = 1; i <= ctx->palsize; i++) {
308  ctx->pal[i] = 0xFFU << 24 | bytestream2_get_be24(&ctx->g);
309  }
310  }
311 
312  if (pal) {
313  ctx->pic.palette_has_changed = 1;
314  memcpy(ctx->pal, pal, AVPALETTE_SIZE);
315  }
316 
317  if (ctx->setpal) {
318  ctx->setpal = 0;
319  ctx->pic.palette_has_changed = 1;
320  }
321 
322  /* make the palette available on the way out */
323  memcpy(ctx->pic.data[1], ctx->pal, 1024);
324 
325  blocksize = bytestream2_get_byte(&ctx->g);
326 
327  if (blocksize != 8 && blocksize != 127) {
328  av_log(avctx, AV_LOG_ERROR, "Block size = %i\n", blocksize);
329  return AVERROR_INVALIDDATA;
330  }
331  memset(ctx->cur, 0, 320 * 200);
332  switch (header & KMVC_METHOD) {
333  case 0:
334  case 1: // used in palette changed event
335  memcpy(ctx->cur, ctx->prev, 320 * 200);
336  break;
337  case 3:
338  kmvc_decode_intra_8x8(ctx, avctx->width, avctx->height);
339  break;
340  case 4:
341  kmvc_decode_inter_8x8(ctx, avctx->width, avctx->height);
342  break;
343  default:
344  av_log(avctx, AV_LOG_ERROR, "Unknown compression method %i\n", header & KMVC_METHOD);
345  return AVERROR_INVALIDDATA;
346  }
347 
348  out = ctx->pic.data[0];
349  src = ctx->cur;
350  for (i = 0; i < avctx->height; i++) {
351  memcpy(out, src, avctx->width);
352  src += 320;
353  out += ctx->pic.linesize[0];
354  }
355 
356  /* flip buffers */
357  if (ctx->cur == ctx->frm0) {
358  ctx->cur = ctx->frm1;
359  ctx->prev = ctx->frm0;
360  } else {
361  ctx->cur = ctx->frm0;
362  ctx->prev = ctx->frm1;
363  }
364 
365  *got_frame = 1;
366  *(AVFrame *) data = ctx->pic;
367 
368  /* always report that the buffer was completely consumed */
369  return avpkt->size;
370 }
371 
372 
373 
374 /*
375  * Init kmvc decoder
376  */
377 static av_cold int decode_init(AVCodecContext * avctx)
378 {
379  KmvcContext *const c = avctx->priv_data;
380  int i;
381 
382  c->avctx = avctx;
383 
384  if (avctx->width > 320 || avctx->height > 200) {
385  av_log(avctx, AV_LOG_ERROR, "KMVC supports frames <= 320x200\n");
386  return AVERROR_INVALIDDATA;
387  }
388 
389  c->frm0 = av_mallocz(320 * 200);
390  c->frm1 = av_mallocz(320 * 200);
391  c->cur = c->frm0;
392  c->prev = c->frm1;
393 
394  for (i = 0; i < 256; i++) {
395  c->pal[i] = 0xFFU << 24 | i * 0x10101;
396  }
397 
398  if (avctx->extradata_size < 12) {
399  av_log(avctx, AV_LOG_WARNING,
400  "Extradata missing, decoding may not work properly...\n");
401  c->palsize = 127;
402  } else {
403  c->palsize = AV_RL16(avctx->extradata + 10);
404  if (c->palsize >= (unsigned)MAX_PALSIZE) {
405  c->palsize = 127;
406  av_log(avctx, AV_LOG_ERROR, "KMVC palette too large\n");
407  return AVERROR_INVALIDDATA;
408  }
409  }
410 
411  if (avctx->extradata_size == 1036) { // palette in extradata
412  uint8_t *src = avctx->extradata + 12;
413  for (i = 0; i < 256; i++) {
414  c->pal[i] = AV_RL32(src);
415  src += 4;
416  }
417  c->setpal = 1;
418  }
419 
420  avcodec_get_frame_defaults(&c->pic);
421  avctx->pix_fmt = AV_PIX_FMT_PAL8;
422 
423  return 0;
424 }
425 
426 
427 
428 /*
429  * Uninit kmvc decoder
430  */
431 static av_cold int decode_end(AVCodecContext * avctx)
432 {
433  KmvcContext *const c = avctx->priv_data;
434 
435  av_freep(&c->frm0);
436  av_freep(&c->frm1);
437  if (c->pic.data[0])
438  avctx->release_buffer(avctx, &c->pic);
439 
440  return 0;
441 }
442 
443 AVCodec ff_kmvc_decoder = {
444  .name = "kmvc",
445  .type = AVMEDIA_TYPE_VIDEO,
446  .id = AV_CODEC_ID_KMVC,
447  .priv_data_size = sizeof(KmvcContext),
448  .init = decode_init,
449  .close = decode_end,
450  .decode = decode_frame,
451  .capabilities = CODEC_CAP_DR1,
452  .long_name = NULL_IF_CONFIG_SMALL("Karl Morton's video codec"),
453 };
Generated on Sat May 25 2013 03:58:35 for FFmpeg by   doxygen 1.8.2