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kmvc.c
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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 
45  int setpal;
46  int palsize;
47  uint32_t pal[MAX_PALSIZE];
48  uint8_t *cur, *prev;
49  uint8_t *frm0, *frm1;
50  GetByteContext g;
51 } KmvcContext;
52 
53 typedef struct BitBuf {
54  int bits;
55  int bitbuf;
56 } BitBuf;
57 
58 #define BLK(data, x, y) data[(x) + (y) * 320]
59 
60 #define kmvc_init_getbits(bb, g) bb.bits = 7; bb.bitbuf = bytestream2_get_byte(g);
61 
62 #define kmvc_getbit(bb, g, res) {\
63  res = 0; \
64  if (bb.bitbuf & (1 << bb.bits)) res = 1; \
65  bb.bits--; \
66  if(bb.bits == -1) { \
67  bb.bitbuf = bytestream2_get_byte(g); \
68  bb.bits = 7; \
69  } \
70 }
71 
72 static int kmvc_decode_intra_8x8(KmvcContext * ctx, int w, int h)
73 {
74  BitBuf bb;
75  int res, val;
76  int i, j;
77  int bx, by;
78  int l0x, l1x, l0y, l1y;
79  int mx, my;
80 
81  kmvc_init_getbits(bb, &ctx->g);
82 
83  for (by = 0; by < h; by += 8)
84  for (bx = 0; bx < w; bx += 8) {
85  if (!bytestream2_get_bytes_left(&ctx->g)) {
86  av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n");
87  return AVERROR_INVALIDDATA;
88  }
89  kmvc_getbit(bb, &ctx->g, res);
90  if (!res) { // fill whole 8x8 block
91  val = bytestream2_get_byte(&ctx->g);
92  for (i = 0; i < 64; i++)
93  BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) = val;
94  } else { // handle four 4x4 subblocks
95  for (i = 0; i < 4; i++) {
96  l0x = bx + (i & 1) * 4;
97  l0y = by + (i & 2) * 2;
98  kmvc_getbit(bb, &ctx->g, res);
99  if (!res) {
100  kmvc_getbit(bb, &ctx->g, res);
101  if (!res) { // fill whole 4x4 block
102  val = bytestream2_get_byte(&ctx->g);
103  for (j = 0; j < 16; j++)
104  BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) = val;
105  } else { // copy block from already decoded place
106  val = bytestream2_get_byte(&ctx->g);
107  mx = val & 0xF;
108  my = val >> 4;
109  if ((l0x-mx) + 320*(l0y-my) < 0 || (l0x-mx) + 320*(l0y-my) > 316*196) {
110  av_log(ctx->avctx, AV_LOG_ERROR, "Invalid MV\n");
111  return AVERROR_INVALIDDATA;
112  }
113  for (j = 0; j < 16; j++)
114  BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) =
115  BLK(ctx->cur, l0x + (j & 3) - mx, l0y + (j >> 2) - my);
116  }
117  } else { // descend to 2x2 sub-sub-blocks
118  for (j = 0; j < 4; j++) {
119  l1x = l0x + (j & 1) * 2;
120  l1y = l0y + (j & 2);
121  kmvc_getbit(bb, &ctx->g, res);
122  if (!res) {
123  kmvc_getbit(bb, &ctx->g, res);
124  if (!res) { // fill whole 2x2 block
125  val = bytestream2_get_byte(&ctx->g);
126  BLK(ctx->cur, l1x, l1y) = val;
127  BLK(ctx->cur, l1x + 1, l1y) = val;
128  BLK(ctx->cur, l1x, l1y + 1) = val;
129  BLK(ctx->cur, l1x + 1, l1y + 1) = val;
130  } else { // copy block from already decoded place
131  val = bytestream2_get_byte(&ctx->g);
132  mx = val & 0xF;
133  my = val >> 4;
134  if ((l1x-mx) + 320*(l1y-my) < 0 || (l1x-mx) + 320*(l1y-my) > 318*198) {
135  av_log(ctx->avctx, AV_LOG_ERROR, "Invalid MV\n");
136  return AVERROR_INVALIDDATA;
137  }
138  BLK(ctx->cur, l1x, l1y) = BLK(ctx->cur, l1x - mx, l1y - my);
139  BLK(ctx->cur, l1x + 1, l1y) =
140  BLK(ctx->cur, l1x + 1 - mx, l1y - my);
141  BLK(ctx->cur, l1x, l1y + 1) =
142  BLK(ctx->cur, l1x - mx, l1y + 1 - my);
143  BLK(ctx->cur, l1x + 1, l1y + 1) =
144  BLK(ctx->cur, l1x + 1 - mx, l1y + 1 - my);
145  }
146  } else { // read values for block
147  BLK(ctx->cur, l1x, l1y) = bytestream2_get_byte(&ctx->g);
148  BLK(ctx->cur, l1x + 1, l1y) = bytestream2_get_byte(&ctx->g);
149  BLK(ctx->cur, l1x, l1y + 1) = bytestream2_get_byte(&ctx->g);
150  BLK(ctx->cur, l1x + 1, l1y + 1) = bytestream2_get_byte(&ctx->g);
151  }
152  }
153  }
154  }
155  }
156  }
157 
158  return 0;
159 }
160 
161 static int kmvc_decode_inter_8x8(KmvcContext * ctx, int w, int h)
162 {
163  BitBuf bb;
164  int res, val;
165  int i, j;
166  int bx, by;
167  int l0x, l1x, l0y, l1y;
168  int mx, my;
169 
170  kmvc_init_getbits(bb, &ctx->g);
171 
172  for (by = 0; by < h; by += 8)
173  for (bx = 0; bx < w; bx += 8) {
174  kmvc_getbit(bb, &ctx->g, res);
175  if (!res) {
176  kmvc_getbit(bb, &ctx->g, res);
177  if (!res) { // fill whole 8x8 block
178  if (!bytestream2_get_bytes_left(&ctx->g)) {
179  av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n");
180  return AVERROR_INVALIDDATA;
181  }
182  val = bytestream2_get_byte(&ctx->g);
183  for (i = 0; i < 64; i++)
184  BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) = val;
185  } else { // copy block from previous frame
186  for (i = 0; i < 64; i++)
187  BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) =
188  BLK(ctx->prev, bx + (i & 0x7), by + (i >> 3));
189  }
190  } else { // handle four 4x4 subblocks
191  if (!bytestream2_get_bytes_left(&ctx->g)) {
192  av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n");
193  return AVERROR_INVALIDDATA;
194  }
195  for (i = 0; i < 4; i++) {
196  l0x = bx + (i & 1) * 4;
197  l0y = by + (i & 2) * 2;
198  kmvc_getbit(bb, &ctx->g, res);
199  if (!res) {
200  kmvc_getbit(bb, &ctx->g, res);
201  if (!res) { // fill whole 4x4 block
202  val = bytestream2_get_byte(&ctx->g);
203  for (j = 0; j < 16; j++)
204  BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) = val;
205  } else { // copy block
206  val = bytestream2_get_byte(&ctx->g);
207  mx = (val & 0xF) - 8;
208  my = (val >> 4) - 8;
209  if ((l0x+mx) + 320*(l0y+my) < 0 || (l0x+mx) + 320*(l0y+my) > 318*198) {
210  av_log(ctx->avctx, AV_LOG_ERROR, "Invalid MV\n");
211  return AVERROR_INVALIDDATA;
212  }
213  for (j = 0; j < 16; j++)
214  BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) =
215  BLK(ctx->prev, l0x + (j & 3) + mx, l0y + (j >> 2) + my);
216  }
217  } else { // descend to 2x2 sub-sub-blocks
218  for (j = 0; j < 4; j++) {
219  l1x = l0x + (j & 1) * 2;
220  l1y = l0y + (j & 2);
221  kmvc_getbit(bb, &ctx->g, res);
222  if (!res) {
223  kmvc_getbit(bb, &ctx->g, res);
224  if (!res) { // fill whole 2x2 block
225  val = bytestream2_get_byte(&ctx->g);
226  BLK(ctx->cur, l1x, l1y) = val;
227  BLK(ctx->cur, l1x + 1, l1y) = val;
228  BLK(ctx->cur, l1x, l1y + 1) = val;
229  BLK(ctx->cur, l1x + 1, l1y + 1) = val;
230  } else { // copy block
231  val = bytestream2_get_byte(&ctx->g);
232  mx = (val & 0xF) - 8;
233  my = (val >> 4) - 8;
234  if ((l1x+mx) + 320*(l1y+my) < 0 || (l1x+mx) + 320*(l1y+my) > 318*198) {
235  av_log(ctx->avctx, AV_LOG_ERROR, "Invalid MV\n");
236  return AVERROR_INVALIDDATA;
237  }
238  BLK(ctx->cur, l1x, l1y) = BLK(ctx->prev, l1x + mx, l1y + my);
239  BLK(ctx->cur, l1x + 1, l1y) =
240  BLK(ctx->prev, l1x + 1 + mx, l1y + my);
241  BLK(ctx->cur, l1x, l1y + 1) =
242  BLK(ctx->prev, l1x + mx, l1y + 1 + my);
243  BLK(ctx->cur, l1x + 1, l1y + 1) =
244  BLK(ctx->prev, l1x + 1 + mx, l1y + 1 + my);
245  }
246  } else { // read values for block
247  BLK(ctx->cur, l1x, l1y) = bytestream2_get_byte(&ctx->g);
248  BLK(ctx->cur, l1x + 1, l1y) = bytestream2_get_byte(&ctx->g);
249  BLK(ctx->cur, l1x, l1y + 1) = bytestream2_get_byte(&ctx->g);
250  BLK(ctx->cur, l1x + 1, l1y + 1) = bytestream2_get_byte(&ctx->g);
251  }
252  }
253  }
254  }
255  }
256  }
257 
258  return 0;
259 }
260 
261 static int decode_frame(AVCodecContext * avctx, void *data, int *got_frame,
262  AVPacket *avpkt)
263 {
264  KmvcContext *const ctx = avctx->priv_data;
265  AVFrame *frame = data;
266  uint8_t *out, *src;
267  int i, ret;
268  int header;
269  int blocksize;
270  const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
271 
272  bytestream2_init(&ctx->g, avpkt->data, avpkt->size);
273 
274  if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
275  return ret;
276 
277  header = bytestream2_get_byte(&ctx->g);
278 
279  /* blocksize 127 is really palette change event */
280  if (bytestream2_peek_byte(&ctx->g) == 127) {
281  bytestream2_skip(&ctx->g, 3);
282  for (i = 0; i < 127; i++) {
283  ctx->pal[i + (header & 0x81)] = 0xFFU << 24 | bytestream2_get_be24(&ctx->g);
284  bytestream2_skip(&ctx->g, 1);
285  }
286  bytestream2_seek(&ctx->g, -127 * 4 - 3, SEEK_CUR);
287  }
288 
289  if (header & KMVC_KEYFRAME) {
290  frame->key_frame = 1;
291  frame->pict_type = AV_PICTURE_TYPE_I;
292  } else {
293  frame->key_frame = 0;
294  frame->pict_type = AV_PICTURE_TYPE_P;
295  }
296 
297  if (header & KMVC_PALETTE) {
298  frame->palette_has_changed = 1;
299  // palette starts from index 1 and has 127 entries
300  for (i = 1; i <= ctx->palsize; i++) {
301  ctx->pal[i] = 0xFFU << 24 | bytestream2_get_be24(&ctx->g);
302  }
303  }
304 
305  if (pal) {
306  frame->palette_has_changed = 1;
307  memcpy(ctx->pal, pal, AVPALETTE_SIZE);
308  }
309 
310  if (ctx->setpal) {
311  ctx->setpal = 0;
312  frame->palette_has_changed = 1;
313  }
314 
315  /* make the palette available on the way out */
316  memcpy(frame->data[1], ctx->pal, 1024);
317 
318  blocksize = bytestream2_get_byte(&ctx->g);
319 
320  if (blocksize != 8 && blocksize != 127) {
321  av_log(avctx, AV_LOG_ERROR, "Block size = %i\n", blocksize);
322  return AVERROR_INVALIDDATA;
323  }
324  memset(ctx->cur, 0, 320 * 200);
325  switch (header & KMVC_METHOD) {
326  case 0:
327  case 1: // used in palette changed event
328  memcpy(ctx->cur, ctx->prev, 320 * 200);
329  break;
330  case 3:
331  kmvc_decode_intra_8x8(ctx, avctx->width, avctx->height);
332  break;
333  case 4:
334  kmvc_decode_inter_8x8(ctx, avctx->width, avctx->height);
335  break;
336  default:
337  av_log(avctx, AV_LOG_ERROR, "Unknown compression method %i\n", header & KMVC_METHOD);
338  return AVERROR_INVALIDDATA;
339  }
340 
341  out = frame->data[0];
342  src = ctx->cur;
343  for (i = 0; i < avctx->height; i++) {
344  memcpy(out, src, avctx->width);
345  src += 320;
346  out += frame->linesize[0];
347  }
348 
349  /* flip buffers */
350  if (ctx->cur == ctx->frm0) {
351  ctx->cur = ctx->frm1;
352  ctx->prev = ctx->frm0;
353  } else {
354  ctx->cur = ctx->frm0;
355  ctx->prev = ctx->frm1;
356  }
357 
358  *got_frame = 1;
359 
360  /* always report that the buffer was completely consumed */
361  return avpkt->size;
362 }
363 
364 
365 
366 /*
367  * Init kmvc decoder
368  */
369 static av_cold int decode_init(AVCodecContext * avctx)
370 {
371  KmvcContext *const c = avctx->priv_data;
372  int i;
373 
374  c->avctx = avctx;
375 
376  if (avctx->width > 320 || avctx->height > 200) {
377  av_log(avctx, AV_LOG_ERROR, "KMVC supports frames <= 320x200\n");
378  return AVERROR(EINVAL);
379  }
380 
381  c->frm0 = av_mallocz(320 * 200);
382  c->frm1 = av_mallocz(320 * 200);
383  c->cur = c->frm0;
384  c->prev = c->frm1;
385 
386  for (i = 0; i < 256; i++) {
387  c->pal[i] = 0xFFU << 24 | i * 0x10101;
388  }
389 
390  if (avctx->extradata_size < 12) {
391  av_log(avctx, AV_LOG_WARNING,
392  "Extradata missing, decoding may not work properly...\n");
393  c->palsize = 127;
394  } else {
395  c->palsize = AV_RL16(avctx->extradata + 10);
396  if (c->palsize >= (unsigned)MAX_PALSIZE) {
397  c->palsize = 127;
398  av_log(avctx, AV_LOG_ERROR, "KMVC palette too large\n");
399  return AVERROR_INVALIDDATA;
400  }
401  }
402 
403  if (avctx->extradata_size == 1036) { // palette in extradata
404  uint8_t *src = avctx->extradata + 12;
405  for (i = 0; i < 256; i++) {
406  c->pal[i] = AV_RL32(src);
407  src += 4;
408  }
409  c->setpal = 1;
410  }
411 
412  avctx->pix_fmt = AV_PIX_FMT_PAL8;
413 
414  return 0;
415 }
416 
417 
418 
419 /*
420  * Uninit kmvc decoder
421  */
422 static av_cold int decode_end(AVCodecContext * avctx)
423 {
424  KmvcContext *const c = avctx->priv_data;
425 
426  av_freep(&c->frm0);
427  av_freep(&c->frm1);
428 
429  return 0;
430 }
431 
432 AVCodec ff_kmvc_decoder = {
433  .name = "kmvc",
434  .type = AVMEDIA_TYPE_VIDEO,
435  .id = AV_CODEC_ID_KMVC,
436  .priv_data_size = sizeof(KmvcContext),
437  .init = decode_init,
438  .close = decode_end,
439  .decode = decode_frame,
440  .capabilities = CODEC_CAP_DR1,
441  .long_name = NULL_IF_CONFIG_SMALL("Karl Morton's video codec"),
442 };
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