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g2meet.c
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1 /*
2  * Go2Webinar decoder
3  * Copyright (c) 2012 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  * Go2Webinar decoder
25  */
26 
27 #include <zlib.h>
28 
29 #include "libavutil/intreadwrite.h"
30 #include "avcodec.h"
31 #include "bytestream.h"
32 #include "dsputil.h"
33 #include "get_bits.h"
34 #include "internal.h"
35 #include "mjpeg.h"
36 
37 enum ChunkType {
38  FRAME_INFO = 0xC8,
39  TILE_DATA,
40  CURSOR_POS,
41  CURSOR_SHAPE,
42  CHUNK_CC,
43  CHUNK_CD
44 };
45 
46 enum Compression {
47  COMPR_EPIC_J_B = 2,
48  COMPR_KEMPF_J_B,
49 };
50 
51 static const uint8_t luma_quant[64] = {
52  8, 6, 5, 8, 12, 20, 26, 31,
53  6, 6, 7, 10, 13, 29, 30, 28,
54  7, 7, 8, 12, 20, 29, 35, 28,
55  7, 9, 11, 15, 26, 44, 40, 31,
56  9, 11, 19, 28, 34, 55, 52, 39,
57  12, 18, 28, 32, 41, 52, 57, 46,
58  25, 32, 39, 44, 52, 61, 60, 51,
59  36, 46, 48, 49, 56, 50, 52, 50
60 };
61 
62 static const uint8_t chroma_quant[64] = {
63  9, 9, 12, 24, 50, 50, 50, 50,
64  9, 11, 13, 33, 50, 50, 50, 50,
65  12, 13, 28, 50, 50, 50, 50, 50,
66  24, 33, 50, 50, 50, 50, 50, 50,
67  50, 50, 50, 50, 50, 50, 50, 50,
68  50, 50, 50, 50, 50, 50, 50, 50,
69  50, 50, 50, 50, 50, 50, 50, 50,
70  50, 50, 50, 50, 50, 50, 50, 50,
71 };
72 
73 typedef struct JPGContext {
74  DSPContext dsp;
75  ScanTable scantable;
76 
77  VLC dc_vlc[2], ac_vlc[2];
78  int prev_dc[3];
79  DECLARE_ALIGNED(16, int16_t, block)[6][64];
80 
81  uint8_t *buf;
82 } JPGContext;
83 
84 typedef struct G2MContext {
85  JPGContext jc;
86  int version;
87 
88  int compression;
89  int width, height, bpp;
90  int tile_width, tile_height;
91  int tiles_x, tiles_y, tile_x, tile_y;
92 
93  int got_header;
94 
95  uint8_t *framebuf;
96  int framebuf_stride, old_width, old_height;
97 
98  uint8_t *synth_tile, *jpeg_tile;
99  int tile_stride, old_tile_w, old_tile_h;
100 
101  uint8_t *kempf_buf, *kempf_flags;
102 
103  uint8_t *cursor;
104  int cursor_stride;
105  int cursor_fmt;
106  int cursor_w, cursor_h, cursor_x, cursor_y;
107  int cursor_hot_x, cursor_hot_y;
108 } G2MContext;
109 
110 static av_cold int build_vlc(VLC *vlc, const uint8_t *bits_table,
111  const uint8_t *val_table, int nb_codes,
112  int is_ac)
113 {
114  uint8_t huff_size[256] = { 0 };
115  uint16_t huff_code[256];
116  uint16_t huff_sym[256];
117  int i;
118 
119  ff_mjpeg_build_huffman_codes(huff_size, huff_code, bits_table, val_table);
120 
121  for (i = 0; i < 256; i++)
122  huff_sym[i] = i + 16 * is_ac;
123 
124  if (is_ac)
125  huff_sym[0] = 16 * 256;
126 
127  return ff_init_vlc_sparse(vlc, 9, nb_codes, huff_size, 1, 1,
128  huff_code, 2, 2, huff_sym, 2, 2, 0);
129 }
130 
131 static av_cold int jpg_init(AVCodecContext *avctx, JPGContext *c)
132 {
133  int ret;
134 
135  ret = build_vlc(&c->dc_vlc[0], avpriv_mjpeg_bits_dc_luminance,
136  avpriv_mjpeg_val_dc, 12, 0);
137  if (ret)
138  return ret;
139  ret = build_vlc(&c->dc_vlc[1], avpriv_mjpeg_bits_dc_chrominance,
140  avpriv_mjpeg_val_dc, 12, 0);
141  if (ret)
142  return ret;
143  ret = build_vlc(&c->ac_vlc[0], avpriv_mjpeg_bits_ac_luminance,
144  avpriv_mjpeg_val_ac_luminance, 251, 1);
145  if (ret)
146  return ret;
147  ret = build_vlc(&c->ac_vlc[1], avpriv_mjpeg_bits_ac_chrominance,
148  avpriv_mjpeg_val_ac_chrominance, 251, 1);
149  if (ret)
150  return ret;
151 
152  ff_dsputil_init(&c->dsp, avctx);
153  ff_init_scantable(c->dsp.idct_permutation, &c->scantable,
154  ff_zigzag_direct);
155 
156  return 0;
157 }
158 
159 static av_cold void jpg_free_context(JPGContext *ctx)
160 {
161  int i;
162 
163  for (i = 0; i < 2; i++) {
164  ff_free_vlc(&ctx->dc_vlc[i]);
165  ff_free_vlc(&ctx->ac_vlc[i]);
166  }
167 
168  av_freep(&ctx->buf);
169 }
170 
171 static void jpg_unescape(const uint8_t *src, int src_size,
172  uint8_t *dst, int *dst_size)
173 {
174  const uint8_t *src_end = src + src_size;
175  uint8_t *dst_start = dst;
176 
177  while (src < src_end) {
178  uint8_t x = *src++;
179 
180  *dst++ = x;
181 
182  if (x == 0xFF && !*src)
183  src++;
184  }
185  *dst_size = dst - dst_start;
186 }
187 
188 static int jpg_decode_block(JPGContext *c, GetBitContext *gb,
189  int plane, int16_t *block)
190 {
191  int dc, val, pos;
192  const int is_chroma = !!plane;
193  const uint8_t *qmat = is_chroma ? chroma_quant : luma_quant;
194 
195  c->dsp.clear_block(block);
196  dc = get_vlc2(gb, c->dc_vlc[is_chroma].table, 9, 3);
197  if (dc < 0)
198  return AVERROR_INVALIDDATA;
199  if (dc)
200  dc = get_xbits(gb, dc);
201  dc = dc * qmat[0] + c->prev_dc[plane];
202  block[0] = dc;
203  c->prev_dc[plane] = dc;
204 
205  pos = 0;
206  while (pos < 63) {
207  val = get_vlc2(gb, c->ac_vlc[is_chroma].table, 9, 3);
208  if (val < 0)
209  return AVERROR_INVALIDDATA;
210  pos += val >> 4;
211  val &= 0xF;
212  if (pos > 63)
213  return val ? AVERROR_INVALIDDATA : 0;
214  if (val) {
215  int nbits = val;
216 
217  val = get_xbits(gb, nbits);
218  val *= qmat[ff_zigzag_direct[pos]];
219  block[c->scantable.permutated[pos]] = val;
220  }
221  }
222  return 0;
223 }
224 
225 static inline void yuv2rgb(uint8_t *out, int Y, int U, int V)
226 {
227  out[0] = av_clip_uint8(Y + ( 91881 * V + 32768 >> 16));
228  out[1] = av_clip_uint8(Y + (-22554 * U - 46802 * V + 32768 >> 16));
229  out[2] = av_clip_uint8(Y + (116130 * U + 32768 >> 16));
230 }
231 
232 static int jpg_decode_data(JPGContext *c, int width, int height,
233  const uint8_t *src, int src_size,
234  uint8_t *dst, int dst_stride,
235  const uint8_t *mask, int mask_stride, int num_mbs,
236  int swapuv)
237 {
238  GetBitContext gb;
239  uint8_t *tmp;
240  int mb_w, mb_h, mb_x, mb_y, i, j;
241  int bx, by;
242  int unesc_size;
243  int ret;
244 
245  tmp = av_realloc(c->buf, src_size + FF_INPUT_BUFFER_PADDING_SIZE);
246  if (!tmp)
247  return AVERROR(ENOMEM);
248  c->buf = tmp;
249  jpg_unescape(src, src_size, c->buf, &unesc_size);
250  memset(c->buf + unesc_size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
251  init_get_bits(&gb, c->buf, unesc_size * 8);
252 
253  width = FFALIGN(width, 16);
254  mb_w = width >> 4;
255  mb_h = (height + 15) >> 4;
256 
257  if (!num_mbs)
258  num_mbs = mb_w * mb_h;
259 
260  for (i = 0; i < 3; i++)
261  c->prev_dc[i] = 1024;
262  bx = by = 0;
263  for (mb_y = 0; mb_y < mb_h; mb_y++) {
264  for (mb_x = 0; mb_x < mb_w; mb_x++) {
265  if (mask && !mask[mb_x]) {
266  bx += 16;
267  continue;
268  }
269  for (j = 0; j < 2; j++) {
270  for (i = 0; i < 2; i++) {
271  if ((ret = jpg_decode_block(c, &gb, 0,
272  c->block[i + j * 2])) != 0)
273  return ret;
274  c->dsp.idct(c->block[i + j * 2]);
275  }
276  }
277  for (i = 1; i < 3; i++) {
278  if ((ret = jpg_decode_block(c, &gb, i, c->block[i + 3])) != 0)
279  return ret;
280  c->dsp.idct(c->block[i + 3]);
281  }
282 
283  for (j = 0; j < 16; j++) {
284  uint8_t *out = dst + bx * 3 + (by + j) * dst_stride;
285  for (i = 0; i < 16; i++) {
286  int Y, U, V;
287 
288  Y = c->block[(j >> 3) * 2 + (i >> 3)][(i & 7) + (j & 7) * 8];
289  U = c->block[4 ^ swapuv][(i >> 1) + (j >> 1) * 8] - 128;
290  V = c->block[5 ^ swapuv][(i >> 1) + (j >> 1) * 8] - 128;
291  yuv2rgb(out + i * 3, Y, U, V);
292  }
293  }
294 
295  if (!--num_mbs)
296  return 0;
297  bx += 16;
298  }
299  bx = 0;
300  by += 16;
301  if (mask)
302  mask += mask_stride;
303  }
304 
305  return 0;
306 }
307 
308 static void kempf_restore_buf(const uint8_t *src, int len,
309  uint8_t *dst, int stride,
310  const uint8_t *jpeg_tile, int tile_stride,
311  int width, int height,
312  const uint8_t *pal, int npal, int tidx)
313 {
314  GetBitContext gb;
315  int i, j, nb, col;
316 
317  init_get_bits(&gb, src, len * 8);
318 
319  if (npal <= 2) nb = 1;
320  else if (npal <= 4) nb = 2;
321  else if (npal <= 16) nb = 4;
322  else nb = 8;
323 
324  for (j = 0; j < height; j++, dst += stride, jpeg_tile += tile_stride) {
325  if (get_bits(&gb, 8))
326  continue;
327  for (i = 0; i < width; i++) {
328  col = get_bits(&gb, nb);
329  if (col != tidx)
330  memcpy(dst + i * 3, pal + col * 3, 3);
331  else
332  memcpy(dst + i * 3, jpeg_tile + i * 3, 3);
333  }
334  }
335 }
336 
337 static int kempf_decode_tile(G2MContext *c, int tile_x, int tile_y,
338  const uint8_t *src, int src_size)
339 {
340  int width, height;
341  int hdr, zsize, npal, tidx = -1, ret;
342  int i, j;
343  const uint8_t *src_end = src + src_size;
344  uint8_t pal[768], transp[3];
345  uLongf dlen = (c->tile_width + 1) * c->tile_height;
346  int sub_type;
347  int nblocks, cblocks, bstride;
348  int bits, bitbuf, coded;
349  uint8_t *dst = c->framebuf + tile_x * c->tile_width * 3 +
350  tile_y * c->tile_height * c->framebuf_stride;
351 
352  if (src_size < 2)
353  return AVERROR_INVALIDDATA;
354 
355  width = FFMIN(c->width - tile_x * c->tile_width, c->tile_width);
356  height = FFMIN(c->height - tile_y * c->tile_height, c->tile_height);
357 
358  hdr = *src++;
359  sub_type = hdr >> 5;
360  if (sub_type == 0) {
361  int j;
362  memcpy(transp, src, 3);
363  src += 3;
364  for (j = 0; j < height; j++, dst += c->framebuf_stride)
365  for (i = 0; i < width; i++)
366  memcpy(dst + i * 3, transp, 3);
367  return 0;
368  } else if (sub_type == 1) {
369  return jpg_decode_data(&c->jc, width, height, src, src_end - src,
370  dst, c->framebuf_stride, NULL, 0, 0, 0);
371  }
372 
373  if (sub_type != 2) {
374  memcpy(transp, src, 3);
375  src += 3;
376  }
377  npal = *src++ + 1;
378  memcpy(pal, src, npal * 3); src += npal * 3;
379  if (sub_type != 2) {
380  for (i = 0; i < npal; i++) {
381  if (!memcmp(pal + i * 3, transp, 3)) {
382  tidx = i;
383  break;
384  }
385  }
386  }
387 
388  if (src_end - src < 2)
389  return 0;
390  zsize = (src[0] << 8) | src[1]; src += 2;
391 
392  if (src_end - src < zsize)
393  return AVERROR_INVALIDDATA;
394 
395  ret = uncompress(c->kempf_buf, &dlen, src, zsize);
396  if (ret)
397  return AVERROR_INVALIDDATA;
398  src += zsize;
399 
400  if (sub_type == 2) {
401  kempf_restore_buf(c->kempf_buf, dlen, dst, c->framebuf_stride,
402  NULL, 0, width, height, pal, npal, tidx);
403  return 0;
404  }
405 
406  nblocks = *src++ + 1;
407  cblocks = 0;
408  bstride = FFALIGN(width, 16) >> 4;
409  // blocks are coded LSB and we need normal bitreader for JPEG data
410  bits = 0;
411  for (i = 0; i < (FFALIGN(height, 16) >> 4); i++) {
412  for (j = 0; j < (FFALIGN(width, 16) >> 4); j++) {
413  if (!bits) {
414  bitbuf = *src++;
415  bits = 8;
416  }
417  coded = bitbuf & 1;
418  bits--;
419  bitbuf >>= 1;
420  cblocks += coded;
421  if (cblocks > nblocks)
422  return AVERROR_INVALIDDATA;
423  c->kempf_flags[j + i * bstride] = coded;
424  }
425  }
426 
427  memset(c->jpeg_tile, 0, c->tile_stride * height);
428  jpg_decode_data(&c->jc, width, height, src, src_end - src,
429  c->jpeg_tile, c->tile_stride,
430  c->kempf_flags, bstride, nblocks, 0);
431 
432  kempf_restore_buf(c->kempf_buf, dlen, dst, c->framebuf_stride,
433  c->jpeg_tile, c->tile_stride,
434  width, height, pal, npal, tidx);
435 
436  return 0;
437 }
438 
439 static int g2m_init_buffers(G2MContext *c)
440 {
441  int aligned_height;
442 
443  if (!c->framebuf || c->old_width < c->width || c->old_height < c->height) {
444  c->framebuf_stride = FFALIGN(c->width * 3, 16);
445  aligned_height = FFALIGN(c->height, 16);
446  av_free(c->framebuf);
447  c->framebuf = av_mallocz(c->framebuf_stride * aligned_height);
448  if (!c->framebuf)
449  return AVERROR(ENOMEM);
450  }
451  if (!c->synth_tile || !c->jpeg_tile ||
452  c->old_tile_w < c->tile_width ||
453  c->old_tile_h < c->tile_height) {
454  c->tile_stride = FFALIGN(c->tile_width * 3, 16);
455  aligned_height = FFALIGN(c->tile_height, 16);
456  av_free(c->synth_tile);
457  av_free(c->jpeg_tile);
458  av_free(c->kempf_buf);
459  av_free(c->kempf_flags);
460  c->synth_tile = av_mallocz(c->tile_stride * aligned_height);
461  c->jpeg_tile = av_mallocz(c->tile_stride * aligned_height);
462  c->kempf_buf = av_mallocz((c->tile_width + 1) * aligned_height
463  + FF_INPUT_BUFFER_PADDING_SIZE);
464  c->kempf_flags = av_mallocz( c->tile_width * aligned_height);
465  if (!c->synth_tile || !c->jpeg_tile ||
466  !c->kempf_buf || !c->kempf_flags)
467  return AVERROR(ENOMEM);
468  }
469 
470  return 0;
471 }
472 
473 static int g2m_load_cursor(AVCodecContext *avctx, G2MContext *c,
474  GetByteContext *gb)
475 {
476  int i, j, k;
477  uint8_t *dst;
478  uint32_t bits;
479  uint32_t cur_size, cursor_w, cursor_h, cursor_stride;
480  uint32_t cursor_hot_x, cursor_hot_y;
481  int cursor_fmt;
482  uint8_t *tmp;
483 
484  cur_size = bytestream2_get_be32(gb);
485  cursor_w = bytestream2_get_byte(gb);
486  cursor_h = bytestream2_get_byte(gb);
487  cursor_hot_x = bytestream2_get_byte(gb);
488  cursor_hot_y = bytestream2_get_byte(gb);
489  cursor_fmt = bytestream2_get_byte(gb);
490 
491  cursor_stride = cursor_w * 4;
492 
493  if (cursor_w < 1 || cursor_w > 256 ||
494  cursor_h < 1 || cursor_h > 256) {
495  av_log(avctx, AV_LOG_ERROR, "Invalid cursor dimensions %dx%d\n",
496  cursor_w, cursor_h);
497  return AVERROR_INVALIDDATA;
498  }
499  if (cursor_hot_x > cursor_w || cursor_hot_y > cursor_h) {
500  av_log(avctx, AV_LOG_WARNING, "Invalid hotspot position %d,%d\n",
501  cursor_hot_x, cursor_hot_y);
502  cursor_hot_x = FFMIN(cursor_hot_x, cursor_w - 1);
503  cursor_hot_y = FFMIN(cursor_hot_y, cursor_h - 1);
504  }
505  if (cur_size - 9 > bytestream2_get_bytes_left(gb) ||
506  c->cursor_w * c->cursor_h / 4 > cur_size) {
507  av_log(avctx, AV_LOG_ERROR, "Invalid cursor data size %d/%d\n",
508  cur_size, bytestream2_get_bytes_left(gb));
509  return AVERROR_INVALIDDATA;
510  }
511  if (cursor_fmt != 1 && cursor_fmt != 32) {
512  avpriv_report_missing_feature(avctx, "Cursor format %d",
513  cursor_fmt);
514  return AVERROR_PATCHWELCOME;
515  }
516 
517  if (cursor_fmt == 1 && cursor_w % 32) {
518  avpriv_report_missing_feature(avctx, "odd monochrome cursor width %d", cursor_w);
519  return AVERROR_PATCHWELCOME;
520  }
521 
522  tmp = av_realloc(c->cursor, cursor_stride * cursor_h);
523  if (!tmp) {
524  av_log(avctx, AV_LOG_ERROR, "Cannot allocate cursor buffer\n");
525  return AVERROR(ENOMEM);
526  }
527 
528  c->cursor = tmp;
529  c->cursor_w = cursor_w;
530  c->cursor_h = cursor_h;
531  c->cursor_hot_x = cursor_hot_x;
532  c->cursor_hot_y = cursor_hot_y;
533  c->cursor_fmt = cursor_fmt;
534  c->cursor_stride = cursor_stride;
535 
536  dst = c->cursor;
537  switch (c->cursor_fmt) {
538  case 1: // old monochrome
539  for (j = 0; j < c->cursor_h; j++) {
540  for (i = 0; i < c->cursor_w; i += 32) {
541  bits = bytestream2_get_be32(gb);
542  for (k = 0; k < 32; k++) {
543  dst[0] = !!(bits & 0x80000000);
544  dst += 4;
545  bits <<= 1;
546  }
547  }
548  }
549 
550  dst = c->cursor;
551  for (j = 0; j < c->cursor_h; j++) {
552  for (i = 0; i < c->cursor_w; i += 32) {
553  bits = bytestream2_get_be32(gb);
554  for (k = 0; k < 32; k++) {
555  int mask_bit = !!(bits & 0x80000000);
556  switch (dst[0] * 2 + mask_bit) {
557  case 0:
558  dst[0] = 0xFF; dst[1] = 0x00;
559  dst[2] = 0x00; dst[3] = 0x00;
560  break;
561  case 1:
562  dst[0] = 0xFF; dst[1] = 0xFF;
563  dst[2] = 0xFF; dst[3] = 0xFF;
564  break;
565  default:
566  dst[0] = 0x00; dst[1] = 0x00;
567  dst[2] = 0x00; dst[3] = 0x00;
568  }
569  dst += 4;
570  bits <<= 1;
571  }
572  }
573  }
574  break;
575  case 32: // full colour
576  /* skip monochrome version of the cursor and decode RGBA instead */
577  bytestream2_skip(gb, c->cursor_h * (FFALIGN(c->cursor_w, 32) >> 3));
578  for (j = 0; j < c->cursor_h; j++) {
579  for (i = 0; i < c->cursor_w; i++) {
580  int val = bytestream2_get_be32(gb);
581  *dst++ = val >> 0;
582  *dst++ = val >> 8;
583  *dst++ = val >> 16;
584  *dst++ = val >> 24;
585  }
586  }
587  break;
588  default:
589  return AVERROR_PATCHWELCOME;
590  }
591  return 0;
592 }
593 
594 #define APPLY_ALPHA(src, new, alpha) \
595  src = (src * (256 - alpha) + new * alpha) >> 8
596 
597 static void g2m_paint_cursor(G2MContext *c, uint8_t *dst, int stride)
598 {
599  int i, j;
600  int x, y, w, h;
601  const uint8_t *cursor;
602 
603  if (!c->cursor)
604  return;
605 
606  x = c->cursor_x - c->cursor_hot_x;
607  y = c->cursor_y - c->cursor_hot_y;
608 
609  cursor = c->cursor;
610  w = c->cursor_w;
611  h = c->cursor_h;
612 
613  if (x + w > c->width)
614  w = c->width - x;
615  if (y + h > c->height)
616  h = c->height - y;
617  if (x < 0) {
618  w += x;
619  cursor += -x * 4;
620  } else {
621  dst += x * 3;
622  }
623  if (y < 0) {
624  h += y;
625  cursor += -y * c->cursor_stride;
626  } else {
627  dst += y * stride;
628  }
629  if (w < 0 || h < 0)
630  return;
631 
632  for (j = 0; j < h; j++) {
633  for (i = 0; i < w; i++) {
634  uint8_t alpha = cursor[i * 4];
635  APPLY_ALPHA(dst[i * 3 + 0], cursor[i * 4 + 1], alpha);
636  APPLY_ALPHA(dst[i * 3 + 1], cursor[i * 4 + 2], alpha);
637  APPLY_ALPHA(dst[i * 3 + 2], cursor[i * 4 + 3], alpha);
638  }
639  dst += stride;
640  cursor += c->cursor_stride;
641  }
642 }
643 
644 static int g2m_decode_frame(AVCodecContext *avctx, void *data,
645  int *got_picture_ptr, AVPacket *avpkt)
646 {
647  const uint8_t *buf = avpkt->data;
648  int buf_size = avpkt->size;
649  G2MContext *c = avctx->priv_data;
650  AVFrame *pic = data;
651  GetByteContext bc, tbc;
652  int magic;
653  int got_header = 0;
654  uint32_t chunk_size;
655  int chunk_type;
656  int i;
657  int ret;
658 
659  if (buf_size < 12) {
660  av_log(avctx, AV_LOG_ERROR,
661  "Frame should have at least 12 bytes, got %d instead\n",
662  buf_size);
663  return AVERROR_INVALIDDATA;
664  }
665 
666  bytestream2_init(&bc, buf, buf_size);
667 
668  magic = bytestream2_get_be32(&bc);
669  if ((magic & ~0xF) != MKBETAG('G', '2', 'M', '0') ||
670  (magic & 0xF) < 2 || (magic & 0xF) > 4) {
671  av_log(avctx, AV_LOG_ERROR, "Wrong magic %08X\n", magic);
672  return AVERROR_INVALIDDATA;
673  }
674 
675  if ((magic & 0xF) != 4) {
676  av_log(avctx, AV_LOG_ERROR, "G2M2 and G2M3 are not yet supported\n");
677  return AVERROR(ENOSYS);
678  }
679 
680  while (bytestream2_get_bytes_left(&bc) > 5) {
681  chunk_size = bytestream2_get_le32(&bc) - 1;
682  chunk_type = bytestream2_get_byte(&bc);
683  if (chunk_size > bytestream2_get_bytes_left(&bc)) {
684  av_log(avctx, AV_LOG_ERROR, "Invalid chunk size %d type %02X\n",
685  chunk_size, chunk_type);
686  break;
687  }
688  switch (chunk_type) {
689  case FRAME_INFO:
690  c->got_header = 0;
691  if (chunk_size < 21) {
692  av_log(avctx, AV_LOG_ERROR, "Invalid frame info size %d\n",
693  chunk_size);
694  break;
695  }
696  c->width = bytestream2_get_be32(&bc);
697  c->height = bytestream2_get_be32(&bc);
698  if (c->width < 16 || c->width > avctx->width ||
699  c->height < 16 || c->height > avctx->height) {
700  av_log(avctx, AV_LOG_ERROR,
701  "Invalid frame dimensions %dx%d\n",
702  c->width, c->height);
703  ret = AVERROR_INVALIDDATA;
704  goto header_fail;
705  }
706  if (c->width != avctx->width || c->height != avctx->height)
707  avcodec_set_dimensions(avctx, c->width, c->height);
708  c->compression = bytestream2_get_be32(&bc);
709  if (c->compression != 2 && c->compression != 3) {
710  av_log(avctx, AV_LOG_ERROR,
711  "Unknown compression method %d\n",
712  c->compression);
713  return AVERROR_PATCHWELCOME;
714  }
715  c->tile_width = bytestream2_get_be32(&bc);
716  c->tile_height = bytestream2_get_be32(&bc);
717  if (!c->tile_width || !c->tile_height) {
718  av_log(avctx, AV_LOG_ERROR,
719  "Invalid tile dimensions %dx%d\n",
720  c->tile_width, c->tile_height);
721  ret = AVERROR_INVALIDDATA;
722  goto header_fail;
723  }
724  c->tiles_x = (c->width + c->tile_width - 1) / c->tile_width;
725  c->tiles_y = (c->height + c->tile_height - 1) / c->tile_height;
726  c->bpp = bytestream2_get_byte(&bc);
727  chunk_size -= 21;
728  bytestream2_skip(&bc, chunk_size);
729  if (g2m_init_buffers(c)) {
730  ret = AVERROR(ENOMEM);
731  goto header_fail;
732  }
733  got_header = 1;
734  break;
735  case TILE_DATA:
736  if (!c->tiles_x || !c->tiles_y) {
737  av_log(avctx, AV_LOG_WARNING,
738  "No frame header - skipping tile\n");
739  bytestream2_skip(&bc, bytestream2_get_bytes_left(&bc));
740  break;
741  }
742  if (chunk_size < 2) {
743  av_log(avctx, AV_LOG_ERROR, "Invalid tile data size %d\n",
744  chunk_size);
745  break;
746  }
747  c->tile_x = bytestream2_get_byte(&bc);
748  c->tile_y = bytestream2_get_byte(&bc);
749  if (c->tile_x >= c->tiles_x || c->tile_y >= c->tiles_y) {
750  av_log(avctx, AV_LOG_ERROR,
751  "Invalid tile pos %d,%d (in %dx%d grid)\n",
752  c->tile_x, c->tile_y, c->tiles_x, c->tiles_y);
753  break;
754  }
755  chunk_size -= 2;
756  ret = 0;
757  switch (c->compression) {
758  case COMPR_EPIC_J_B:
759  av_log(avctx, AV_LOG_ERROR,
760  "ePIC j-b compression is not implemented yet\n");
761  return AVERROR(ENOSYS);
762  case COMPR_KEMPF_J_B:
763  ret = kempf_decode_tile(c, c->tile_x, c->tile_y,
764  buf + bytestream2_tell(&bc),
765  chunk_size);
766  break;
767  }
768  if (ret && c->framebuf)
769  av_log(avctx, AV_LOG_ERROR, "Error decoding tile %d,%d\n",
770  c->tile_x, c->tile_y);
771  bytestream2_skip(&bc, chunk_size);
772  break;
773  case CURSOR_POS:
774  if (chunk_size < 5) {
775  av_log(avctx, AV_LOG_ERROR, "Invalid cursor pos size %d\n",
776  chunk_size);
777  break;
778  }
779  c->cursor_x = bytestream2_get_be16(&bc);
780  c->cursor_y = bytestream2_get_be16(&bc);
781  bytestream2_skip(&bc, chunk_size - 4);
782  break;
783  case CURSOR_SHAPE:
784  if (chunk_size < 8) {
785  av_log(avctx, AV_LOG_ERROR, "Invalid cursor data size %d\n",
786  chunk_size);
787  break;
788  }
789  bytestream2_init(&tbc, buf + bytestream2_tell(&bc),
790  chunk_size - 4);
791  g2m_load_cursor(avctx, c, &tbc);
792  bytestream2_skip(&bc, chunk_size);
793  break;
794  case CHUNK_CC:
795  case CHUNK_CD:
796  bytestream2_skip(&bc, chunk_size);
797  break;
798  default:
799  av_log(avctx, AV_LOG_WARNING, "Skipping chunk type %02X\n",
800  chunk_type);
801  bytestream2_skip(&bc, chunk_size);
802  }
803  }
804  if (got_header)
805  c->got_header = 1;
806 
807  if (c->width && c->height && c->framebuf) {
808  if ((ret = ff_get_buffer(avctx, pic, 0)) < 0) {
809  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
810  return ret;
811  }
812 
813  pic->key_frame = got_header;
814  pic->pict_type = got_header ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;
815 
816  for (i = 0; i < avctx->height; i++)
817  memcpy(pic->data[0] + i * pic->linesize[0],
818  c->framebuf + i * c->framebuf_stride,
819  c->width * 3);
820  g2m_paint_cursor(c, pic->data[0], pic->linesize[0]);
821 
822  *got_picture_ptr = 1;
823  }
824 
825  return buf_size;
826 header_fail:
827  c->width = c->height = 0;
828  c->tiles_x = c->tiles_y = 0;
829  return ret;
830 }
831 
832 static av_cold int g2m_decode_init(AVCodecContext *avctx)
833 {
834  G2MContext * const c = avctx->priv_data;
835  int ret;
836 
837  if ((ret = jpg_init(avctx, &c->jc)) != 0) {
838  av_log(avctx, AV_LOG_ERROR, "Cannot initialise VLCs\n");
839  jpg_free_context(&c->jc);
840  return AVERROR(ENOMEM);
841  }
842 
843  avctx->pix_fmt = AV_PIX_FMT_RGB24;
844 
845  return 0;
846 }
847 
848 static av_cold int g2m_decode_end(AVCodecContext *avctx)
849 {
850  G2MContext * const c = avctx->priv_data;
851 
852  jpg_free_context(&c->jc);
853 
854  av_freep(&c->kempf_buf);
855  av_freep(&c->kempf_flags);
856  av_freep(&c->synth_tile);
857  av_freep(&c->jpeg_tile);
858  av_freep(&c->cursor);
859  av_freep(&c->framebuf);
860 
861  return 0;
862 }
863 
864 AVCodec ff_g2m_decoder = {
865  .name = "g2m",
866  .long_name = NULL_IF_CONFIG_SMALL("Go2Meeting"),
867  .type = AVMEDIA_TYPE_VIDEO,
868  .id = AV_CODEC_ID_G2M,
869  .priv_data_size = sizeof(G2MContext),
870  .init = g2m_decode_init,
871  .close = g2m_decode_end,
872  .decode = g2m_decode_frame,
873  .capabilities = CODEC_CAP_DR1,
874 };
Generated on Wed Jul 10 2013 23:47:58 for FFmpeg by   doxygen 1.8.2