FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
g2meet.c
Go to the documentation of this file.
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 <inttypes.h>
28 #include <zlib.h>
29 
30 #include "libavutil/intreadwrite.h"
31 #include "avcodec.h"
32 #include "blockdsp.h"
33 #include "bytestream.h"
34 #include "idctdsp.h"
35 #include "get_bits.h"
36 #include "internal.h"
37 #include "mjpeg.h"
38 
39 enum ChunkType {
40  DISPLAY_INFO = 0xC8,
41  TILE_DATA,
42  CURSOR_POS,
43  CURSOR_SHAPE,
44  CHUNK_CC,
45  CHUNK_CD
46 };
47 
48 enum Compression {
49  COMPR_EPIC_J_B = 2,
50  COMPR_KEMPF_J_B,
51 };
52 
53 static const uint8_t luma_quant[64] = {
54  8, 6, 5, 8, 12, 20, 26, 31,
55  6, 6, 7, 10, 13, 29, 30, 28,
56  7, 7, 8, 12, 20, 29, 35, 28,
57  7, 9, 11, 15, 26, 44, 40, 31,
58  9, 11, 19, 28, 34, 55, 52, 39,
59  12, 18, 28, 32, 41, 52, 57, 46,
60  25, 32, 39, 44, 52, 61, 60, 51,
61  36, 46, 48, 49, 56, 50, 52, 50
62 };
63 
64 static const uint8_t chroma_quant[64] = {
65  9, 9, 12, 24, 50, 50, 50, 50,
66  9, 11, 13, 33, 50, 50, 50, 50,
67  12, 13, 28, 50, 50, 50, 50, 50,
68  24, 33, 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  50, 50, 50, 50, 50, 50, 50, 50,
72  50, 50, 50, 50, 50, 50, 50, 50,
73 };
74 
75 typedef struct JPGContext {
76  BlockDSPContext bdsp;
77  IDCTDSPContext idsp;
78  ScanTable scantable;
79 
80  VLC dc_vlc[2], ac_vlc[2];
81  int prev_dc[3];
82  DECLARE_ALIGNED(16, int16_t, block)[6][64];
83 
84  uint8_t *buf;
85 } JPGContext;
86 
87 typedef struct G2MContext {
88  JPGContext jc;
89  int version;
90 
91  int compression;
92  int width, height, bpp;
93  int orig_width, orig_height;
94  int tile_width, tile_height;
95  int tiles_x, tiles_y, tile_x, tile_y;
96 
97  int got_header;
98 
99  uint8_t *framebuf;
100  int framebuf_stride, old_width, old_height;
101 
102  uint8_t *synth_tile, *jpeg_tile;
103  int tile_stride, old_tile_w, old_tile_h;
104 
105  uint8_t *kempf_buf, *kempf_flags;
106 
107  uint8_t *cursor;
108  int cursor_stride;
109  int cursor_fmt;
110  int cursor_w, cursor_h, cursor_x, cursor_y;
111  int cursor_hot_x, cursor_hot_y;
112 } G2MContext;
113 
114 static av_cold int build_vlc(VLC *vlc, const uint8_t *bits_table,
115  const uint8_t *val_table, int nb_codes,
116  int is_ac)
117 {
118  uint8_t huff_size[256] = { 0 };
119  uint16_t huff_code[256];
120  uint16_t huff_sym[256];
121  int i;
122 
123  ff_mjpeg_build_huffman_codes(huff_size, huff_code, bits_table, val_table);
124 
125  for (i = 0; i < 256; i++)
126  huff_sym[i] = i + 16 * is_ac;
127 
128  if (is_ac)
129  huff_sym[0] = 16 * 256;
130 
131  return ff_init_vlc_sparse(vlc, 9, nb_codes, huff_size, 1, 1,
132  huff_code, 2, 2, huff_sym, 2, 2, 0);
133 }
134 
135 static av_cold int jpg_init(AVCodecContext *avctx, JPGContext *c)
136 {
137  int ret;
138 
139  ret = build_vlc(&c->dc_vlc[0], avpriv_mjpeg_bits_dc_luminance,
140  avpriv_mjpeg_val_dc, 12, 0);
141  if (ret)
142  return ret;
143  ret = build_vlc(&c->dc_vlc[1], avpriv_mjpeg_bits_dc_chrominance,
144  avpriv_mjpeg_val_dc, 12, 0);
145  if (ret)
146  return ret;
147  ret = build_vlc(&c->ac_vlc[0], avpriv_mjpeg_bits_ac_luminance,
148  avpriv_mjpeg_val_ac_luminance, 251, 1);
149  if (ret)
150  return ret;
151  ret = build_vlc(&c->ac_vlc[1], avpriv_mjpeg_bits_ac_chrominance,
152  avpriv_mjpeg_val_ac_chrominance, 251, 1);
153  if (ret)
154  return ret;
155 
156  ff_blockdsp_init(&c->bdsp, avctx);
157  ff_idctdsp_init(&c->idsp, avctx);
158  ff_init_scantable(c->idsp.idct_permutation, &c->scantable,
159  ff_zigzag_direct);
160 
161  return 0;
162 }
163 
164 static av_cold void jpg_free_context(JPGContext *ctx)
165 {
166  int i;
167 
168  for (i = 0; i < 2; i++) {
169  ff_free_vlc(&ctx->dc_vlc[i]);
170  ff_free_vlc(&ctx->ac_vlc[i]);
171  }
172 
173  av_freep(&ctx->buf);
174 }
175 
176 static void jpg_unescape(const uint8_t *src, int src_size,
177  uint8_t *dst, int *dst_size)
178 {
179  const uint8_t *src_end = src + src_size;
180  uint8_t *dst_start = dst;
181 
182  while (src < src_end) {
183  uint8_t x = *src++;
184 
185  *dst++ = x;
186 
187  if (x == 0xFF && !*src)
188  src++;
189  }
190  *dst_size = dst - dst_start;
191 }
192 
193 static int jpg_decode_block(JPGContext *c, GetBitContext *gb,
194  int plane, int16_t *block)
195 {
196  int dc, val, pos;
197  const int is_chroma = !!plane;
198  const uint8_t *qmat = is_chroma ? chroma_quant : luma_quant;
199 
200  c->bdsp.clear_block(block);
201  dc = get_vlc2(gb, c->dc_vlc[is_chroma].table, 9, 3);
202  if (dc < 0)
203  return AVERROR_INVALIDDATA;
204  if (dc)
205  dc = get_xbits(gb, dc);
206  dc = dc * qmat[0] + c->prev_dc[plane];
207  block[0] = dc;
208  c->prev_dc[plane] = dc;
209 
210  pos = 0;
211  while (pos < 63) {
212  val = get_vlc2(gb, c->ac_vlc[is_chroma].table, 9, 3);
213  if (val < 0)
214  return AVERROR_INVALIDDATA;
215  pos += val >> 4;
216  val &= 0xF;
217  if (pos > 63)
218  return val ? AVERROR_INVALIDDATA : 0;
219  if (val) {
220  int nbits = val;
221 
222  val = get_xbits(gb, nbits);
223  val *= qmat[ff_zigzag_direct[pos]];
224  block[c->scantable.permutated[pos]] = val;
225  }
226  }
227  return 0;
228 }
229 
230 static inline void yuv2rgb(uint8_t *out, int Y, int U, int V)
231 {
232  out[0] = av_clip_uint8(Y + ( 91881 * V + 32768 >> 16));
233  out[1] = av_clip_uint8(Y + (-22554 * U - 46802 * V + 32768 >> 16));
234  out[2] = av_clip_uint8(Y + (116130 * U + 32768 >> 16));
235 }
236 
237 static int jpg_decode_data(JPGContext *c, int width, int height,
238  const uint8_t *src, int src_size,
239  uint8_t *dst, int dst_stride,
240  const uint8_t *mask, int mask_stride, int num_mbs,
241  int swapuv)
242 {
243  GetBitContext gb;
244  int mb_w, mb_h, mb_x, mb_y, i, j;
245  int bx, by;
246  int unesc_size;
247  int ret;
248 
249  if ((ret = av_reallocp(&c->buf,
250  src_size + FF_INPUT_BUFFER_PADDING_SIZE)) < 0)
251  return ret;
252  jpg_unescape(src, src_size, c->buf, &unesc_size);
253  memset(c->buf + unesc_size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
254  init_get_bits(&gb, c->buf, unesc_size * 8);
255 
256  width = FFALIGN(width, 16);
257  mb_w = width >> 4;
258  mb_h = (height + 15) >> 4;
259 
260  if (!num_mbs)
261  num_mbs = mb_w * mb_h * 4;
262 
263  for (i = 0; i < 3; i++)
264  c->prev_dc[i] = 1024;
265  bx = by = 0;
266  c->bdsp.clear_blocks(c->block[0]);
267  for (mb_y = 0; mb_y < mb_h; mb_y++) {
268  for (mb_x = 0; mb_x < mb_w; mb_x++) {
269  if (mask && !mask[mb_x * 2] && !mask[mb_x * 2 + 1] &&
270  !mask[mb_x * 2 + mask_stride] &&
271  !mask[mb_x * 2 + 1 + mask_stride]) {
272  bx += 16;
273  continue;
274  }
275  for (j = 0; j < 2; j++) {
276  for (i = 0; i < 2; i++) {
277  if (mask && !mask[mb_x * 2 + i + j * mask_stride])
278  continue;
279  num_mbs--;
280  if ((ret = jpg_decode_block(c, &gb, 0,
281  c->block[i + j * 2])) != 0)
282  return ret;
283  c->idsp.idct(c->block[i + j * 2]);
284  }
285  }
286  for (i = 1; i < 3; i++) {
287  if ((ret = jpg_decode_block(c, &gb, i, c->block[i + 3])) != 0)
288  return ret;
289  c->idsp.idct(c->block[i + 3]);
290  }
291 
292  for (j = 0; j < 16; j++) {
293  uint8_t *out = dst + bx * 3 + (by + j) * dst_stride;
294  for (i = 0; i < 16; i++) {
295  int Y, U, V;
296 
297  Y = c->block[(j >> 3) * 2 + (i >> 3)][(i & 7) + (j & 7) * 8];
298  U = c->block[4 ^ swapuv][(i >> 1) + (j >> 1) * 8] - 128;
299  V = c->block[5 ^ swapuv][(i >> 1) + (j >> 1) * 8] - 128;
300  yuv2rgb(out + i * 3, Y, U, V);
301  }
302  }
303 
304  if (!num_mbs)
305  return 0;
306  bx += 16;
307  }
308  bx = 0;
309  by += 16;
310  if (mask)
311  mask += mask_stride * 2;
312  }
313 
314  return 0;
315 }
316 
317 static void kempf_restore_buf(const uint8_t *src, int len,
318  uint8_t *dst, int stride,
319  const uint8_t *jpeg_tile, int tile_stride,
320  int width, int height,
321  const uint8_t *pal, int npal, int tidx)
322 {
323  GetBitContext gb;
324  int i, j, nb, col;
325 
326  init_get_bits(&gb, src, len * 8);
327 
328  if (npal <= 2) nb = 1;
329  else if (npal <= 4) nb = 2;
330  else if (npal <= 16) nb = 4;
331  else nb = 8;
332 
333  for (j = 0; j < height; j++, dst += stride, jpeg_tile += tile_stride) {
334  if (get_bits(&gb, 8))
335  continue;
336  for (i = 0; i < width; i++) {
337  col = get_bits(&gb, nb);
338  if (col != tidx)
339  memcpy(dst + i * 3, pal + col * 3, 3);
340  else
341  memcpy(dst + i * 3, jpeg_tile + i * 3, 3);
342  }
343  }
344 }
345 
346 static int kempf_decode_tile(G2MContext *c, int tile_x, int tile_y,
347  const uint8_t *src, int src_size)
348 {
349  int width, height;
350  int hdr, zsize, npal, tidx = -1, ret;
351  int i, j;
352  const uint8_t *src_end = src + src_size;
353  uint8_t pal[768], transp[3];
354  uLongf dlen = (c->tile_width + 1) * c->tile_height;
355  int sub_type;
356  int nblocks, cblocks, bstride;
357  int bits, bitbuf, coded;
358  uint8_t *dst = c->framebuf + tile_x * c->tile_width * 3 +
359  tile_y * c->tile_height * c->framebuf_stride;
360 
361  if (src_size < 2)
362  return AVERROR_INVALIDDATA;
363 
364  width = FFMIN(c->width - tile_x * c->tile_width, c->tile_width);
365  height = FFMIN(c->height - tile_y * c->tile_height, c->tile_height);
366 
367  hdr = *src++;
368  sub_type = hdr >> 5;
369  if (sub_type == 0) {
370  int j;
371  memcpy(transp, src, 3);
372  src += 3;
373  for (j = 0; j < height; j++, dst += c->framebuf_stride)
374  for (i = 0; i < width; i++)
375  memcpy(dst + i * 3, transp, 3);
376  return 0;
377  } else if (sub_type == 1) {
378  return jpg_decode_data(&c->jc, width, height, src, src_end - src,
379  dst, c->framebuf_stride, NULL, 0, 0, 0);
380  }
381 
382  if (sub_type != 2) {
383  memcpy(transp, src, 3);
384  src += 3;
385  }
386  npal = *src++ + 1;
387  if (src_end - src < npal * 3)
388  return AVERROR_INVALIDDATA;
389  memcpy(pal, src, npal * 3);
390  src += npal * 3;
391  if (sub_type != 2) {
392  for (i = 0; i < npal; i++) {
393  if (!memcmp(pal + i * 3, transp, 3)) {
394  tidx = i;
395  break;
396  }
397  }
398  }
399 
400  if (src_end - src < 2)
401  return 0;
402  zsize = (src[0] << 8) | src[1];
403  src += 2;
404 
405  if (src_end - src < zsize + (sub_type != 2))
406  return AVERROR_INVALIDDATA;
407 
408  ret = uncompress(c->kempf_buf, &dlen, src, zsize);
409  if (ret)
410  return AVERROR_INVALIDDATA;
411  src += zsize;
412 
413  if (sub_type == 2) {
414  kempf_restore_buf(c->kempf_buf, dlen, dst, c->framebuf_stride,
415  NULL, 0, width, height, pal, npal, tidx);
416  return 0;
417  }
418 
419  nblocks = *src++ + 1;
420  cblocks = 0;
421  bstride = FFALIGN(width, 16) >> 3;
422  // blocks are coded LSB and we need normal bitreader for JPEG data
423  bits = 0;
424  for (i = 0; i < (FFALIGN(height, 16) >> 4); i++) {
425  for (j = 0; j < (FFALIGN(width, 16) >> 4); j++) {
426  if (!bits) {
427  if (src >= src_end)
428  return AVERROR_INVALIDDATA;
429  bitbuf = *src++;
430  bits = 8;
431  }
432  coded = bitbuf & 1;
433  bits--;
434  bitbuf >>= 1;
435  cblocks += coded;
436  if (cblocks > nblocks)
437  return AVERROR_INVALIDDATA;
438  c->kempf_flags[j * 2 + i * 2 * bstride] =
439  c->kempf_flags[j * 2 + 1 + i * 2 * bstride] =
440  c->kempf_flags[j * 2 + (i * 2 + 1) * bstride] =
441  c->kempf_flags[j * 2 + 1 + (i * 2 + 1) * bstride] = coded;
442  }
443  }
444 
445  memset(c->jpeg_tile, 0, c->tile_stride * height);
446  jpg_decode_data(&c->jc, width, height, src, src_end - src,
447  c->jpeg_tile, c->tile_stride,
448  c->kempf_flags, bstride, nblocks * 4, 0);
449 
450  kempf_restore_buf(c->kempf_buf, dlen, dst, c->framebuf_stride,
451  c->jpeg_tile, c->tile_stride,
452  width, height, pal, npal, tidx);
453 
454  return 0;
455 }
456 
457 static int g2m_init_buffers(G2MContext *c)
458 {
459  int aligned_height;
460 
461  if (!c->framebuf || c->old_width < c->width || c->old_height < c->height) {
462  c->framebuf_stride = FFALIGN(c->width + 15, 16) * 3;
463  aligned_height = c->height + 15;
464  av_free(c->framebuf);
465  c->framebuf = av_mallocz(c->framebuf_stride * aligned_height);
466  if (!c->framebuf)
467  return AVERROR(ENOMEM);
468  }
469  if (!c->synth_tile || !c->jpeg_tile ||
470  c->old_tile_w < c->tile_width ||
471  c->old_tile_h < c->tile_height) {
472  c->tile_stride = FFALIGN(c->tile_width, 16) * 3;
473  aligned_height = FFALIGN(c->tile_height, 16);
474  av_free(c->synth_tile);
475  av_free(c->jpeg_tile);
476  av_free(c->kempf_buf);
477  av_free(c->kempf_flags);
478  c->synth_tile = av_mallocz(c->tile_stride * aligned_height);
479  c->jpeg_tile = av_mallocz(c->tile_stride * aligned_height);
480  c->kempf_buf = av_mallocz((c->tile_width + 1) * aligned_height
481  + FF_INPUT_BUFFER_PADDING_SIZE);
482  c->kempf_flags = av_mallocz( c->tile_width * aligned_height);
483  if (!c->synth_tile || !c->jpeg_tile ||
484  !c->kempf_buf || !c->kempf_flags)
485  return AVERROR(ENOMEM);
486  }
487 
488  return 0;
489 }
490 
491 static int g2m_load_cursor(AVCodecContext *avctx, G2MContext *c,
492  GetByteContext *gb)
493 {
494  int i, j, k;
495  uint8_t *dst;
496  uint32_t bits;
497  uint32_t cur_size, cursor_w, cursor_h, cursor_stride;
498  uint32_t cursor_hot_x, cursor_hot_y;
499  int cursor_fmt, err;
500 
501  cur_size = bytestream2_get_be32(gb);
502  cursor_w = bytestream2_get_byte(gb);
503  cursor_h = bytestream2_get_byte(gb);
504  cursor_hot_x = bytestream2_get_byte(gb);
505  cursor_hot_y = bytestream2_get_byte(gb);
506  cursor_fmt = bytestream2_get_byte(gb);
507 
508  cursor_stride = FFALIGN(cursor_w, cursor_fmt==1 ? 32 : 1) * 4;
509 
510  if (cursor_w < 1 || cursor_w > 256 ||
511  cursor_h < 1 || cursor_h > 256) {
512  av_log(avctx, AV_LOG_ERROR, "Invalid cursor dimensions %"PRIu32"x%"PRIu32"\n",
513  cursor_w, cursor_h);
514  return AVERROR_INVALIDDATA;
515  }
516  if (cursor_hot_x > cursor_w || cursor_hot_y > cursor_h) {
517  av_log(avctx, AV_LOG_WARNING, "Invalid hotspot position %"PRIu32",%"PRIu32"\n",
518  cursor_hot_x, cursor_hot_y);
519  cursor_hot_x = FFMIN(cursor_hot_x, cursor_w - 1);
520  cursor_hot_y = FFMIN(cursor_hot_y, cursor_h - 1);
521  }
522  if (cur_size - 9 > bytestream2_get_bytes_left(gb) ||
523  c->cursor_w * c->cursor_h / 4 > cur_size) {
524  av_log(avctx, AV_LOG_ERROR, "Invalid cursor data size %"PRIu32"/%u\n",
525  cur_size, bytestream2_get_bytes_left(gb));
526  return AVERROR_INVALIDDATA;
527  }
528  if (cursor_fmt != 1 && cursor_fmt != 32) {
529  avpriv_report_missing_feature(avctx, "Cursor format %d",
530  cursor_fmt);
531  return AVERROR_PATCHWELCOME;
532  }
533 
534  if ((err = av_reallocp(&c->cursor, cursor_stride * cursor_h)) < 0) {
535  av_log(avctx, AV_LOG_ERROR, "Cannot allocate cursor buffer\n");
536  return err;
537  }
538 
539  c->cursor_w = cursor_w;
540  c->cursor_h = cursor_h;
541  c->cursor_hot_x = cursor_hot_x;
542  c->cursor_hot_y = cursor_hot_y;
543  c->cursor_fmt = cursor_fmt;
544  c->cursor_stride = cursor_stride;
545 
546  dst = c->cursor;
547  switch (c->cursor_fmt) {
548  case 1: // old monochrome
549  for (j = 0; j < c->cursor_h; j++) {
550  for (i = 0; i < c->cursor_w; i += 32) {
551  bits = bytestream2_get_be32(gb);
552  for (k = 0; k < 32; k++) {
553  dst[0] = !!(bits & 0x80000000);
554  dst += 4;
555  bits <<= 1;
556  }
557  }
558  }
559 
560  dst = c->cursor;
561  for (j = 0; j < c->cursor_h; j++) {
562  for (i = 0; i < c->cursor_w; i += 32) {
563  bits = bytestream2_get_be32(gb);
564  for (k = 0; k < 32; k++) {
565  int mask_bit = !!(bits & 0x80000000);
566  switch (dst[0] * 2 + mask_bit) {
567  case 0:
568  dst[0] = 0xFF;
569  dst[1] = 0x00;
570  dst[2] = 0x00;
571  dst[3] = 0x00;
572  break;
573  case 1:
574  dst[0] = 0xFF;
575  dst[1] = 0xFF;
576  dst[2] = 0xFF;
577  dst[3] = 0xFF;
578  break;
579  default:
580  dst[0] = 0x00;
581  dst[1] = 0x00;
582  dst[2] = 0x00;
583  dst[3] = 0x00;
584  }
585  dst += 4;
586  bits <<= 1;
587  }
588  }
589  }
590  break;
591  case 32: // full colour
592  /* skip monochrome version of the cursor and decode RGBA instead */
593  bytestream2_skip(gb, c->cursor_h * (FFALIGN(c->cursor_w, 32) >> 3));
594  for (j = 0; j < c->cursor_h; j++) {
595  for (i = 0; i < c->cursor_w; i++) {
596  int val = bytestream2_get_be32(gb);
597  *dst++ = val >> 0;
598  *dst++ = val >> 8;
599  *dst++ = val >> 16;
600  *dst++ = val >> 24;
601  }
602  }
603  break;
604  default:
605  return AVERROR_PATCHWELCOME;
606  }
607  return 0;
608 }
609 
610 #define APPLY_ALPHA(src, new, alpha) \
611  src = (src * (256 - alpha) + new * alpha) >> 8
612 
613 static void g2m_paint_cursor(G2MContext *c, uint8_t *dst, int stride)
614 {
615  int i, j;
616  int x, y, w, h;
617  const uint8_t *cursor;
618 
619  if (!c->cursor)
620  return;
621 
622  x = c->cursor_x - c->cursor_hot_x;
623  y = c->cursor_y - c->cursor_hot_y;
624 
625  cursor = c->cursor;
626  w = c->cursor_w;
627  h = c->cursor_h;
628 
629  if (x + w > c->width)
630  w = c->width - x;
631  if (y + h > c->height)
632  h = c->height - y;
633  if (x < 0) {
634  w += x;
635  cursor += -x * 4;
636  } else {
637  dst += x * 3;
638  }
639  if (y < 0) {
640  h += y;
641  cursor += -y * c->cursor_stride;
642  } else {
643  dst += y * stride;
644  }
645  if (w < 0 || h < 0)
646  return;
647 
648  for (j = 0; j < h; j++) {
649  for (i = 0; i < w; i++) {
650  uint8_t alpha = cursor[i * 4];
651  APPLY_ALPHA(dst[i * 3 + 0], cursor[i * 4 + 1], alpha);
652  APPLY_ALPHA(dst[i * 3 + 1], cursor[i * 4 + 2], alpha);
653  APPLY_ALPHA(dst[i * 3 + 2], cursor[i * 4 + 3], alpha);
654  }
655  dst += stride;
656  cursor += c->cursor_stride;
657  }
658 }
659 
660 static int g2m_decode_frame(AVCodecContext *avctx, void *data,
661  int *got_picture_ptr, AVPacket *avpkt)
662 {
663  const uint8_t *buf = avpkt->data;
664  int buf_size = avpkt->size;
665  G2MContext *c = avctx->priv_data;
666  AVFrame *pic = data;
667  GetByteContext bc, tbc;
668  int magic;
669  int got_header = 0;
670  uint32_t chunk_size, r_mask, g_mask, b_mask;
671  int chunk_type, chunk_start;
672  int i;
673  int ret;
674 
675  if (buf_size < 12) {
676  av_log(avctx, AV_LOG_ERROR,
677  "Frame should have at least 12 bytes, got %d instead\n",
678  buf_size);
679  return AVERROR_INVALIDDATA;
680  }
681 
682  bytestream2_init(&bc, buf, buf_size);
683 
684  magic = bytestream2_get_be32(&bc);
685  if ((magic & ~0xF) != MKBETAG('G', '2', 'M', '0') ||
686  (magic & 0xF) < 2 || (magic & 0xF) > 4) {
687  av_log(avctx, AV_LOG_ERROR, "Wrong magic %08X\n", magic);
688  return AVERROR_INVALIDDATA;
689  }
690 
691  if ((magic & 0xF) != 4) {
692  av_log(avctx, AV_LOG_ERROR, "G2M2 and G2M3 are not yet supported\n");
693  return AVERROR(ENOSYS);
694  }
695 
696  while (bytestream2_get_bytes_left(&bc) > 5) {
697  chunk_size = bytestream2_get_le32(&bc) - 1;
698  chunk_type = bytestream2_get_byte(&bc);
699  chunk_start = bytestream2_tell(&bc);
700  if (chunk_size > bytestream2_get_bytes_left(&bc)) {
701  av_log(avctx, AV_LOG_ERROR, "Invalid chunk size %"PRIu32" type %02X\n",
702  chunk_size, chunk_type);
703  break;
704  }
705  switch (chunk_type) {
706  case DISPLAY_INFO:
707  got_header =
708  c->got_header = 0;
709  if (chunk_size < 21) {
710  av_log(avctx, AV_LOG_ERROR, "Invalid display info size %"PRIu32"\n",
711  chunk_size);
712  break;
713  }
714  c->width = bytestream2_get_be32(&bc);
715  c->height = bytestream2_get_be32(&bc);
716  if (c->width < 16 || c->width > c->orig_width ||
717  c->height < 16 || c->height > c->orig_height) {
718  av_log(avctx, AV_LOG_ERROR,
719  "Invalid frame dimensions %dx%d\n",
720  c->width, c->height);
721  ret = AVERROR_INVALIDDATA;
722  goto header_fail;
723  }
724  if (c->width != avctx->width || c->height != avctx->height) {
725  ret = ff_set_dimensions(avctx, c->width, c->height);
726  if (ret < 0)
727  goto header_fail;
728  }
729  c->compression = bytestream2_get_be32(&bc);
730  if (c->compression != 2 && c->compression != 3) {
731  av_log(avctx, AV_LOG_ERROR,
732  "Unknown compression method %d\n",
733  c->compression);
734  ret = AVERROR_PATCHWELCOME;
735  goto header_fail;
736  }
737  c->tile_width = bytestream2_get_be32(&bc);
738  c->tile_height = bytestream2_get_be32(&bc);
739  if (!c->tile_width || !c->tile_height ||
740  ((c->tile_width | c->tile_height) & 0xF)) {
741  av_log(avctx, AV_LOG_ERROR,
742  "Invalid tile dimensions %dx%d\n",
743  c->tile_width, c->tile_height);
744  ret = AVERROR_INVALIDDATA;
745  goto header_fail;
746  }
747  c->tiles_x = (c->width + c->tile_width - 1) / c->tile_width;
748  c->tiles_y = (c->height + c->tile_height - 1) / c->tile_height;
749  c->bpp = bytestream2_get_byte(&bc);
750  if (c->bpp == 32) {
751  if (bytestream2_get_bytes_left(&bc) < 16 ||
752  (chunk_size - 21) < 16) {
753  av_log(avctx, AV_LOG_ERROR,
754  "Display info: missing bitmasks!\n");
755  ret = AVERROR_INVALIDDATA;
756  goto header_fail;
757  }
758  r_mask = bytestream2_get_be32(&bc);
759  g_mask = bytestream2_get_be32(&bc);
760  b_mask = bytestream2_get_be32(&bc);
761  if (r_mask != 0xFF0000 || g_mask != 0xFF00 || b_mask != 0xFF) {
762  av_log(avctx, AV_LOG_ERROR,
763  "Invalid or unsupported bitmasks: R=%"PRIX32", G=%"PRIX32", B=%"PRIX32"\n",
764  r_mask, g_mask, b_mask);
765  ret = AVERROR_PATCHWELCOME;
766  goto header_fail;
767  }
768  } else {
769  avpriv_request_sample(avctx, "bpp=%d", c->bpp);
770  ret = AVERROR_PATCHWELCOME;
771  goto header_fail;
772  }
773  if (g2m_init_buffers(c)) {
774  ret = AVERROR(ENOMEM);
775  goto header_fail;
776  }
777  got_header = 1;
778  break;
779  case TILE_DATA:
780  if (!c->tiles_x || !c->tiles_y) {
781  av_log(avctx, AV_LOG_WARNING,
782  "No display info - skipping tile\n");
783  break;
784  }
785  if (chunk_size < 2) {
786  av_log(avctx, AV_LOG_ERROR, "Invalid tile data size %"PRIu32"\n",
787  chunk_size);
788  break;
789  }
790  c->tile_x = bytestream2_get_byte(&bc);
791  c->tile_y = bytestream2_get_byte(&bc);
792  if (c->tile_x >= c->tiles_x || c->tile_y >= c->tiles_y) {
793  av_log(avctx, AV_LOG_ERROR,
794  "Invalid tile pos %d,%d (in %dx%d grid)\n",
795  c->tile_x, c->tile_y, c->tiles_x, c->tiles_y);
796  break;
797  }
798  ret = 0;
799  switch (c->compression) {
800  case COMPR_EPIC_J_B:
801  av_log(avctx, AV_LOG_ERROR,
802  "ePIC j-b compression is not implemented yet\n");
803  return AVERROR(ENOSYS);
804  case COMPR_KEMPF_J_B:
805  ret = kempf_decode_tile(c, c->tile_x, c->tile_y,
806  buf + bytestream2_tell(&bc),
807  chunk_size - 2);
808  break;
809  }
810  if (ret && c->framebuf)
811  av_log(avctx, AV_LOG_ERROR, "Error decoding tile %d,%d\n",
812  c->tile_x, c->tile_y);
813  break;
814  case CURSOR_POS:
815  if (chunk_size < 5) {
816  av_log(avctx, AV_LOG_ERROR, "Invalid cursor pos size %"PRIu32"\n",
817  chunk_size);
818  break;
819  }
820  c->cursor_x = bytestream2_get_be16(&bc);
821  c->cursor_y = bytestream2_get_be16(&bc);
822  break;
823  case CURSOR_SHAPE:
824  if (chunk_size < 8) {
825  av_log(avctx, AV_LOG_ERROR, "Invalid cursor data size %"PRIu32"\n",
826  chunk_size);
827  break;
828  }
829  bytestream2_init(&tbc, buf + bytestream2_tell(&bc),
830  chunk_size - 4);
831  g2m_load_cursor(avctx, c, &tbc);
832  break;
833  case CHUNK_CC:
834  case CHUNK_CD:
835  break;
836  default:
837  av_log(avctx, AV_LOG_WARNING, "Skipping chunk type %02d\n",
838  chunk_type);
839  }
840 
841  /* navigate to next chunk */
842  bytestream2_skip(&bc, chunk_start + chunk_size - bytestream2_tell(&bc));
843  }
844  if (got_header)
845  c->got_header = 1;
846 
847  if (c->width && c->height && c->framebuf) {
848  if ((ret = ff_get_buffer(avctx, pic, 0)) < 0)
849  return ret;
850 
851  pic->key_frame = got_header;
852  pic->pict_type = got_header ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;
853 
854  for (i = 0; i < avctx->height; i++)
855  memcpy(pic->data[0] + i * pic->linesize[0],
856  c->framebuf + i * c->framebuf_stride,
857  c->width * 3);
858  g2m_paint_cursor(c, pic->data[0], pic->linesize[0]);
859 
860  *got_picture_ptr = 1;
861  }
862 
863  return buf_size;
864 
865 header_fail:
866  c->width =
867  c->height = 0;
868  c->tiles_x =
869  c->tiles_y = 0;
870  return ret;
871 }
872 
873 static av_cold int g2m_decode_init(AVCodecContext *avctx)
874 {
875  G2MContext *const c = avctx->priv_data;
876  int ret;
877 
878  if ((ret = jpg_init(avctx, &c->jc)) != 0) {
879  av_log(avctx, AV_LOG_ERROR, "Cannot initialise VLCs\n");
880  jpg_free_context(&c->jc);
881  return AVERROR(ENOMEM);
882  }
883 
884  avctx->pix_fmt = AV_PIX_FMT_RGB24;
885 
886  // store original sizes and check against those if resize happens
887  c->orig_width = avctx->width;
888  c->orig_height = avctx->height;
889 
890  return 0;
891 }
892 
893 static av_cold int g2m_decode_end(AVCodecContext *avctx)
894 {
895  G2MContext *const c = avctx->priv_data;
896 
897  jpg_free_context(&c->jc);
898 
899  av_freep(&c->kempf_buf);
900  av_freep(&c->kempf_flags);
901  av_freep(&c->synth_tile);
902  av_freep(&c->jpeg_tile);
903  av_freep(&c->cursor);
904  av_freep(&c->framebuf);
905 
906  return 0;
907 }
908 
909 AVCodec ff_g2m_decoder = {
910  .name = "g2m",
911  .long_name = NULL_IF_CONFIG_SMALL("Go2Meeting"),
912  .type = AVMEDIA_TYPE_VIDEO,
913  .id = AV_CODEC_ID_G2M,
914  .priv_data_size = sizeof(G2MContext),
915  .init = g2m_decode_init,
916  .close = g2m_decode_end,
917  .decode = g2m_decode_frame,
918  .capabilities = CODEC_CAP_DR1,
919 };
Generated on Sun Sep 14 2014 18:55:55 for FFmpeg by   doxygen 1.8.2