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FFmpeg/libavcodec/g2meet.c

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  1. /*

  2.  * Go2Webinar decoder

  3.  * Copyright (c) 2012 Konstantin Shishkov

  4.  *

  5.  * This file is part of Libav.

  6.  *

  7.  * Libav 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.  * Libav 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 Libav; 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->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.         c->synth_tile  = av_mallocz(c->tile_stride      * aligned_height);

  459.         c->jpeg_tile   = av_mallocz(c->tile_stride      * aligned_height);

  460.         c->kempf_buf   = av_mallocz((c->tile_width + 1) * aligned_height

  461.                                     + FF_INPUT_BUFFER_PADDING_SIZE);

  462.         c->kempf_flags = av_mallocz( c->tile_width      * aligned_height);

  463.         if (!c->synth_tile || !c->jpeg_tile ||

  464.             !c->kempf_buf || !c->kempf_flags)

  465.             return AVERROR(ENOMEM);

  466.     }

  467. 

  468.     return 0;

  469. }

  470. 

  471. static int g2m_load_cursor(G2MContext *c, GetByteContext *gb)

  472. {

  473.     int i, j, k;

  474.     uint8_t *dst;

  475.     uint32_t bits;

  476. 

  477.     c->cursor_stride = c->cursor_w * 4;

  478.     c->cursor        = av_realloc(c->cursor, c->cursor_stride * c->cursor_h);

  479.     if (!c->cursor)

  480.         return AVERROR(ENOMEM);

  481. 

  482.     dst = c->cursor;

  483.     switch (c->cursor_fmt) {

  484.     case 1: // old monochrome

  485.         for (j = 0; j < c->cursor_h; j++) {

  486.             for (i = 0; i < c->cursor_w; i += 32) {

  487.                 bits = bytestream2_get_be32(gb);

  488.                 for (k = 0; k < 32; k++) {

  489.                     dst[0] = !!(bits & 0x80000000);

  490.                     dst += 4;

  491.                     bits <<= 1;

  492.                 }

  493.             }

  494.         }

  495. 

  496.         dst = c->cursor;

  497.         for (j = 0; j < c->cursor_h; j++) {

  498.             for (i = 0; i < c->cursor_w; i += 32) {

  499.                 bits = bytestream2_get_be32(gb);

  500.                 for (k = 0; k < 32; k++) {

  501.                     int mask_bit = !!(bits & 0x80000000);

  502.                     switch (dst[0] * 2 + mask_bit) {

  503.                     case 0:

  504.                         dst[0] = 0xFF; dst[1] = 0x00;

  505.                         dst[2] = 0x00; dst[3] = 0x00;

  506.                         break;

  507.                     case 1:

  508.                         dst[0] = 0xFF; dst[1] = 0xFF;

  509.                         dst[2] = 0xFF; dst[3] = 0xFF;

  510.                         break;

  511.                     default:

  512.                         dst[0] = 0x00; dst[1] = 0x00;

  513.                         dst[2] = 0x00; dst[3] = 0x00;

  514.                     }

  515.                     dst += 4;

  516.                     bits <<= 1;

  517.                 }

  518.             }

  519.         }

  520.         break;

  521.     case 32: // full colour

  522.         /* skip monochrome version of the cursor and decode RGBA instead */

  523.         bytestream2_skip(gb, c->cursor_h * (FFALIGN(c->cursor_w, 32) >> 3));

  524.         for (j = 0; j < c->cursor_h; j++) {

  525.             for (i = 0; i < c->cursor_w; i++) {

  526.                 int val = bytestream2_get_be32(gb);

  527.                 *dst++ = val >>  0;

  528.                 *dst++ = val >>  8;

  529.                 *dst++ = val >> 16;

  530.                 *dst++ = val >> 24;

  531.             }

  532.         }

  533.         break;

  534.     default:

  535.         return AVERROR_PATCHWELCOME;

  536.     }

  537.     return 0;

  538. }

  539. 

  540. #define APPLY_ALPHA(src, new, alpha) \

  541.     src = (src * (256 - alpha) + new * alpha) >> 8

  542. 

  543. static void g2m_paint_cursor(G2MContext *c, uint8_t *dst, int stride)

  544. {

  545.     int i, j;

  546.     int x, y, w, h;

  547.     const uint8_t *cursor;

  548. 

  549.     if (!c->cursor)

  550.         return;

  551. 

  552.     x = c->cursor_x - c->cursor_hot_x;

  553.     y = c->cursor_y - c->cursor_hot_y;

  554. 

  555.     cursor = c->cursor;

  556.     w      = c->cursor_w;

  557.     h      = c->cursor_h;

  558. 

  559.     if (x + w > c->width)

  560.         w = c->width - x;

  561.     if (y + h > c->height)

  562.         h = c->height - y;

  563.     if (x < 0) {

  564.         w      +=  x;

  565.         cursor += -x * 4;

  566.     } else {

  567.         dst    +=  x * 3;

  568.     }

  569.     if (y < 0) {

  570.         h      +=  y;

  571.         cursor += -y * c->cursor_stride;

  572.     } else {

  573.         dst    +=  y * stride;

  574.     }

  575.     if (w < 0 || h < 0)

  576.         return;

  577. 

  578.     for (j = 0; j < h; j++) {

  579.         for (i = 0; i < w; i++) {

  580.             uint8_t alpha = cursor[i * 4];

  581.             APPLY_ALPHA(dst[i * 3 + 0], cursor[i * 4 + 1], alpha);

  582.             APPLY_ALPHA(dst[i * 3 + 1], cursor[i * 4 + 2], alpha);

  583.             APPLY_ALPHA(dst[i * 3 + 2], cursor[i * 4 + 3], alpha);

  584.         }

  585.         dst    += stride;

  586.         cursor += c->cursor_stride;

  587.     }

  588. }

  589. 

  590. static int g2m_decode_frame(AVCodecContext *avctx, void *data,

  591.                             int *got_picture_ptr, AVPacket *avpkt)

  592. {

  593.     const uint8_t *buf = avpkt->data;

  594.     int buf_size = avpkt->size;

  595.     G2MContext *c = avctx->priv_data;

  596.     AVFrame *pic = data;

  597.     GetByteContext bc, tbc;

  598.     int magic;

  599.     int got_header = 0;

  600.     uint32_t chunk_size, cur_size;

  601.     int chunk_type;

  602.     int i;

  603.     int ret;

  604. 

  605.     if (buf_size < 12) {

  606.         av_log(avctx, AV_LOG_ERROR,

  607.                "Frame should have at least 12 bytes, got %d instead\n",

  608.                buf_size);

  609.         return AVERROR_INVALIDDATA;

  610.     }

  611. 

  612.     bytestream2_init(&bc, buf, buf_size);

  613. 

  614.     magic = bytestream2_get_be32(&bc);

  615.     if ((magic & ~0xF) != MKBETAG('G', '2', 'M', '0') ||

  616.         (magic & 0xF) < 2 || (magic & 0xF) > 4) {

  617.         av_log(avctx, AV_LOG_ERROR, "Wrong magic %08X\n", magic);

  618.         return AVERROR_INVALIDDATA;

  619.     }

  620. 

  621.     if ((magic & 0xF) != 4) {

  622.         av_log(avctx, AV_LOG_ERROR, "G2M2 and G2M3 are not yet supported\n");

  623.         return AVERROR(ENOSYS);

  624.     }

  625. 

  626.     while (bytestream2_get_bytes_left(&bc) > 5) {

  627.         chunk_size = bytestream2_get_le32(&bc) - 1;

  628.         chunk_type = bytestream2_get_byte(&bc);

  629.         if (chunk_size > bytestream2_get_bytes_left(&bc)) {

  630.             av_log(avctx, AV_LOG_ERROR, "Invalid chunk size %d type %02X\n",

  631.                    chunk_size, chunk_type);

  632.             break;

  633.         }

  634.         switch (chunk_type) {

  635.         case FRAME_INFO:

  636.             c->got_header = 0;

  637.             if (chunk_size < 21) {

  638.                 av_log(avctx, AV_LOG_ERROR, "Invalid frame info size %d\n",

  639.                        chunk_size);

  640.                 break;

  641.             }

  642.             c->width  = bytestream2_get_be32(&bc);

  643.             c->height = bytestream2_get_be32(&bc);

  644.             if (c->width  < 16 || c->width  > avctx->width ||

  645.                 c->height < 16 || c->height > avctx->height) {

  646.                 av_log(avctx, AV_LOG_ERROR,

  647.                        "Invalid frame dimensions %dx%d\n",

  648.                        c->width, c->height);

  649.                 c->width = c->height = 0;

  650.                 bytestream2_skip(&bc, bytestream2_get_bytes_left(&bc));

  651.             }

  652.             if (c->width != avctx->width || c->height != avctx->height)

  653.                 avcodec_set_dimensions(avctx, c->width, c->height);

  654.             c->compression = bytestream2_get_be32(&bc);

  655.             if (c->compression != 2 && c->compression != 3) {

  656.                 av_log(avctx, AV_LOG_ERROR,

  657.                        "Unknown compression method %d\n",

  658.                        c->compression);

  659.                 return AVERROR_PATCHWELCOME;

  660.             }

  661.             c->tile_width  = bytestream2_get_be32(&bc);

  662.             c->tile_height = bytestream2_get_be32(&bc);

  663.             if (!c->tile_width || !c->tile_height) {

  664.                 av_log(avctx, AV_LOG_ERROR,

  665.                        "Invalid tile dimensions %dx%d\n",

  666.                        c->tile_width, c->tile_height);

  667.                 return AVERROR_INVALIDDATA;

  668.             }

  669.             c->tiles_x = (c->width  + c->tile_width  - 1) / c->tile_width;

  670.             c->tiles_y = (c->height + c->tile_height - 1) / c->tile_height;

  671.             c->bpp = bytestream2_get_byte(&bc);

  672.             chunk_size -= 21;

  673.             bytestream2_skip(&bc, chunk_size);

  674.             if (g2m_init_buffers(c))

  675.                 return AVERROR(ENOMEM);

  676.             got_header = 1;

  677.             break;

  678.         case TILE_DATA:

  679.             if (!c->tiles_x || !c->tiles_y) {

  680.                 av_log(avctx, AV_LOG_WARNING,

  681.                        "No frame header - skipping tile\n");

  682.                 bytestream2_skip(&bc, bytestream2_get_bytes_left(&bc));

  683.                 break;

  684.             }

  685.             if (chunk_size < 2) {

  686.                 av_log(avctx, AV_LOG_ERROR, "Invalid tile data size %d\n",

  687.                        chunk_size);

  688.                 break;

  689.             }

  690.             c->tile_x = bytestream2_get_byte(&bc);

  691.             c->tile_y = bytestream2_get_byte(&bc);

  692.             if (c->tile_x >= c->tiles_x || c->tile_y >= c->tiles_y) {

  693.                 av_log(avctx, AV_LOG_ERROR,

  694.                        "Invalid tile pos %d,%d (in %dx%d grid)\n",

  695.                        c->tile_x, c->tile_y, c->tiles_x, c->tiles_y);

  696.                 break;

  697.             }

  698.             chunk_size -= 2;

  699.             ret = 0;

  700.             switch (c->compression) {

  701.             case COMPR_EPIC_J_B:

  702.                 av_log(avctx, AV_LOG_ERROR,

  703.                        "ePIC j-b compression is not implemented yet\n");

  704.                 return AVERROR(ENOSYS);

  705.             case COMPR_KEMPF_J_B:

  706.                 ret = kempf_decode_tile(c, c->tile_x, c->tile_y,

  707.                                         buf + bytestream2_tell(&bc),

  708.                                         chunk_size);

  709.                 break;

  710.             }

  711.             if (ret && c->framebuf)

  712.                 av_log(avctx, AV_LOG_ERROR, "Error decoding tile %d,%d\n",

  713.                        c->tile_x, c->tile_y);

  714.             bytestream2_skip(&bc, chunk_size);

  715.             break;

  716.         case CURSOR_POS:

  717.             if (chunk_size < 5) {

  718.                 av_log(avctx, AV_LOG_ERROR, "Invalid cursor pos size %d\n",

  719.                        chunk_size);

  720.                 break;

  721.             }

  722.             c->cursor_x = bytestream2_get_be16(&bc);

  723.             c->cursor_y = bytestream2_get_be16(&bc);

  724.             bytestream2_skip(&bc, chunk_size - 4);

  725.             break;

  726.         case CURSOR_SHAPE:

  727.             if (chunk_size < 8) {

  728.                 av_log(avctx, AV_LOG_ERROR, "Invalid cursor data size %d\n",

  729.                        chunk_size);

  730.                 break;

  731.             }

  732.             bytestream2_init(&tbc, buf + bytestream2_tell(&bc),

  733.                              chunk_size - 4);

  734.             cur_size        = bytestream2_get_be32(&tbc);

  735.             c->cursor_w     = bytestream2_get_byte(&tbc);

  736.             c->cursor_h     = bytestream2_get_byte(&tbc);

  737.             c->cursor_hot_x = bytestream2_get_byte(&tbc);

  738.             c->cursor_hot_y = bytestream2_get_byte(&tbc);

  739.             c->cursor_fmt   = bytestream2_get_byte(&tbc);

  740.             if (cur_size >= chunk_size ||

  741.                 c->cursor_w * c->cursor_h / 4 > cur_size) {

  742.                 av_log(avctx, AV_LOG_ERROR, "Invalid cursor data size %d\n",

  743.                        chunk_size);

  744.                 break;

  745.             }

  746.             g2m_load_cursor(c, &tbc);

  747.             bytestream2_skip(&bc, chunk_size);

  748.             break;

  749.         case CHUNK_CC:

  750.         case CHUNK_CD:

  751.             bytestream2_skip(&bc, chunk_size);

  752.             break;

  753.         default:

  754.             av_log(avctx, AV_LOG_WARNING, "Skipping chunk type %02X\n",

  755.                    chunk_type);

  756.             bytestream2_skip(&bc, chunk_size);

  757.         }

  758.     }

  759.     if (got_header)

  760.         c->got_header = 1;

  761. 

  762.     if (c->width && c->height) {

  763.         if ((ret = ff_get_buffer(avctx, pic, 0)) < 0) {

  764.             av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");

  765.             return ret;

  766.         }

  767. 

  768.         pic->key_frame = got_header;

  769.         pic->pict_type = got_header ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;

  770. 

  771.         for (i = 0; i < avctx->height; i++)

  772.             memcpy(pic->data[0] + i * pic->linesize[0],

  773.                    c->framebuf  + i * c->framebuf_stride,

  774.                    c->width * 3);

  775.         g2m_paint_cursor(c, pic->data[0], pic->linesize[0]);

  776. 

  777.         *got_picture_ptr = 1;

  778.     }

  779. 

  780.     return buf_size;

  781. }

  782. 

  783. static av_cold int g2m_decode_init(AVCodecContext *avctx)

  784. {

  785.     G2MContext * const c = avctx->priv_data;

  786.     int ret;

  787. 

  788.     if ((ret = jpg_init(avctx, &c->jc)) != 0) {

  789.         av_log(avctx, AV_LOG_ERROR, "Cannot initialise VLCs\n");

  790.         jpg_free_context(&c->jc);

  791.         return AVERROR(ENOMEM);

  792.     }

  793. 

  794.     avctx->pix_fmt     = PIX_FMT_RGB24;

  795. 

  796.     return 0;

  797. }

  798. 

  799. static av_cold int g2m_decode_end(AVCodecContext *avctx)

  800. {

  801.     G2MContext * const c = avctx->priv_data;

  802. 

  803.     jpg_free_context(&c->jc);

  804. 

  805.     av_freep(&c->kempf_buf);

  806.     av_freep(&c->kempf_flags);

  807.     av_freep(&c->synth_tile);

  808.     av_freep(&c->jpeg_tile);

  809.     av_freep(&c->cursor);

  810.     av_freep(&c->framebuf);

  811. 

  812.     return 0;

  813. }

  814. 

  815. AVCodec ff_g2m_decoder = {

  816.     .name           = "g2m",

  817.     .long_name      = NULL_IF_CONFIG_SMALL("Go2Meeting"),

  818.     .type           = AVMEDIA_TYPE_VIDEO,

  819.     .id             = AV_CODEC_ID_G2M,

  820.     .priv_data_size = sizeof(G2MContext),

  821.     .init           = g2m_decode_init,

  822.     .close          = g2m_decode_end,

  823.     .decode         = g2m_decode_frame,

  824.     .capabilities   = CODEC_CAP_DR1,

  825. };