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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 <inttypes.h>

  28. #include <zlib.h>

  29. 

  30. #include "libavutil/intreadwrite.h"

  31. 

  32. #include "avcodec.h"

  33. #include "blockdsp.h"

  34. #include "bytestream.h"

  35. #include "get_bits.h"

  36. #include "idctdsp.h"

  37. #include "internal.h"

  38. #include "jpegtables.h"

  39. #include "mjpeg.h"

  40. 

  41. enum ChunkType {

  42.     DISPLAY_INFO = 0xC8,

  43.     TILE_DATA,

  44.     CURSOR_POS,

  45.     CURSOR_SHAPE,

  46.     CHUNK_CC,

  47.     CHUNK_CD

  48. };

  49. 

  50. enum Compression {

  51.     COMPR_EPIC_J_B = 2,

  52.     COMPR_KEMPF_J_B,

  53. };

  54. 

  55. static const uint8_t luma_quant[64] = {

  56.      8,  6,  5,  8, 12, 20, 26, 31,

  57.      6,  6,  7, 10, 13, 29, 30, 28,

  58.      7,  7,  8, 12, 20, 29, 35, 28,

  59.      7,  9, 11, 15, 26, 44, 40, 31,

  60.      9, 11, 19, 28, 34, 55, 52, 39,

  61.     12, 18, 28, 32, 41, 52, 57, 46,

  62.     25, 32, 39, 44, 52, 61, 60, 51,

  63.     36, 46, 48, 49, 56, 50, 52, 50

  64. };

  65. 

  66. static const uint8_t chroma_quant[64] = {

  67.      9,  9, 12, 24, 50, 50, 50, 50,

  68.      9, 11, 13, 33, 50, 50, 50, 50,

  69.     12, 13, 28, 50, 50, 50, 50, 50,

  70.     24, 33, 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.     50, 50, 50, 50, 50, 50, 50, 50,

  74.     50, 50, 50, 50, 50, 50, 50, 50,

  75. };

  76. 

  77. typedef struct JPGContext {

  78.     BlockDSPContext bdsp;

  79.     IDCTDSPContext idsp;

  80.     ScanTable  scantable;

  81. 

  82.     VLC        dc_vlc[2], ac_vlc[2];

  83.     int        prev_dc[3];

  84.     DECLARE_ALIGNED(16, int16_t, block)[6][64];

  85. 

  86.     uint8_t    *buf;

  87. } JPGContext;

  88. 

  89. typedef struct G2MContext {

  90.     JPGContext jc;

  91.     int        version;

  92. 

  93.     int        compression;

  94.     int        width, height, bpp;

  95.     int        orig_width, orig_height;

  96.     int        tile_width, tile_height;

  97.     int        tiles_x, tiles_y, tile_x, tile_y;

  98. 

  99.     int        got_header;

  100. 

  101.     uint8_t    *framebuf;

  102.     int        framebuf_stride, old_width, old_height;

  103. 

  104.     uint8_t    *synth_tile, *jpeg_tile;

  105.     int        tile_stride, old_tile_w, old_tile_h;

  106. 

  107.     uint8_t    *kempf_buf, *kempf_flags;

  108. 

  109.     uint8_t    *cursor;

  110.     int        cursor_stride;

  111.     int        cursor_fmt;

  112.     int        cursor_w, cursor_h, cursor_x, cursor_y;

  113.     int        cursor_hot_x, cursor_hot_y;

  114. } G2MContext;

  115. 

  116. static av_cold int build_vlc(VLC *vlc, const uint8_t *bits_table,

  117.                              const uint8_t *val_table, int nb_codes,

  118.                              int is_ac)

  119. {

  120.     uint8_t  huff_size[256] = { 0 };

  121.     uint16_t huff_code[256];

  122.     uint16_t huff_sym[256];

  123.     int i;

  124. 

  125.     ff_mjpeg_build_huffman_codes(huff_size, huff_code, bits_table, val_table);

  126. 

  127.     for (i = 0; i < 256; i++)

  128.         huff_sym[i] = i + 16 * is_ac;

  129. 

  130.     if (is_ac)

  131.         huff_sym[0] = 16 * 256;

  132. 

  133.     return ff_init_vlc_sparse(vlc, 9, nb_codes, huff_size, 1, 1,

  134.                               huff_code, 2, 2, huff_sym, 2, 2, 0);

  135. }

  136. 

  137. static av_cold int jpg_init(AVCodecContext *avctx, JPGContext *c)

  138. {

  139.     int ret;

  140. 

  141.     ret = build_vlc(&c->dc_vlc[0], avpriv_mjpeg_bits_dc_luminance,

  142.                     avpriv_mjpeg_val_dc, 12, 0);

  143.     if (ret)

  144.         return ret;

  145.     ret = build_vlc(&c->dc_vlc[1], avpriv_mjpeg_bits_dc_chrominance,

  146.                     avpriv_mjpeg_val_dc, 12, 0);

  147.     if (ret)

  148.         return ret;

  149.     ret = build_vlc(&c->ac_vlc[0], avpriv_mjpeg_bits_ac_luminance,

  150.                     avpriv_mjpeg_val_ac_luminance, 251, 1);

  151.     if (ret)

  152.         return ret;

  153.     ret = build_vlc(&c->ac_vlc[1], avpriv_mjpeg_bits_ac_chrominance,

  154.                     avpriv_mjpeg_val_ac_chrominance, 251, 1);

  155.     if (ret)

  156.         return ret;

  157. 

  158.     ff_blockdsp_init(&c->bdsp, avctx);

  159.     ff_idctdsp_init(&c->idsp, avctx);

  160.     ff_init_scantable(c->idsp.idct_permutation, &c->scantable,

  161.                       ff_zigzag_direct);

  162. 

  163.     return 0;

  164. }

  165. 

  166. static av_cold void jpg_free_context(JPGContext *ctx)

  167. {

  168.     int i;

  169. 

  170.     for (i = 0; i < 2; i++) {

  171.         ff_free_vlc(&ctx->dc_vlc[i]);

  172.         ff_free_vlc(&ctx->ac_vlc[i]);

  173.     }

  174. 

  175.     av_freep(&ctx->buf);

  176. }

  177. 

  178. static void jpg_unescape(const uint8_t *src, int src_size,

  179.                          uint8_t *dst, int *dst_size)

  180. {

  181.     const uint8_t *src_end = src + src_size;

  182.     uint8_t *dst_start = dst;

  183. 

  184.     while (src < src_end) {

  185.         uint8_t x = *src++;

  186. 

  187.         *dst++ = x;

  188. 

  189.         if (x == 0xFF && !*src)

  190.             src++;

  191.     }

  192.     *dst_size = dst - dst_start;

  193. }

  194. 

  195. static int jpg_decode_block(JPGContext *c, GetBitContext *gb,

  196.                             int plane, int16_t *block)

  197. {

  198.     int dc, val, pos;

  199.     const int is_chroma = !!plane;

  200.     const uint8_t *qmat = is_chroma ? chroma_quant : luma_quant;

  201. 

  202.     c->bdsp.clear_block(block);

  203.     dc = get_vlc2(gb, c->dc_vlc[is_chroma].table, 9, 3);

  204.     if (dc < 0)

  205.         return AVERROR_INVALIDDATA;

  206.     if (dc)

  207.         dc = get_xbits(gb, dc);

  208.     dc                = dc * qmat[0] + c->prev_dc[plane];

  209.     block[0]          = dc;

  210.     c->prev_dc[plane] = dc;

  211. 

  212.     pos = 0;

  213.     while (pos < 63) {

  214.         val = get_vlc2(gb, c->ac_vlc[is_chroma].table, 9, 3);

  215.         if (val < 0)

  216.             return AVERROR_INVALIDDATA;

  217.         pos += val >> 4;

  218.         val &= 0xF;

  219.         if (pos > 63)

  220.             return val ? AVERROR_INVALIDDATA : 0;

  221.         if (val) {

  222.             int nbits = val;

  223. 

  224.             val                                 = get_xbits(gb, nbits);

  225.             val                                *= qmat[ff_zigzag_direct[pos]];

  226.             block[c->scantable.permutated[pos]] = val;

  227.         }

  228.     }

  229.     return 0;

  230. }

  231. 

  232. static inline void yuv2rgb(uint8_t *out, int Y, int U, int V)

  233. {

  234.     out[0] = av_clip_uint8(Y + (             91881 * V + 32768 >> 16));

  235.     out[1] = av_clip_uint8(Y + (-22554 * U - 46802 * V + 32768 >> 16));

  236.     out[2] = av_clip_uint8(Y + (116130 * U             + 32768 >> 16));

  237. }

  238. 

  239. static int jpg_decode_data(JPGContext *c, int width, int height,

  240.                            const uint8_t *src, int src_size,

  241.                            uint8_t *dst, int dst_stride,

  242.                            const uint8_t *mask, int mask_stride, int num_mbs,

  243.                            int swapuv)

  244. {

  245.     GetBitContext gb;

  246.     int mb_w, mb_h, mb_x, mb_y, i, j;

  247.     int bx, by;

  248.     int unesc_size;

  249.     int ret;

  250. 

  251.     if ((ret = av_reallocp(&c->buf,

  252.                            src_size + FF_INPUT_BUFFER_PADDING_SIZE)) < 0)

  253.         return ret;

  254.     jpg_unescape(src, src_size, c->buf, &unesc_size);

  255.     memset(c->buf + unesc_size, 0, FF_INPUT_BUFFER_PADDING_SIZE);

  256.     init_get_bits(&gb, c->buf, unesc_size * 8);

  257. 

  258.     width = FFALIGN(width, 16);

  259.     mb_w  =  width        >> 4;

  260.     mb_h  = (height + 15) >> 4;

  261. 

  262.     if (!num_mbs)

  263.         num_mbs = mb_w * mb_h * 4;

  264. 

  265.     for (i = 0; i < 3; i++)

  266.         c->prev_dc[i] = 1024;

  267.     bx =

  268.     by = 0;

  269.     c->bdsp.clear_blocks(c->block[0]);

  270.     for (mb_y = 0; mb_y < mb_h; mb_y++) {

  271.         for (mb_x = 0; mb_x < mb_w; mb_x++) {

  272.             if (mask && !mask[mb_x * 2] && !mask[mb_x * 2 + 1] &&

  273.                 !mask[mb_x * 2 +     mask_stride] &&

  274.                 !mask[mb_x * 2 + 1 + mask_stride]) {

  275.                 bx += 16;

  276.                 continue;

  277.             }

  278.             for (j = 0; j < 2; j++) {

  279.                 for (i = 0; i < 2; i++) {

  280.                     if (mask && !mask[mb_x * 2 + i + j * mask_stride])

  281.                         continue;

  282.                     num_mbs--;

  283.                     if ((ret = jpg_decode_block(c, &gb, 0,

  284.                                                 c->block[i + j * 2])) != 0)

  285.                         return ret;

  286.                     c->idsp.idct(c->block[i + j * 2]);

  287.                 }

  288.             }

  289.             for (i = 1; i < 3; i++) {

  290.                 if ((ret = jpg_decode_block(c, &gb, i, c->block[i + 3])) != 0)

  291.                     return ret;

  292.                 c->idsp.idct(c->block[i + 3]);

  293.             }

  294. 

  295.             for (j = 0; j < 16; j++) {

  296.                 uint8_t *out = dst + bx * 3 + (by + j) * dst_stride;

  297.                 for (i = 0; i < 16; i++) {

  298.                     int Y, U, V;

  299. 

  300.                     Y = c->block[(j >> 3) * 2 + (i >> 3)][(i & 7) + (j & 7) * 8];

  301.                     U = c->block[4 ^ swapuv][(i >> 1) + (j >> 1) * 8] - 128;

  302.                     V = c->block[5 ^ swapuv][(i >> 1) + (j >> 1) * 8] - 128;

  303.                     yuv2rgb(out + i * 3, Y, U, V);

  304.                 }

  305.             }

  306. 

  307.             if (!num_mbs)

  308.                 return 0;

  309.             bx += 16;

  310.         }

  311.         bx  = 0;

  312.         by += 16;

  313.         if (mask)

  314.             mask += mask_stride * 2;

  315.     }

  316. 

  317.     return 0;

  318. }

  319. 

  320. static void kempf_restore_buf(const uint8_t *src, int len,

  321.                               uint8_t *dst, int stride,

  322.                               const uint8_t *jpeg_tile, int tile_stride,

  323.                               int width, int height,

  324.                               const uint8_t *pal, int npal, int tidx)

  325. {

  326.     GetBitContext gb;

  327.     int i, j, nb, col;

  328. 

  329.     init_get_bits(&gb, src, len * 8);

  330. 

  331.     if (npal <= 2)       nb = 1;

  332.     else if (npal <= 4)  nb = 2;

  333.     else if (npal <= 16) nb = 4;

  334.     else                 nb = 8;

  335. 

  336.     for (j = 0; j < height; j++, dst += stride, jpeg_tile += tile_stride) {

  337.         if (get_bits(&gb, 8))

  338.             continue;

  339.         for (i = 0; i < width; i++) {

  340.             col = get_bits(&gb, nb);

  341.             if (col != tidx)

  342.                 memcpy(dst + i * 3, pal + col * 3, 3);

  343.             else

  344.                 memcpy(dst + i * 3, jpeg_tile + i * 3, 3);

  345.         }

  346.     }

  347. }

  348. 

  349. static int kempf_decode_tile(G2MContext *c, int tile_x, int tile_y,

  350.                              const uint8_t *src, int src_size)

  351. {

  352.     int width, height;

  353.     int hdr, zsize, npal, tidx = -1, ret;

  354.     int i, j;

  355.     const uint8_t *src_end = src + src_size;

  356.     uint8_t pal[768], transp[3];

  357.     uLongf dlen = (c->tile_width + 1) * c->tile_height;

  358.     int sub_type;

  359.     int nblocks, cblocks, bstride;

  360.     int bits, bitbuf, coded;

  361.     uint8_t *dst = c->framebuf + tile_x * c->tile_width * 3 +

  362.                    tile_y * c->tile_height * c->framebuf_stride;

  363. 

  364.     if (src_size < 2)

  365.         return AVERROR_INVALIDDATA;

  366. 

  367.     width  = FFMIN(c->width  - tile_x * c->tile_width,  c->tile_width);

  368.     height = FFMIN(c->height - tile_y * c->tile_height, c->tile_height);

  369. 

  370.     hdr      = *src++;

  371.     sub_type = hdr >> 5;

  372.     if (sub_type == 0) {

  373.         int j;

  374.         memcpy(transp, src, 3);

  375.         src += 3;

  376.         for (j = 0; j < height; j++, dst += c->framebuf_stride)

  377.             for (i = 0; i < width; i++)

  378.                 memcpy(dst + i * 3, transp, 3);

  379.         return 0;

  380.     } else if (sub_type == 1) {

  381.         return jpg_decode_data(&c->jc, width, height, src, src_end - src,

  382.                                dst, c->framebuf_stride, NULL, 0, 0, 0);

  383.     }

  384. 

  385.     if (sub_type != 2) {

  386.         memcpy(transp, src, 3);

  387.         src += 3;

  388.     }

  389.     npal = *src++ + 1;

  390.     memcpy(pal, src, npal * 3);

  391.     src += npal * 3;

  392.     if (sub_type != 2) {

  393.         for (i = 0; i < npal; i++) {

  394.             if (!memcmp(pal + i * 3, transp, 3)) {

  395.                 tidx = i;

  396.                 break;

  397.             }

  398.         }

  399.     }

  400. 

  401.     if (src_end - src < 2)

  402.         return 0;

  403.     zsize = (src[0] << 8) | src[1];

  404.     src  += 2;

  405. 

  406.     if (src_end - src < zsize)

  407.         return AVERROR_INVALIDDATA;

  408. 

  409.     ret = uncompress(c->kempf_buf, &dlen, src, zsize);

  410.     if (ret)

  411.         return AVERROR_INVALIDDATA;

  412.     src += zsize;

  413. 

  414.     if (sub_type == 2) {

  415.         kempf_restore_buf(c->kempf_buf, dlen, dst, c->framebuf_stride,

  416.                           NULL, 0, width, height, pal, npal, tidx);

  417.         return 0;

  418.     }

  419. 

  420.     nblocks = *src++ + 1;

  421.     cblocks = 0;

  422.     bstride = FFALIGN(width, 16) >> 3;

  423.     // blocks are coded LSB and we need normal bitreader for JPEG data

  424.     bits = 0;

  425.     for (i = 0; i < (FFALIGN(height, 16) >> 4); i++) {

  426.         for (j = 0; j < (FFALIGN(width, 16) >> 4); j++) {

  427.             if (!bits) {

  428.                 bitbuf = *src++;

  429.                 bits   = 8;

  430.             }

  431.             coded = bitbuf & 1;

  432.             bits--;

  433.             bitbuf >>= 1;

  434.             cblocks += coded;

  435.             if (cblocks > nblocks)

  436.                 return AVERROR_INVALIDDATA;

  437.             c->kempf_flags[j * 2 +      i * 2      * bstride] =

  438.             c->kempf_flags[j * 2 + 1 +  i * 2      * bstride] =

  439.             c->kempf_flags[j * 2 +     (i * 2 + 1) * bstride] =

  440.             c->kempf_flags[j * 2 + 1 + (i * 2 + 1) * bstride] = coded;

  441.         }

  442.     }

  443. 

  444.     memset(c->jpeg_tile, 0, c->tile_stride * height);

  445.     jpg_decode_data(&c->jc, width, height, src, src_end - src,

  446.                     c->jpeg_tile, c->tile_stride,

  447.                     c->kempf_flags, bstride, nblocks * 4, 0);

  448. 

  449.     kempf_restore_buf(c->kempf_buf, dlen, dst, c->framebuf_stride,

  450.                       c->jpeg_tile, c->tile_stride,

  451.                       width, height, pal, npal, tidx);

  452. 

  453.     return 0;

  454. }

  455. 

  456. static int g2m_init_buffers(G2MContext *c)

  457. {

  458.     int aligned_height;

  459. 

  460.     if (!c->framebuf || c->old_width < c->width || c->old_height < c->height) {

  461.         c->framebuf_stride = FFALIGN(c->width * 3, 16);

  462.         aligned_height     = FFALIGN(c->height,    16);

  463.         av_free(c->framebuf);

  464.         c->framebuf = av_mallocz(c->framebuf_stride * aligned_height);

  465.         if (!c->framebuf)

  466.             return AVERROR(ENOMEM);

  467.     }

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

  469.         c->old_tile_w < c->tile_width ||

  470.         c->old_tile_h < c->tile_height) {

  471.         c->tile_stride = FFALIGN(c->tile_width * 3, 16);

  472.         aligned_height = FFALIGN(c->tile_height,    16);

  473.         av_free(c->synth_tile);

  474.         av_free(c->jpeg_tile);

  475.         av_free(c->kempf_buf);

  476.         av_free(c->kempf_flags);

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

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

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

  480.                                     + FF_INPUT_BUFFER_PADDING_SIZE);

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

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

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

  484.             return AVERROR(ENOMEM);

  485.     }

  486. 

  487.     return 0;

  488. }

  489. 

  490. static int g2m_load_cursor(AVCodecContext *avctx, G2MContext *c,

  491.                            GetByteContext *gb)

  492. {

  493.     int i, j, k;

  494.     uint8_t *dst;

  495.     uint32_t bits;

  496.     uint32_t cur_size, cursor_w, cursor_h, cursor_stride;

  497.     uint32_t cursor_hot_x, cursor_hot_y;

  498.     int cursor_fmt, err;

  499. 

  500.     cur_size     = bytestream2_get_be32(gb);

  501.     cursor_w     = bytestream2_get_byte(gb);

  502.     cursor_h     = bytestream2_get_byte(gb);

  503.     cursor_hot_x = bytestream2_get_byte(gb);

  504.     cursor_hot_y = bytestream2_get_byte(gb);

  505.     cursor_fmt   = bytestream2_get_byte(gb);

  506. 

  507.     cursor_stride = FFALIGN(cursor_w, 32) * 4;

  508. 

  509.     if (cursor_w < 1 || cursor_w > 256 ||

  510.         cursor_h < 1 || cursor_h > 256) {

  511.         av_log(avctx, AV_LOG_ERROR, "Invalid cursor dimensions %"PRIu32"x%"PRIu32"\n",

  512.                cursor_w, cursor_h);

  513.         return AVERROR_INVALIDDATA;

  514.     }

  515.     if (cursor_hot_x > cursor_w || cursor_hot_y > cursor_h) {

  516.         av_log(avctx, AV_LOG_WARNING, "Invalid hotspot position %"PRIu32",%"PRIu32"\n",

  517.                cursor_hot_x, cursor_hot_y);

  518.         cursor_hot_x = FFMIN(cursor_hot_x, cursor_w - 1);

  519.         cursor_hot_y = FFMIN(cursor_hot_y, cursor_h - 1);

  520.     }

  521.     if (cur_size - 9 > bytestream2_get_bytes_left(gb) ||

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

  523.         av_log(avctx, AV_LOG_ERROR, "Invalid cursor data size %"PRIu32"/%u\n",

  524.                cur_size, bytestream2_get_bytes_left(gb));

  525.         return AVERROR_INVALIDDATA;

  526.     }

  527.     if (cursor_fmt != 1 && cursor_fmt != 32) {

  528.         avpriv_report_missing_feature(avctx, "Cursor format %d",

  529.                                       cursor_fmt);

  530.         return AVERROR_PATCHWELCOME;

  531.     }

  532. 

  533.     if ((err = av_reallocp(&c->cursor, cursor_stride * cursor_h)) < 0) {

  534.         av_log(avctx, AV_LOG_ERROR, "Cannot allocate cursor buffer\n");

  535.         return err;

  536.     }

  537. 

  538.     c->cursor_w      = cursor_w;

  539.     c->cursor_h      = cursor_h;

  540.     c->cursor_hot_x  = cursor_hot_x;

  541.     c->cursor_hot_y  = cursor_hot_y;

  542.     c->cursor_fmt    = cursor_fmt;

  543.     c->cursor_stride = cursor_stride;

  544. 

  545.     dst = c->cursor;

  546.     switch (c->cursor_fmt) {

  547.     case 1: // old monochrome

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

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

  550.                 bits = bytestream2_get_be32(gb);

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

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

  553.                     dst   += 4;

  554.                     bits <<= 1;

  555.                 }

  556.             }

  557.             dst += c->cursor_stride - c->cursor_w * 4;

  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.             dst += c->cursor_stride - c->cursor_w * 4;

  590.         }

  591.         break;

  592.     case 32: // full colour

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

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

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

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

  597.                 int val = bytestream2_get_be32(gb);

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

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

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

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

  602.             }

  603.             dst += c->cursor_stride - c->cursor_w * 4;

  604.         }

  605.         break;

  606.     default:

  607.         return AVERROR_PATCHWELCOME;

  608.     }

  609.     return 0;

  610. }

  611. 

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

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

  614. 

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

  616. {

  617.     int i, j;

  618.     int x, y, w, h;

  619.     const uint8_t *cursor;

  620. 

  621.     if (!c->cursor)

  622.         return;

  623. 

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

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

  626. 

  627.     cursor = c->cursor;

  628.     w      = c->cursor_w;

  629.     h      = c->cursor_h;

  630. 

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

  632.         w = c->width - x;

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

  634.         h = c->height - y;

  635.     if (x < 0) {

  636.         w      +=  x;

  637.         cursor += -x * 4;

  638.     } else {

  639.         dst    +=  x * 3;

  640.     }

  641.     if (y < 0) {

  642.         h      +=  y;

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

  644.     } else {

  645.         dst    +=  y * stride;

  646.     }

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

  648.         return;

  649. 

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

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

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

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

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

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

  656.         }

  657.         dst    += stride;

  658.         cursor += c->cursor_stride;

  659.     }

  660. }

  661. 

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

  663.                             int *got_picture_ptr, AVPacket *avpkt)

  664. {

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

  666.     int buf_size = avpkt->size;

  667.     G2MContext *c = avctx->priv_data;

  668.     AVFrame *pic = data;

  669.     GetByteContext bc, tbc;

  670.     int magic;

  671.     int got_header = 0;

  672.     uint32_t chunk_size, r_mask, g_mask, b_mask;

  673.     int chunk_type, chunk_start;

  674.     int i;

  675.     int ret;

  676. 

  677.     if (buf_size < 12) {

  678.         av_log(avctx, AV_LOG_ERROR,

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

  680.                buf_size);

  681.         return AVERROR_INVALIDDATA;

  682.     }

  683. 

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

  685. 

  686.     magic = bytestream2_get_be32(&bc);

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

  688.         (magic & 0xF) < 2 || (magic & 0xF) > 5) {

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

  690.         return AVERROR_INVALIDDATA;

  691.     }

  692. 

  693.     if ((magic & 0xF) < 4) {

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

  695.         return AVERROR(ENOSYS);

  696.     }

  697. 

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

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

  700.         chunk_type  = bytestream2_get_byte(&bc);

  701.         chunk_start = bytestream2_tell(&bc);

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

  703.             av_log(avctx, AV_LOG_ERROR, "Invalid chunk size %"PRIu32" type %02X\n",

  704.                    chunk_size, chunk_type);

  705.             break;

  706.         }

  707.         switch (chunk_type) {

  708.         case DISPLAY_INFO:

  709.             c->got_header = 0;

  710.             if (chunk_size < 21) {

  711.                 av_log(avctx, AV_LOG_ERROR, "Invalid display info size %"PRIu32"\n",

  712.                        chunk_size);

  713.                 break;

  714.             }

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

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

  717.             if (c->width  < 16 || c->width  > c->orig_width ||

  718.                 c->height < 16 || c->height > c->orig_height) {

  719.                 av_log(avctx, AV_LOG_ERROR,

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

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

  722.                 ret = AVERROR_INVALIDDATA;

  723.                 goto header_fail;

  724.             }

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

  726.                 ret = ff_set_dimensions(avctx, c->width, c->height);

  727.                 if (ret < 0)

  728.                     return ret;

  729.             }

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

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

  732.                 av_log(avctx, AV_LOG_ERROR,

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

  734.                        c->compression);

  735.                 return AVERROR_PATCHWELCOME;

  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.                     return AVERROR_INVALIDDATA;

  756.                 }

  757.                 r_mask = bytestream2_get_be32(&bc);

  758.                 g_mask = bytestream2_get_be32(&bc);

  759.                 b_mask = bytestream2_get_be32(&bc);

  760.                 if (r_mask != 0xFF0000 || g_mask != 0xFF00 || b_mask != 0xFF) {

  761.                     av_log(avctx, AV_LOG_ERROR,

  762.                            "Invalid or unsupported bitmasks: R=%"PRIX32", G=%"PRIX32", B=%"PRIX32"\n",

  763.                            r_mask, g_mask, b_mask);

  764.                     return AVERROR_PATCHWELCOME;

  765.                 }

  766.             } else {

  767.                 avpriv_request_sample(avctx, "bpp=%d", c->bpp);

  768.                 return AVERROR_PATCHWELCOME;

  769.             }

  770.             if (g2m_init_buffers(c)) {

  771.                 ret = AVERROR(ENOMEM);

  772.                 goto header_fail;

  773.             }

  774.             got_header = 1;

  775.             break;

  776.         case TILE_DATA:

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

  778.                 av_log(avctx, AV_LOG_WARNING,

  779.                        "No display info - skipping tile\n");

  780.                 break;

  781.             }

  782.             if (chunk_size < 2) {

  783.                 av_log(avctx, AV_LOG_ERROR, "Invalid tile data size %"PRIu32"\n",

  784.                        chunk_size);

  785.                 break;

  786.             }

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

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

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

  790.                 av_log(avctx, AV_LOG_ERROR,

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

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

  793.                 break;

  794.             }

  795.             ret = 0;

  796.             switch (c->compression) {

  797.             case COMPR_EPIC_J_B:

  798.                 av_log(avctx, AV_LOG_ERROR,

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

  800.                 return AVERROR(ENOSYS);

  801.             case COMPR_KEMPF_J_B:

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

  803.                                         buf + bytestream2_tell(&bc),

  804.                                         chunk_size - 2);

  805.                 break;

  806.             }

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

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

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

  810.             break;

  811.         case CURSOR_POS:

  812.             if (chunk_size < 5) {

  813.                 av_log(avctx, AV_LOG_ERROR, "Invalid cursor pos size %"PRIu32"\n",

  814.                        chunk_size);

  815.                 break;

  816.             }

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

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

  819.             break;

  820.         case CURSOR_SHAPE:

  821.             if (chunk_size < 8) {

  822.                 av_log(avctx, AV_LOG_ERROR, "Invalid cursor data size %"PRIu32"\n",

  823.                        chunk_size);

  824.                 break;

  825.             }

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

  827.                              chunk_size - 4);

  828.             g2m_load_cursor(avctx, c, &tbc);

  829.             break;

  830.         case CHUNK_CC:

  831.         case CHUNK_CD:

  832.             break;

  833.         default:

  834.             av_log(avctx, AV_LOG_WARNING, "Skipping chunk type %02d\n",

  835.                    chunk_type);

  836.         }

  837. 

  838.         /* navigate to next chunk */

  839.         bytestream2_skip(&bc, chunk_start + chunk_size - bytestream2_tell(&bc));

  840.     }

  841.     if (got_header)

  842.         c->got_header = 1;

  843. 

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

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

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

  847.             return ret;

  848.         }

  849. 

  850.         pic->key_frame = got_header;

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

  852. 

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

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

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

  856.                    c->width * 3);

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

  858. 

  859.         *got_picture_ptr = 1;

  860.     }

  861. 

  862.     return buf_size;

  863. 

  864. header_fail:

  865.     c->width   =

  866.     c->height  = 0;

  867.     c->tiles_x =

  868.     c->tiles_y = 0;

  869.     return ret;

  870. }

  871. 

  872. static av_cold int g2m_decode_init(AVCodecContext *avctx)

  873. {

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

  875.     int ret;

  876. 

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

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

  879.         jpg_free_context(&c->jc);

  880.         return AVERROR(ENOMEM);

  881.     }

  882. 

  883.     avctx->pix_fmt = AV_PIX_FMT_RGB24;

  884. 

  885.     // store original sizes and check against those if resize happens

  886.     c->orig_width  = avctx->width;

  887.     c->orig_height = avctx->height;

  888. 

  889.     return 0;

  890. }

  891. 

  892. static av_cold int g2m_decode_end(AVCodecContext *avctx)

  893. {

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

  895. 

  896.     jpg_free_context(&c->jc);

  897. 

  898.     av_freep(&c->kempf_buf);

  899.     av_freep(&c->kempf_flags);

  900.     av_freep(&c->synth_tile);

  901.     av_freep(&c->jpeg_tile);

  902.     av_freep(&c->cursor);

  903.     av_freep(&c->framebuf);

  904. 

  905.     return 0;

  906. }

  907. 

  908. AVCodec ff_g2m_decoder = {

  909.     .name           = "g2m",

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

  911.     .type           = AVMEDIA_TYPE_VIDEO,

  912.     .id             = AV_CODEC_ID_G2M,

  913.     .priv_data_size = sizeof(G2MContext),

  914.     .init           = g2m_decode_init,

  915.     .close          = g2m_decode_end,

  916.     .decode         = g2m_decode_frame,

  917.     .capabilities   = CODEC_CAP_DR1,

  918. };