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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 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 "bytestream.h"

  33. #include "dsputil.h"

  34. #include "get_bits.h"

  35. #include "internal.h"

  36. #include "mjpeg.h"

  37. 

  38. enum ChunkType {

  39.     DISPLAY_INFO = 0xC8,

  40.     TILE_DATA,

  41.     CURSOR_POS,

  42.     CURSOR_SHAPE,

  43.     CHUNK_CC,

  44.     CHUNK_CD

  45. };

  46. 

  47. enum Compression {

  48.     COMPR_EPIC_J_B = 2,

  49.     COMPR_KEMPF_J_B,

  50. };

  51. 

  52. static const uint8_t luma_quant[64] = {

  53.      8,  6,  5,  8, 12, 20, 26, 31,

  54.      6,  6,  7, 10, 13, 29, 30, 28,

  55.      7,  7,  8, 12, 20, 29, 35, 28,

  56.      7,  9, 11, 15, 26, 44, 40, 31,

  57.      9, 11, 19, 28, 34, 55, 52, 39,

  58.     12, 18, 28, 32, 41, 52, 57, 46,

  59.     25, 32, 39, 44, 52, 61, 60, 51,

  60.     36, 46, 48, 49, 56, 50, 52, 50

  61. };

  62. 

  63. static const uint8_t chroma_quant[64] = {

  64.      9,  9, 12, 24, 50, 50, 50, 50,

  65.      9, 11, 13, 33, 50, 50, 50, 50,

  66.     12, 13, 28, 50, 50, 50, 50, 50,

  67.     24, 33, 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.     50, 50, 50, 50, 50, 50, 50, 50,

  72. };

  73. 

  74. typedef struct JPGContext {

  75.     DSPContext dsp;

  76.     ScanTable  scantable;

  77. 

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

  79.     int        prev_dc[3];

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

  81. 

  82.     uint8_t    *buf;

  83. } JPGContext;

  84. 

  85. typedef struct G2MContext {

  86.     JPGContext jc;

  87.     int        version;

  88. 

  89.     int        compression;

  90.     int        width, height, bpp;

  91.     int        tile_width, tile_height;

  92.     int        tiles_x, tiles_y, tile_x, tile_y;

  93. 

  94.     int        got_header;

  95. 

  96.     uint8_t    *framebuf;

  97.     int        framebuf_stride, old_width, old_height;

  98. 

  99.     uint8_t    *synth_tile, *jpeg_tile;

  100.     int        tile_stride, old_tile_w, old_tile_h;

  101. 

  102.     uint8_t    *kempf_buf, *kempf_flags;

  103. 

  104.     uint8_t    *cursor;

  105.     int        cursor_stride;

  106.     int        cursor_fmt;

  107.     int        cursor_w, cursor_h, cursor_x, cursor_y;

  108.     int        cursor_hot_x, cursor_hot_y;

  109. } G2MContext;

  110. 

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

  112.                              const uint8_t *val_table, int nb_codes,

  113.                              int is_ac)

  114. {

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

  116.     uint16_t huff_code[256];

  117.     uint16_t huff_sym[256];

  118.     int i;

  119. 

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

  121. 

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

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

  124. 

  125.     if (is_ac)

  126.         huff_sym[0] = 16 * 256;

  127. 

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

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

  130. }

  131. 

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

  133. {

  134.     int ret;

  135. 

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

  137.                     avpriv_mjpeg_val_dc, 12, 0);

  138.     if (ret)

  139.         return ret;

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

  141.                     avpriv_mjpeg_val_dc, 12, 0);

  142.     if (ret)

  143.         return ret;

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

  145.                     avpriv_mjpeg_val_ac_luminance, 251, 1);

  146.     if (ret)

  147.         return ret;

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

  149.                     avpriv_mjpeg_val_ac_chrominance, 251, 1);

  150.     if (ret)

  151.         return ret;

  152. 

  153.     ff_dsputil_init(&c->dsp, avctx);

  154.     ff_init_scantable(c->dsp.idct_permutation, &c->scantable,

  155.                       ff_zigzag_direct);

  156. 

  157.     return 0;

  158. }

  159. 

  160. static av_cold void jpg_free_context(JPGContext *ctx)

  161. {

  162.     int i;

  163. 

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

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

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

  167.     }

  168. 

  169.     av_freep(&ctx->buf);

  170. }

  171. 

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

  173.                          uint8_t *dst, int *dst_size)

  174. {

  175.     const uint8_t *src_end = src + src_size;

  176.     uint8_t *dst_start = dst;

  177. 

  178.     while (src < src_end) {

  179.         uint8_t x = *src++;

  180. 

  181.         *dst++ = x;

  182. 

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

  184.             src++;

  185.     }

  186.     *dst_size = dst - dst_start;

  187. }

  188. 

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

  190.                             int plane, int16_t *block)

  191. {

  192.     int dc, val, pos;

  193.     const int is_chroma = !!plane;

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

  195. 

  196.     c->dsp.clear_block(block);

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

  198.     if (dc < 0)

  199.         return AVERROR_INVALIDDATA;

  200.     if (dc)

  201.         dc = get_xbits(gb, dc);

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

  203.     block[0]          = dc;

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

  205. 

  206.     pos = 0;

  207.     while (pos < 63) {

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

  209.         if (val < 0)

  210.             return AVERROR_INVALIDDATA;

  211.         pos += val >> 4;

  212.         val &= 0xF;

  213.         if (pos > 63)

  214.             return val ? AVERROR_INVALIDDATA : 0;

  215.         if (val) {

  216.             int nbits = val;

  217. 

  218.             val                                 = get_xbits(gb, nbits);

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

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

  221.         }

  222.     }

  223.     return 0;

  224. }

  225. 

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

  227. {

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

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

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

  231. }

  232. 

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

  234.                            const uint8_t *src, int src_size,

  235.                            uint8_t *dst, int dst_stride,

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

  237.                            int swapuv)

  238. {

  239.     GetBitContext gb;

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

  246.                            src_size + FF_INPUT_BUFFER_PADDING_SIZE)) < 0)

  247.         return ret;

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

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

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

  251. 

  252.     width = FFALIGN(width, 16);

  253.     mb_w  =  width        >> 4;

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

  255. 

  256.     if (!num_mbs)

  257.         num_mbs = mb_w * mb_h * 4;

  258. 

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

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

  261.     bx = by = 0;

  262.     c->dsp.clear_blocks(c->block[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 * 2] && !mask[mb_x * 2 + 1] &&

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

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

  268.                 bx += 16;

  269.                 continue;

  270.             }

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

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

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

  274.                         continue;

  275.                     num_mbs--;

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

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

  278.                         return ret;

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

  280.                 }

  281.             }

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

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

  284.                     return ret;

  285.                 c->dsp.idct(c->block[i + 3]);

  286.             }

  287. 

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

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

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

  291.                     int Y, U, V;

  292. 

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

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

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

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

  297.                 }

  298.             }

  299. 

  300.             if (!num_mbs)

  301.                 return 0;

  302.             bx += 16;

  303.         }

  304.         bx  = 0;

  305.         by += 16;

  306.         if (mask)

  307.             mask += mask_stride * 2;

  308.     }

  309. 

  310.     return 0;

  311. }

  312. 

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

  314.                               uint8_t *dst, int stride,

  315.                               const uint8_t *jpeg_tile, int tile_stride,

  316.                               int width, int height,

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

  318. {

  319.     GetBitContext gb;

  320.     int i, j, nb, col;

  321. 

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

  323. 

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

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

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

  327.     else                 nb = 8;

  328. 

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

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

  331.             continue;

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

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

  334.             if (col != tidx)

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

  336.             else

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

  338.         }

  339.     }

  340. }

  341. 

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

  343.                              const uint8_t *src, int src_size)

  344. {

  345.     int width, height;

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

  347.     int i, j;

  348.     const uint8_t *src_end = src + src_size;

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

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

  351.     int sub_type;

  352.     int nblocks, cblocks, bstride;

  353.     int bits, bitbuf, coded;

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

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

  356. 

  357.     if (src_size < 2)

  358.         return AVERROR_INVALIDDATA;

  359. 

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

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

  362. 

  363.     hdr      = *src++;

  364.     sub_type = hdr >> 5;

  365.     if (sub_type == 0) {

  366.         int j;

  367.         memcpy(transp, src, 3);

  368.         src += 3;

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

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

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

  372.         return 0;

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

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

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

  376.     }

  377. 

  378.     if (sub_type != 2) {

  379.         memcpy(transp, src, 3);

  380.         src += 3;

  381.     }

  382.     npal = *src++ + 1;

  383.     if (src_end - src < npal * 3)

  384.         return AVERROR_INVALIDDATA;

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

  386.     src += npal * 3;

  387.     if (sub_type != 2) {

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

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

  390.                 tidx = i;

  391.                 break;

  392.             }

  393.         }

  394.     }

  395. 

  396.     if (src_end - src < 2)

  397.         return 0;

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

  399.     src  += 2;

  400. 

  401.     if (src_end - src < zsize + (sub_type != 2))

  402.         return AVERROR_INVALIDDATA;

  403. 

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

  405.     if (ret)

  406.         return AVERROR_INVALIDDATA;

  407.     src += zsize;

  408. 

  409.     if (sub_type == 2) {

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

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

  412.         return 0;

  413.     }

  414. 

  415.     nblocks = *src++ + 1;

  416.     cblocks = 0;

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

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

  419.     bits = 0;

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

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

  422.             if (!bits) {

  423.                 if (src >= src_end)

  424.                     return AVERROR_INVALIDDATA;

  425.                 bitbuf = *src++;

  426.                 bits   = 8;

  427.             }

  428.             coded = bitbuf & 1;

  429.             bits--;

  430.             bitbuf >>= 1;

  431.             cblocks += coded;

  432.             if (cblocks > nblocks)

  433.                 return AVERROR_INVALIDDATA;

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

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

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

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

  438.         }

  439.     }

  440. 

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

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

  443.                     c->jpeg_tile, c->tile_stride,

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

  445. 

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

  447.                       c->jpeg_tile, c->tile_stride,

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

  449. 

  450.     return 0;

  451. }

  452. 

  453. static int g2m_init_buffers(G2MContext *c)

  454. {

  455.     int aligned_height;

  456. 

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

  458.         c->framebuf_stride = FFALIGN(c->width + 15, 16) * 3;

  459.         aligned_height     = c->height + 15;

  460.         av_free(c->framebuf);

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

  462.         if (!c->framebuf)

  463.             return AVERROR(ENOMEM);

  464.     }

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

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

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

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

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

  470.         av_free(c->synth_tile);

  471.         av_free(c->jpeg_tile);

  472.         av_free(c->kempf_buf);

  473.         av_free(c->kempf_flags);

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

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

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

  477.                                     + FF_INPUT_BUFFER_PADDING_SIZE);

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

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

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

  481.             return AVERROR(ENOMEM);

  482.     }

  483. 

  484.     return 0;

  485. }

  486. 

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

  488.                            GetByteContext *gb)

  489. {

  490.     int i, j, k;

  491.     uint8_t *dst;

  492.     uint32_t bits;

  493.     uint32_t cur_size, cursor_w, cursor_h, cursor_stride;

  494.     uint32_t cursor_hot_x, cursor_hot_y;

  495.     int cursor_fmt, err;

  496. 

  497.     cur_size     = bytestream2_get_be32(gb);

  498.     cursor_w     = bytestream2_get_byte(gb);

  499.     cursor_h     = bytestream2_get_byte(gb);

  500.     cursor_hot_x = bytestream2_get_byte(gb);

  501.     cursor_hot_y = bytestream2_get_byte(gb);

  502.     cursor_fmt   = bytestream2_get_byte(gb);

  503. 

  504.     cursor_stride = FFALIGN(cursor_w, cursor_fmt==1 ? 32 : 1) * 4;

  505. 

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

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

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

  509.                cursor_w, cursor_h);

  510.         return AVERROR_INVALIDDATA;

  511.     }

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

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

  514.                cursor_hot_x, cursor_hot_y);

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

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

  517.     }

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

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

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

  521.                cur_size, bytestream2_get_bytes_left(gb));

  522.         return AVERROR_INVALIDDATA;

  523.     }

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

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

  526.                                       cursor_fmt);

  527.         return AVERROR_PATCHWELCOME;

  528.     }

  529. 

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

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

  532.         return err;

  533.     }

  534. 

  535.     c->cursor_w      = cursor_w;

  536.     c->cursor_h      = cursor_h;

  537.     c->cursor_hot_x  = cursor_hot_x;

  538.     c->cursor_hot_y  = cursor_hot_y;

  539.     c->cursor_fmt    = cursor_fmt;

  540.     c->cursor_stride = cursor_stride;

  541. 

  542.     dst = c->cursor;

  543.     switch (c->cursor_fmt) {

  544.     case 1: // old monochrome

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

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

  547.                 bits = bytestream2_get_be32(gb);

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

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

  550.                     dst   += 4;

  551.                     bits <<= 1;

  552.                 }

  553.             }

  554.         }

  555. 

  556.         dst = c->cursor;

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

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

  559.                 bits = bytestream2_get_be32(gb);

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

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

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

  563.                     case 0:

  564.                         dst[0] = 0xFF;

  565.                         dst[1] = 0x00;

  566.                         dst[2] = 0x00;

  567.                         dst[3] = 0x00;

  568.                         break;

  569.                     case 1:

  570.                         dst[0] = 0xFF;

  571.                         dst[1] = 0xFF;

  572.                         dst[2] = 0xFF;

  573.                         dst[3] = 0xFF;

  574.                         break;

  575.                     default:

  576.                         dst[0] = 0x00;

  577.                         dst[1] = 0x00;

  578.                         dst[2] = 0x00;

  579.                         dst[3] = 0x00;

  580.                     }

  581.                     dst   += 4;

  582.                     bits <<= 1;

  583.                 }

  584.             }

  585.         }

  586.         break;

  587.     case 32: // full colour

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

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

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

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

  592.                 int val = bytestream2_get_be32(gb);

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

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

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

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

  597.             }

  598.         }

  599.         break;

  600.     default:

  601.         return AVERROR_PATCHWELCOME;

  602.     }

  603.     return 0;

  604. }

  605. 

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

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

  608. 

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

  610. {

  611.     int i, j;

  612.     int x, y, w, h;

  613.     const uint8_t *cursor;

  614. 

  615.     if (!c->cursor)

  616.         return;

  617. 

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

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

  620. 

  621.     cursor = c->cursor;

  622.     w      = c->cursor_w;

  623.     h      = c->cursor_h;

  624. 

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

  626.         w = c->width - x;

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

  628.         h = c->height - y;

  629.     if (x < 0) {

  630.         w      +=  x;

  631.         cursor += -x * 4;

  632.     } else {

  633.         dst    +=  x * 3;

  634.     }

  635.     if (y < 0) {

  636.         h      +=  y;

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

  638.     } else {

  639.         dst    +=  y * stride;

  640.     }

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

  642.         return;

  643. 

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

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

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

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

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

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

  650.         }

  651.         dst    += stride;

  652.         cursor += c->cursor_stride;

  653.     }

  654. }

  655. 

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

  657.                             int *got_picture_ptr, AVPacket *avpkt)

  658. {

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

  660.     int buf_size = avpkt->size;

  661.     G2MContext *c = avctx->priv_data;

  662.     AVFrame *pic = data;

  663.     GetByteContext bc, tbc;

  664.     int magic;

  665.     int got_header = 0;

  666.     uint32_t chunk_size, r_mask, g_mask, b_mask;

  667.     int chunk_type, chunk_start;

  668.     int i;

  669.     int ret;

  670. 

  671.     if (buf_size < 12) {

  672.         av_log(avctx, AV_LOG_ERROR,

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

  674.                buf_size);

  675.         return AVERROR_INVALIDDATA;

  676.     }

  677. 

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

  679. 

  680.     magic = bytestream2_get_be32(&bc);

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

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

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

  684.         return AVERROR_INVALIDDATA;

  685.     }

  686. 

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

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

  689.         return AVERROR(ENOSYS);

  690.     }

  691. 

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

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

  694.         chunk_type  = bytestream2_get_byte(&bc);

  695.         chunk_start = bytestream2_tell(&bc);

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

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

  698.                    chunk_size, chunk_type);

  699.             break;

  700.         }

  701.         switch (chunk_type) {

  702.         case DISPLAY_INFO:

  703.             got_header =

  704.             c->got_header = 0;

  705.             if (chunk_size < 21) {

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

  707.                        chunk_size);

  708.                 break;

  709.             }

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

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

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

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

  714.                 av_log(avctx, AV_LOG_ERROR,

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

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

  717.                 ret = AVERROR_INVALIDDATA;

  718.                 goto header_fail;

  719.             }

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

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

  722.                 if (ret < 0)

  723.                     goto header_fail;

  724.             }

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

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

  727.                 av_log(avctx, AV_LOG_ERROR,

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

  729.                        c->compression);

  730.                 ret = AVERROR_PATCHWELCOME;

  731.                 goto header_fail;

  732.             }

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

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

  735.             if (!c->tile_width || !c->tile_height ||

  736.                 ((c->tile_width | c->tile_height) & 0xF)) {

  737.                 av_log(avctx, AV_LOG_ERROR,

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

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

  740.                 ret = AVERROR_INVALIDDATA;

  741.                 goto header_fail;

  742.             }

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

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

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

  746.             if (c->bpp == 32) {

  747.                 if (bytestream2_get_bytes_left(&bc) < 16 ||

  748.                     (chunk_size - 21) < 16) {

  749.                     av_log(avctx, AV_LOG_ERROR,

  750.                            "Display info: missing bitmasks!\n");

  751.                     ret = AVERROR_INVALIDDATA;

  752.                     goto header_fail;

  753.                 }

  754.                 r_mask = bytestream2_get_be32(&bc);

  755.                 g_mask = bytestream2_get_be32(&bc);

  756.                 b_mask = bytestream2_get_be32(&bc);

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

  758.                     av_log(avctx, AV_LOG_ERROR,

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

  760.                            r_mask, g_mask, b_mask);

  761.                     ret = AVERROR_PATCHWELCOME;

  762.                     goto header_fail;

  763.                 }

  764.             } else {

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

  766.                 ret = AVERROR_PATCHWELCOME;

  767.                 goto header_fail;

  768.             }

  769.             if (g2m_init_buffers(c)) {

  770.                 ret = AVERROR(ENOMEM);

  771.                 goto header_fail;

  772.             }

  773.             got_header = 1;

  774.             break;

  775.         case TILE_DATA:

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

  777.                 av_log(avctx, AV_LOG_WARNING,

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

  779.                 break;

  780.             }

  781.             if (chunk_size < 2) {

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

  783.                        chunk_size);

  784.                 break;

  785.             }

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

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

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

  789.                 av_log(avctx, AV_LOG_ERROR,

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

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

  792.                 break;

  793.             }

  794.             ret = 0;

  795.             switch (c->compression) {

  796.             case COMPR_EPIC_J_B:

  797.                 av_log(avctx, AV_LOG_ERROR,

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

  799.                 return AVERROR(ENOSYS);

  800.             case COMPR_KEMPF_J_B:

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

  802.                                         buf + bytestream2_tell(&bc),

  803.                                         chunk_size - 2);

  804.                 break;

  805.             }

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

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

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

  809.             break;

  810.         case CURSOR_POS:

  811.             if (chunk_size < 5) {

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

  813.                        chunk_size);

  814.                 break;

  815.             }

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

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

  818.             break;

  819.         case CURSOR_SHAPE:

  820.             if (chunk_size < 8) {

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

  822.                        chunk_size);

  823.                 break;

  824.             }

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

  826.                              chunk_size - 4);

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

  828.             break;

  829.         case CHUNK_CC:

  830.         case CHUNK_CD:

  831.             break;

  832.         default:

  833.             av_log(avctx, AV_LOG_WARNING, "Skipping chunk type %02"PRIX32"\n",

  834.                    chunk_type);

  835.         }

  836. 

  837.         /* navigate to next chunk */

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

  839.     }

  840.     if (got_header)

  841.         c->got_header = 1;

  842. 

  843.     if (c->width && c->height && c->framebuf) {

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

  845.             return ret;

  846. 

  847.         pic->key_frame = got_header;

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

  849. 

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

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

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

  853.                    c->width * 3);

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

  855. 

  856.         *got_picture_ptr = 1;

  857.     }

  858. 

  859.     return buf_size;

  860. 

  861. header_fail:

  862.     c->width   =

  863.     c->height  = 0;

  864.     c->tiles_x =

  865.     c->tiles_y = 0;

  866.     return ret;

  867. }

  868. 

  869. static av_cold int g2m_decode_init(AVCodecContext *avctx)

  870. {

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

  872.     int ret;

  873. 

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

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

  876.         jpg_free_context(&c->jc);

  877.         return AVERROR(ENOMEM);

  878.     }

  879. 

  880.     avctx->pix_fmt = AV_PIX_FMT_RGB24;

  881. 

  882.     return 0;

  883. }

  884. 

  885. static av_cold int g2m_decode_end(AVCodecContext *avctx)

  886. {

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

  888. 

  889.     jpg_free_context(&c->jc);

  890. 

  891.     av_freep(&c->kempf_buf);

  892.     av_freep(&c->kempf_flags);

  893.     av_freep(&c->synth_tile);

  894.     av_freep(&c->jpeg_tile);

  895.     av_freep(&c->cursor);

  896.     av_freep(&c->framebuf);

  897. 

  898.     return 0;

  899. }

  900. 

  901. AVCodec ff_g2m_decoder = {

  902.     .name           = "g2m",

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

  904.     .type           = AVMEDIA_TYPE_VIDEO,

  905.     .id             = AV_CODEC_ID_G2M,

  906.     .priv_data_size = sizeof(G2MContext),

  907.     .init           = g2m_decode_init,

  908.     .close          = g2m_decode_end,

  909.     .decode         = g2m_decode_frame,

  910.     .capabilities   = CODEC_CAP_DR1,

  911. };