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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. #include "avcodec.h"

  32. #include "blockdsp.h"

  33. #include "bytestream.h"

  34. #include "idctdsp.h"

  35. #include "get_bits.h"

  36. #include "internal.h"

  37. #include "mjpeg.h"

  38. 

  39. enum ChunkType {

  40.     DISPLAY_INFO = 0xC8,

  41.     TILE_DATA,

  42.     CURSOR_POS,

  43.     CURSOR_SHAPE,

  44.     CHUNK_CC,

  45.     CHUNK_CD

  46. };

  47. 

  48. enum Compression {

  49.     COMPR_EPIC_J_B = 2,

  50.     COMPR_KEMPF_J_B,

  51. };

  52. 

  53. static const uint8_t luma_quant[64] = {

  54.      8,  6,  5,  8, 12, 20, 26, 31,

  55.      6,  6,  7, 10, 13, 29, 30, 28,

  56.      7,  7,  8, 12, 20, 29, 35, 28,

  57.      7,  9, 11, 15, 26, 44, 40, 31,

  58.      9, 11, 19, 28, 34, 55, 52, 39,

  59.     12, 18, 28, 32, 41, 52, 57, 46,

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

  61.     36, 46, 48, 49, 56, 50, 52, 50

  62. };

  63. 

  64. static const uint8_t chroma_quant[64] = {

  65.      9,  9, 12, 24, 50, 50, 50, 50,

  66.      9, 11, 13, 33, 50, 50, 50, 50,

  67.     12, 13, 28, 50, 50, 50, 50, 50,

  68.     24, 33, 50, 50, 50, 50, 50, 50,

  69.     50, 50, 50, 50, 50, 50, 50, 50,

  70.     50, 50, 50, 50, 50, 50, 50, 50,

  71.     50, 50, 50, 50, 50, 50, 50, 50,

  72.     50, 50, 50, 50, 50, 50, 50, 50,

  73. };

  74. 

  75. typedef struct JPGContext {

  76.     BlockDSPContext bdsp;

  77.     IDCTDSPContext idsp;

  78.     ScanTable  scantable;

  79. 

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

  81.     int        prev_dc[3];

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

  83. 

  84.     uint8_t    *buf;

  85. } JPGContext;

  86. 

  87. typedef struct G2MContext {

  88.     JPGContext jc;

  89.     int        version;

  90. 

  91.     int        compression;

  92.     int        width, height, bpp;

  93.     int        orig_width, orig_height;

  94.     int        tile_width, tile_height;

  95.     int        tiles_x, tiles_y, tile_x, tile_y;

  96. 

  97.     int        got_header;

  98. 

  99.     uint8_t    *framebuf;

  100.     int        framebuf_stride, old_width, old_height;

  101. 

  102.     uint8_t    *synth_tile, *jpeg_tile;

  103.     int        tile_stride, old_tile_w, old_tile_h;

  104. 

  105.     uint8_t    *kempf_buf, *kempf_flags;

  106. 

  107.     uint8_t    *cursor;

  108.     int        cursor_stride;

  109.     int        cursor_fmt;

  110.     int        cursor_w, cursor_h, cursor_x, cursor_y;

  111.     int        cursor_hot_x, cursor_hot_y;

  112. } G2MContext;

  113. 

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

  115.                              const uint8_t *val_table, int nb_codes,

  116.                              int is_ac)

  117. {

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

  119.     uint16_t huff_code[256];

  120.     uint16_t huff_sym[256];

  121.     int i;

  122. 

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

  124. 

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

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

  127. 

  128.     if (is_ac)

  129.         huff_sym[0] = 16 * 256;

  130. 

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

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

  133. }

  134. 

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

  136. {

  137.     int ret;

  138. 

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

  140.                     avpriv_mjpeg_val_dc, 12, 0);

  141.     if (ret)

  142.         return ret;

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

  144.                     avpriv_mjpeg_val_dc, 12, 0);

  145.     if (ret)

  146.         return ret;

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

  148.                     avpriv_mjpeg_val_ac_luminance, 251, 1);

  149.     if (ret)

  150.         return ret;

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

  152.                     avpriv_mjpeg_val_ac_chrominance, 251, 1);

  153.     if (ret)

  154.         return ret;

  155. 

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

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

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

  159.                       ff_zigzag_direct);

  160. 

  161.     return 0;

  162. }

  163. 

  164. static av_cold void jpg_free_context(JPGContext *ctx)

  165. {

  166.     int i;

  167. 

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

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

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

  171.     }

  172. 

  173.     av_freep(&ctx->buf);

  174. }

  175. 

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

  177.                          uint8_t *dst, int *dst_size)

  178. {

  179.     const uint8_t *src_end = src + src_size;

  180.     uint8_t *dst_start = dst;

  181. 

  182.     while (src < src_end) {

  183.         uint8_t x = *src++;

  184. 

  185.         *dst++ = x;

  186. 

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

  188.             src++;

  189.     }

  190.     *dst_size = dst - dst_start;

  191. }

  192. 

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

  194.                             int plane, int16_t *block)

  195. {

  196.     int dc, val, pos;

  197.     const int is_chroma = !!plane;

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

  199. 

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

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

  202.     if (dc < 0)

  203.         return AVERROR_INVALIDDATA;

  204.     if (dc)

  205.         dc = get_xbits(gb, dc);

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

  207.     block[0]          = dc;

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

  209. 

  210.     pos = 0;

  211.     while (pos < 63) {

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

  213.         if (val < 0)

  214.             return AVERROR_INVALIDDATA;

  215.         pos += val >> 4;

  216.         val &= 0xF;

  217.         if (pos > 63)

  218.             return val ? AVERROR_INVALIDDATA : 0;

  219.         if (val) {

  220.             int nbits = val;

  221. 

  222.             val                                 = get_xbits(gb, nbits);

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

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

  225.         }

  226.     }

  227.     return 0;

  228. }

  229. 

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

  231. {

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

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

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

  235. }

  236. 

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

  238.                            const uint8_t *src, int src_size,

  239.                            uint8_t *dst, int dst_stride,

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

  241.                            int swapuv)

  242. {

  243.     GetBitContext gb;

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

  245.     int bx, by;

  246.     int unesc_size;

  247.     int ret;

  248. 

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

  250.                            src_size + FF_INPUT_BUFFER_PADDING_SIZE)) < 0)

  251.         return ret;

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

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

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

  255. 

  256.     width = FFALIGN(width, 16);

  257.     mb_w  =  width        >> 4;

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

  259. 

  260.     if (!num_mbs)

  261.         num_mbs = mb_w * mb_h * 4;

  262. 

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

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

  265.     bx = by = 0;

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

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

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

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

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

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

  272.                 bx += 16;

  273.                 continue;

  274.             }

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

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

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

  278.                         continue;

  279.                     num_mbs--;

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

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

  282.                         return ret;

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

  284.                 }

  285.             }

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

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

  288.                     return ret;

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

  290.             }

  291. 

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

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

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

  295.                     int Y, U, V;

  296. 

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

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

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

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

  301.                 }

  302.             }

  303. 

  304.             if (!num_mbs)

  305.                 return 0;

  306.             bx += 16;

  307.         }

  308.         bx  = 0;

  309.         by += 16;

  310.         if (mask)

  311.             mask += mask_stride * 2;

  312.     }

  313. 

  314.     return 0;

  315. }

  316. 

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

  318.                               uint8_t *dst, int stride,

  319.                               const uint8_t *jpeg_tile, int tile_stride,

  320.                               int width, int height,

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

  322. {

  323.     GetBitContext gb;

  324.     int i, j, nb, col;

  325. 

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

  327. 

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

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

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

  331.     else                 nb = 8;

  332. 

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

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

  335.             continue;

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

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

  338.             if (col != tidx)

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

  340.             else

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

  342.         }

  343.     }

  344. }

  345. 

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

  347.                              const uint8_t *src, int src_size)

  348. {

  349.     int width, height;

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

  351.     int i, j;

  352.     const uint8_t *src_end = src + src_size;

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

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

  355.     int sub_type;

  356.     int nblocks, cblocks, bstride;

  357.     int bits, bitbuf, coded;

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

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

  360. 

  361.     if (src_size < 2)

  362.         return AVERROR_INVALIDDATA;

  363. 

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

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

  366. 

  367.     hdr      = *src++;

  368.     sub_type = hdr >> 5;

  369.     if (sub_type == 0) {

  370.         int j;

  371.         memcpy(transp, src, 3);

  372.         src += 3;

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

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

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

  376.         return 0;

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

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

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

  380.     }

  381. 

  382.     if (sub_type != 2) {

  383.         memcpy(transp, src, 3);

  384.         src += 3;

  385.     }

  386.     npal = *src++ + 1;

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

  388.     src += npal * 3;

  389.     if (sub_type != 2) {

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

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

  392.                 tidx = i;

  393.                 break;

  394.             }

  395.         }

  396.     }

  397. 

  398.     if (src_end - src < 2)

  399.         return 0;

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

  401.     src  += 2;

  402. 

  403.     if (src_end - src < zsize)

  404.         return AVERROR_INVALIDDATA;

  405. 

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

  407.     if (ret)

  408.         return AVERROR_INVALIDDATA;

  409.     src += zsize;

  410. 

  411.     if (sub_type == 2) {

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

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

  414.         return 0;

  415.     }

  416. 

  417.     nblocks = *src++ + 1;

  418.     cblocks = 0;

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

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

  421.     bits = 0;

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

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

  424.             if (!bits) {

  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 * 3, 16);

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

  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 * 3, 16);

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

  555.         }

  556. 

  557.         dst = c->cursor;

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

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

  560.                 bits = bytestream2_get_be32(gb);

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

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

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

  564.                     case 0:

  565.                         dst[0] = 0xFF;

  566.                         dst[1] = 0x00;

  567.                         dst[2] = 0x00;

  568.                         dst[3] = 0x00;

  569.                         break;

  570.                     case 1:

  571.                         dst[0] = 0xFF;

  572.                         dst[1] = 0xFF;

  573.                         dst[2] = 0xFF;

  574.                         dst[3] = 0xFF;

  575.                         break;

  576.                     default:

  577.                         dst[0] = 0x00;

  578.                         dst[1] = 0x00;

  579.                         dst[2] = 0x00;

  580.                         dst[3] = 0x00;

  581.                     }

  582.                     dst   += 4;

  583.                     bits <<= 1;

  584.                 }

  585.             }

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

  587.         }

  588.         break;

  589.     case 32: // full colour

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

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

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

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

  594.                 int val = bytestream2_get_be32(gb);

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

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

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

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

  599.             }

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

  601.         }

  602.         break;

  603.     default:

  604.         return AVERROR_PATCHWELCOME;

  605.     }

  606.     return 0;

  607. }

  608. 

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

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

  611. 

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

  613. {

  614.     int i, j;

  615.     int x, y, w, h;

  616.     const uint8_t *cursor;

  617. 

  618.     if (!c->cursor)

  619.         return;

  620. 

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

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

  623. 

  624.     cursor = c->cursor;

  625.     w      = c->cursor_w;

  626.     h      = c->cursor_h;

  627. 

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

  629.         w = c->width - x;

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

  631.         h = c->height - y;

  632.     if (x < 0) {

  633.         w      +=  x;

  634.         cursor += -x * 4;

  635.     } else {

  636.         dst    +=  x * 3;

  637.     }

  638.     if (y < 0) {

  639.         h      +=  y;

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

  641.     } else {

  642.         dst    +=  y * stride;

  643.     }

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

  645.         return;

  646. 

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

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

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

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

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

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

  653.         }

  654.         dst    += stride;

  655.         cursor += c->cursor_stride;

  656.     }

  657. }

  658. 

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

  660.                             int *got_picture_ptr, AVPacket *avpkt)

  661. {

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

  663.     int buf_size = avpkt->size;

  664.     G2MContext *c = avctx->priv_data;

  665.     AVFrame *pic = data;

  666.     GetByteContext bc, tbc;

  667.     int magic;

  668.     int got_header = 0;

  669.     uint32_t chunk_size, r_mask, g_mask, b_mask;

  670.     int chunk_type, chunk_start;

  671.     int i;

  672.     int ret;

  673. 

  674.     if (buf_size < 12) {

  675.         av_log(avctx, AV_LOG_ERROR,

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

  677.                buf_size);

  678.         return AVERROR_INVALIDDATA;

  679.     }

  680. 

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

  682. 

  683.     magic = bytestream2_get_be32(&bc);

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

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

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

  687.         return AVERROR_INVALIDDATA;

  688.     }

  689. 

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

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

  692.         return AVERROR(ENOSYS);

  693.     }

  694. 

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

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

  697.         chunk_type  = bytestream2_get_byte(&bc);

  698.         chunk_start = bytestream2_tell(&bc);

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

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

  701.                    chunk_size, chunk_type);

  702.             break;

  703.         }

  704.         switch (chunk_type) {

  705.         case DISPLAY_INFO:

  706.             c->got_header = 0;

  707.             if (chunk_size < 21) {

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

  709.                        chunk_size);

  710.                 break;

  711.             }

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

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

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

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

  716.                 av_log(avctx, AV_LOG_ERROR,

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

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

  719.                 ret = AVERROR_INVALIDDATA;

  720.                 goto header_fail;

  721.             }

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

  723.                 ff_set_dimensions(avctx, c->width, c->height);

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

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

  726.                 av_log(avctx, AV_LOG_ERROR,

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

  728.                        c->compression);

  729.                 return AVERROR_PATCHWELCOME;

  730.             }

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

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

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

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

  735.                 av_log(avctx, AV_LOG_ERROR,

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

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

  738.                 ret = AVERROR_INVALIDDATA;

  739.                 goto header_fail;

  740.             }

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

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

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

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

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

  746.                     (chunk_size - 21) < 16) {

  747.                     av_log(avctx, AV_LOG_ERROR,

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

  749.                     return AVERROR_INVALIDDATA;

  750.                 }

  751.                 r_mask = bytestream2_get_be32(&bc);

  752.                 g_mask = bytestream2_get_be32(&bc);

  753.                 b_mask = bytestream2_get_be32(&bc);

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

  755.                     av_log(avctx, AV_LOG_ERROR,

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

  757.                            r_mask, g_mask, b_mask);

  758.                     return AVERROR_PATCHWELCOME;

  759.                 }

  760.             } else {

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

  762.                 return AVERROR_PATCHWELCOME;

  763.             }

  764.             if (g2m_init_buffers(c)) {

  765.                 ret = AVERROR(ENOMEM);

  766.                 goto header_fail;

  767.             }

  768.             got_header = 1;

  769.             break;

  770.         case TILE_DATA:

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

  772.                 av_log(avctx, AV_LOG_WARNING,

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

  774.                 break;

  775.             }

  776.             if (chunk_size < 2) {

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

  778.                        chunk_size);

  779.                 break;

  780.             }

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

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

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

  784.                 av_log(avctx, AV_LOG_ERROR,

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

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

  787.                 break;

  788.             }

  789.             ret = 0;

  790.             switch (c->compression) {

  791.             case COMPR_EPIC_J_B:

  792.                 av_log(avctx, AV_LOG_ERROR,

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

  794.                 return AVERROR(ENOSYS);

  795.             case COMPR_KEMPF_J_B:

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

  797.                                         buf + bytestream2_tell(&bc),

  798.                                         chunk_size - 2);

  799.                 break;

  800.             }

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

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

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

  804.             break;

  805.         case CURSOR_POS:

  806.             if (chunk_size < 5) {

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

  808.                        chunk_size);

  809.                 break;

  810.             }

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

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

  813.             break;

  814.         case CURSOR_SHAPE:

  815.             if (chunk_size < 8) {

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

  817.                        chunk_size);

  818.                 break;

  819.             }

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

  821.                              chunk_size - 4);

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

  823.             break;

  824.         case CHUNK_CC:

  825.         case CHUNK_CD:

  826.             break;

  827.         default:

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

  829.                    chunk_type);

  830.         }

  831. 

  832.         /* navigate to next chunk */

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

  834.     }

  835.     if (got_header)

  836.         c->got_header = 1;

  837. 

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

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

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

  841.             return ret;

  842.         }

  843. 

  844.         pic->key_frame = got_header;

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

  846. 

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

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

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

  850.                    c->width * 3);

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

  852. 

  853.         *got_picture_ptr = 1;

  854.     }

  855. 

  856.     return buf_size;

  857. 

  858. header_fail:

  859.     c->width   =

  860.     c->height  = 0;

  861.     c->tiles_x =

  862.     c->tiles_y = 0;

  863.     return ret;

  864. }

  865. 

  866. static av_cold int g2m_decode_init(AVCodecContext *avctx)

  867. {

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

  869.     int ret;

  870. 

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

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

  873.         jpg_free_context(&c->jc);

  874.         return AVERROR(ENOMEM);

  875.     }

  876. 

  877.     avctx->pix_fmt = AV_PIX_FMT_RGB24;

  878. 

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

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

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

  882. 

  883.     return 0;

  884. }

  885. 

  886. static av_cold int g2m_decode_end(AVCodecContext *avctx)

  887. {

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

  889. 

  890.     jpg_free_context(&c->jc);

  891. 

  892.     av_freep(&c->kempf_buf);

  893.     av_freep(&c->kempf_flags);

  894.     av_freep(&c->synth_tile);

  895.     av_freep(&c->jpeg_tile);

  896.     av_freep(&c->cursor);

  897.     av_freep(&c->framebuf);

  898. 

  899.     return 0;

  900. }

  901. 

  902. AVCodec ff_g2m_decoder = {

  903.     .name           = "g2m",

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

  905.     .type           = AVMEDIA_TYPE_VIDEO,

  906.     .id             = AV_CODEC_ID_G2M,

  907.     .priv_data_size = sizeof(G2MContext),

  908.     .init           = g2m_decode_init,

  909.     .close          = g2m_decode_end,

  910.     .decode         = g2m_decode_frame,

  911.     .capabilities   = CODEC_CAP_DR1,

  912. };