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FFmpeg/libavcodec/g2meet.c

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  1. /*

  2.  * Go2Webinar decoder

  3.  * Copyright (c) 2012 Konstantin Shishkov

  4.  *

  5.  * This file is part of Libav.

  6.  *

  7.  * Libav is free software; you can redistribute it and/or

  8.  * modify it under the terms of the GNU Lesser General Public

  9.  * License as published by the Free Software Foundation; either

  10.  * version 2.1 of the License, or (at your option) any later version.

  11.  *

  12.  * Libav is distributed in the hope that it will be useful,

  13.  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  14.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

  15.  * Lesser General Public License for more details.

  16.  *

  17.  * You should have received a copy of the GNU Lesser General Public

  18.  * License along with Libav; if not, write to the Free Software

  19.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

  20.  */

  21. 

  22. /**

  23.  * @file

  24.  * Go2Webinar decoder

  25.  */

  26. 

  27. #include <zlib.h>

  28. 

  29. #include "libavutil/intreadwrite.h"

  30. #include "avcodec.h"

  31. #include "bytestream.h"

  32. #include "dsputil.h"

  33. #include "get_bits.h"

  34. #include "internal.h"

  35. #include "mjpeg.h"

  36. 

  37. enum ChunkType {

  38.     DISPLAY_INFO = 0xC8,

  39.     TILE_DATA,

  40.     CURSOR_POS,

  41.     CURSOR_SHAPE,

  42.     CHUNK_CC,

  43.     CHUNK_CD

  44. };

  45. 

  46. enum Compression {

  47.     COMPR_EPIC_J_B = 2,

  48.     COMPR_KEMPF_J_B,

  49. };

  50. 

  51. static const uint8_t luma_quant[64] = {

  52.      8,  6,  5,  8, 12, 20, 26, 31,

  53.      6,  6,  7, 10, 13, 29, 30, 28,

  54.      7,  7,  8, 12, 20, 29, 35, 28,

  55.      7,  9, 11, 15, 26, 44, 40, 31,

  56.      9, 11, 19, 28, 34, 55, 52, 39,

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

  58.     25, 32, 39, 44, 52, 61, 60, 51,

  59.     36, 46, 48, 49, 56, 50, 52, 50

  60. };

  61. 

  62. static const uint8_t chroma_quant[64] = {

  63.      9,  9, 12, 24, 50, 50, 50, 50,

  64.      9, 11, 13, 33, 50, 50, 50, 50,

  65.     12, 13, 28, 50, 50, 50, 50, 50,

  66.     24, 33, 50, 50, 50, 50, 50, 50,

  67.     50, 50, 50, 50, 50, 50, 50, 50,

  68.     50, 50, 50, 50, 50, 50, 50, 50,

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

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

  71. };

  72. 

  73. typedef struct JPGContext {

  74.     DSPContext dsp;

  75.     ScanTable  scantable;

  76. 

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

  78.     int        prev_dc[3];

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

  80. 

  81.     uint8_t    *buf;

  82. } JPGContext;

  83. 

  84. typedef struct G2MContext {

  85.     JPGContext jc;

  86.     int        version;

  87. 

  88.     int        compression;

  89.     int        width, height, bpp;

  90.     int        tile_width, tile_height;

  91.     int        tiles_x, tiles_y, tile_x, tile_y;

  92. 

  93.     int        got_header;

  94. 

  95.     uint8_t    *framebuf;

  96.     int        framebuf_stride, old_width, old_height;

  97. 

  98.     uint8_t    *synth_tile, *jpeg_tile;

  99.     int        tile_stride, old_tile_w, old_tile_h;

  100. 

  101.     uint8_t    *kempf_buf, *kempf_flags;

  102. 

  103.     uint8_t    *cursor;

  104.     int        cursor_stride;

  105.     int        cursor_fmt;

  106.     int        cursor_w, cursor_h, cursor_x, cursor_y;

  107.     int        cursor_hot_x, cursor_hot_y;

  108. } G2MContext;

  109. 

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

  111.                              const uint8_t *val_table, int nb_codes,

  112.                              int is_ac)

  113. {

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

  115.     uint16_t huff_code[256];

  116.     uint16_t huff_sym[256];

  117.     int i;

  118. 

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

  120. 

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

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

  123. 

  124.     if (is_ac)

  125.         huff_sym[0] = 16 * 256;

  126. 

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

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

  129. }

  130. 

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

  132. {

  133.     int ret;

  134. 

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

  136.                     avpriv_mjpeg_val_dc, 12, 0);

  137.     if (ret)

  138.         return ret;

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

  140.                     avpriv_mjpeg_val_dc, 12, 0);

  141.     if (ret)

  142.         return ret;

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

  144.                     avpriv_mjpeg_val_ac_luminance, 251, 1);

  145.     if (ret)

  146.         return ret;

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

  148.                     avpriv_mjpeg_val_ac_chrominance, 251, 1);

  149.     if (ret)

  150.         return ret;

  151. 

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

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

  154.                       ff_zigzag_direct);

  155. 

  156.     return 0;

  157. }

  158. 

  159. static av_cold void jpg_free_context(JPGContext *ctx)

  160. {

  161.     int i;

  162. 

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

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

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

  166.     }

  167. 

  168.     av_freep(&ctx->buf);

  169. }

  170. 

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

  172.                          uint8_t *dst, int *dst_size)

  173. {

  174.     const uint8_t *src_end = src + src_size;

  175.     uint8_t *dst_start = dst;

  176. 

  177.     while (src < src_end) {

  178.         uint8_t x = *src++;

  179. 

  180.         *dst++ = x;

  181. 

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

  183.             src++;

  184.     }

  185.     *dst_size = dst - dst_start;

  186. }

  187. 

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

  189.                             int plane, int16_t *block)

  190. {

  191.     int dc, val, pos;

  192.     const int is_chroma = !!plane;

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

  194. 

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

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

  197.     if (dc < 0)

  198.         return AVERROR_INVALIDDATA;

  199.     if (dc)

  200.         dc = get_xbits(gb, dc);

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

  202.     block[0]          = dc;

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

  204. 

  205.     pos = 0;

  206.     while (pos < 63) {

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

  208.         if (val < 0)

  209.             return AVERROR_INVALIDDATA;

  210.         pos += val >> 4;

  211.         val &= 0xF;

  212.         if (pos > 63)

  213.             return val ? AVERROR_INVALIDDATA : 0;

  214.         if (val) {

  215.             int nbits = val;

  216. 

  217.             val                                 = get_xbits(gb, nbits);

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

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

  220.         }

  221.     }

  222.     return 0;

  223. }

  224. 

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

  226. {

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

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

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

  230. }

  231. 

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

  233.                            const uint8_t *src, int src_size,

  234.                            uint8_t *dst, int dst_stride,

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

  236.                            int swapuv)

  237. {

  238.     GetBitContext gb;

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

  240.     int bx, by;

  241.     int unesc_size;

  242.     int ret;

  243. 

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

  245.                            src_size + FF_INPUT_BUFFER_PADDING_SIZE)) < 0)

  246.         return ret;

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

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

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

  250. 

  251.     width = FFALIGN(width, 16);

  252.     mb_w  =  width        >> 4;

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

  254. 

  255.     if (!num_mbs)

  256.         num_mbs = mb_w * mb_h * 4;

  257. 

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

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

  260.     bx = by = 0;

  261.     c->dsp.clear_blocks(c->block[0]);

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

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

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

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

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

  267.                 bx += 16;

  268.                 continue;

  269.             }

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

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

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

  273.                         continue;

  274.                     num_mbs--;

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

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

  277.                         return ret;

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

  279.                 }

  280.             }

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

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

  283.                     return ret;

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

  285.             }

  286. 

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

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

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

  290.                     int Y, U, V;

  291. 

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

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

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

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

  296.                 }

  297.             }

  298. 

  299.             if (!num_mbs)

  300.                 return 0;

  301.             bx += 16;

  302.         }

  303.         bx  = 0;

  304.         by += 16;

  305.         if (mask)

  306.             mask += mask_stride * 2;

  307.     }

  308. 

  309.     return 0;

  310. }

  311. 

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

  313.                               uint8_t *dst, int stride,

  314.                               const uint8_t *jpeg_tile, int tile_stride,

  315.                               int width, int height,

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

  317. {

  318.     GetBitContext gb;

  319.     int i, j, nb, col;

  320. 

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

  322. 

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

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

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

  326.     else                 nb = 8;

  327. 

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

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

  330.             continue;

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

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

  333.             if (col != tidx)

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

  335.             else

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

  337.         }

  338.     }

  339. }

  340. 

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

  342.                              const uint8_t *src, int src_size)

  343. {

  344.     int width, height;

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

  346.     int i, j;

  347.     const uint8_t *src_end = src + src_size;

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

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

  350.     int sub_type;

  351.     int nblocks, cblocks, bstride;

  352.     int bits, bitbuf, coded;

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

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

  355. 

  356.     if (src_size < 2)

  357.         return AVERROR_INVALIDDATA;

  358. 

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

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

  361. 

  362.     hdr      = *src++;

  363.     sub_type = hdr >> 5;

  364.     if (sub_type == 0) {

  365.         int j;

  366.         memcpy(transp, src, 3);

  367.         src += 3;

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

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

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

  371.         return 0;

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

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

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

  375.     }

  376. 

  377.     if (sub_type != 2) {

  378.         memcpy(transp, src, 3);

  379.         src += 3;

  380.     }

  381.     npal = *src++ + 1;

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

  383.     src += npal * 3;

  384.     if (sub_type != 2) {

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

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

  387.                 tidx = i;

  388.                 break;

  389.             }

  390.         }

  391.     }

  392. 

  393.     if (src_end - src < 2)

  394.         return 0;

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

  396.     src  += 2;

  397. 

  398.     if (src_end - src < zsize)

  399.         return AVERROR_INVALIDDATA;

  400. 

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

  402.     if (ret)

  403.         return AVERROR_INVALIDDATA;

  404.     src += zsize;

  405. 

  406.     if (sub_type == 2) {

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

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

  409.         return 0;

  410.     }

  411. 

  412.     nblocks = *src++ + 1;

  413.     cblocks = 0;

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

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

  416.     bits = 0;

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

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

  419.             if (!bits) {

  420.                 bitbuf = *src++;

  421.                 bits   = 8;

  422.             }

  423.             coded = bitbuf & 1;

  424.             bits--;

  425.             bitbuf >>= 1;

  426.             cblocks += coded;

  427.             if (cblocks > nblocks)

  428.                 return AVERROR_INVALIDDATA;

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

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

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

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

  433.         }

  434.     }

  435. 

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

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

  438.                     c->jpeg_tile, c->tile_stride,

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

  440. 

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

  442.                       c->jpeg_tile, c->tile_stride,

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

  444. 

  445.     return 0;

  446. }

  447. 

  448. static int g2m_init_buffers(G2MContext *c)

  449. {

  450.     int aligned_height;

  451. 

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

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

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

  455.         av_free(c->framebuf);

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

  457.         if (!c->framebuf)

  458.             return AVERROR(ENOMEM);

  459.     }

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

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

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

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

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

  465.         av_free(c->synth_tile);

  466.         av_free(c->jpeg_tile);

  467.         av_free(c->kempf_buf);

  468.         av_free(c->kempf_flags);

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

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

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

  472.                                     + FF_INPUT_BUFFER_PADDING_SIZE);

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

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

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

  476.             return AVERROR(ENOMEM);

  477.     }

  478. 

  479.     return 0;

  480. }

  481. 

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

  483.                            GetByteContext *gb)

  484. {

  485.     int i, j, k;

  486.     uint8_t *dst;

  487.     uint32_t bits;

  488.     uint32_t cur_size, cursor_w, cursor_h, cursor_stride;

  489.     uint32_t cursor_hot_x, cursor_hot_y;

  490.     int cursor_fmt, err;

  491. 

  492.     cur_size     = bytestream2_get_be32(gb);

  493.     cursor_w     = bytestream2_get_byte(gb);

  494.     cursor_h     = bytestream2_get_byte(gb);

  495.     cursor_hot_x = bytestream2_get_byte(gb);

  496.     cursor_hot_y = bytestream2_get_byte(gb);

  497.     cursor_fmt   = bytestream2_get_byte(gb);

  498. 

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

  500. 

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

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

  503.         av_log(avctx, AV_LOG_ERROR, "Invalid cursor dimensions %dx%d\n",

  504.                cursor_w, cursor_h);

  505.         return AVERROR_INVALIDDATA;

  506.     }

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

  508.         av_log(avctx, AV_LOG_WARNING, "Invalid hotspot position %d,%d\n",

  509.                cursor_hot_x, cursor_hot_y);

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

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

  512.     }

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

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

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

  516.                cur_size, bytestream2_get_bytes_left(gb));

  517.         return AVERROR_INVALIDDATA;

  518.     }

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

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

  521.                                       cursor_fmt);

  522.         return AVERROR_PATCHWELCOME;

  523.     }

  524. 

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

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

  527.         return err;

  528.     }

  529. 

  530.     c->cursor_w      = cursor_w;

  531.     c->cursor_h      = cursor_h;

  532.     c->cursor_hot_x  = cursor_hot_x;

  533.     c->cursor_hot_y  = cursor_hot_y;

  534.     c->cursor_fmt    = cursor_fmt;

  535.     c->cursor_stride = cursor_stride;

  536. 

  537.     dst = c->cursor;

  538.     switch (c->cursor_fmt) {

  539.     case 1: // old monochrome

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

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

  542.                 bits = bytestream2_get_be32(gb);

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

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

  545.                     dst   += 4;

  546.                     bits <<= 1;

  547.                 }

  548.             }

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

  550.         }

  551. 

  552.         dst = c->cursor;

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

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

  555.                 bits = bytestream2_get_be32(gb);

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

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

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

  559.                     case 0:

  560.                         dst[0] = 0xFF;

  561.                         dst[1] = 0x00;

  562.                         dst[2] = 0x00;

  563.                         dst[3] = 0x00;

  564.                         break;

  565.                     case 1:

  566.                         dst[0] = 0xFF;

  567.                         dst[1] = 0xFF;

  568.                         dst[2] = 0xFF;

  569.                         dst[3] = 0xFF;

  570.                         break;

  571.                     default:

  572.                         dst[0] = 0x00;

  573.                         dst[1] = 0x00;

  574.                         dst[2] = 0x00;

  575.                         dst[3] = 0x00;

  576.                     }

  577.                     dst   += 4;

  578.                     bits <<= 1;

  579.                 }

  580.             }

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

  582.         }

  583.         break;

  584.     case 32: // full colour

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

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

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

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

  589.                 int val = bytestream2_get_be32(gb);

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

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

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

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

  594.             }

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

  596.         }

  597.         break;

  598.     default:

  599.         return AVERROR_PATCHWELCOME;

  600.     }

  601.     return 0;

  602. }

  603. 

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

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

  606. 

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

  608. {

  609.     int i, j;

  610.     int x, y, w, h;

  611.     const uint8_t *cursor;

  612. 

  613.     if (!c->cursor)

  614.         return;

  615. 

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

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

  618. 

  619.     cursor = c->cursor;

  620.     w      = c->cursor_w;

  621.     h      = c->cursor_h;

  622. 

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

  624.         w = c->width - x;

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

  626.         h = c->height - y;

  627.     if (x < 0) {

  628.         w      +=  x;

  629.         cursor += -x * 4;

  630.     } else {

  631.         dst    +=  x * 3;

  632.     }

  633.     if (y < 0) {

  634.         h      +=  y;

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

  636.     } else {

  637.         dst    +=  y * stride;

  638.     }

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

  640.         return;

  641. 

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

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

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

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

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

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

  648.         }

  649.         dst    += stride;

  650.         cursor += c->cursor_stride;

  651.     }

  652. }

  653. 

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

  655.                             int *got_picture_ptr, AVPacket *avpkt)

  656. {

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

  658.     int buf_size = avpkt->size;

  659.     G2MContext *c = avctx->priv_data;

  660.     AVFrame *pic = data;

  661.     GetByteContext bc, tbc;

  662.     int magic;

  663.     int got_header = 0;

  664.     uint32_t chunk_size, r_mask, g_mask, b_mask;

  665.     int chunk_type, chunk_start;

  666.     int i;

  667.     int ret;

  668. 

  669.     if (buf_size < 12) {

  670.         av_log(avctx, AV_LOG_ERROR,

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

  672.                buf_size);

  673.         return AVERROR_INVALIDDATA;

  674.     }

  675. 

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

  677. 

  678.     magic = bytestream2_get_be32(&bc);

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

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

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

  682.         return AVERROR_INVALIDDATA;

  683.     }

  684. 

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

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

  687.         return AVERROR(ENOSYS);

  688.     }

  689. 

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

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

  692.         chunk_type  = bytestream2_get_byte(&bc);

  693.         chunk_start = bytestream2_tell(&bc);

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

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

  696.                    chunk_size, chunk_type);

  697.             break;

  698.         }

  699.         switch (chunk_type) {

  700.         case DISPLAY_INFO:

  701.             c->got_header = 0;

  702.             if (chunk_size < 21) {

  703.                 av_log(avctx, AV_LOG_ERROR, "Invalid display info size %d\n",

  704.                        chunk_size);

  705.                 break;

  706.             }

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

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

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

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

  711.                 av_log(avctx, AV_LOG_ERROR,

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

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

  714.                 ret = AVERROR_INVALIDDATA;

  715.                 goto header_fail;

  716.             }

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

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

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

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

  721.                 av_log(avctx, AV_LOG_ERROR,

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

  723.                        c->compression);

  724.                 return AVERROR_PATCHWELCOME;

  725.             }

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

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

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

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

  730.                 av_log(avctx, AV_LOG_ERROR,

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

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

  733.                 ret = AVERROR_INVALIDDATA;

  734.                 goto header_fail;

  735.             }

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

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

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

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

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

  741.                     (chunk_size - 21) < 16) {

  742.                     av_log(avctx, AV_LOG_ERROR,

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

  744.                     return AVERROR_INVALIDDATA;

  745.                 }

  746.                 r_mask = bytestream2_get_be32(&bc);

  747.                 g_mask = bytestream2_get_be32(&bc);

  748.                 b_mask = bytestream2_get_be32(&bc);

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

  750.                     av_log(avctx, AV_LOG_ERROR,

  751.                            "Invalid or unsupported bitmasks: R=%X, G=%X, B=%X\n",

  752.                            r_mask, g_mask, b_mask);

  753.                     return AVERROR_PATCHWELCOME;

  754.                 }

  755.             } else {

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

  757.                 return AVERROR_PATCHWELCOME;

  758.             }

  759.             if (g2m_init_buffers(c)) {

  760.                 ret = AVERROR(ENOMEM);

  761.                 goto header_fail;

  762.             }

  763.             got_header = 1;

  764.             break;

  765.         case TILE_DATA:

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

  767.                 av_log(avctx, AV_LOG_WARNING,

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

  769.                 break;

  770.             }

  771.             if (chunk_size < 2) {

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

  773.                        chunk_size);

  774.                 break;

  775.             }

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

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

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

  779.                 av_log(avctx, AV_LOG_ERROR,

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

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

  782.                 break;

  783.             }

  784.             ret = 0;

  785.             switch (c->compression) {

  786.             case COMPR_EPIC_J_B:

  787.                 av_log(avctx, AV_LOG_ERROR,

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

  789.                 return AVERROR(ENOSYS);

  790.             case COMPR_KEMPF_J_B:

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

  792.                                         buf + bytestream2_tell(&bc),

  793.                                         chunk_size - 2);

  794.                 break;

  795.             }

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

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

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

  799.             break;

  800.         case CURSOR_POS:

  801.             if (chunk_size < 5) {

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

  803.                        chunk_size);

  804.                 break;

  805.             }

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

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

  808.             break;

  809.         case CURSOR_SHAPE:

  810.             if (chunk_size < 8) {

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

  812.                        chunk_size);

  813.                 break;

  814.             }

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

  816.                              chunk_size - 4);

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

  818.             break;

  819.         case CHUNK_CC:

  820.         case CHUNK_CD:

  821.             break;

  822.         default:

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

  824.                    chunk_type);

  825.         }

  826. 

  827.         /* navigate to next chunk */

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

  829.     }

  830.     if (got_header)

  831.         c->got_header = 1;

  832. 

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

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

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

  836.             return ret;

  837.         }

  838. 

  839.         pic->key_frame = got_header;

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

  841. 

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

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

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

  845.                    c->width * 3);

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

  847. 

  848.         *got_picture_ptr = 1;

  849.     }

  850. 

  851.     return buf_size;

  852. 

  853. header_fail:

  854.     c->width   =

  855.     c->height  = 0;

  856.     c->tiles_x =

  857.     c->tiles_y = 0;

  858.     return ret;

  859. }

  860. 

  861. static av_cold int g2m_decode_init(AVCodecContext *avctx)

  862. {

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

  864.     int ret;

  865. 

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

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

  868.         jpg_free_context(&c->jc);

  869.         return AVERROR(ENOMEM);

  870.     }

  871. 

  872.     avctx->pix_fmt = AV_PIX_FMT_RGB24;

  873. 

  874.     return 0;

  875. }

  876. 

  877. static av_cold int g2m_decode_end(AVCodecContext *avctx)

  878. {

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

  880. 

  881.     jpg_free_context(&c->jc);

  882. 

  883.     av_freep(&c->kempf_buf);

  884.     av_freep(&c->kempf_flags);

  885.     av_freep(&c->synth_tile);

  886.     av_freep(&c->jpeg_tile);

  887.     av_freep(&c->cursor);

  888.     av_freep(&c->framebuf);

  889. 

  890.     return 0;

  891. }

  892. 

  893. AVCodec ff_g2m_decoder = {

  894.     .name           = "g2m",

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

  896.     .type           = AVMEDIA_TYPE_VIDEO,

  897.     .id             = AV_CODEC_ID_G2M,

  898.     .priv_data_size = sizeof(G2MContext),

  899.     .init           = g2m_decode_init,

  900.     .close          = g2m_decode_end,

  901.     .decode         = g2m_decode_frame,

  902.     .capabilities   = CODEC_CAP_DR1,

  903. };