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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 "dsputil.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.     DSPContext dsp;

  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        tile_width, tile_height;

  94.     int        tiles_x, tiles_y, tile_x, tile_y;

  95. 

  96.     int        got_header;

  97. 

  98.     uint8_t    *framebuf;

  99.     int        framebuf_stride, old_width, old_height;

  100. 

  101.     uint8_t    *synth_tile, *jpeg_tile;

  102.     int        tile_stride, old_tile_w, old_tile_h;

  103. 

  104.     uint8_t    *kempf_buf, *kempf_flags;

  105. 

  106.     uint8_t    *cursor;

  107.     int        cursor_stride;

  108.     int        cursor_fmt;

  109.     int        cursor_w, cursor_h, cursor_x, cursor_y;

  110.     int        cursor_hot_x, cursor_hot_y;

  111. } G2MContext;

  112. 

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

  114.                              const uint8_t *val_table, int nb_codes,

  115.                              int is_ac)

  116. {

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

  118.     uint16_t huff_code[256];

  119.     uint16_t huff_sym[256];

  120.     int i;

  121. 

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

  123. 

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

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

  126. 

  127.     if (is_ac)

  128.         huff_sym[0] = 16 * 256;

  129. 

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

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

  132. }

  133. 

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

  135. {

  136.     int ret;

  137. 

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

  139.                     avpriv_mjpeg_val_dc, 12, 0);

  140.     if (ret)

  141.         return ret;

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

  143.                     avpriv_mjpeg_val_dc, 12, 0);

  144.     if (ret)

  145.         return ret;

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

  147.                     avpriv_mjpeg_val_ac_luminance, 251, 1);

  148.     if (ret)

  149.         return ret;

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

  151.                     avpriv_mjpeg_val_ac_chrominance, 251, 1);

  152.     if (ret)

  153.         return ret;

  154. 

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

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

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

  158.                       ff_zigzag_direct);

  159. 

  160.     return 0;

  161. }

  162. 

  163. static av_cold void jpg_free_context(JPGContext *ctx)

  164. {

  165.     int i;

  166. 

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

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

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

  170.     }

  171. 

  172.     av_freep(&ctx->buf);

  173. }

  174. 

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

  176.                          uint8_t *dst, int *dst_size)

  177. {

  178.     const uint8_t *src_end = src + src_size;

  179.     uint8_t *dst_start = dst;

  180. 

  181.     while (src < src_end) {

  182.         uint8_t x = *src++;

  183. 

  184.         *dst++ = x;

  185. 

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

  187.             src++;

  188.     }

  189.     *dst_size = dst - dst_start;

  190. }

  191. 

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

  193.                             int plane, int16_t *block)

  194. {

  195.     int dc, val, pos;

  196.     const int is_chroma = !!plane;

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

  198. 

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

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

  201.     if (dc < 0)

  202.         return AVERROR_INVALIDDATA;

  203.     if (dc)

  204.         dc = get_xbits(gb, dc);

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

  206.     block[0]          = dc;

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

  208. 

  209.     pos = 0;

  210.     while (pos < 63) {

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

  212.         if (val < 0)

  213.             return AVERROR_INVALIDDATA;

  214.         pos += val >> 4;

  215.         val &= 0xF;

  216.         if (pos > 63)

  217.             return val ? AVERROR_INVALIDDATA : 0;

  218.         if (val) {

  219.             int nbits = val;

  220. 

  221.             val                                 = get_xbits(gb, nbits);

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

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

  224.         }

  225.     }

  226.     return 0;

  227. }

  228. 

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

  230. {

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

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

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

  234. }

  235. 

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

  237.                            const uint8_t *src, int src_size,

  238.                            uint8_t *dst, int dst_stride,

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

  240.                            int swapuv)

  241. {

  242.     GetBitContext gb;

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

  244.     int bx, by;

  245.     int unesc_size;

  246.     int ret;

  247. 

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

  249.                            src_size + FF_INPUT_BUFFER_PADDING_SIZE)) < 0)

  250.         return ret;

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

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

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

  254. 

  255.     width = FFALIGN(width, 16);

  256.     mb_w  =  width        >> 4;

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

  258. 

  259.     if (!num_mbs)

  260.         num_mbs = mb_w * mb_h * 4;

  261. 

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

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

  264.     bx = by = 0;

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

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

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

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

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

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

  271.                 bx += 16;

  272.                 continue;

  273.             }

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

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

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

  277.                         continue;

  278.                     num_mbs--;

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

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

  281.                         return ret;

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

  283.                 }

  284.             }

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

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

  287.                     return ret;

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

  289.             }

  290. 

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

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

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

  294.                     int Y, U, V;

  295. 

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

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

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

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

  300.                 }

  301.             }

  302. 

  303.             if (!num_mbs)

  304.                 return 0;

  305.             bx += 16;

  306.         }

  307.         bx  = 0;

  308.         by += 16;

  309.         if (mask)

  310.             mask += mask_stride * 2;

  311.     }

  312. 

  313.     return 0;

  314. }

  315. 

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

  317.                               uint8_t *dst, int stride,

  318.                               const uint8_t *jpeg_tile, int tile_stride,

  319.                               int width, int height,

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

  321. {

  322.     GetBitContext gb;

  323.     int i, j, nb, col;

  324. 

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

  326. 

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

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

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

  330.     else                 nb = 8;

  331. 

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

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

  334.             continue;

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

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

  337.             if (col != tidx)

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

  339.             else

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

  341.         }

  342.     }

  343. }

  344. 

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

  346.                              const uint8_t *src, int src_size)

  347. {

  348.     int width, height;

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

  350.     int i, j;

  351.     const uint8_t *src_end = src + src_size;

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

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

  354.     int sub_type;

  355.     int nblocks, cblocks, bstride;

  356.     int bits, bitbuf, coded;

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

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

  359. 

  360.     if (src_size < 2)

  361.         return AVERROR_INVALIDDATA;

  362. 

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

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

  365. 

  366.     hdr      = *src++;

  367.     sub_type = hdr >> 5;

  368.     if (sub_type == 0) {

  369.         int j;

  370.         memcpy(transp, src, 3);

  371.         src += 3;

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

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

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

  375.         return 0;

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

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

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

  379.     }

  380. 

  381.     if (sub_type != 2) {

  382.         memcpy(transp, src, 3);

  383.         src += 3;

  384.     }

  385.     npal = *src++ + 1;

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

  387.     src += npal * 3;

  388.     if (sub_type != 2) {

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

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

  391.                 tidx = i;

  392.                 break;

  393.             }

  394.         }

  395.     }

  396. 

  397.     if (src_end - src < 2)

  398.         return 0;

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

  400.     src  += 2;

  401. 

  402.     if (src_end - src < zsize)

  403.         return AVERROR_INVALIDDATA;

  404. 

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

  406.     if (ret)

  407.         return AVERROR_INVALIDDATA;

  408.     src += zsize;

  409. 

  410.     if (sub_type == 2) {

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

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

  413.         return 0;

  414.     }

  415. 

  416.     nblocks = *src++ + 1;

  417.     cblocks = 0;

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

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

  420.     bits = 0;

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

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

  423.             if (!bits) {

  424.                 bitbuf = *src++;

  425.                 bits   = 8;

  426.             }

  427.             coded = bitbuf & 1;

  428.             bits--;

  429.             bitbuf >>= 1;

  430.             cblocks += coded;

  431.             if (cblocks > nblocks)

  432.                 return AVERROR_INVALIDDATA;

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

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

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

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

  437.         }

  438.     }

  439. 

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

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

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

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

  444. 

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

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

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

  448. 

  449.     return 0;

  450. }

  451. 

  452. static int g2m_init_buffers(G2MContext *c)

  453. {

  454.     int aligned_height;

  455. 

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

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

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

  459.         av_free(c->framebuf);

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

  461.         if (!c->framebuf)

  462.             return AVERROR(ENOMEM);

  463.     }

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

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

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

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

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

  469.         av_free(c->synth_tile);

  470.         av_free(c->jpeg_tile);

  471.         av_free(c->kempf_buf);

  472.         av_free(c->kempf_flags);

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

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

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

  476.                                     + FF_INPUT_BUFFER_PADDING_SIZE);

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

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

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

  480.             return AVERROR(ENOMEM);

  481.     }

  482. 

  483.     return 0;

  484. }

  485. 

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

  487.                            GetByteContext *gb)

  488. {

  489.     int i, j, k;

  490.     uint8_t *dst;

  491.     uint32_t bits;

  492.     uint32_t cur_size, cursor_w, cursor_h, cursor_stride;

  493.     uint32_t cursor_hot_x, cursor_hot_y;

  494.     int cursor_fmt, err;

  495. 

  496.     cur_size     = bytestream2_get_be32(gb);

  497.     cursor_w     = bytestream2_get_byte(gb);

  498.     cursor_h     = bytestream2_get_byte(gb);

  499.     cursor_hot_x = bytestream2_get_byte(gb);

  500.     cursor_hot_y = bytestream2_get_byte(gb);

  501.     cursor_fmt   = bytestream2_get_byte(gb);

  502. 

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

  504. 

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

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

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

  508.                cursor_w, cursor_h);

  509.         return AVERROR_INVALIDDATA;

  510.     }

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

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

  513.                cursor_hot_x, cursor_hot_y);

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

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

  516.     }

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

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

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

  520.                cur_size, bytestream2_get_bytes_left(gb));

  521.         return AVERROR_INVALIDDATA;

  522.     }

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

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

  525.                                       cursor_fmt);

  526.         return AVERROR_PATCHWELCOME;

  527.     }

  528. 

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

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

  531.         return err;

  532.     }

  533. 

  534.     c->cursor_w      = cursor_w;

  535.     c->cursor_h      = cursor_h;

  536.     c->cursor_hot_x  = cursor_hot_x;

  537.     c->cursor_hot_y  = cursor_hot_y;

  538.     c->cursor_fmt    = cursor_fmt;

  539.     c->cursor_stride = cursor_stride;

  540. 

  541.     dst = c->cursor;

  542.     switch (c->cursor_fmt) {

  543.     case 1: // old monochrome

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

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

  546.                 bits = bytestream2_get_be32(gb);

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

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

  549.                     dst   += 4;

  550.                     bits <<= 1;

  551.                 }

  552.             }

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

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

  586.         }

  587.         break;

  588.     case 32: // full colour

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

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

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

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

  593.                 int val = bytestream2_get_be32(gb);

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

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

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

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

  598.             }

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

  600.         }

  601.         break;

  602.     default:

  603.         return AVERROR_PATCHWELCOME;

  604.     }

  605.     return 0;

  606. }

  607. 

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

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

  610. 

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

  612. {

  613.     int i, j;

  614.     int x, y, w, h;

  615.     const uint8_t *cursor;

  616. 

  617.     if (!c->cursor)

  618.         return;

  619. 

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

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

  622. 

  623.     cursor = c->cursor;

  624.     w      = c->cursor_w;

  625.     h      = c->cursor_h;

  626. 

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

  628.         w = c->width - x;

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

  630.         h = c->height - y;

  631.     if (x < 0) {

  632.         w      +=  x;

  633.         cursor += -x * 4;

  634.     } else {

  635.         dst    +=  x * 3;

  636.     }

  637.     if (y < 0) {

  638.         h      +=  y;

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

  640.     } else {

  641.         dst    +=  y * stride;

  642.     }

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

  644.         return;

  645. 

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

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

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

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

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

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

  652.         }

  653.         dst    += stride;

  654.         cursor += c->cursor_stride;

  655.     }

  656. }

  657. 

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

  659.                             int *got_picture_ptr, AVPacket *avpkt)

  660. {

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

  662.     int buf_size = avpkt->size;

  663.     G2MContext *c = avctx->priv_data;

  664.     AVFrame *pic = data;

  665.     GetByteContext bc, tbc;

  666.     int magic;

  667.     int got_header = 0;

  668.     uint32_t chunk_size, r_mask, g_mask, b_mask;

  669.     int chunk_type, chunk_start;

  670.     int i;

  671.     int ret;

  672. 

  673.     if (buf_size < 12) {

  674.         av_log(avctx, AV_LOG_ERROR,

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

  676.                buf_size);

  677.         return AVERROR_INVALIDDATA;

  678.     }

  679. 

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

  681. 

  682.     magic = bytestream2_get_be32(&bc);

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

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

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

  686.         return AVERROR_INVALIDDATA;

  687.     }

  688. 

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

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

  691.         return AVERROR(ENOSYS);

  692.     }

  693. 

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

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

  696.         chunk_type  = bytestream2_get_byte(&bc);

  697.         chunk_start = bytestream2_tell(&bc);

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

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

  700.                    chunk_size, chunk_type);

  701.             break;

  702.         }

  703.         switch (chunk_type) {

  704.         case DISPLAY_INFO:

  705.             c->got_header = 0;

  706.             if (chunk_size < 21) {

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

  708.                        chunk_size);

  709.                 break;

  710.             }

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

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

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

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

  715.                 av_log(avctx, AV_LOG_ERROR,

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

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

  718.                 ret = AVERROR_INVALIDDATA;

  719.                 goto header_fail;

  720.             }

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

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

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

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

  725.                 av_log(avctx, AV_LOG_ERROR,

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

  727.                        c->compression);

  728.                 return AVERROR_PATCHWELCOME;

  729.             }

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

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

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

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

  734.                 av_log(avctx, AV_LOG_ERROR,

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

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

  737.                 ret = AVERROR_INVALIDDATA;

  738.                 goto header_fail;

  739.             }

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

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

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

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

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

  745.                     (chunk_size - 21) < 16) {

  746.                     av_log(avctx, AV_LOG_ERROR,

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

  748.                     return AVERROR_INVALIDDATA;

  749.                 }

  750.                 r_mask = bytestream2_get_be32(&bc);

  751.                 g_mask = bytestream2_get_be32(&bc);

  752.                 b_mask = bytestream2_get_be32(&bc);

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

  754.                     av_log(avctx, AV_LOG_ERROR,

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

  756.                            r_mask, g_mask, b_mask);

  757.                     return AVERROR_PATCHWELCOME;

  758.                 }

  759.             } else {

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

  761.                 return AVERROR_PATCHWELCOME;

  762.             }

  763.             if (g2m_init_buffers(c)) {

  764.                 ret = AVERROR(ENOMEM);

  765.                 goto header_fail;

  766.             }

  767.             got_header = 1;

  768.             break;

  769.         case TILE_DATA:

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

  771.                 av_log(avctx, AV_LOG_WARNING,

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

  773.                 break;

  774.             }

  775.             if (chunk_size < 2) {

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

  777.                        chunk_size);

  778.                 break;

  779.             }

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

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

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

  783.                 av_log(avctx, AV_LOG_ERROR,

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

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

  786.                 break;

  787.             }

  788.             ret = 0;

  789.             switch (c->compression) {

  790.             case COMPR_EPIC_J_B:

  791.                 av_log(avctx, AV_LOG_ERROR,

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

  793.                 return AVERROR(ENOSYS);

  794.             case COMPR_KEMPF_J_B:

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

  796.                                         buf + bytestream2_tell(&bc),

  797.                                         chunk_size - 2);

  798.                 break;

  799.             }

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

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

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

  803.             break;

  804.         case CURSOR_POS:

  805.             if (chunk_size < 5) {

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

  807.                        chunk_size);

  808.                 break;

  809.             }

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

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

  812.             break;

  813.         case CURSOR_SHAPE:

  814.             if (chunk_size < 8) {

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

  816.                        chunk_size);

  817.                 break;

  818.             }

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

  820.                              chunk_size - 4);

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

  822.             break;

  823.         case CHUNK_CC:

  824.         case CHUNK_CD:

  825.             break;

  826.         default:

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

  828.                    chunk_type);

  829.         }

  830. 

  831.         /* navigate to next chunk */

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

  833.     }

  834.     if (got_header)

  835.         c->got_header = 1;

  836. 

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

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

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

  840.             return ret;

  841.         }

  842. 

  843.         pic->key_frame = got_header;

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

  845. 

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

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

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

  849.                    c->width * 3);

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

  851. 

  852.         *got_picture_ptr = 1;

  853.     }

  854. 

  855.     return buf_size;

  856. 

  857. header_fail:

  858.     c->width   =

  859.     c->height  = 0;

  860.     c->tiles_x =

  861.     c->tiles_y = 0;

  862.     return ret;

  863. }

  864. 

  865. static av_cold int g2m_decode_init(AVCodecContext *avctx)

  866. {

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

  868.     int ret;

  869. 

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

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

  872.         jpg_free_context(&c->jc);

  873.         return AVERROR(ENOMEM);

  874.     }

  875. 

  876.     avctx->pix_fmt = AV_PIX_FMT_RGB24;

  877. 

  878.     return 0;

  879. }

  880. 

  881. static av_cold int g2m_decode_end(AVCodecContext *avctx)

  882. {

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

  884. 

  885.     jpg_free_context(&c->jc);

  886. 

  887.     av_freep(&c->kempf_buf);

  888.     av_freep(&c->kempf_flags);

  889.     av_freep(&c->synth_tile);

  890.     av_freep(&c->jpeg_tile);

  891.     av_freep(&c->cursor);

  892.     av_freep(&c->framebuf);

  893. 

  894.     return 0;

  895. }

  896. 

  897. AVCodec ff_g2m_decoder = {

  898.     .name           = "g2m",

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

  900.     .type           = AVMEDIA_TYPE_VIDEO,

  901.     .id             = AV_CODEC_ID_G2M,

  902.     .priv_data_size = sizeof(G2MContext),

  903.     .init           = g2m_decode_init,

  904.     .close          = g2m_decode_end,

  905.     .decode         = g2m_decode_frame,

  906.     .capabilities   = CODEC_CAP_DR1,

  907. };