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  1. /*
  2.  * Flash Screen Video Version 2 encoder
  3.  * Copyright (C) 2009 Joshua Warner
  4.  *
  5.  * This file is part of FFmpeg.
  6.  *
  7.  * FFmpeg is free software; you can redistribute it and/or
  8.  * modify it under the terms of the GNU Lesser General Public
  9.  * License as published by the Free Software Foundation; either
  10.  * version 2.1 of the License, or (at your option) any later version.
  11.  *
  12.  * FFmpeg is distributed in the hope that it will be useful,
  13.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15.  * Lesser General Public License for more details.
  16.  *
  17.  * You should have received a copy of the GNU Lesser General Public
  18.  * License along with FFmpeg; if not, write to the Free Software
  19.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20.  */
  21.  
  22. /**
  23.  * @file
  24.  * Flash Screen Video Version 2 encoder
  25.  * @author Joshua Warner
  26.  */
  27.  
  28. /* Differences from version 1 stream:
  29.  * NOTE: Currently, the only player that supports version 2 streams is Adobe Flash Player itself.
  30.  * * Supports sending only a range of scanlines in a block,
  31.  *   indicating a difference from the corresponding block in the last keyframe.
  32.  * * Supports initializing the zlib dictionary with data from the corresponding
  33.  *   block in the last keyframe, to improve compression.
  34.  * * Supports a hybrid 15-bit rgb / 7-bit palette color space.
  35.  */
  36.  
  37. /* TODO:
  38.  * Don't keep Block structures for both current frame and keyframe.
  39.  * Make better heuristics for deciding stream parameters (optimum_* functions).  Currently these return constants.
  40.  * Figure out how to encode palette information in the stream, choose an optimum palette at each keyframe.
  41.  * Figure out how the zlibPrimeCompressCurrent flag works, implement support.
  42.  * Find other sample files (that weren't generated here), develop a decoder.
  43.  */
  44.  
  45. #include <stdio.h>
  46. #include <stdlib.h>
  47. #include <zlib.h>
  48.  
  49. #include "libavutil/imgutils.h"
  50. #include "avcodec.h"
  51. #include "internal.h"
  52. #include "put_bits.h"
  53. #include "bytestream.h"
  54.  
  55. #define HAS_IFRAME_IMAGE 0x02
  56. #define HAS_PALLET_INFO 0x01
  57.  
  58. #define COLORSPACE_BGR 0x00
  59. #define COLORSPACE_15_7 0x10
  60. #define HAS_DIFF_BLOCKS 0x04
  61. #define ZLIB_PRIME_COMPRESS_CURRENT 0x02
  62. #define ZLIB_PRIME_COMPRESS_PREVIOUS 0x01
  63.  
  64. // Disables experimental "smart" parameter-choosing code, as well as the statistics that it depends on.
  65. // At the moment, the "smart" code is a great example of how the parameters *shouldn't* be chosen.
  66. #define FLASHSV2_DUMB
  67.  
  68. typedef struct Block {
  69.     uint8_t *enc;
  70.     uint8_t *sl_begin, *sl_end;
  71.     int enc_size;
  72.     uint8_t *data;
  73.     unsigned long data_size;
  74.  
  75.     uint8_t start, len;
  76.     uint8_t dirty;
  77.     uint8_t col, row, width, height;
  78.     uint8_t flags;
  79. } Block;
  80.  
  81. typedef struct Palette {
  82.     unsigned colors[128];
  83.     uint8_t index[1 << 15];
  84. } Palette;
  85.  
  86. typedef struct FlashSV2Context {
  87.     AVCodecContext *avctx;
  88.     uint8_t *current_frame;
  89.     uint8_t *key_frame;
  90.     AVFrame frame;
  91.     uint8_t *encbuffer;
  92.     uint8_t *keybuffer;
  93.     uint8_t *databuffer;
  94.  
  95.     uint8_t *blockbuffer;
  96.     int blockbuffer_size;
  97.  
  98.     Block *frame_blocks;
  99.     Block *key_blocks;
  100.     int frame_size;
  101.     int blocks_size;
  102.  
  103.     int use15_7, dist, comp;
  104.  
  105.     int rows, cols;
  106.  
  107.     int last_key_frame;
  108.  
  109.     int image_width, image_height;
  110.     int block_width, block_height;
  111.     uint8_t flags;
  112.     uint8_t use_custom_palette;
  113.     uint8_t palette_type;       ///< 0=>default, 1=>custom - changed when palette regenerated.
  114.     Palette palette;
  115. #ifndef FLASHSV2_DUMB
  116.     double tot_blocks;          ///< blocks encoded since last keyframe
  117.     double diff_blocks;         ///< blocks that were different since last keyframe
  118.     double tot_lines;           ///< total scanlines in image since last keyframe
  119.     double diff_lines;          ///< scanlines that were different since last keyframe
  120.     double raw_size;            ///< size of raw frames since last keyframe
  121.     double comp_size;           ///< size of compressed data since last keyframe
  122.     double uncomp_size;         ///< size of uncompressed data since last keyframe
  123.  
  124.     double total_bits;          ///< total bits written to stream so far
  125. #endif
  126. } FlashSV2Context;
  127.  
  128. static av_cold void cleanup(FlashSV2Context * s)
  129. {
  130.     av_freep(&s->encbuffer);
  131.     av_freep(&s->keybuffer);
  132.     av_freep(&s->databuffer);
  133.     av_freep(&s->blockbuffer);
  134.     av_freep(&s->current_frame);
  135.     av_freep(&s->key_frame);
  136.  
  137.     av_freep(&s->frame_blocks);
  138.     av_freep(&s->key_blocks);
  139. }
  140.  
  141. static void init_blocks(FlashSV2Context * s, Block * blocks,
  142.                         uint8_t * encbuf, uint8_t * databuf)
  143. {
  144.     int row, col;
  145.     Block *b;
  146.     for (col = 0; col < s->cols; col++) {
  147.         for (row = 0; row < s->rows; row++) {
  148.             b = blocks + (col + row * s->cols);
  149.             b->width = (col < s->cols - 1) ?
  150.                 s->block_width :
  151.                 s->image_width - col * s->block_width;
  152.  
  153.             b->height = (row < s->rows - 1) ?
  154.                 s->block_height :
  155.                 s->image_height - row * s->block_height;
  156.  
  157.             b->row   = row;
  158.             b->col   = col;
  159.             b->enc   = encbuf;
  160.             b->data  = databuf;
  161.             encbuf  += b->width * b->height * 3;
  162.             databuf += !databuf ? 0 : b->width * b->height * 6;
  163.         }
  164.     }
  165. }
  166.  
  167. static void reset_stats(FlashSV2Context * s)
  168. {
  169. #ifndef FLASHSV2_DUMB
  170.     s->diff_blocks = 0.1;
  171.     s->tot_blocks = 1;
  172.     s->diff_lines = 0.1;
  173.     s->tot_lines = 1;
  174.     s->raw_size = s->comp_size = s->uncomp_size = 10;
  175. #endif
  176. }
  177.  
  178. static av_cold int flashsv2_encode_init(AVCodecContext * avctx)
  179. {
  180.     FlashSV2Context *s = avctx->priv_data;
  181.  
  182.     s->avctx = avctx;
  183.  
  184.     s->comp = avctx->compression_level;
  185.     if (s->comp == -1)
  186.         s->comp = 9;
  187.     if (s->comp < 0 || s->comp > 9) {
  188.         av_log(avctx, AV_LOG_ERROR,
  189.                "Compression level should be 0-9, not %d\n", s->comp);
  190.         return -1;
  191.     }
  192.  
  193.  
  194.     if ((avctx->width > 4095) || (avctx->height > 4095)) {
  195.         av_log(avctx, AV_LOG_ERROR,
  196.                "Input dimensions too large, input must be max 4096x4096 !\n");
  197.         return -1;
  198.     }
  199.     if ((avctx->width < 16) || (avctx->height < 16)) {
  200.         av_log(avctx, AV_LOG_ERROR,
  201.                "Input dimensions too small, input must be at least 16x16 !\n");
  202.         return -1;
  203.     }
  204.  
  205.     if (av_image_check_size(avctx->width, avctx->height, 0, avctx) < 0)
  206.         return -1;
  207.  
  208.  
  209.     s->last_key_frame = 0;
  210.  
  211.     s->image_width  = avctx->width;
  212.     s->image_height = avctx->height;
  213.  
  214.     s->block_width  = (s->image_width /  12) & ~15;
  215.     s->block_height = (s->image_height / 12) & ~15;
  216.  
  217.     if(!s->block_width)
  218.         s->block_width = 1;
  219.     if(!s->block_height)
  220.         s->block_height = 1;
  221.  
  222.     s->rows = (s->image_height + s->block_height - 1) / s->block_height;
  223.     s->cols = (s->image_width +  s->block_width -  1) / s->block_width;
  224.  
  225.     s->frame_size  = s->image_width * s->image_height * 3;
  226.     s->blocks_size = s->rows * s->cols * sizeof(Block);
  227.  
  228.     s->encbuffer     = av_mallocz(s->frame_size);
  229.     s->keybuffer     = av_mallocz(s->frame_size);
  230.     s->databuffer    = av_mallocz(s->frame_size * 6);
  231.     s->current_frame = av_mallocz(s->frame_size);
  232.     s->key_frame     = av_mallocz(s->frame_size);
  233.     s->frame_blocks  = av_mallocz(s->blocks_size);
  234.     s->key_blocks    = av_mallocz(s->blocks_size);
  235.  
  236.     s->blockbuffer      = NULL;
  237.     s->blockbuffer_size = 0;
  238.  
  239.     init_blocks(s, s->frame_blocks, s->encbuffer, s->databuffer);
  240.     init_blocks(s, s->key_blocks,   s->keybuffer, 0);
  241.     reset_stats(s);
  242. #ifndef FLASHSV2_DUMB
  243.     s->total_bits = 1;
  244. #endif
  245.  
  246.     s->use_custom_palette =  0;
  247.     s->palette_type       = -1;        // so that the palette will be generated in reconfigure_at_keyframe
  248.  
  249.     if (!s->encbuffer || !s->keybuffer || !s->databuffer
  250.         || !s->current_frame || !s->key_frame || !s->key_blocks
  251.         || !s->frame_blocks) {
  252.         av_log(avctx, AV_LOG_ERROR, "Memory allocation failed.\n");
  253.         cleanup(s);
  254.         return -1;
  255.     }
  256.  
  257.     return 0;
  258. }
  259.  
  260. static int new_key_frame(FlashSV2Context * s)
  261. {
  262.     int i;
  263.     memcpy(s->key_blocks, s->frame_blocks, s->blocks_size);
  264.     memcpy(s->key_frame, s->current_frame, s->frame_size);
  265.  
  266.     for (i = 0; i < s->rows * s->cols; i++) {
  267.         s->key_blocks[i].enc += (s->keybuffer - s->encbuffer);
  268.         s->key_blocks[i].sl_begin = 0;
  269.         s->key_blocks[i].sl_end   = 0;
  270.         s->key_blocks[i].data     = 0;
  271.     }
  272.     memcpy(s->keybuffer, s->encbuffer, s->frame_size);
  273.  
  274.     return 0;
  275. }
  276.  
  277. static int write_palette(FlashSV2Context * s, uint8_t * buf, int buf_size)
  278. {
  279.     //this isn't implemented yet!  Default palette only!
  280.     return -1;
  281. }
  282.  
  283. static int write_header(FlashSV2Context * s, uint8_t * buf, int buf_size)
  284. {
  285.     PutBitContext pb;
  286.     int buf_pos, len;
  287.  
  288.     if (buf_size < 5)
  289.         return -1;
  290.  
  291.     init_put_bits(&pb, buf, buf_size * 8);
  292.  
  293.     put_bits(&pb, 4, (s->block_width  >> 4) - 1);
  294.     put_bits(&pb, 12, s->image_width);
  295.     put_bits(&pb, 4, (s->block_height >> 4) - 1);
  296.     put_bits(&pb, 12, s->image_height);
  297.  
  298.     flush_put_bits(&pb);
  299.     buf_pos = 4;
  300.  
  301.     buf[buf_pos++] = s->flags;
  302.  
  303.     if (s->flags & HAS_PALLET_INFO) {
  304.         len = write_palette(s, buf + buf_pos, buf_size - buf_pos);
  305.         if (len < 0)
  306.             return -1;
  307.         buf_pos += len;
  308.     }
  309.  
  310.     return buf_pos;
  311. }
  312.  
  313. static int write_block(Block * b, uint8_t * buf, int buf_size)
  314. {
  315.     int buf_pos = 0;
  316.     unsigned block_size = b->data_size;
  317.  
  318.     if (b->flags & HAS_DIFF_BLOCKS)
  319.         block_size += 2;
  320.     if (b->flags & ZLIB_PRIME_COMPRESS_CURRENT)
  321.         block_size += 2;
  322.     if (block_size > 0)
  323.         block_size += 1;
  324.     if (buf_size < block_size + 2)
  325.         return -1;
  326.  
  327.     buf[buf_pos++] = block_size >> 8;
  328.     buf[buf_pos++] = block_size;
  329.  
  330.     if (block_size == 0)
  331.         return buf_pos;
  332.  
  333.     buf[buf_pos++] = b->flags;
  334.  
  335.     if (b->flags & HAS_DIFF_BLOCKS) {
  336.         buf[buf_pos++] = (b->start);
  337.         buf[buf_pos++] = (b->len);
  338.     }
  339.  
  340.     if (b->flags & ZLIB_PRIME_COMPRESS_CURRENT) {
  341.         //This feature of the format is poorly understood, and as of now, unused.
  342.         buf[buf_pos++] = (b->col);
  343.         buf[buf_pos++] = (b->row);
  344.     }
  345.  
  346.     memcpy(buf + buf_pos, b->data, b->data_size);
  347.  
  348.     buf_pos += b->data_size;
  349.  
  350.     return buf_pos;
  351. }
  352.  
  353. static int encode_zlib(Block * b, uint8_t * buf, unsigned long *buf_size, int comp)
  354. {
  355.     int res = compress2(buf, buf_size, b->sl_begin, b->sl_end - b->sl_begin, comp);
  356.     return res == Z_OK ? 0 : -1;
  357. }
  358.  
  359. static int encode_zlibprime(Block * b, Block * prime, uint8_t * buf,
  360.                             int *buf_size, int comp)
  361. {
  362.     z_stream s;
  363.     int res;
  364.     s.zalloc = NULL;
  365.     s.zfree  = NULL;
  366.     s.opaque = NULL;
  367.     res = deflateInit(&s, comp);
  368.     if (res < 0)
  369.         return -1;
  370.  
  371.     s.next_in  = prime->enc;
  372.     s.avail_in = prime->enc_size;
  373.     while (s.avail_in > 0) {
  374.         s.next_out  = buf;
  375.         s.avail_out = *buf_size;
  376.         res = deflate(&s, Z_SYNC_FLUSH);
  377.         if (res < 0)
  378.             return -1;
  379.     }
  380.  
  381.     s.next_in   = b->sl_begin;
  382.     s.avail_in  = b->sl_end - b->sl_begin;
  383.     s.next_out  = buf;
  384.     s.avail_out = *buf_size;
  385.     res = deflate(&s, Z_FINISH);
  386.     deflateEnd(&s);
  387.     *buf_size -= s.avail_out;
  388.     if (res != Z_STREAM_END)
  389.         return -1;
  390.     return 0;
  391. }
  392.  
  393. static int encode_bgr(Block * b, const uint8_t * src, int stride)
  394. {
  395.     int i;
  396.     uint8_t *ptr = b->enc;
  397.     for (i = 0; i < b->start; i++)
  398.         memcpy(ptr + i * b->width * 3, src + i * stride, b->width * 3);
  399.     b->sl_begin = ptr + i * b->width * 3;
  400.     for (; i < b->start + b->len; i++)
  401.         memcpy(ptr + i * b->width * 3, src + i * stride, b->width * 3);
  402.     b->sl_end = ptr + i * b->width * 3;
  403.     for (; i < b->height; i++)
  404.         memcpy(ptr + i * b->width * 3, src + i * stride, b->width * 3);
  405.     b->enc_size = ptr + i * b->width * 3 - b->enc;
  406.     return b->enc_size;
  407. }
  408.  
  409. static inline unsigned pixel_color15(const uint8_t * src)
  410. {
  411.     return (src[0] >> 3) | ((src[1] & 0xf8) << 2) | ((src[2] & 0xf8) << 7);
  412. }
  413.  
  414. static inline unsigned int chroma_diff(unsigned int c1, unsigned int c2)
  415. {
  416.     unsigned int t1 = (c1 & 0x000000ff) + ((c1 & 0x0000ff00) >> 8) + ((c1 & 0x00ff0000) >> 16);
  417.     unsigned int t2 = (c2 & 0x000000ff) + ((c2 & 0x0000ff00) >> 8) + ((c2 & 0x00ff0000) >> 16);
  418.  
  419.     return abs(t1 - t2) + abs((c1 & 0x000000ff) - (c2 & 0x000000ff)) +
  420.         abs(((c1 & 0x0000ff00) >> 8) - ((c2 & 0x0000ff00) >> 8)) +
  421.         abs(((c1 & 0x00ff0000) >> 16) - ((c2 & 0x00ff0000) >> 16));
  422. }
  423.  
  424. static inline int pixel_color7_fast(Palette * palette, unsigned c15)
  425. {
  426.     return palette->index[c15];
  427. }
  428.  
  429. static int pixel_color7_slow(Palette * palette, unsigned color)
  430. {
  431.     int i, min = 0x7fffffff;
  432.     int minc = -1;
  433.     for (i = 0; i < 128; i++) {
  434.         int c1 = palette->colors[i];
  435.         int diff = chroma_diff(c1, color);
  436.         if (diff < min) {
  437.             min = diff;
  438.             minc = i;
  439.         }
  440.     }
  441.     return minc;
  442. }
  443.  
  444. static inline unsigned pixel_bgr(const uint8_t * src)
  445. {
  446.     return (src[0]) | (src[1] << 8) | (src[2] << 16);
  447. }
  448.  
  449. static int write_pixel_15_7(Palette * palette, uint8_t * dest, const uint8_t * src,
  450.                             int dist)
  451. {
  452.     unsigned c15 = pixel_color15(src);
  453.     unsigned color = pixel_bgr(src);
  454.     int d15 = chroma_diff(color, color & 0x00f8f8f8);
  455.     int c7 = pixel_color7_fast(palette, c15);
  456.     int d7 = chroma_diff(color, palette->colors[c7]);
  457.     if (dist + d15 >= d7) {
  458.         dest[0] = c7;
  459.         return 1;
  460.     } else {
  461.         dest[0] = 0x80 | (c15 >> 8);
  462.         dest[1] = c15 & 0xff;
  463.         return 2;
  464.     }
  465. }
  466.  
  467. static int update_palette_index(Palette * palette)
  468. {
  469.     int r, g, b;
  470.     unsigned int bgr, c15, index;
  471.     for (r = 4; r < 256; r += 8) {
  472.         for (g = 4; g < 256; g += 8) {
  473.             for (b = 4; b < 256; b += 8) {
  474.                 bgr = b | (g << 8) | (r << 16);
  475.                 c15 = (b >> 3) | ((g & 0xf8) << 2) | ((r & 0xf8) << 7);
  476.                 index = pixel_color7_slow(palette, bgr);
  477.  
  478.                 palette->index[c15] = index;
  479.             }
  480.         }
  481.     }
  482.     return 0;
  483. }
  484.  
  485. static const unsigned int default_screen_video_v2_palette[128] = {
  486.     0x00000000, 0x00333333, 0x00666666, 0x00999999, 0x00CCCCCC, 0x00FFFFFF,
  487.     0x00330000, 0x00660000, 0x00990000, 0x00CC0000, 0x00FF0000, 0x00003300,
  488.     0x00006600, 0x00009900, 0x0000CC00, 0x0000FF00, 0x00000033, 0x00000066,
  489.     0x00000099, 0x000000CC, 0x000000FF, 0x00333300, 0x00666600, 0x00999900,
  490.     0x00CCCC00, 0x00FFFF00, 0x00003333, 0x00006666, 0x00009999, 0x0000CCCC,
  491.     0x0000FFFF, 0x00330033, 0x00660066, 0x00990099, 0x00CC00CC, 0x00FF00FF,
  492.     0x00FFFF33, 0x00FFFF66, 0x00FFFF99, 0x00FFFFCC, 0x00FF33FF, 0x00FF66FF,
  493.     0x00FF99FF, 0x00FFCCFF, 0x0033FFFF, 0x0066FFFF, 0x0099FFFF, 0x00CCFFFF,
  494.     0x00CCCC33, 0x00CCCC66, 0x00CCCC99, 0x00CCCCFF, 0x00CC33CC, 0x00CC66CC,
  495.     0x00CC99CC, 0x00CCFFCC, 0x0033CCCC, 0x0066CCCC, 0x0099CCCC, 0x00FFCCCC,
  496.     0x00999933, 0x00999966, 0x009999CC, 0x009999FF, 0x00993399, 0x00996699,
  497.     0x0099CC99, 0x0099FF99, 0x00339999, 0x00669999, 0x00CC9999, 0x00FF9999,
  498.     0x00666633, 0x00666699, 0x006666CC, 0x006666FF, 0x00663366, 0x00669966,
  499.     0x0066CC66, 0x0066FF66, 0x00336666, 0x00996666, 0x00CC6666, 0x00FF6666,
  500.     0x00333366, 0x00333399, 0x003333CC, 0x003333FF, 0x00336633, 0x00339933,
  501.     0x0033CC33, 0x0033FF33, 0x00663333, 0x00993333, 0x00CC3333, 0x00FF3333,
  502.     0x00003366, 0x00336600, 0x00660033, 0x00006633, 0x00330066, 0x00663300,
  503.     0x00336699, 0x00669933, 0x00993366, 0x00339966, 0x00663399, 0x00996633,
  504.     0x006699CC, 0x0099CC66, 0x00CC6699, 0x0066CC99, 0x009966CC, 0x00CC9966,
  505.     0x0099CCFF, 0x00CCFF99, 0x00FF99CC, 0x0099FFCC, 0x00CC99FF, 0x00FFCC99,
  506.     0x00111111, 0x00222222, 0x00444444, 0x00555555, 0x00AAAAAA, 0x00BBBBBB,
  507.     0x00DDDDDD, 0x00EEEEEE
  508. };
  509.  
  510. static int generate_default_palette(Palette * palette)
  511. {
  512.     memcpy(palette->colors, default_screen_video_v2_palette,
  513.            sizeof(default_screen_video_v2_palette));
  514.  
  515.     return update_palette_index(palette);
  516. }
  517.  
  518. static int generate_optimum_palette(Palette * palette, const uint8_t * image,
  519.                                    int width, int height, int stride)
  520. {
  521.     //this isn't implemented yet!  Default palette only!
  522.     return -1;
  523. }
  524.  
  525. static inline int encode_15_7_sl(Palette * palette, uint8_t * dest,
  526.                                  const uint8_t * src, int width, int dist)
  527. {
  528.     int len = 0, x;
  529.     for (x = 0; x < width; x++) {
  530.         len += write_pixel_15_7(palette, dest + len, src + 3 * x, dist);
  531.     }
  532.     return len;
  533. }
  534.  
  535. static int encode_15_7(Palette * palette, Block * b, const uint8_t * src,
  536.                        int stride, int dist)
  537. {
  538.     int i;
  539.     uint8_t *ptr = b->enc;
  540.     for (i = 0; i < b->start; i++)
  541.         ptr += encode_15_7_sl(palette, ptr, src + i * stride, b->width, dist);
  542.     b->sl_begin = ptr;
  543.     for (; i < b->start + b->len; i++)
  544.         ptr += encode_15_7_sl(palette, ptr, src + i * stride, b->width, dist);
  545.     b->sl_end = ptr;
  546.     for (; i < b->height; i++)
  547.         ptr += encode_15_7_sl(palette, ptr, src + i * stride, b->width, dist);
  548.     b->enc_size = ptr - b->enc;
  549.     return b->enc_size;
  550. }
  551.  
  552. static int encode_block(FlashSV2Context *s, Palette * palette, Block * b,
  553.                         Block * prev, const uint8_t * src, int stride, int comp,
  554.                         int dist, int keyframe)
  555. {
  556.     unsigned buf_size = b->width * b->height * 6;
  557.     uint8_t *buf = s->blockbuffer;
  558.     int res;
  559.  
  560.     if (b->flags & COLORSPACE_15_7) {
  561.         encode_15_7(palette, b, src, stride, dist);
  562.     } else {
  563.         encode_bgr(b, src, stride);
  564.     }
  565.  
  566.     if (b->len > 0) {
  567.         b->data_size = buf_size;
  568.         res = encode_zlib(b, b->data, &b->data_size, comp);
  569.         if (res)
  570.             return res;
  571.  
  572.         if (!keyframe) {
  573.             res = encode_zlibprime(b, prev, buf, &buf_size, comp);
  574.             if (res)
  575.                 return res;
  576.  
  577.             if (buf_size < b->data_size) {
  578.                 b->data_size = buf_size;
  579.                 memcpy(b->data, buf, buf_size);
  580.                 b->flags |= ZLIB_PRIME_COMPRESS_PREVIOUS;
  581.             }
  582.         }
  583.     } else {
  584.         b->data_size = 0;
  585.     }
  586.     return 0;
  587. }
  588.  
  589. static int compare_sl(FlashSV2Context * s, Block * b, const uint8_t * src,
  590.                       uint8_t * frame, uint8_t * key, int y, int keyframe)
  591. {
  592.     if (memcmp(src, frame, b->width * 3) != 0) {
  593.         b->dirty = 1;
  594.         memcpy(frame, src, b->width * 3);
  595. #ifndef FLASHSV2_DUMB
  596.         s->diff_lines++;
  597. #endif
  598.     }
  599.     if (memcmp(src, key, b->width * 3) != 0) {
  600.         if (b->len == 0)
  601.             b->start = y;
  602.         b->len = y + 1 - b->start;
  603.     }
  604.     return 0;
  605. }
  606.  
  607. static int mark_all_blocks(FlashSV2Context * s, const uint8_t * src, int stride,
  608.                            int keyframe)
  609. {
  610.     int sl, rsl, col, pos, possl;
  611.     Block *b;
  612.     for (sl = s->image_height - 1; sl >= 0; sl--) {
  613.         for (col = 0; col < s->cols; col++) {
  614.             rsl = s->image_height - sl - 1;
  615.             b = s->frame_blocks + col + rsl / s->block_height * s->cols;
  616.             possl = stride * sl + col * s->block_width * 3;
  617.             pos = s->image_width * rsl * 3 + col * s->block_width * 3;
  618.             compare_sl(s, b, src + possl, s->current_frame + pos,
  619.                        s->key_frame + pos, rsl % s->block_height, keyframe);
  620.         }
  621.     }
  622. #ifndef FLASHSV2_DUMB
  623.     s->tot_lines += s->image_height * s->cols;
  624. #endif
  625.     return 0;
  626. }
  627.  
  628. static int encode_all_blocks(FlashSV2Context * s, int keyframe)
  629. {
  630.     int row, col, res;
  631.     uint8_t *data;
  632.     Block *b, *prev;
  633.     for (row = 0; row < s->rows; row++) {
  634.         for (col = 0; col < s->cols; col++) {
  635.             b = s->frame_blocks + (row * s->cols + col);
  636.             prev = s->key_blocks + (row * s->cols + col);
  637.             b->flags = s->use15_7 ? COLORSPACE_15_7 : 0;
  638.             if (keyframe) {
  639.                 b->start = 0;
  640.                 b->len = b->height;
  641.             } else if (!b->dirty) {
  642.                 b->start = 0;
  643.                 b->len = 0;
  644.                 b->data_size = 0;
  645.                 continue;
  646.             } else if (b->start != 0 || b->len != b->height) {
  647.                 b->flags |= HAS_DIFF_BLOCKS;
  648.             }
  649.             data = s->current_frame + s->image_width * 3 * s->block_height * row + s->block_width * col * 3;
  650.             res = encode_block(s, &s->palette, b, prev, data, s->image_width * 3, s->comp, s->dist, keyframe);
  651. #ifndef FLASHSV2_DUMB
  652.             if (b->dirty)
  653.                 s->diff_blocks++;
  654.             s->comp_size += b->data_size;
  655.             s->uncomp_size += b->enc_size;
  656. #endif
  657.             if (res)
  658.                 return res;
  659.         }
  660.     }
  661. #ifndef FLASHSV2_DUMB
  662.     s->raw_size += s->image_width * s->image_height * 3;
  663.     s->tot_blocks += s->rows * s->cols;
  664. #endif
  665.     return 0;
  666. }
  667.  
  668. static int write_all_blocks(FlashSV2Context * s, uint8_t * buf,
  669.                             int buf_size)
  670. {
  671.     int row, col, buf_pos = 0, len;
  672.     Block *b;
  673.     for (row = 0; row < s->rows; row++) {
  674.         for (col = 0; col < s->cols; col++) {
  675.             b = s->frame_blocks + row * s->cols + col;
  676.             len = write_block(b, buf + buf_pos, buf_size - buf_pos);
  677.             b->start = b->len = b->dirty = 0;
  678.             if (len < 0)
  679.                 return len;
  680.             buf_pos += len;
  681.         }
  682.     }
  683.     return buf_pos;
  684. }
  685.  
  686. static int write_bitstream(FlashSV2Context * s, const uint8_t * src, int stride,
  687.                            uint8_t * buf, int buf_size, int keyframe)
  688. {
  689.     int buf_pos, res;
  690.  
  691.     res = mark_all_blocks(s, src, stride, keyframe);
  692.     if (res)
  693.         return res;
  694.     res = encode_all_blocks(s, keyframe);
  695.     if (res)
  696.         return res;
  697.  
  698.     res = write_header(s, buf, buf_size);
  699.     if (res < 0) {
  700.         return res;
  701.     } else {
  702.         buf_pos = res;
  703.     }
  704.     res = write_all_blocks(s, buf + buf_pos, buf_size - buf_pos);
  705.     if (res < 0)
  706.         return res;
  707.     buf_pos += res;
  708. #ifndef FLASHSV2_DUMB
  709.     s->total_bits += ((double) buf_pos) * 8.0;
  710. #endif
  711.  
  712.     return buf_pos;
  713. }
  714.  
  715. static void recommend_keyframe(FlashSV2Context * s, int *keyframe)
  716. {
  717. #ifndef FLASHSV2_DUMB
  718.     double block_ratio, line_ratio, enc_ratio, comp_ratio, data_ratio;
  719.     if (s->avctx->gop_size > 0) {
  720.         block_ratio = s->diff_blocks / s->tot_blocks;
  721.         line_ratio = s->diff_lines / s->tot_lines;
  722.         enc_ratio = s->uncomp_size / s->raw_size;
  723.         comp_ratio = s->comp_size / s->uncomp_size;
  724.         data_ratio = s->comp_size / s->raw_size;
  725.  
  726.         if ((block_ratio >= 0.5 && line_ratio / block_ratio <= 0.5) || line_ratio >= 0.95) {
  727.             *keyframe = 1;
  728.             return;
  729.         }
  730.     }
  731. #else
  732.     return;
  733. #endif
  734. }
  735.  
  736. static const double block_size_fraction = 1.0 / 300;
  737. static int optimum_block_width(FlashSV2Context * s)
  738. {
  739. #ifndef FLASHSV2_DUMB
  740.     double save = (1-pow(s->diff_lines/s->diff_blocks/s->block_height, 0.5)) * s->comp_size/s->tot_blocks;
  741.     double width = block_size_fraction * sqrt(0.5 * save * s->rows * s->cols) * s->image_width;
  742.     int pwidth = ((int) width);
  743.     return FFCLIP(pwidth & ~15, 256, 16);
  744. #else
  745.     return 64;
  746. #endif
  747. }
  748.  
  749. static int optimum_block_height(FlashSV2Context * s)
  750. {
  751. #ifndef FLASHSV2_DUMB
  752.     double save = (1-pow(s->diff_lines/s->diff_blocks/s->block_height, 0.5)) * s->comp_size/s->tot_blocks;
  753.     double height = block_size_fraction * sqrt(0.5 * save * s->rows * s->cols) * s->image_height;
  754.     int pheight = ((int) height);
  755.     return FFCLIP(pheight & ~15, 256, 16);
  756. #else
  757.     return 64;
  758. #endif
  759. }
  760.  
  761. static const double use15_7_threshold = 8192;
  762.  
  763. static int optimum_use15_7(FlashSV2Context * s)
  764. {
  765. #ifndef FLASHSV2_DUMB
  766.     double ideal = ((double)(s->avctx->bit_rate * s->avctx->time_base.den * s->avctx->ticks_per_frame)) /
  767.         ((double) s->avctx->time_base.num) * s->avctx->frame_number;
  768.     if (ideal + use15_7_threshold < s->total_bits) {
  769.         return 1;
  770.     } else {
  771.         return 0;
  772.     }
  773. #else
  774.     return s->avctx->global_quality == 0;
  775. #endif
  776. }
  777.  
  778. static const double color15_7_factor = 100;
  779.  
  780. static int optimum_dist(FlashSV2Context * s)
  781. {
  782. #ifndef FLASHSV2_DUMB
  783.     double ideal =
  784.         s->avctx->bit_rate * s->avctx->time_base.den *
  785.         s->avctx->ticks_per_frame;
  786.     int dist = pow((s->total_bits / ideal) * color15_7_factor, 3);
  787.     av_log(s->avctx, AV_LOG_DEBUG, "dist: %d\n", dist);
  788.     return dist;
  789. #else
  790.     return 15;
  791. #endif
  792. }
  793.  
  794.  
  795. static int reconfigure_at_keyframe(FlashSV2Context * s, const uint8_t * image,
  796.                                    int stride)
  797. {
  798.     int update_palette = 0;
  799.     int res;
  800.     int block_width  = optimum_block_width (s);
  801.     int block_height = optimum_block_height(s);
  802.  
  803.     s->rows = (s->image_height + block_height - 1) / block_height;
  804.     s->cols = (s->image_width  + block_width  - 1) / block_width;
  805.  
  806.     if (block_width != s->block_width || block_height != s->block_height) {
  807.         s->block_width  = block_width;
  808.         s->block_height = block_height;
  809.         if (s->rows * s->cols > s->blocks_size / sizeof(Block)) {
  810.             s->frame_blocks = av_realloc(s->frame_blocks, s->rows * s->cols * sizeof(Block));
  811.             s->key_blocks = av_realloc(s->key_blocks, s->cols * s->rows * sizeof(Block));
  812.             if (!s->frame_blocks || !s->key_blocks) {
  813.                 av_log(s->avctx, AV_LOG_ERROR, "Memory allocation failed.\n");
  814.                 return -1;
  815.             }
  816.             s->blocks_size = s->rows * s->cols * sizeof(Block);
  817.         }
  818.         init_blocks(s, s->frame_blocks, s->encbuffer, s->databuffer);
  819.         init_blocks(s, s->key_blocks, s->keybuffer, 0);
  820.  
  821.         av_fast_malloc(&s->blockbuffer, &s->blockbuffer_size, block_width * block_height * 6);
  822.         if (!s->blockbuffer) {
  823.             av_log(s->avctx, AV_LOG_ERROR, "Could not allocate block buffer.\n");
  824.             return AVERROR(ENOMEM);
  825.         }
  826.     }
  827.  
  828.     s->use15_7 = optimum_use15_7(s);
  829.     if (s->use15_7) {
  830.         if ((s->use_custom_palette && s->palette_type != 1) || update_palette) {
  831.             res = generate_optimum_palette(&s->palette, image, s->image_width, s->image_height, stride);
  832.             if (res)
  833.                 return res;
  834.             s->palette_type = 1;
  835.             av_log(s->avctx, AV_LOG_DEBUG, "Generated optimum palette\n");
  836.         } else if (!s->use_custom_palette && s->palette_type != 0) {
  837.             res = generate_default_palette(&s->palette);
  838.             if (res)
  839.                 return res;
  840.             s->palette_type = 0;
  841.             av_log(s->avctx, AV_LOG_DEBUG, "Generated default palette\n");
  842.         }
  843.     }
  844.  
  845.  
  846.     reset_stats(s);
  847.  
  848.     return 0;
  849. }
  850.  
  851. static int flashsv2_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
  852.                                  const AVFrame *pict, int *got_packet)
  853. {
  854.     FlashSV2Context *const s = avctx->priv_data;
  855.     AVFrame *const p = &s->frame;
  856.     int res;
  857.     int keyframe = 0;
  858.  
  859.     *p = *pict;
  860.  
  861.     if ((res = ff_alloc_packet2(avctx, pkt, s->frame_size + FF_MIN_BUFFER_SIZE)) < 0)
  862.         return res;
  863.  
  864.     /* First frame needs to be a keyframe */
  865.     if (avctx->frame_number == 0)
  866.         keyframe = 1;
  867.  
  868.     /* Check the placement of keyframes */
  869.     if (avctx->gop_size > 0) {
  870.         if (avctx->frame_number >= s->last_key_frame + avctx->gop_size)
  871.             keyframe = 1;
  872.     }
  873.  
  874.     if (!keyframe
  875.         && avctx->frame_number > s->last_key_frame + avctx->keyint_min) {
  876.         recommend_keyframe(s, &keyframe);
  877.         if (keyframe)
  878.             av_log(avctx, AV_LOG_DEBUG, "Recommending key frame at frame %d\n", avctx->frame_number);
  879.     }
  880.  
  881.     if (keyframe) {
  882.         res = reconfigure_at_keyframe(s, p->data[0], p->linesize[0]);
  883.         if (res)
  884.             return res;
  885.     }
  886.  
  887.     if (s->use15_7)
  888.         s->dist = optimum_dist(s);
  889.  
  890.     res = write_bitstream(s, p->data[0], p->linesize[0], pkt->data, pkt->size, keyframe);
  891.  
  892.     if (keyframe) {
  893.         new_key_frame(s);
  894.         p->pict_type = AV_PICTURE_TYPE_I;
  895.         p->key_frame = 1;
  896.         s->last_key_frame = avctx->frame_number;
  897.         pkt->flags |= AV_PKT_FLAG_KEY;
  898.         av_log(avctx, AV_LOG_DEBUG, "Inserting key frame at frame %d\n", avctx->frame_number);
  899.     } else {
  900.         p->pict_type = AV_PICTURE_TYPE_P;
  901.         p->key_frame = 0;
  902.     }
  903.  
  904.     avctx->coded_frame = p;
  905.  
  906.     pkt->size = res;
  907.     *got_packet = 1;
  908.  
  909.     return 0;
  910. }
  911.  
  912. static av_cold int flashsv2_encode_end(AVCodecContext * avctx)
  913. {
  914.     FlashSV2Context *s = avctx->priv_data;
  915.  
  916.     cleanup(s);
  917.  
  918.     return 0;
  919. }
  920.  
  921. AVCodec ff_flashsv2_encoder = {
  922.     .name           = "flashsv2",
  923.     .long_name      = NULL_IF_CONFIG_SMALL("Flash Screen Video Version 2"),
  924.     .type           = AVMEDIA_TYPE_VIDEO,
  925.     .id             = AV_CODEC_ID_FLASHSV2,
  926.     .priv_data_size = sizeof(FlashSV2Context),
  927.     .init           = flashsv2_encode_init,
  928.     .encode2        = flashsv2_encode_frame,
  929.     .close          = flashsv2_encode_end,
  930.     .pix_fmts       = (const enum AVPixelFormat[]){ AV_PIX_FMT_BGR24, AV_PIX_FMT_NONE },
  931. };
  932.