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FFmpeg/libavcodec/flashsv2enc.c
Ganesh Ajjanagadde 0fe1c50e50 all: do standards compliant absdiff computation 
This resolves implementation defined behavior, and also silences -Wabsolute-value in clang 3.5+.
Moreover, the generated asm is identical to before modulo nop padding.

Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
2015-09-18 22:42:38 +02:00

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/*
* Flash Screen Video Version 2 encoder
* Copyright (C) 2009 Joshua Warner
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* Flash Screen Video Version 2 encoder
* @author Joshua Warner
*/
/* Differences from version 1 stream:
* NOTE: Currently, the only player that supports version 2 streams is Adobe Flash Player itself.
* * Supports sending only a range of scanlines in a block,
* indicating a difference from the corresponding block in the last keyframe.
* * Supports initializing the zlib dictionary with data from the corresponding
* block in the last keyframe, to improve compression.
* * Supports a hybrid 15-bit rgb / 7-bit palette color space.
*/
/* TODO:
* Don't keep Block structures for both current frame and keyframe.
* Make better heuristics for deciding stream parameters (optimum_* functions). Currently these return constants.
* Figure out how to encode palette information in the stream, choose an optimum palette at each keyframe.
* Figure out how the zlibPrimeCompressCurrent flag works, implement support.
* Find other sample files (that weren't generated here), develop a decoder.
*/
#include <stdio.h>
#include <stdlib.h>
#include <zlib.h>
#include "libavutil/imgutils.h"
#include "avcodec.h"
#include "internal.h"
#include "put_bits.h"
#include "bytestream.h"
#define HAS_IFRAME_IMAGE 0x02
#define HAS_PALLET_INFO 0x01
#define COLORSPACE_BGR 0x00
#define COLORSPACE_15_7 0x10
#define HAS_DIFF_BLOCKS 0x04
#define ZLIB_PRIME_COMPRESS_CURRENT 0x02
#define ZLIB_PRIME_COMPRESS_PREVIOUS 0x01
// Disables experimental "smart" parameter-choosing code, as well as the statistics that it depends on.
// At the moment, the "smart" code is a great example of how the parameters *shouldn't* be chosen.
#define FLASHSV2_DUMB
typedef struct Block {
uint8_t *enc;
uint8_t *sl_begin, *sl_end;
int enc_size;
uint8_t *data;
unsigned long data_size;
uint8_t start, len;
uint8_t dirty;
uint8_t col, row, width, height;
uint8_t flags;
} Block;
typedef struct Palette {
unsigned colors[128];
uint8_t index[1 << 15];
} Palette;
typedef struct FlashSV2Context {
AVCodecContext *avctx;
uint8_t *current_frame;
uint8_t *key_frame;
uint8_t *encbuffer;
uint8_t *keybuffer;
uint8_t *databuffer;
uint8_t *blockbuffer;
int blockbuffer_size;
Block *frame_blocks;
Block *key_blocks;
int frame_size;
int blocks_size;
int use15_7, dist, comp;
int rows, cols;
int last_key_frame;
int image_width, image_height;
int block_width, block_height;
uint8_t flags;
uint8_t use_custom_palette;
uint8_t palette_type; ///< 0=>default, 1=>custom - changed when palette regenerated.
Palette palette;
#ifndef FLASHSV2_DUMB
double tot_blocks; ///< blocks encoded since last keyframe
double diff_blocks; ///< blocks that were different since last keyframe
double tot_lines; ///< total scanlines in image since last keyframe
double diff_lines; ///< scanlines that were different since last keyframe
double raw_size; ///< size of raw frames since last keyframe
double comp_size; ///< size of compressed data since last keyframe
double uncomp_size; ///< size of uncompressed data since last keyframe
double total_bits; ///< total bits written to stream so far
#endif
} FlashSV2Context;
static av_cold void cleanup(FlashSV2Context * s)
{
av_freep(&s->encbuffer);
av_freep(&s->keybuffer);
av_freep(&s->databuffer);
av_freep(&s->blockbuffer);
av_freep(&s->current_frame);
av_freep(&s->key_frame);
av_freep(&s->frame_blocks);
av_freep(&s->key_blocks);
}
static void init_blocks(FlashSV2Context * s, Block * blocks,
uint8_t * encbuf, uint8_t * databuf)
{
int row, col;
Block *b;
for (col = 0; col < s->cols; col++) {
for (row = 0; row < s->rows; row++) {
b = blocks + (col + row * s->cols);
b->width = (col < s->cols - 1) ?
s->block_width :
s->image_width - col * s->block_width;
b->height = (row < s->rows - 1) ?
s->block_height :
s->image_height - row * s->block_height;
b->row = row;
b->col = col;
b->enc = encbuf;
b->data = databuf;
encbuf += b->width * b->height * 3;
databuf += !databuf ? 0 : b->width * b->height * 6;
}
}
}
static void reset_stats(FlashSV2Context * s)
{
#ifndef FLASHSV2_DUMB
s->diff_blocks = 0.1;
s->tot_blocks = 1;
s->diff_lines = 0.1;
s->tot_lines = 1;
s->raw_size = s->comp_size = s->uncomp_size = 10;
#endif
}
static av_cold int flashsv2_encode_init(AVCodecContext * avctx)
{
FlashSV2Context *s = avctx->priv_data;
s->avctx = avctx;
s->comp = avctx->compression_level;
if (s->comp == -1)
s->comp = 9;
if (s->comp < 0 || s->comp > 9) {
av_log(avctx, AV_LOG_ERROR,
"Compression level should be 0-9, not %d\n", s->comp);
return -1;
}
if ((avctx->width > 4095) || (avctx->height > 4095)) {
av_log(avctx, AV_LOG_ERROR,
"Input dimensions too large, input must be max 4095x4095 !\n");
return -1;
}
if ((avctx->width < 16) || (avctx->height < 16)) {
av_log(avctx, AV_LOG_ERROR,
"Input dimensions too small, input must be at least 16x16 !\n");
return -1;
}
if (av_image_check_size(avctx->width, avctx->height, 0, avctx) < 0)
return -1;
s->last_key_frame = 0;
s->image_width = avctx->width;
s->image_height = avctx->height;
s->block_width = (s->image_width / 12) & ~15;
s->block_height = (s->image_height / 12) & ~15;
if(!s->block_width)
s->block_width = 1;
if(!s->block_height)
s->block_height = 1;
s->rows = (s->image_height + s->block_height - 1) / s->block_height;
s->cols = (s->image_width + s->block_width - 1) / s->block_width;
s->frame_size = s->image_width * s->image_height * 3;
s->blocks_size = s->rows * s->cols * sizeof(Block);
s->encbuffer = av_mallocz(s->frame_size);
s->keybuffer = av_mallocz(s->frame_size);
s->databuffer = av_mallocz(s->frame_size * 6);
s->current_frame = av_mallocz(s->frame_size);
s->key_frame = av_mallocz(s->frame_size);
s->frame_blocks = av_mallocz(s->blocks_size);
s->key_blocks = av_mallocz(s->blocks_size);
s->blockbuffer = NULL;
s->blockbuffer_size = 0;
init_blocks(s, s->frame_blocks, s->encbuffer, s->databuffer);
init_blocks(s, s->key_blocks, s->keybuffer, 0);
reset_stats(s);
#ifndef FLASHSV2_DUMB
s->total_bits = 1;
#endif
s->use_custom_palette = 0;
s->palette_type = -1; // so that the palette will be generated in reconfigure_at_keyframe
if (!s->encbuffer || !s->keybuffer || !s->databuffer
|| !s->current_frame || !s->key_frame || !s->key_blocks
|| !s->frame_blocks) {
av_log(avctx, AV_LOG_ERROR, "Memory allocation failed.\n");
cleanup(s);
return -1;
}
return 0;
}
static int new_key_frame(FlashSV2Context * s)
{
int i;
memcpy(s->key_blocks, s->frame_blocks, s->blocks_size);
memcpy(s->key_frame, s->current_frame, s->frame_size);
for (i = 0; i < s->rows * s->cols; i++) {
s->key_blocks[i].enc += (s->keybuffer - s->encbuffer);
s->key_blocks[i].sl_begin = 0;
s->key_blocks[i].sl_end = 0;
s->key_blocks[i].data = 0;
}
memcpy(s->keybuffer, s->encbuffer, s->frame_size);
return 0;
}
static int write_palette(FlashSV2Context * s, uint8_t * buf, int buf_size)
{
//this isn't implemented yet! Default palette only!
return -1;
}
static int write_header(FlashSV2Context * s, uint8_t * buf, int buf_size)
{
PutBitContext pb;
int buf_pos, len;
if (buf_size < 5)
return -1;
init_put_bits(&pb, buf, buf_size);
put_bits(&pb, 4, (s->block_width >> 4) - 1);
put_bits(&pb, 12, s->image_width);
put_bits(&pb, 4, (s->block_height >> 4) - 1);
put_bits(&pb, 12, s->image_height);
flush_put_bits(&pb);
buf_pos = 4;
buf[buf_pos++] = s->flags;
if (s->flags & HAS_PALLET_INFO) {
len = write_palette(s, buf + buf_pos, buf_size - buf_pos);
if (len < 0)
return -1;
buf_pos += len;
}
return buf_pos;
}
static int write_block(Block * b, uint8_t * buf, int buf_size)
{
int buf_pos = 0;
unsigned block_size = b->data_size;
if (b->flags & HAS_DIFF_BLOCKS)
block_size += 2;
if (b->flags & ZLIB_PRIME_COMPRESS_CURRENT)
block_size += 2;
if (block_size > 0)
block_size += 1;
if (buf_size < block_size + 2)
return -1;
buf[buf_pos++] = block_size >> 8;
buf[buf_pos++] = block_size;
if (block_size == 0)
return buf_pos;
buf[buf_pos++] = b->flags;
if (b->flags & HAS_DIFF_BLOCKS) {
buf[buf_pos++] = (b->start);
buf[buf_pos++] = (b->len);
}
if (b->flags & ZLIB_PRIME_COMPRESS_CURRENT) {
//This feature of the format is poorly understood, and as of now, unused.
buf[buf_pos++] = (b->col);
buf[buf_pos++] = (b->row);
}
memcpy(buf + buf_pos, b->data, b->data_size);
buf_pos += b->data_size;
return buf_pos;
}
static int encode_zlib(Block * b, uint8_t * buf, unsigned long *buf_size, int comp)
{
int res = compress2(buf, buf_size, b->sl_begin, b->sl_end - b->sl_begin, comp);
return res == Z_OK ? 0 : -1;
}
static int encode_zlibprime(Block * b, Block * prime, uint8_t * buf,
int *buf_size, int comp)
{
z_stream s;
int res;
s.zalloc = NULL;
s.zfree = NULL;
s.opaque = NULL;
res = deflateInit(&s, comp);
if (res < 0)
return -1;
s.next_in = prime->enc;
s.avail_in = prime->enc_size;
while (s.avail_in > 0) {
s.next_out = buf;
s.avail_out = *buf_size;
res = deflate(&s, Z_SYNC_FLUSH);
if (res < 0)
return -1;
}
s.next_in = b->sl_begin;
s.avail_in = b->sl_end - b->sl_begin;
s.next_out = buf;
s.avail_out = *buf_size;
res = deflate(&s, Z_FINISH);
deflateEnd(&s);
*buf_size -= s.avail_out;
if (res != Z_STREAM_END)
return -1;
return 0;
}
static int encode_bgr(Block * b, const uint8_t * src, int stride)
{
int i;
uint8_t *ptr = b->enc;
for (i = 0; i < b->start; i++)
memcpy(ptr + i * b->width * 3, src + i * stride, b->width * 3);
b->sl_begin = ptr + i * b->width * 3;
for (; i < b->start + b->len; i++)
memcpy(ptr + i * b->width * 3, src + i * stride, b->width * 3);
b->sl_end = ptr + i * b->width * 3;
for (; i < b->height; i++)
memcpy(ptr + i * b->width * 3, src + i * stride, b->width * 3);
b->enc_size = ptr + i * b->width * 3 - b->enc;
return b->enc_size;
}
static inline unsigned pixel_color15(const uint8_t * src)
{
return (src[0] >> 3) | ((src[1] & 0xf8) << 2) | ((src[2] & 0xf8) << 7);
}
static inline unsigned int chroma_diff(unsigned int c1, unsigned int c2)
{
#define ABSDIFF(a,b) (abs((int)(a)-(int)(b)))
unsigned int t1 = (c1 & 0x000000ff) + ((c1 & 0x0000ff00) >> 8) + ((c1 & 0x00ff0000) >> 16);
unsigned int t2 = (c2 & 0x000000ff) + ((c2 & 0x0000ff00) >> 8) + ((c2 & 0x00ff0000) >> 16);
return ABSDIFF(t1, t2) + ABSDIFF(c1 & 0x000000ff, c2 & 0x000000ff) +
ABSDIFF((c1 & 0x0000ff00) >> 8 , (c2 & 0x0000ff00) >> 8) +
ABSDIFF((c1 & 0x00ff0000) >> 16, (c2 & 0x00ff0000) >> 16);
}
static inline int pixel_color7_fast(Palette * palette, unsigned c15)
{
return palette->index[c15];
}
static int pixel_color7_slow(Palette * palette, unsigned color)
{
int i, min = 0x7fffffff;
int minc = -1;
for (i = 0; i < 128; i++) {
int c1 = palette->colors[i];
int diff = chroma_diff(c1, color);
if (diff < min) {
min = diff;
minc = i;
}
}
return minc;
}
static inline unsigned pixel_bgr(const uint8_t * src)
{
return (src[0]) | (src[1] << 8) | (src[2] << 16);
}
static int write_pixel_15_7(Palette * palette, uint8_t * dest, const uint8_t * src,
int dist)
{
unsigned c15 = pixel_color15(src);
unsigned color = pixel_bgr(src);
int d15 = chroma_diff(color, color & 0x00f8f8f8);
int c7 = pixel_color7_fast(palette, c15);
int d7 = chroma_diff(color, palette->colors[c7]);
if (dist + d15 >= d7) {
dest[0] = c7;
return 1;
} else {
dest[0] = 0x80 | (c15 >> 8);
dest[1] = c15 & 0xff;
return 2;
}
}
static int update_palette_index(Palette * palette)
{
int r, g, b;
unsigned int bgr, c15, index;
for (r = 4; r < 256; r += 8) {
for (g = 4; g < 256; g += 8) {
for (b = 4; b < 256; b += 8) {
bgr = b | (g << 8) | (r << 16);
c15 = (b >> 3) | ((g & 0xf8) << 2) | ((r & 0xf8) << 7);
index = pixel_color7_slow(palette, bgr);
palette->index[c15] = index;
}
}
}
return 0;
}
static const unsigned int default_screen_video_v2_palette[128] = {
0x00000000, 0x00333333, 0x00666666, 0x00999999, 0x00CCCCCC, 0x00FFFFFF,
0x00330000, 0x00660000, 0x00990000, 0x00CC0000, 0x00FF0000, 0x00003300,
0x00006600, 0x00009900, 0x0000CC00, 0x0000FF00, 0x00000033, 0x00000066,
0x00000099, 0x000000CC, 0x000000FF, 0x00333300, 0x00666600, 0x00999900,
0x00CCCC00, 0x00FFFF00, 0x00003333, 0x00006666, 0x00009999, 0x0000CCCC,
0x0000FFFF, 0x00330033, 0x00660066, 0x00990099, 0x00CC00CC, 0x00FF00FF,
0x00FFFF33, 0x00FFFF66, 0x00FFFF99, 0x00FFFFCC, 0x00FF33FF, 0x00FF66FF,
0x00FF99FF, 0x00FFCCFF, 0x0033FFFF, 0x0066FFFF, 0x0099FFFF, 0x00CCFFFF,
0x00CCCC33, 0x00CCCC66, 0x00CCCC99, 0x00CCCCFF, 0x00CC33CC, 0x00CC66CC,
0x00CC99CC, 0x00CCFFCC, 0x0033CCCC, 0x0066CCCC, 0x0099CCCC, 0x00FFCCCC,
0x00999933, 0x00999966, 0x009999CC, 0x009999FF, 0x00993399, 0x00996699,
0x0099CC99, 0x0099FF99, 0x00339999, 0x00669999, 0x00CC9999, 0x00FF9999,
0x00666633, 0x00666699, 0x006666CC, 0x006666FF, 0x00663366, 0x00669966,
0x0066CC66, 0x0066FF66, 0x00336666, 0x00996666, 0x00CC6666, 0x00FF6666,
0x00333366, 0x00333399, 0x003333CC, 0x003333FF, 0x00336633, 0x00339933,
0x0033CC33, 0x0033FF33, 0x00663333, 0x00993333, 0x00CC3333, 0x00FF3333,
0x00003366, 0x00336600, 0x00660033, 0x00006633, 0x00330066, 0x00663300,
0x00336699, 0x00669933, 0x00993366, 0x00339966, 0x00663399, 0x00996633,
0x006699CC, 0x0099CC66, 0x00CC6699, 0x0066CC99, 0x009966CC, 0x00CC9966,
0x0099CCFF, 0x00CCFF99, 0x00FF99CC, 0x0099FFCC, 0x00CC99FF, 0x00FFCC99,
0x00111111, 0x00222222, 0x00444444, 0x00555555, 0x00AAAAAA, 0x00BBBBBB,
0x00DDDDDD, 0x00EEEEEE
};
static int generate_default_palette(Palette * palette)
{
memcpy(palette->colors, default_screen_video_v2_palette,
sizeof(default_screen_video_v2_palette));
return update_palette_index(palette);
}
static int generate_optimum_palette(Palette * palette, const uint8_t * image,
int width, int height, int stride)
{
//this isn't implemented yet! Default palette only!
return -1;
}
static inline int encode_15_7_sl(Palette * palette, uint8_t * dest,
const uint8_t * src, int width, int dist)
{
int len = 0, x;
for (x = 0; x < width; x++) {
len += write_pixel_15_7(palette, dest + len, src + 3 * x, dist);
}
return len;
}
static int encode_15_7(Palette * palette, Block * b, const uint8_t * src,
int stride, int dist)
{
int i;
uint8_t *ptr = b->enc;
for (i = 0; i < b->start; i++)
ptr += encode_15_7_sl(palette, ptr, src + i * stride, b->width, dist);
b->sl_begin = ptr;
for (; i < b->start + b->len; i++)
ptr += encode_15_7_sl(palette, ptr, src + i * stride, b->width, dist);
b->sl_end = ptr;
for (; i < b->height; i++)
ptr += encode_15_7_sl(palette, ptr, src + i * stride, b->width, dist);
b->enc_size = ptr - b->enc;
return b->enc_size;
}
static int encode_block(FlashSV2Context *s, Palette * palette, Block * b,
Block * prev, const uint8_t * src, int stride, int comp,
int dist, int keyframe)
{
unsigned buf_size = b->width * b->height * 6;
uint8_t *buf = s->blockbuffer;
int res;
if (b->flags & COLORSPACE_15_7) {
encode_15_7(palette, b, src, stride, dist);
} else {
encode_bgr(b, src, stride);
}
if (b->len > 0) {
b->data_size = buf_size;
res = encode_zlib(b, b->data, &b->data_size, comp);
if (res)
return res;
if (!keyframe) {
res = encode_zlibprime(b, prev, buf, &buf_size, comp);
if (res)
return res;
if (buf_size < b->data_size) {
b->data_size = buf_size;
memcpy(b->data, buf, buf_size);
b->flags |= ZLIB_PRIME_COMPRESS_PREVIOUS;
}
}
} else {
b->data_size = 0;
}
return 0;
}
static int compare_sl(FlashSV2Context * s, Block * b, const uint8_t * src,
uint8_t * frame, uint8_t * key, int y, int keyframe)
{
if (memcmp(src, frame, b->width * 3) != 0) {
b->dirty = 1;
memcpy(frame, src, b->width * 3);
#ifndef FLASHSV2_DUMB
s->diff_lines++;
#endif
}
if (memcmp(src, key, b->width * 3) != 0) {
if (b->len == 0)
b->start = y;
b->len = y + 1 - b->start;
}
return 0;
}
static int mark_all_blocks(FlashSV2Context * s, const uint8_t * src, int stride,
int keyframe)
{
int sl, rsl, col, pos, possl;
Block *b;
for (sl = s->image_height - 1; sl >= 0; sl--) {
for (col = 0; col < s->cols; col++) {
rsl = s->image_height - sl - 1;
b = s->frame_blocks + col + rsl / s->block_height * s->cols;
possl = stride * sl + col * s->block_width * 3;
pos = s->image_width * rsl * 3 + col * s->block_width * 3;
compare_sl(s, b, src + possl, s->current_frame + pos,
s->key_frame + pos, rsl % s->block_height, keyframe);
}
}
#ifndef FLASHSV2_DUMB
s->tot_lines += s->image_height * s->cols;
#endif
return 0;
}
static int encode_all_blocks(FlashSV2Context * s, int keyframe)
{
int row, col, res;
uint8_t *data;
Block *b, *prev;
for (row = 0; row < s->rows; row++) {
for (col = 0; col < s->cols; col++) {
b = s->frame_blocks + (row * s->cols + col);
prev = s->key_blocks + (row * s->cols + col);
b->flags = s->use15_7 ? COLORSPACE_15_7 : 0;
if (keyframe) {
b->start = 0;
b->len = b->height;
} else if (!b->dirty) {
b->start = 0;
b->len = 0;
b->data_size = 0;
continue;
} else if (b->start != 0 || b->len != b->height) {
b->flags |= HAS_DIFF_BLOCKS;
}
data = s->current_frame + s->image_width * 3 * s->block_height * row + s->block_width * col * 3;
res = encode_block(s, &s->palette, b, prev, data, s->image_width * 3, s->comp, s->dist, keyframe);
#ifndef FLASHSV2_DUMB
if (b->dirty)
s->diff_blocks++;
s->comp_size += b->data_size;
s->uncomp_size += b->enc_size;
#endif
if (res)
return res;
}
}
#ifndef FLASHSV2_DUMB
s->raw_size += s->image_width * s->image_height * 3;
s->tot_blocks += s->rows * s->cols;
#endif
return 0;
}
static int write_all_blocks(FlashSV2Context * s, uint8_t * buf,
int buf_size)
{
int row, col, buf_pos = 0, len;
Block *b;
for (row = 0; row < s->rows; row++) {
for (col = 0; col < s->cols; col++) {
b = s->frame_blocks + row * s->cols + col;
len = write_block(b, buf + buf_pos, buf_size - buf_pos);
b->start = b->len = b->dirty = 0;
if (len < 0)
return len;
buf_pos += len;
}
}
return buf_pos;
}
static int write_bitstream(FlashSV2Context * s, const uint8_t * src, int stride,
uint8_t * buf, int buf_size, int keyframe)
{
int buf_pos, res;
res = mark_all_blocks(s, src, stride, keyframe);
if (res)
return res;
res = encode_all_blocks(s, keyframe);
if (res)
return res;
res = write_header(s, buf, buf_size);
if (res < 0) {
return res;
} else {
buf_pos = res;
}
res = write_all_blocks(s, buf + buf_pos, buf_size - buf_pos);
if (res < 0)
return res;
buf_pos += res;
#ifndef FLASHSV2_DUMB
s->total_bits += ((double) buf_pos) * 8.0;
#endif
return buf_pos;
}
static void recommend_keyframe(FlashSV2Context * s, int *keyframe)
{
#ifndef FLASHSV2_DUMB
double block_ratio, line_ratio, enc_ratio, comp_ratio, data_ratio;
if (s->avctx->gop_size > 0) {
block_ratio = s->diff_blocks / s->tot_blocks;
line_ratio = s->diff_lines / s->tot_lines;
enc_ratio = s->uncomp_size / s->raw_size;
comp_ratio = s->comp_size / s->uncomp_size;
data_ratio = s->comp_size / s->raw_size;
if ((block_ratio >= 0.5 && line_ratio / block_ratio <= 0.5) || line_ratio >= 0.95) {
*keyframe = 1;
return;
}
}
#else
return;
#endif
}
#ifndef FLASHSV2_DUMB
static const double block_size_fraction = 1.0 / 300;
static const double use15_7_threshold = 8192;
static const double color15_7_factor = 100;
#endif
static int optimum_block_width(FlashSV2Context * s)
{
#ifndef FLASHSV2_DUMB
double save = (1-pow(s->diff_lines/s->diff_blocks/s->block_height, 0.5)) * s->comp_size/s->tot_blocks;
double width = block_size_fraction * sqrt(0.5 * save * s->rows * s->cols) * s->image_width;
int pwidth = ((int) width);
return FFCLIP(pwidth & ~15, 256, 16);
#else
return 64;
#endif
}
static int optimum_block_height(FlashSV2Context * s)
{
#ifndef FLASHSV2_DUMB
double save = (1-pow(s->diff_lines/s->diff_blocks/s->block_height, 0.5)) * s->comp_size/s->tot_blocks;
double height = block_size_fraction * sqrt(0.5 * save * s->rows * s->cols) * s->image_height;
int pheight = ((int) height);
return FFCLIP(pheight & ~15, 256, 16);
#else
return 64;
#endif
}
static int optimum_use15_7(FlashSV2Context * s)
{
#ifndef FLASHSV2_DUMB
double ideal = ((double)(s->avctx->bit_rate * s->avctx->time_base.den * s->avctx->ticks_per_frame)) /
((double) s->avctx->time_base.num) * s->avctx->frame_number;
if (ideal + use15_7_threshold < s->total_bits) {
return 1;
} else {
return 0;
}
#else
return s->avctx->global_quality == 0;
#endif
}
static int optimum_dist(FlashSV2Context * s)
{
#ifndef FLASHSV2_DUMB
double ideal =
s->avctx->bit_rate * s->avctx->time_base.den *
s->avctx->ticks_per_frame;
int dist = pow((s->total_bits / ideal) * color15_7_factor, 3);
av_log(s->avctx, AV_LOG_DEBUG, "dist: %d\n", dist);
return dist;
#else
return 15;
#endif
}
static int reconfigure_at_keyframe(FlashSV2Context * s, const uint8_t * image,
int stride)
{
int update_palette = 0;
int res;
int block_width = optimum_block_width (s);
int block_height = optimum_block_height(s);
s->rows = (s->image_height + block_height - 1) / block_height;
s->cols = (s->image_width + block_width - 1) / block_width;
if (block_width != s->block_width || block_height != s->block_height) {
s->block_width = block_width;
s->block_height = block_height;
if (s->rows * s->cols > s->blocks_size / sizeof(Block)) {
s->frame_blocks = av_realloc_array(s->frame_blocks, s->rows, s->cols * sizeof(Block));
s->key_blocks = av_realloc_array(s->key_blocks, s->cols, s->rows * sizeof(Block));
if (!s->frame_blocks || !s->key_blocks) {
av_log(s->avctx, AV_LOG_ERROR, "Memory allocation failed.\n");
return -1;
}
s->blocks_size = s->rows * s->cols * sizeof(Block);
}
init_blocks(s, s->frame_blocks, s->encbuffer, s->databuffer);
init_blocks(s, s->key_blocks, s->keybuffer, 0);
av_fast_malloc(&s->blockbuffer, &s->blockbuffer_size, block_width * block_height * 6);
if (!s->blockbuffer) {
av_log(s->avctx, AV_LOG_ERROR, "Could not allocate block buffer.\n");
return AVERROR(ENOMEM);
}
}
s->use15_7 = optimum_use15_7(s);
if (s->use15_7) {
if ((s->use_custom_palette && s->palette_type != 1) || update_palette) {
res = generate_optimum_palette(&s->palette, image, s->image_width, s->image_height, stride);
if (res)
return res;
s->palette_type = 1;
av_log(s->avctx, AV_LOG_DEBUG, "Generated optimum palette\n");
} else if (!s->use_custom_palette && s->palette_type != 0) {
res = generate_default_palette(&s->palette);
if (res)
return res;
s->palette_type = 0;
av_log(s->avctx, AV_LOG_DEBUG, "Generated default palette\n");
}
}
reset_stats(s);
return 0;
}
static int flashsv2_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
const AVFrame *p, int *got_packet)
{
FlashSV2Context *const s = avctx->priv_data;
int res;
int keyframe = 0;
if ((res = ff_alloc_packet2(avctx, pkt, s->frame_size + AV_INPUT_BUFFER_MIN_SIZE, 0)) < 0)
return res;
/* First frame needs to be a keyframe */
if (avctx->frame_number == 0)
keyframe = 1;
/* Check the placement of keyframes */
if (avctx->gop_size > 0) {
if (avctx->frame_number >= s->last_key_frame + avctx->gop_size)
keyframe = 1;
}
if (!keyframe
&& avctx->frame_number > s->last_key_frame + avctx->keyint_min) {
recommend_keyframe(s, &keyframe);
if (keyframe)
av_log(avctx, AV_LOG_DEBUG, "Recommending key frame at frame %d\n", avctx->frame_number);
}
if (keyframe) {
res = reconfigure_at_keyframe(s, p->data[0], p->linesize[0]);
if (res)
return res;
}
if (s->use15_7)
s->dist = optimum_dist(s);
res = write_bitstream(s, p->data[0], p->linesize[0], pkt->data, pkt->size, keyframe);
if (keyframe) {
new_key_frame(s);
s->last_key_frame = avctx->frame_number;
pkt->flags |= AV_PKT_FLAG_KEY;
av_log(avctx, AV_LOG_DEBUG, "Inserting key frame at frame %d\n", avctx->frame_number);
}
pkt->size = res;
*got_packet = 1;
return 0;
}
static av_cold int flashsv2_encode_end(AVCodecContext * avctx)
{
FlashSV2Context *s = avctx->priv_data;
cleanup(s);
return 0;
}
AVCodec ff_flashsv2_encoder = {
.name = "flashsv2",
.long_name = NULL_IF_CONFIG_SMALL("Flash Screen Video Version 2"),
.type = AVMEDIA_TYPE_VIDEO,
.id = AV_CODEC_ID_FLASHSV2,
.priv_data_size = sizeof(FlashSV2Context),
.init = flashsv2_encode_init,
.encode2 = flashsv2_encode_frame,
.close = flashsv2_encode_end,
.pix_fmts = (const enum AVPixelFormat[]){ AV_PIX_FMT_BGR24, AV_PIX_FMT_NONE },
};
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