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FFmpeg/libavcodec/flashsv2enc.c
Andreas Rheinhardt 56e9e0273a avcodec/encode: Always use intermediate buffer in ff_alloc_packet2() 
Up until now, ff_alloc_packet2() has a min_size parameter:
It is supposed to be a lower bound on the final size of the packet
to allocate. If it is not too far from the upper bound (namely,
if it is at least half the upper bound), then ff_alloc_packet2()
already allocates the final, already refcounted packet; if it is
not, then the packet is not refcounted and its data only points to
a buffer owned by the AVCodecContext (in this case, the packet will
be made refcounted in encode_simple_internal() in libavcodec/encode.c).
The goal of this was to avoid data copies and intermediate buffers
if one has a precise lower bound.

Yet those encoders for which precise lower bounds exist have recently
been switched to ff_get_encode_buffer() (which automatically allocates
final buffers), leaving only two encoders to actually set the min_size
to something else than zero (namely aliaspixenc and hapenc). Both of
these encoders use a very low lower bound that is not helpful in any
nontrivial case.

This commit therefore removes the min_size parameter as well as the
codepath in ff_alloc_packet2() for the allocation of final buffers.
Furthermore, the function has been renamed to ff_alloc_packet() and
moved to encode.h alongside ff_get_encode_buffer().

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2021-06-08 12:52:50 +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 "encode.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;
memset(blocks, 0, s->cols * s->rows * sizeof(*blocks));
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 ? databuf + b->width * b->height * 6 : NULL;
}
}
}
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 int update_block_dimensions(FlashSV2Context *s, int block_width, int block_height)
{
s->block_width = block_width;
s->block_height = block_height;
s->rows = (s->image_height + s->block_height - 1) / s->block_height;
s->cols = (s->image_width + s->block_width - 1) / s->block_width;
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 AVERROR(ENOMEM);
}
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);
}
return 0;
}
static av_cold int flashsv2_encode_init(AVCodecContext * avctx)
{
FlashSV2Context *s = avctx->priv_data;
int ret;
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 AVERROR(EINVAL);
}
if ((avctx->width > 4095) || (avctx->height > 4095)) {
av_log(avctx, AV_LOG_ERROR,
"Input dimensions too large, input must be max 4095x4095 !\n");
return AVERROR(EINVAL);
}
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 AVERROR(EINVAL);
}
if ((ret = av_image_check_size(avctx->width, avctx->height, 0, avctx)) < 0)
return ret;
s->last_key_frame = 0;
s->image_width = avctx->width;
s->image_height = avctx->height;
s->frame_size = s->image_width * s->image_height * 3;
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);
if (!s->encbuffer || !s->keybuffer || !s->databuffer
|| !s->current_frame || !s->key_frame) {
av_log(avctx, AV_LOG_ERROR, "Memory allocation failed.\n");
return AVERROR(ENOMEM);
}
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
return update_block_dimensions(s, 64, 64);
}
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);
if (block_width != s->block_width || block_height != s->block_height) {
res = update_block_dimensions(s, block_width, block_height);
if (res < 0)
return res;
}
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_packet(avctx, pkt, s->frame_size + AV_INPUT_BUFFER_MIN_SIZE)) < 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;
}
const 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 },
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
};
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