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FFmpeg/libavcodec/a64multienc.c
Andreas Rheinhardt 0ca09335aa avcodec/a64multienc: Don't use static buffers, fix potential races
render_charset() used static buffers that are always completely
initialized before every use, so that it is unnecessary for the
values in these arrays to be kept after leaving the function.
Given that this is not only unnecessary, but harmful due to the
possibility of data races if several instances of a64multi/a64multi5
run simultaneously these buffers have been replaced by ordinary buffers
on the stack (they are small enough for this).

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2021-04-03 13:07:43 +02:00

431 lines
14 KiB
C

/*
* a64 video encoder - multicolor modes
* Copyright (c) 2009 Tobias Bindhammer
*
* 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
* a64 video encoder - multicolor modes
*/
#include "a64colors.h"
#include "a64tables.h"
#include "elbg.h"
#include "internal.h"
#include "libavutil/avassert.h"
#include "libavutil/common.h"
#include "libavutil/intreadwrite.h"
#define DITHERSTEPS 8
#define CHARSET_CHARS 256
#define INTERLACED 1
#define CROP_SCREENS 1
#define C64XRES 320
#define C64YRES 200
typedef struct A64Context {
/* variables for multicolor modes */
AVLFG randctx;
int mc_lifetime;
int mc_use_5col;
unsigned mc_frame_counter;
int *mc_meta_charset;
int *mc_charmap;
int *mc_best_cb;
int mc_luma_vals[5];
uint8_t *mc_charset;
uint8_t *mc_colram;
uint8_t *mc_palette;
int mc_pal_size;
/* pts of the next packet that will be output */
int64_t next_pts;
} A64Context;
/* gray gradient */
static const uint8_t mc_colors[5]={0x0,0xb,0xc,0xf,0x1};
/* other possible gradients - to be tested */
//static const uint8_t mc_colors[5]={0x0,0x8,0xa,0xf,0x7};
//static const uint8_t mc_colors[5]={0x0,0x9,0x8,0xa,0x3};
static void to_meta_with_crop(AVCodecContext *avctx,
const AVFrame *p, int *dest)
{
int blockx, blocky, x, y;
int luma = 0;
int height = FFMIN(avctx->height, C64YRES);
int width = FFMIN(avctx->width , C64XRES);
uint8_t *src = p->data[0];
for (blocky = 0; blocky < C64YRES; blocky += 8) {
for (blockx = 0; blockx < C64XRES; blockx += 8) {
for (y = blocky; y < blocky + 8 && y < C64YRES; y++) {
for (x = blockx; x < blockx + 8 && x < C64XRES; x += 2) {
if(x < width && y < height) {
if (x + 1 < width) {
/* build average over 2 pixels */
luma = (src[(x + 0 + y * p->linesize[0])] +
src[(x + 1 + y * p->linesize[0])]) / 2;
} else {
luma = src[(x + y * p->linesize[0])];
}
/* write blocks as linear data now so they are suitable for elbg */
dest[0] = luma;
}
dest++;
}
}
}
}
}
static void render_charset(AVCodecContext *avctx, uint8_t *charset,
uint8_t *colrammap)
{
A64Context *c = avctx->priv_data;
uint8_t row1, row2;
int charpos, x, y;
int a, b;
uint8_t pix;
int lowdiff, highdiff;
int *best_cb = c->mc_best_cb;
uint8_t index1[256];
uint8_t index2[256];
uint8_t dither[256];
int i;
int distance;
/* Generate lookup-tables for dither and index before looping.
* This code relies on c->mc_luma_vals[c->mc_pal_size - 1] being
* the maximum of all the mc_luma_vals values and on the minimum
* being zero; this ensures that dither is properly initialized. */
i = 0;
for (a=0; a < 256; a++) {
if(i < c->mc_pal_size -1 && a == c->mc_luma_vals[i + 1]) {
distance = c->mc_luma_vals[i + 1] - c->mc_luma_vals[i];
for(b = 0; b <= distance; b++) {
dither[c->mc_luma_vals[i] + b] = b * (DITHERSTEPS - 1) / distance;
}
i++;
}
if(i >= c->mc_pal_size - 1) dither[a] = 0;
index1[a] = i;
index2[a] = FFMIN(i + 1, c->mc_pal_size - 1);
}
/* and render charset */
for (charpos = 0; charpos < CHARSET_CHARS; charpos++) {
lowdiff = 0;
highdiff = 0;
for (y = 0; y < 8; y++) {
row1 = 0; row2 = 0;
for (x = 0; x < 4; x++) {
pix = best_cb[y * 4 + x];
/* accumulate error for brightest/darkest color */
if (index1[pix] >= 3)
highdiff += pix - c->mc_luma_vals[3];
if (index1[pix] < 1)
lowdiff += c->mc_luma_vals[1] - pix;
row1 <<= 2;
if (INTERLACED) {
row2 <<= 2;
if (interlaced_dither_patterns[dither[pix]][(y & 3) * 2 + 0][x & 3])
row1 |= 3-(index2[pix] & 3);
else
row1 |= 3-(index1[pix] & 3);
if (interlaced_dither_patterns[dither[pix]][(y & 3) * 2 + 1][x & 3])
row2 |= 3-(index2[pix] & 3);
else
row2 |= 3-(index1[pix] & 3);
}
else {
if (multi_dither_patterns[dither[pix]][(y & 3)][x & 3])
row1 |= 3-(index2[pix] & 3);
else
row1 |= 3-(index1[pix] & 3);
}
}
charset[y+0x000] = row1;
if (INTERLACED) charset[y+0x800] = row2;
}
/* do we need to adjust pixels? */
if (highdiff > 0 && lowdiff > 0 && c->mc_use_5col) {
if (lowdiff > highdiff) {
for (x = 0; x < 32; x++)
best_cb[x] = FFMIN(c->mc_luma_vals[3], best_cb[x]);
} else {
for (x = 0; x < 32; x++)
best_cb[x] = FFMAX(c->mc_luma_vals[1], best_cb[x]);
}
charpos--; /* redo now adjusted char */
/* no adjustment needed, all fine */
} else {
/* advance pointers */
best_cb += 32;
charset += 8;
/* remember colorram value */
colrammap[charpos] = (highdiff > 0);
}
}
}
static av_cold int a64multi_close_encoder(AVCodecContext *avctx)
{
A64Context *c = avctx->priv_data;
av_freep(&c->mc_meta_charset);
av_freep(&c->mc_best_cb);
av_freep(&c->mc_charset);
av_freep(&c->mc_charmap);
av_freep(&c->mc_colram);
return 0;
}
static av_cold int a64multi_encode_init(AVCodecContext *avctx)
{
A64Context *c = avctx->priv_data;
int a;
av_lfg_init(&c->randctx, 1);
if (avctx->global_quality < 1) {
c->mc_lifetime = 4;
} else {
c->mc_lifetime = avctx->global_quality /= FF_QP2LAMBDA;
}
av_log(avctx, AV_LOG_INFO, "charset lifetime set to %d frame(s)\n", c->mc_lifetime);
c->mc_frame_counter = 0;
c->mc_use_5col = avctx->codec->id == AV_CODEC_ID_A64_MULTI5;
c->mc_pal_size = 4 + c->mc_use_5col;
/* precalc luma values for later use */
for (a = 0; a < c->mc_pal_size; a++) {
c->mc_luma_vals[a]=a64_palette[mc_colors[a]][0] * 0.30 +
a64_palette[mc_colors[a]][1] * 0.59 +
a64_palette[mc_colors[a]][2] * 0.11;
}
if (!(c->mc_meta_charset = av_mallocz_array(c->mc_lifetime, 32000 * sizeof(int))) ||
!(c->mc_best_cb = av_malloc(CHARSET_CHARS * 32 * sizeof(int))) ||
!(c->mc_charmap = av_mallocz_array(c->mc_lifetime, 1000 * sizeof(int))) ||
!(c->mc_colram = av_mallocz(CHARSET_CHARS * sizeof(uint8_t))) ||
!(c->mc_charset = av_malloc(0x800 * (INTERLACED+1) * sizeof(uint8_t)))) {
av_log(avctx, AV_LOG_ERROR, "Failed to allocate buffer memory.\n");
return AVERROR(ENOMEM);
}
/* set up extradata */
if (!(avctx->extradata = av_mallocz(8 * 4 + AV_INPUT_BUFFER_PADDING_SIZE))) {
av_log(avctx, AV_LOG_ERROR, "Failed to allocate memory for extradata.\n");
return AVERROR(ENOMEM);
}
avctx->extradata_size = 8 * 4;
AV_WB32(avctx->extradata, c->mc_lifetime);
AV_WB32(avctx->extradata + 16, INTERLACED);
if (!avctx->codec_tag)
avctx->codec_tag = AV_RL32("a64m");
c->next_pts = AV_NOPTS_VALUE;
return 0;
}
static void a64_compress_colram(unsigned char *buf, int *charmap, uint8_t *colram)
{
int a;
uint8_t temp;
/* only needs to be done in 5col mode */
/* XXX could be squeezed to 0x80 bytes */
for (a = 0; a < 256; a++) {
temp = colram[charmap[a + 0x000]] << 0;
temp |= colram[charmap[a + 0x100]] << 1;
temp |= colram[charmap[a + 0x200]] << 2;
if (a < 0xe8) temp |= colram[charmap[a + 0x300]] << 3;
buf[a] = temp << 2;
}
}
static int a64multi_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
const AVFrame *p, int *got_packet)
{
A64Context *c = avctx->priv_data;
int frame;
int x, y;
int b_height;
int b_width;
int req_size, ret;
uint8_t *buf = NULL;
int *charmap = c->mc_charmap;
uint8_t *colram = c->mc_colram;
uint8_t *charset = c->mc_charset;
int *meta = c->mc_meta_charset;
int *best_cb = c->mc_best_cb;
int charset_size = 0x800 * (INTERLACED + 1);
int colram_size = 0x100 * c->mc_use_5col;
int screen_size;
if(CROP_SCREENS) {
b_height = FFMIN(avctx->height,C64YRES) >> 3;
b_width = FFMIN(avctx->width ,C64XRES) >> 3;
screen_size = b_width * b_height;
} else {
b_height = C64YRES >> 3;
b_width = C64XRES >> 3;
screen_size = 0x400;
}
/* no data, means end encoding asap */
if (!p) {
/* all done, end encoding */
if (!c->mc_lifetime) return 0;
/* no more frames in queue, prepare to flush remaining frames */
if (!c->mc_frame_counter) {
c->mc_lifetime = 0;
}
/* still frames in queue so limit lifetime to remaining frames */
else c->mc_lifetime = c->mc_frame_counter;
/* still new data available */
} else {
/* fill up mc_meta_charset with data until lifetime exceeds */
if (c->mc_frame_counter < c->mc_lifetime) {
to_meta_with_crop(avctx, p, meta + 32000 * c->mc_frame_counter);
c->mc_frame_counter++;
if (c->next_pts == AV_NOPTS_VALUE)
c->next_pts = p->pts;
/* lifetime is not reached so wait for next frame first */
return 0;
}
}
/* lifetime reached so now convert X frames at once */
if (c->mc_frame_counter == c->mc_lifetime) {
req_size = 0;
/* any frames to encode? */
if (c->mc_lifetime) {
int alloc_size = charset_size + c->mc_lifetime*(screen_size + colram_size);
if ((ret = ff_alloc_packet2(avctx, pkt, alloc_size, 0)) < 0)
return ret;
buf = pkt->data;
/* calc optimal new charset + charmaps */
ret = avpriv_init_elbg(meta, 32, 1000 * c->mc_lifetime, best_cb,
CHARSET_CHARS, 50, charmap, &c->randctx);
if (ret < 0)
return ret;
ret = avpriv_do_elbg(meta, 32, 1000 * c->mc_lifetime, best_cb,
CHARSET_CHARS, 50, charmap, &c->randctx);
if (ret < 0)
return ret;
/* create colorram map and a c64 readable charset */
render_charset(avctx, charset, colram);
/* copy charset to buf */
memcpy(buf, charset, charset_size);
/* advance pointers */
buf += charset_size;
req_size += charset_size;
}
/* write x frames to buf */
for (frame = 0; frame < c->mc_lifetime; frame++) {
/* copy charmap to buf. buf is uchar*, charmap is int*, so no memcpy here, sorry */
for (y = 0; y < b_height; y++) {
for (x = 0; x < b_width; x++) {
buf[y * b_width + x] = charmap[y * b_width + x];
}
}
/* advance pointers */
buf += screen_size;
req_size += screen_size;
/* compress and copy colram to buf */
if (c->mc_use_5col) {
a64_compress_colram(buf, charmap, colram);
/* advance pointers */
buf += colram_size;
req_size += colram_size;
}
/* advance to next charmap */
charmap += 1000;
}
AV_WB32(avctx->extradata + 4, c->mc_frame_counter);
AV_WB32(avctx->extradata + 8, charset_size);
AV_WB32(avctx->extradata + 12, screen_size + colram_size);
/* reset counter */
c->mc_frame_counter = 0;
pkt->pts = pkt->dts = c->next_pts;
c->next_pts = AV_NOPTS_VALUE;
av_assert0(pkt->size >= req_size);
pkt->size = req_size;
pkt->flags |= AV_PKT_FLAG_KEY;
*got_packet = !!req_size;
}
return 0;
}
#if CONFIG_A64MULTI_ENCODER
AVCodec ff_a64multi_encoder = {
.name = "a64multi",
.long_name = NULL_IF_CONFIG_SMALL("Multicolor charset for Commodore 64"),
.type = AVMEDIA_TYPE_VIDEO,
.id = AV_CODEC_ID_A64_MULTI,
.priv_data_size = sizeof(A64Context),
.init = a64multi_encode_init,
.encode2 = a64multi_encode_frame,
.close = a64multi_close_encoder,
.pix_fmts = (const enum AVPixelFormat[]) {AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE},
.capabilities = AV_CODEC_CAP_DELAY,
.caps_internal = FF_CODEC_CAP_INIT_CLEANUP | FF_CODEC_CAP_INIT_THREADSAFE,
};
#endif
#if CONFIG_A64MULTI5_ENCODER
AVCodec ff_a64multi5_encoder = {
.name = "a64multi5",
.long_name = NULL_IF_CONFIG_SMALL("Multicolor charset for Commodore 64, extended with 5th color (colram)"),
.type = AVMEDIA_TYPE_VIDEO,
.id = AV_CODEC_ID_A64_MULTI5,
.priv_data_size = sizeof(A64Context),
.init = a64multi_encode_init,
.encode2 = a64multi_encode_frame,
.close = a64multi_close_encoder,
.pix_fmts = (const enum AVPixelFormat[]) {AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE},
.capabilities = AV_CODEC_CAP_DELAY,
.caps_internal = FF_CODEC_CAP_INIT_CLEANUP | FF_CODEC_CAP_INIT_THREADSAFE,
};
#endif