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FFmpeg/libavcodec/xfacedec.c
Andreas Rheinhardt a247ac640d avcodec: Constify AVCodecs
Given that the AVCodec.next pointer has now been removed, most of the
AVCodecs are not modified at all any more and can therefore be made
const (as this patch does); the only exceptions are the very few codecs
for external libraries that have a init_static_data callback.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Signed-off-by: James Almer <jamrial@gmail.com>
2021-04-27 10:43:15 -03:00

190 lines
5.8 KiB
C

/*
* Copyright (c) 1990 James Ashton - Sydney University
* Copyright (c) 2012 Stefano Sabatini
*
* 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
* X-Face decoder, based on libcompface, by James Ashton.
*/
#include "libavutil/pixdesc.h"
#include "avcodec.h"
#include "bytestream.h"
#include "internal.h"
#include "xface.h"
static int pop_integer(BigInt *b, const ProbRange *pranges)
{
uint8_t r;
int i;
/* extract the last byte into r, and shift right b by 8 bits */
ff_big_div(b, 0, &r);
i = 0;
while (r < pranges->offset || r >= pranges->range + pranges->offset) {
pranges++;
i++;
}
ff_big_mul(b, pranges->range);
ff_big_add(b, r - pranges->offset);
return i;
}
static void pop_greys(BigInt *b, char *bitmap, int w, int h)
{
if (w > 3) {
w /= 2;
h /= 2;
pop_greys(b, bitmap, w, h);
pop_greys(b, bitmap + w, w, h);
pop_greys(b, bitmap + XFACE_WIDTH * h, w, h);
pop_greys(b, bitmap + XFACE_WIDTH * h + w, w, h);
} else {
w = pop_integer(b, ff_xface_probranges_2x2);
if (w & 1) bitmap[0] = 1;
if (w & 2) bitmap[1] = 1;
if (w & 4) bitmap[XFACE_WIDTH] = 1;
if (w & 8) bitmap[XFACE_WIDTH + 1] = 1;
}
}
static void decode_block(BigInt *b, char *bitmap, int w, int h, int level)
{
switch (pop_integer(b, &ff_xface_probranges_per_level[level][0])) {
case XFACE_COLOR_WHITE:
return;
case XFACE_COLOR_BLACK:
pop_greys(b, bitmap, w, h);
return;
default:
w /= 2;
h /= 2;
level++;
decode_block(b, bitmap, w, h, level);
decode_block(b, bitmap + w, w, h, level);
decode_block(b, bitmap + h * XFACE_WIDTH, w, h, level);
decode_block(b, bitmap + w + h * XFACE_WIDTH, w, h, level);
return;
}
}
typedef struct XFaceContext {
uint8_t bitmap[XFACE_PIXELS]; ///< image used internally for decoding
} XFaceContext;
static av_cold int xface_decode_init(AVCodecContext *avctx)
{
if (avctx->width || avctx->height) {
if (avctx->width != XFACE_WIDTH || avctx->height != XFACE_HEIGHT) {
av_log(avctx, AV_LOG_ERROR,
"Size value %dx%d not supported, only accepts a size of %dx%d\n",
avctx->width, avctx->height, XFACE_WIDTH, XFACE_HEIGHT);
return AVERROR(EINVAL);
}
}
avctx->width = XFACE_WIDTH;
avctx->height = XFACE_HEIGHT;
avctx->pix_fmt = AV_PIX_FMT_MONOWHITE;
return 0;
}
static int xface_decode_frame(AVCodecContext *avctx,
void *data, int *got_frame,
AVPacket *avpkt)
{
XFaceContext *xface = avctx->priv_data;
int ret, i, j, k;
uint8_t byte;
BigInt b = {0};
char *buf;
int64_t c;
AVFrame *frame = data;
if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
return ret;
for (i = 0, k = 0; i < avpkt->size && avpkt->data[i]; i++) {
c = avpkt->data[i];
/* ignore invalid digits */
if (c < XFACE_FIRST_PRINT || c > XFACE_LAST_PRINT)
continue;
if (++k > XFACE_MAX_DIGITS) {
av_log(avctx, AV_LOG_WARNING,
"Buffer is longer than expected, truncating at byte %d\n", i);
break;
}
ff_big_mul(&b, XFACE_PRINTS);
ff_big_add(&b, c - XFACE_FIRST_PRINT);
}
/* decode image and put it in bitmap */
memset(xface->bitmap, 0, XFACE_PIXELS);
buf = xface->bitmap;
decode_block(&b, buf, 16, 16, 0);
decode_block(&b, buf + 16, 16, 16, 0);
decode_block(&b, buf + 32, 16, 16, 0);
decode_block(&b, buf + XFACE_WIDTH * 16, 16, 16, 0);
decode_block(&b, buf + XFACE_WIDTH * 16 + 16, 16, 16, 0);
decode_block(&b, buf + XFACE_WIDTH * 16 + 32, 16, 16, 0);
decode_block(&b, buf + XFACE_WIDTH * 32 , 16, 16, 0);
decode_block(&b, buf + XFACE_WIDTH * 32 + 16, 16, 16, 0);
decode_block(&b, buf + XFACE_WIDTH * 32 + 32, 16, 16, 0);
ff_xface_generate_face(xface->bitmap, xface->bitmap);
/* convert image from 1=black 0=white bitmap to MONOWHITE */
buf = frame->data[0];
for (i = 0, j = 0, k = 0, byte = 0; i < XFACE_PIXELS; i++) {
byte += xface->bitmap[i];
if (k == 7) {
buf[j++] = byte;
byte = k = 0;
} else {
k++;
byte <<= 1;
}
if (j == XFACE_WIDTH/8) {
j = 0;
buf += frame->linesize[0];
}
}
*got_frame = 1;
return avpkt->size;
}
const AVCodec ff_xface_decoder = {
.name = "xface",
.long_name = NULL_IF_CONFIG_SMALL("X-face image"),
.type = AVMEDIA_TYPE_VIDEO,
.id = AV_CODEC_ID_XFACE,
.priv_data_size = sizeof(XFaceContext),
.init = xface_decode_init,
.decode = xface_decode_frame,
.pix_fmts = (const enum AVPixelFormat[]) { AV_PIX_FMT_MONOWHITE, AV_PIX_FMT_NONE },
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
};