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FFmpeg/libavcodec/microdvddec.c
Andreas Rheinhardt 20f9727018 avcodec/codec_internal: Add FFCodec, hide internal part of AVCodec
Up until now, codec.h contains both public and private parts
of AVCodec. This exposes the internals of AVCodec to users
and leads them into the temptation of actually using them
and forces us to forward-declare structures and types that
users can't use at all.

This commit changes this by adding a new structure FFCodec to
codec_internal.h that extends AVCodec, i.e. contains the public
AVCodec as first member; the private fields of AVCodec are moved
to this structure, leaving codec.h clean.

Reviewed-by: Anton Khirnov <anton@khirnov.net>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2022-03-21 01:33:09 +01:00

383 lines
11 KiB
C

/*
* Copyright (c) 2012 Clément Bœsch
*
* 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
* MicroDVD subtitle decoder
*
* Based on the specifications found here:
* https://trac.videolan.org/vlc/ticket/1825#comment:6
*/
#include "libavutil/avstring.h"
#include "libavutil/parseutils.h"
#include "libavutil/bprint.h"
#include "avcodec.h"
#include "ass.h"
#include "codec_internal.h"
static int indexof(const char *s, int c)
{
char *f = strchr(s, c);
return f ? (f - s) : -1;
}
struct microdvd_tag {
char key;
int persistent;
uint32_t data1;
uint32_t data2;
char *data_string;
int data_string_len;
};
#define MICRODVD_PERSISTENT_OFF 0
#define MICRODVD_PERSISTENT_ON 1
#define MICRODVD_PERSISTENT_OPENED 2
// Color, Font, Size, cHarset, stYle, Position, cOordinate
#define MICRODVD_TAGS "cfshyYpo"
static void microdvd_set_tag(struct microdvd_tag *tags, struct microdvd_tag tag)
{
int tag_index = indexof(MICRODVD_TAGS, tag.key);
if (tag_index < 0)
return;
memcpy(&tags[tag_index], &tag, sizeof(tag));
}
// italic, bold, underline, strike-through
#define MICRODVD_STYLES "ibus"
/* some samples have lines that start with a / indicating non persistent italic
* marker */
static char *check_for_italic_slash_marker(struct microdvd_tag *tags, char *s)
{
if (*s == '/') {
struct microdvd_tag tag = tags[indexof(MICRODVD_TAGS, 'y')];
tag.key = 'y';
tag.data1 |= 1 << 0 /* 'i' position in MICRODVD_STYLES */;
microdvd_set_tag(tags, tag);
s++;
}
return s;
}
static char *microdvd_load_tags(struct microdvd_tag *tags, char *s)
{
s = check_for_italic_slash_marker(tags, s);
while (*s == '{') {
char *start = s;
char tag_char = *(s + 1);
struct microdvd_tag tag = {0};
if (!tag_char || *(s + 2) != ':')
break;
s += 3;
switch (tag_char) {
/* Style */
case 'Y':
tag.persistent = MICRODVD_PERSISTENT_ON;
case 'y':
while (*s && *s != '}' && s - start < 256) {
int style_index = indexof(MICRODVD_STYLES, *s);
if (style_index >= 0)
tag.data1 |= (1 << style_index);
s++;
}
if (*s != '}')
break;
/* We must distinguish persistent and non-persistent styles
* to handle this kind of style tags: {y:ib}{Y:us} */
tag.key = tag_char;
break;
/* Color */
case 'C':
tag.persistent = MICRODVD_PERSISTENT_ON;
case 'c':
while (*s == '$' || *s == '#')
s++;
tag.data1 = strtol(s, &s, 16) & 0x00ffffff;
if (*s != '}')
break;
tag.key = 'c';
break;
/* Font name */
case 'F':
tag.persistent = MICRODVD_PERSISTENT_ON;
case 'f': {
int len = indexof(s, '}');
if (len < 0)
break;
tag.data_string = s;
tag.data_string_len = len;
s += len;
tag.key = 'f';
break;
}
/* Font size */
case 'S':
tag.persistent = MICRODVD_PERSISTENT_ON;
case 's':
tag.data1 = strtol(s, &s, 10);
if (*s != '}')
break;
tag.key = 's';
break;
/* Charset */
case 'H': {
//TODO: not yet handled, just parsed.
int len = indexof(s, '}');
if (len < 0)
break;
tag.data_string = s;
tag.data_string_len = len;
s += len;
tag.key = 'h';
break;
}
/* Position */
case 'P':
if (!*s)
break;
tag.persistent = MICRODVD_PERSISTENT_ON;
tag.data1 = (*s++ == '1');
if (*s != '}')
break;
tag.key = 'p';
break;
/* Coordinates */
case 'o':
tag.persistent = MICRODVD_PERSISTENT_ON;
tag.data1 = strtol(s, &s, 10);
if (*s != ',')
break;
s++;
tag.data2 = strtol(s, &s, 10);
if (*s != '}')
break;
tag.key = 'o';
break;
default: /* Unknown tag, we consider it's text */
break;
}
if (tag.key == 0)
return start;
microdvd_set_tag(tags, tag);
s++;
}
return check_for_italic_slash_marker(tags, s);
}
static void microdvd_open_tags(AVBPrint *new_line, struct microdvd_tag *tags)
{
int i, sidx;
for (i = 0; i < sizeof(MICRODVD_TAGS) - 1; i++) {
if (tags[i].persistent == MICRODVD_PERSISTENT_OPENED)
continue;
switch (tags[i].key) {
case 'Y':
case 'y':
for (sidx = 0; sidx < sizeof(MICRODVD_STYLES) - 1; sidx++)
if (tags[i].data1 & (1 << sidx))
av_bprintf(new_line, "{\\%c1}", MICRODVD_STYLES[sidx]);
break;
case 'c':
av_bprintf(new_line, "{\\c&H%06"PRIX32"&}", tags[i].data1);
break;
case 'f':
av_bprintf(new_line, "{\\fn%.*s}",
tags[i].data_string_len, tags[i].data_string);
break;
case 's':
av_bprintf(new_line, "{\\fs%"PRId32"}", tags[i].data1);
break;
case 'p':
if (tags[i].data1 == 0)
av_bprintf(new_line, "{\\an8}");
break;
case 'o':
av_bprintf(new_line, "{\\pos(%"PRId32",%"PRId32")}",
tags[i].data1, tags[i].data2);
break;
}
if (tags[i].persistent == MICRODVD_PERSISTENT_ON)
tags[i].persistent = MICRODVD_PERSISTENT_OPENED;
}
}
static void microdvd_close_no_persistent_tags(AVBPrint *new_line,
struct microdvd_tag *tags)
{
int i, sidx;
for (i = sizeof(MICRODVD_TAGS) - 2; i >= 0; i--) {
if (tags[i].persistent != MICRODVD_PERSISTENT_OFF)
continue;
switch (tags[i].key) {
case 'y':
for (sidx = sizeof(MICRODVD_STYLES) - 2; sidx >= 0; sidx--)
if (tags[i].data1 & (1 << sidx))
av_bprintf(new_line, "{\\%c0}", MICRODVD_STYLES[sidx]);
break;
case 'c':
av_bprintf(new_line, "{\\c}");
break;
case 'f':
av_bprintf(new_line, "{\\fn}");
break;
case 's':
av_bprintf(new_line, "{\\fs}");
break;
}
tags[i].key = 0;
}
}
static int microdvd_decode_frame(AVCodecContext *avctx,
void *data, int *got_sub_ptr, AVPacket *avpkt)
{
AVSubtitle *sub = data;
AVBPrint new_line;
char *line = avpkt->data;
char *end = avpkt->data + avpkt->size;
FFASSDecoderContext *s = avctx->priv_data;
struct microdvd_tag tags[sizeof(MICRODVD_TAGS) - 1] = {{0}};
if (avpkt->size <= 0)
return avpkt->size;
av_bprint_init(&new_line, 0, 2048);
// subtitle content
while (line < end && *line) {
// parse MicroDVD tags, and open them in ASS
line = microdvd_load_tags(tags, line);
microdvd_open_tags(&new_line, tags);
// simple copy until EOL or forced carriage return
while (line < end && *line && *line != '|') {
av_bprint_chars(&new_line, *line, 1);
line++;
}
// line split
if (line < end && *line == '|') {
microdvd_close_no_persistent_tags(&new_line, tags);
av_bprintf(&new_line, "\\N");
line++;
}
}
if (new_line.len) {
int ret = ff_ass_add_rect(sub, new_line.str, s->readorder++, 0, NULL, NULL);
av_bprint_finalize(&new_line, NULL);
if (ret < 0)
return ret;
}
*got_sub_ptr = sub->num_rects > 0;
return avpkt->size;
}
static int microdvd_init(AVCodecContext *avctx)
{
int i, sidx;
AVBPrint font_buf;
int font_size = ASS_DEFAULT_FONT_SIZE;
int color = ASS_DEFAULT_COLOR;
int bold = ASS_DEFAULT_BOLD;
int italic = ASS_DEFAULT_ITALIC;
int underline = ASS_DEFAULT_UNDERLINE;
int alignment = ASS_DEFAULT_ALIGNMENT;
struct microdvd_tag tags[sizeof(MICRODVD_TAGS) - 1] = {{0}};
av_bprint_init(&font_buf, 0, AV_BPRINT_SIZE_AUTOMATIC);
av_bprintf(&font_buf, "%s", ASS_DEFAULT_FONT);
if (avctx->extradata) {
microdvd_load_tags(tags, avctx->extradata);
for (i = 0; i < sizeof(MICRODVD_TAGS) - 1; i++) {
switch (av_tolower(tags[i].key)) {
case 'y':
for (sidx = 0; sidx < sizeof(MICRODVD_STYLES) - 1; sidx++) {
if (tags[i].data1 & (1 << sidx)) {
switch (MICRODVD_STYLES[sidx]) {
case 'i': italic = 1; break;
case 'b': bold = 1; break;
case 'u': underline = 1; break;
}
}
}
break;
case 'c': color = tags[i].data1; break;
case 's': font_size = tags[i].data1; break;
case 'p': alignment = 8; break;
case 'f':
av_bprint_clear(&font_buf);
av_bprintf(&font_buf, "%.*s",
tags[i].data_string_len, tags[i].data_string);
break;
}
}
}
return ff_ass_subtitle_header(avctx, font_buf.str, font_size, color,
ASS_DEFAULT_BACK_COLOR, bold, italic,
underline, ASS_DEFAULT_BORDERSTYLE,
alignment);
}
const FFCodec ff_microdvd_decoder = {
.p.name = "microdvd",
.p.long_name = NULL_IF_CONFIG_SMALL("MicroDVD subtitle"),
.p.type = AVMEDIA_TYPE_SUBTITLE,
.p.id = AV_CODEC_ID_MICRODVD,
.init = microdvd_init,
.decode = microdvd_decode_frame,
.flush = ff_ass_decoder_flush,
.priv_data_size = sizeof(FFASSDecoderContext),
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
};