/*
* 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"
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 != '}') {
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);
}
AVCodec ff_microdvd_decoder = {
.name = "microdvd",
.long_name = NULL_IF_CONFIG_SMALL("MicroDVD subtitle"),
.type = AVMEDIA_TYPE_SUBTITLE,
.id = AV_CODEC_ID_MICRODVD,
.init = microdvd_init,
.decode = microdvd_decode_frame,
.flush = ff_ass_decoder_flush,
.priv_data_size = sizeof(FFASSDecoderContext),
};