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mirror of https://github.com/FFmpeg/FFmpeg.git synced 2024-12-07 11:13:41 +02:00
FFmpeg/libavcodec/ass.c
Oneric 0fc975c0d3 avcodec/ass,webvttdec: implement more portable curly brace escapes
Unlike what the old comment suggested, standard ASS has no character
escape mechanism, but a closing curly bracket doesn't even need one.

For manual authored sub files using a full-width variant of an
appropriate font and with scaling and spacing modifiers is a common
workaround.
This is not an option here, but we can still make things much less bad.
Now the desired opening bracket still shows up in libass, and
standard renders will merely display a backslash in its place
instead of stripping the following text like before.
2024-04-06 09:25:03 +02:00

221 lines
8.4 KiB
C

/*
* SSA/ASS common functions
* Copyright (c) 2010 Aurelien Jacobs <aurel@gnuage.org>
*
* 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
*/
#include "avcodec.h"
#include "ass.h"
#include "libavutil/avstring.h"
#include "libavutil/bprint.h"
#include "libavutil/mem.h"
#include "version.h"
int ff_ass_subtitle_header_full(AVCodecContext *avctx,
int play_res_x, int play_res_y,
const char *font, int font_size,
int primary_color, int secondary_color,
int outline_color, int back_color,
int bold, int italic, int underline,
int border_style, int alignment)
{
avctx->subtitle_header = av_asprintf(
"[Script Info]\r\n"
"; Script generated by FFmpeg/Lavc%s\r\n"
"ScriptType: v4.00+\r\n"
"PlayResX: %d\r\n"
"PlayResY: %d\r\n"
"ScaledBorderAndShadow: yes\r\n"
"YCbCr Matrix: None\r\n"
"\r\n"
"[V4+ Styles]\r\n"
/* ASS (v4+) header */
"Format: Name, "
"Fontname, Fontsize, "
"PrimaryColour, SecondaryColour, OutlineColour, BackColour, "
"Bold, Italic, Underline, StrikeOut, "
"ScaleX, ScaleY, "
"Spacing, Angle, "
"BorderStyle, Outline, Shadow, "
"Alignment, MarginL, MarginR, MarginV, "
"Encoding\r\n"
"Style: "
"Default," /* Name */
"%s,%d," /* Font{name,size} */
"&H%x,&H%x,&H%x,&H%x," /* {Primary,Secondary,Outline,Back}Colour */
"%d,%d,%d,0," /* Bold, Italic, Underline, StrikeOut */
"100,100," /* Scale{X,Y} */
"0,0," /* Spacing, Angle */
"%d,1,0," /* BorderStyle, Outline, Shadow */
"%d,10,10,10," /* Alignment, Margin[LRV] */
"1\r\n" /* Encoding */
"\r\n"
"[Events]\r\n"
"Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text\r\n",
!(avctx->flags & AV_CODEC_FLAG_BITEXACT) ? AV_STRINGIFY(LIBAVCODEC_VERSION) : "",
play_res_x, play_res_y, font, font_size,
primary_color, secondary_color, outline_color, back_color,
-bold, -italic, -underline, border_style, alignment);
if (!avctx->subtitle_header)
return AVERROR(ENOMEM);
avctx->subtitle_header_size = strlen(avctx->subtitle_header);
return 0;
}
int ff_ass_subtitle_header(AVCodecContext *avctx,
const char *font, int font_size,
int color, int back_color,
int bold, int italic, int underline,
int border_style, int alignment)
{
return ff_ass_subtitle_header_full(avctx,
ASS_DEFAULT_PLAYRESX, ASS_DEFAULT_PLAYRESY,
font, font_size, color, color,
back_color, back_color,
bold, italic, underline,
border_style, alignment);
}
int ff_ass_subtitle_header_default(AVCodecContext *avctx)
{
return ff_ass_subtitle_header(avctx, ASS_DEFAULT_FONT,
ASS_DEFAULT_FONT_SIZE,
ASS_DEFAULT_COLOR,
ASS_DEFAULT_BACK_COLOR,
ASS_DEFAULT_BOLD,
ASS_DEFAULT_ITALIC,
ASS_DEFAULT_UNDERLINE,
ASS_DEFAULT_BORDERSTYLE,
ASS_DEFAULT_ALIGNMENT);
}
char *ff_ass_get_dialog(int readorder, int layer, const char *style,
const char *speaker, const char *text)
{
return av_asprintf("%d,%d,%s,%s,0,0,0,,%s",
readorder, layer, style ? style : "Default",
speaker ? speaker : "", text);
}
int ff_ass_add_rect2(AVSubtitle *sub, const char *dialog,
int readorder, int layer, const char *style,
const char *speaker, unsigned *nb_rect_allocated)
{
AVSubtitleRect **rects = sub->rects, *rect;
char *ass_str;
uint64_t new_nb = 0;
if (sub->num_rects >= UINT_MAX)
return AVERROR(ENOMEM);
if (nb_rect_allocated && *nb_rect_allocated <= sub->num_rects) {
if (sub->num_rects < UINT_MAX / 17 * 16) {
new_nb = sub->num_rects + sub->num_rects/16 + 1;
} else
new_nb = UINT_MAX;
} else if (!nb_rect_allocated)
new_nb = sub->num_rects + 1;
if (new_nb) {
rects = av_realloc_array(rects, new_nb, sizeof(*sub->rects));
if (!rects)
return AVERROR(ENOMEM);
if (nb_rect_allocated)
*nb_rect_allocated = new_nb;
sub->rects = rects;
}
rect = av_mallocz(sizeof(*rect));
if (!rect)
return AVERROR(ENOMEM);
rects[sub->num_rects++] = rect;
rect->type = SUBTITLE_ASS;
ass_str = ff_ass_get_dialog(readorder, layer, style, speaker, dialog);
if (!ass_str)
return AVERROR(ENOMEM);
rect->ass = ass_str;
return 0;
}
int ff_ass_add_rect(AVSubtitle *sub, const char *dialog,
int readorder, int layer, const char *style,
const char *speaker)
{
return ff_ass_add_rect2(sub, dialog, readorder, layer, style, speaker, NULL);
}
void ff_ass_decoder_flush(AVCodecContext *avctx)
{
FFASSDecoderContext *s = avctx->priv_data;
if (!(avctx->flags2 & AV_CODEC_FLAG2_RO_FLUSH_NOOP))
s->readorder = 0;
}
void ff_ass_bprint_text_event(AVBPrint *buf, const char *p, int size,
const char *linebreaks, int keep_ass_markup)
{
const char *p_end = p + size;
for (; p < p_end && *p; p++) {
/* forced custom line breaks, not accounted as "normal" EOL */
if (linebreaks && strchr(linebreaks, *p)) {
av_bprintf(buf, "\\N");
/* cancel curly brackets to avoid bogus override tag blocks
* hiding text. Standard ASS has no character escapes,
* though (only) libass provides \{ and \}.
* Unpaired closing brackets don't need escaping at all though and
* to make the situation less bad in standard ASS insert an empty block
*/
} else if (!keep_ass_markup && *p == '{') {
av_bprintf(buf, "\\{{}");
/* append word-joiner U+2060 as UTF-8 to break up sequences like \N */
} else if (!keep_ass_markup && *p == '\\') {
if (p_end - p <= 3 || strncmp(p + 1, "\xe2\x81\xa0", 3))
av_bprintf(buf, "\\\xe2\x81\xa0");
else
av_bprintf(buf, "\\");
/* some packets might end abruptly (no \0 at the end, like for example
* in some cases of demuxing from a classic video container), some
* might be terminated with \n or \r\n which we have to remove (for
* consistency with those who haven't), and we also have to deal with
* evil cases such as \r at the end of the buffer (and no \0 terminated
* character) */
} else if (p[0] == '\n') {
/* some stuff left so we can insert a line break */
if (p < p_end - 1)
av_bprintf(buf, "\\N");
} else if (p[0] == '\r' && p < p_end - 1 && p[1] == '\n') {
/* \r followed by a \n, we can skip it. We don't insert the \N yet
* because we don't know if it is followed by more text */
continue;
/* finally, a sane character */
} else {
av_bprint_chars(buf, *p, 1);
}
}
}