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/*
* 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
* Raw subtitles decoder
*/
#include "avcodec.h"
#include "ass.h"
#include "libavutil/bprint.h"
#include "libavutil/opt.h"
typedef struct {
AVClass *class;
char *linebreaks;
int keep_ass_markup;
} TextContext;
#define OFFSET(x) offsetof(TextContext, x)
#define SD AV_OPT_FLAG_SUBTITLE_PARAM | AV_OPT_FLAG_DECODING_PARAM
static const AVOption options[] = {
{ "linebreaks", "Extra line breaks characters", OFFSET(linebreaks), AV_OPT_TYPE_STRING, {.str=NULL}, .flags=SD },
{ "keep_ass_markup", "Set if ASS tags must be escaped", OFFSET(keep_ass_markup), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, .flags=SD },
{ NULL }
};
static const AVClass text_decoder_class = {
.class_name = "text decoder",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
static int text_event_to_ass(const AVCodecContext *avctx, AVBPrint *buf,
const char *p, const char *p_end)
{
const TextContext *text = avctx->priv_data;
for (; p < p_end && *p; p++) {
/* forced custom line breaks, not accounted as "normal" EOL */
if (text->linebreaks && strchr(text->linebreaks, *p)) {
av_bprintf(buf, "\\N");
/* standard ASS escaping so random characters don't get mis-interpreted
* as ASS */
} else if (!text->keep_ass_markup && strchr("{}\\", *p)) {
av_bprintf(buf, "\\%c", *p);
/* 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);
}
}
av_bprintf(buf, "\r\n");
return 0;
}
static int text_decode_frame(AVCodecContext *avctx, void *data,
int *got_sub_ptr, AVPacket *avpkt)
{
AVBPrint buf;
AVSubtitle *sub = data;
const char *ptr = avpkt->data;
const int ts_start = av_rescale_q(avpkt->pts, avctx->time_base, (AVRational){1,100});
const int ts_duration = avpkt->duration != -1 ?
av_rescale_q(avpkt->duration, avctx->time_base, (AVRational){1,100}) : -1;
av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
if (ptr && avpkt->size > 0 && *ptr &&
!text_event_to_ass(avctx, &buf, ptr, ptr + avpkt->size)) {
if (!av_bprint_is_complete(&buf)) {
av_bprint_finalize(&buf, NULL);
return AVERROR(ENOMEM);
}
ff_ass_add_rect(sub, buf.str, ts_start, ts_duration, 0);
}
*got_sub_ptr = sub->num_rects > 0;
av_bprint_finalize(&buf, NULL);
return avpkt->size;
}
AVCodec ff_text_decoder = {
.name = "text",
.priv_data_size = sizeof(TextContext),
.long_name = NULL_IF_CONFIG_SMALL("Raw text subtitle"),
.type = AVMEDIA_TYPE_SUBTITLE,
.id = AV_CODEC_ID_TEXT,
.decode = text_decode_frame,
.init = ff_ass_subtitle_header_default,
.priv_class = &text_decoder_class,
};
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