mirror of
https://github.com/FFmpeg/FFmpeg.git
synced 2024-11-26 19:01:44 +02:00
115 lines
3.7 KiB
C
115 lines
3.7 KiB
C
/*
|
|
* 3GPP TS 26.245 Timed Text decoder
|
|
* Copyright (c) 2012 Philip Langdale <philipl@overt.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/common.h"
|
|
#include "libavutil/bprint.h"
|
|
#include "libavutil/intreadwrite.h"
|
|
|
|
static int text_to_ass(AVBPrint *buf, const char *text, const char *text_end)
|
|
{
|
|
while (text < text_end) {
|
|
switch (*text) {
|
|
case '\r':
|
|
break;
|
|
case '\n':
|
|
av_bprintf(buf, "\\N");
|
|
break;
|
|
default:
|
|
av_bprint_chars(buf, *text, 1);
|
|
break;
|
|
}
|
|
text++;
|
|
}
|
|
|
|
av_bprintf(buf, "\r\n");
|
|
return 0;
|
|
}
|
|
|
|
static int mov_text_init(AVCodecContext *avctx) {
|
|
/*
|
|
* TODO: Handle the default text style.
|
|
* NB: Most players ignore styles completely, with the result that
|
|
* it's very common to find files where the default style is broken
|
|
* and respecting it results in a worse experience than ignoring it.
|
|
*/
|
|
return ff_ass_subtitle_header_default(avctx);
|
|
}
|
|
|
|
static int mov_text_decode_frame(AVCodecContext *avctx,
|
|
void *data, int *got_sub_ptr, AVPacket *avpkt)
|
|
{
|
|
AVSubtitle *sub = data;
|
|
int ret, ts_start, ts_end;
|
|
AVBPrint buf;
|
|
const char *ptr = avpkt->data;
|
|
const char *end;
|
|
|
|
if (!ptr || avpkt->size < 2)
|
|
return AVERROR_INVALIDDATA;
|
|
|
|
/*
|
|
* A packet of size two with value zero is an empty subtitle
|
|
* used to mark the end of the previous non-empty subtitle.
|
|
* We can just drop them here as we have duration information
|
|
* already. If the value is non-zero, then it's technically a
|
|
* bad packet.
|
|
*/
|
|
if (avpkt->size == 2)
|
|
return AV_RB16(ptr) == 0 ? 0 : AVERROR_INVALIDDATA;
|
|
|
|
/*
|
|
* The first two bytes of the packet are the length of the text string
|
|
* In complex cases, there are style descriptors appended to the string
|
|
* so we can't just assume the packet size is the string size.
|
|
*/
|
|
end = ptr + FFMIN(2 + AV_RB16(ptr), avpkt->size);
|
|
ptr += 2;
|
|
|
|
ts_start = av_rescale_q(avpkt->pts,
|
|
avctx->time_base,
|
|
(AVRational){1,100});
|
|
ts_end = av_rescale_q(avpkt->pts + avpkt->duration,
|
|
avctx->time_base,
|
|
(AVRational){1,100});
|
|
|
|
// Note that the spec recommends lines be no longer than 2048 characters.
|
|
av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
|
|
text_to_ass(&buf, ptr, end);
|
|
ret = ff_ass_add_rect_bprint(sub, &buf, ts_start, ts_end-ts_start, 0);
|
|
av_bprint_finalize(&buf, NULL);
|
|
if (ret < 0)
|
|
return ret;
|
|
*got_sub_ptr = sub->num_rects > 0;
|
|
return avpkt->size;
|
|
}
|
|
|
|
AVCodec ff_movtext_decoder = {
|
|
.name = "mov_text",
|
|
.long_name = NULL_IF_CONFIG_SMALL("3GPP Timed Text subtitle"),
|
|
.type = AVMEDIA_TYPE_SUBTITLE,
|
|
.id = AV_CODEC_ID_MOV_TEXT,
|
|
.init = mov_text_init,
|
|
.decode = mov_text_decode_frame,
|
|
};
|