ffmpeg/libavcodec/srtdec.c

117 lines
4.1 KiB
C

/*
* SubRip subtitle decoder
* 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 "libavutil/avstring.h"
#include "libavutil/common.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/parseutils.h"
#include "avcodec.h"
#include "ass.h"
#include "htmlsubtitles.h"
static void srt_to_ass(AVCodecContext *avctx, AVBPrint *dst,
const char *in, int x1, int y1, int x2, int y2)
{
if (x1 >= 0 && y1 >= 0) {
/* XXX: here we rescale coordinate assuming they are in DVD resolution
* (720x480) since we don't have anything better */
if (x2 >= 0 && y2 >= 0 && (x2 != x1 || y2 != y1) && x2 >= x1 && y2 >= y1) {
/* text rectangle defined, write the text at the center of the rectangle */
const int cx = x1 + (x2 - x1)/2;
const int cy = y1 + (y2 - y1)/2;
const int scaled_x = cx * ASS_DEFAULT_PLAYRESX / 720;
const int scaled_y = cy * ASS_DEFAULT_PLAYRESY / 480;
av_bprintf(dst, "{\\an5}{\\pos(%d,%d)}", scaled_x, scaled_y);
} else {
/* only the top left corner, assume the text starts in that corner */
const int scaled_x = x1 * ASS_DEFAULT_PLAYRESX / 720;
const int scaled_y = y1 * ASS_DEFAULT_PLAYRESY / 480;
av_bprintf(dst, "{\\an1}{\\pos(%d,%d)}", scaled_x, scaled_y);
}
}
ff_htmlmarkup_to_ass(avctx, dst, in);
}
static int srt_decode_frame(AVCodecContext *avctx,
void *data, int *got_sub_ptr, AVPacket *avpkt)
{
AVSubtitle *sub = data;
AVBPrint buffer;
int ts_start, ts_end, x1 = -1, y1 = -1, x2 = -1, y2 = -1;
int size, ret;
const uint8_t *p = av_packet_get_side_data(avpkt, AV_PKT_DATA_SUBTITLE_POSITION, &size);
if (p && size == 16) {
x1 = AV_RL32(p );
y1 = AV_RL32(p + 4);
x2 = AV_RL32(p + 8);
y2 = AV_RL32(p + 12);
}
if (avpkt->size <= 0)
return avpkt->size;
av_bprint_init(&buffer, 0, AV_BPRINT_SIZE_UNLIMITED);
// TODO: reindent
// Do final divide-by-10 outside rescale to force rounding down.
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});
srt_to_ass(avctx, &buffer, avpkt->data, x1, y1, x2, y2);
ret = ff_ass_add_rect_bprint(sub, &buffer, ts_start, ts_end-ts_start);
av_bprint_finalize(&buffer, NULL);
if (ret < 0)
return ret;
*got_sub_ptr = sub->num_rects > 0;
return avpkt->size;
}
#if CONFIG_SRT_DECODER
/* deprecated decoder */
AVCodec ff_srt_decoder = {
.name = "srt",
.long_name = NULL_IF_CONFIG_SMALL("SubRip subtitle"),
.type = AVMEDIA_TYPE_SUBTITLE,
.id = AV_CODEC_ID_SUBRIP,
.init = ff_ass_subtitle_header_default,
.decode = srt_decode_frame,
};
#endif
#if CONFIG_SUBRIP_DECODER
AVCodec ff_subrip_decoder = {
.name = "subrip",
.long_name = NULL_IF_CONFIG_SMALL("SubRip subtitle"),
.type = AVMEDIA_TYPE_SUBTITLE,
.id = AV_CODEC_ID_SUBRIP,
.init = ff_ass_subtitle_header_default,
.decode = srt_decode_frame,
};
#endif