c27b3816e4
The SRT format should never have outputted CODEC_ID_SRT packets in the first place: SRT is a subtitle format containing SubRip text markup events. The timing information is part of the format, not the codec, and thus CODEC_ID_SRT should not exist. Creating packets with the timing information within the payload only leads to problem (such as remuxing with timing alteration not working), especially when the SubRip markup is being used in container like Matroska in addition to this standalone SRT format. The main reason the timing line was included in those CODEC_ID_SRT packets is likely because it contained extra information (the event position) the codec actually needs. This issue is solved by using the AV_PKT_DATA_SUBTITLE_POSITION side data type.
131 lines
4.0 KiB
C
131 lines
4.0 KiB
C
/*
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* SubRip subtitle demuxer
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* Copyright (c) 2010 Aurelien Jacobs <aurel@gnuage.org>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "avformat.h"
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#include "internal.h"
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#include "libavutil/intreadwrite.h"
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static int srt_probe(AVProbeData *p)
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{
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unsigned char *ptr = p->buf;
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int i, v, num = 0;
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if (AV_RB24(ptr) == 0xEFBBBF)
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ptr += 3; /* skip UTF-8 BOM */
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for (i=0; i<2; i++) {
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if (num == i && sscanf(ptr, "%*d:%*2d:%*2d%*1[,.]%*3d --> %*d:%*2d:%*2d%*1[,.]%3d", &v) == 1)
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return AVPROBE_SCORE_MAX;
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num = atoi(ptr);
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ptr += strcspn(ptr, "\n") + 1;
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}
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return 0;
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}
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static int srt_read_header(AVFormatContext *s)
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{
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AVStream *st = avformat_new_stream(s, NULL);
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if (!st)
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return AVERROR(ENOMEM);
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avpriv_set_pts_info(st, 64, 1, 1000);
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st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
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st->codec->codec_id = AV_CODEC_ID_SUBRIP;
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return 0;
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}
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static int64_t get_pts(char **buf, int *duration,
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int32_t *x1, int32_t *y1, int32_t *x2, int32_t *y2)
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{
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int i;
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for (i=0; i<2; i++) {
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int hh1, mm1, ss1, ms1;
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int hh2, mm2, ss2, ms2;
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if (sscanf(*buf, "%d:%2d:%2d%*1[,.]%3d --> %d:%2d:%2d%*1[,.]%3d"
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"%*[ ]X1:%u X2:%u Y1:%u Y2:%u",
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&hh1, &mm1, &ss1, &ms1,
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&hh2, &mm2, &ss2, &ms2,
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x1, x2, y1, y2) >= 8) {
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int64_t start = (hh1*3600LL + mm1*60LL + ss1) * 1000LL + ms1;
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int64_t end = (hh2*3600LL + mm2*60LL + ss2) * 1000LL + ms2;
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*duration = end - start;
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*buf += strcspn(*buf, "\n") + 1;
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return start;
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}
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*buf += strcspn(*buf, "\n") + 1;
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}
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return AV_NOPTS_VALUE;
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}
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static inline int is_eol(char c)
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{
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return c == '\r' || c == '\n';
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}
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static int srt_read_packet(AVFormatContext *s, AVPacket *pkt)
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{
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char buffer[2048], *ptr = buffer, *ptr2;
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int64_t pos = avio_tell(s->pb);
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int res = AVERROR_EOF;
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do {
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ptr2 = ptr;
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ptr += ff_get_line(s->pb, ptr, sizeof(buffer)+buffer-ptr);
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} while (!is_eol(*ptr2) && !url_feof(s->pb) && ptr-buffer<sizeof(buffer)-1);
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if (buffer[0]) {
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int64_t pts;
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int duration;
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const char *end = ptr;
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int32_t x1 = -1, y1 = -1, x2 = -1, y2 = -1;
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ptr = buffer;
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pts = get_pts(&ptr, &duration, &x1, &y1, &x2, &y2);
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if (pts != AV_NOPTS_VALUE &&
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!(res = av_new_packet(pkt, end - ptr))) {
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memcpy(pkt->data, ptr, pkt->size);
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pkt->flags |= AV_PKT_FLAG_KEY;
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pkt->pos = pos;
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pkt->pts = pkt->dts = pts;
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pkt->duration = duration;
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if (x1 != -1) {
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uint8_t *p = av_packet_new_side_data(pkt, AV_PKT_DATA_SUBTITLE_POSITION, 16);
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if (p) {
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AV_WL32(p, x1);
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AV_WL32(p + 4, y1);
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AV_WL32(p + 8, x2);
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AV_WL32(p + 12, y2);
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}
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}
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}
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}
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return res;
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}
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AVInputFormat ff_srt_demuxer = {
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.name = "srt",
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.long_name = NULL_IF_CONFIG_SMALL("SubRip subtitle"),
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.read_probe = srt_probe,
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.read_header = srt_read_header,
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.read_packet = srt_read_packet,
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.flags = AVFMT_GENERIC_INDEX,
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};
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