247 lines
7.7 KiB
C
247 lines
7.7 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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* Copyright (c) 2015 Clément Bœsch <u pkh me>
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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 "subtitles.h"
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#include "libavutil/bprint.h"
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#include "libavutil/intreadwrite.h"
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typedef struct {
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FFDemuxSubtitlesQueue q;
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} SRTContext;
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static int srt_probe(const AVProbeData *p)
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{
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int v;
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char buf[64], *pbuf;
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FFTextReader tr;
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ff_text_init_buf(&tr, p->buf, p->buf_size);
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while (ff_text_peek_r8(&tr) == '\r' || ff_text_peek_r8(&tr) == '\n')
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ff_text_r8(&tr);
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/* Check if the first non-empty line is a number. We do not check what the
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* number is because in practice it can be anything.
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* Also, that number can be followed by random garbage, so we can not
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* unfortunately check that we only have a number. */
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if (ff_subtitles_read_line(&tr, buf, sizeof(buf)) < 0 ||
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strtol(buf, &pbuf, 10) < 0 || pbuf == buf)
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return 0;
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/* Check if the next line matches a SRT timestamp */
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if (ff_subtitles_read_line(&tr, buf, sizeof(buf)) < 0)
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return 0;
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pbuf = buf;
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if (buf[0] == '-')
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pbuf++;
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if (pbuf[0] >= '0' && pbuf[0] <= '9' && strstr(buf, " --> ")
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&& sscanf(buf, "%*d:%*d:%*d%*1[,.]%*d --> %*d:%*d:%*d%*1[,.]%d", &v) == 1)
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return AVPROBE_SCORE_MAX;
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return 0;
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}
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struct event_info {
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int32_t x1, x2, y1, y2;
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int duration;
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int64_t pts;
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int64_t pos;
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};
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static int get_event_info(const char *line, struct event_info *ei)
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{
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int hh1, mm1, ss1, ms1;
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int hh2, mm2, ss2, ms2;
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ei->x1 = ei->x2 = ei->y1 = ei->y2 = ei->duration = -1;
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ei->pts = AV_NOPTS_VALUE;
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ei->pos = -1;
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if (sscanf(line, "%d:%d:%d%*1[,.]%d --> %d:%d:%d%*1[,.]%d"
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"%*[ ]X1:%"PRId32" X2:%"PRId32" Y1:%"PRId32" Y2:%"PRId32,
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&hh1, &mm1, &ss1, &ms1,
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&hh2, &mm2, &ss2, &ms2,
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&ei->x1, &ei->x2, &ei->y1, &ei->y2) >= 8) {
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const int64_t start = (hh1*3600LL + mm1*60LL + ss1) * 1000LL + ms1;
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const int64_t end = (hh2*3600LL + mm2*60LL + ss2) * 1000LL + ms2;
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ei->duration = end - start;
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ei->pts = start;
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return 0;
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}
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return -1;
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}
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static int add_event(FFDemuxSubtitlesQueue *q, AVBPrint *buf, char *line_cache,
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const struct event_info *ei, int append_cache)
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{
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if (append_cache && line_cache[0])
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av_bprintf(buf, "%s\n", line_cache);
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line_cache[0] = 0;
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while (buf->len > 0 && buf->str[buf->len - 1] == '\n')
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buf->str[--buf->len] = 0;
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if (buf->len) {
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AVPacket *sub = ff_subtitles_queue_insert(q, buf->str, buf->len, 0);
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if (!sub)
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return AVERROR(ENOMEM);
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av_bprint_clear(buf);
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sub->pos = ei->pos;
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sub->pts = ei->pts;
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sub->duration = ei->duration;
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if (ei->x1 != -1) {
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uint8_t *p = av_packet_new_side_data(sub, AV_PKT_DATA_SUBTITLE_POSITION, 16);
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if (p) {
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AV_WL32(p, ei->x1);
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AV_WL32(p + 4, ei->y1);
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AV_WL32(p + 8, ei->x2);
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AV_WL32(p + 12, ei->y2);
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}
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}
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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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SRTContext *srt = s->priv_data;
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AVBPrint buf;
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AVStream *st = avformat_new_stream(s, NULL);
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int res = 0;
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char line[4096], line_cache[4096];
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int has_event_info = 0;
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struct event_info ei;
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FFTextReader tr;
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ff_text_init_avio(s, &tr, s->pb);
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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->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
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st->codecpar->codec_id = AV_CODEC_ID_SUBRIP;
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av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
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line_cache[0] = 0;
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while (!ff_text_eof(&tr)) {
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struct event_info tmp_ei;
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const int64_t pos = ff_text_pos(&tr);
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ptrdiff_t len = ff_subtitles_read_line(&tr, line, sizeof(line));
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if (len < 0)
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break;
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if (!len || !line[0])
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continue;
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if (get_event_info(line, &tmp_ei) < 0) {
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char *pline;
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if (!has_event_info)
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continue;
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if (line_cache[0]) {
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/* We got some cache and a new line so we assume the cached
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* line was actually part of the payload */
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av_bprintf(&buf, "%s\n", line_cache);
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line_cache[0] = 0;
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}
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/* If the line doesn't start with a number, we assume it's part of
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* the payload, otherwise is likely an event number preceding the
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* timing information... but we can't be sure of this yet, so we
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* cache it */
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if (strtol(line, &pline, 10) < 0 || line == pline)
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av_bprintf(&buf, "%s\n", line);
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else
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strcpy(line_cache, line);
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} else {
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if (has_event_info) {
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/* We have the information of previous event, append it to the
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* queue. We insert the cached line if and only if the payload
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* is empty and the cached line is not a standalone number. */
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char *pline = NULL;
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const int standalone_number = strtol(line_cache, &pline, 10) >= 0 && pline && !*pline;
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res = add_event(&srt->q, &buf, line_cache, &ei, !buf.len && !standalone_number);
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if (res < 0)
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goto end;
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} else {
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has_event_info = 1;
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}
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tmp_ei.pos = pos;
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ei = tmp_ei;
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}
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}
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/* Append the last event. Here we force the cache to be flushed, because a
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* trailing number is more likely to be geniune (for example a copyright
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* date) and not the event index of an inexistant event */
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if (has_event_info) {
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res = add_event(&srt->q, &buf, line_cache, &ei, 1);
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if (res < 0)
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goto end;
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}
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ff_subtitles_queue_finalize(s, &srt->q);
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end:
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if (res < 0)
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ff_subtitles_queue_clean(&srt->q);
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av_bprint_finalize(&buf, NULL);
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return res;
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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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SRTContext *srt = s->priv_data;
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return ff_subtitles_queue_read_packet(&srt->q, pkt);
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}
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static int srt_read_seek(AVFormatContext *s, int stream_index,
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int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
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{
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SRTContext *srt = s->priv_data;
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return ff_subtitles_queue_seek(&srt->q, s, stream_index,
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min_ts, ts, max_ts, flags);
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}
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static int srt_read_close(AVFormatContext *s)
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{
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SRTContext *srt = s->priv_data;
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ff_subtitles_queue_clean(&srt->q);
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return 0;
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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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.priv_data_size = sizeof(SRTContext),
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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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.read_seek2 = srt_read_seek,
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.read_close = srt_read_close,
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};
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