/* * SubRip subtitle demuxer * Copyright (c) 2010 Aurelien Jacobs <aurel@gnuage.org> * Copyright (c) 2015 Clément Bœsch <u pkh me> * * 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 "avformat.h" #include "internal.h" #include "subtitles.h" #include "libavutil/bprint.h" #include "libavutil/intreadwrite.h" typedef struct { FFDemuxSubtitlesQueue q; } SRTContext; static int srt_probe(const AVProbeData *p) { int v; char buf[64], *pbuf; FFTextReader tr; ff_text_init_buf(&tr, p->buf, p->buf_size); while (ff_text_peek_r8(&tr) == '\r' || ff_text_peek_r8(&tr) == '\n') ff_text_r8(&tr); /* Check if the first non-empty line is a number. We do not check what the * number is because in practice it can be anything. * Also, that number can be followed by random garbage, so we can not * unfortunately check that we only have a number. */ if (ff_subtitles_read_line(&tr, buf, sizeof(buf)) < 0 || strtol(buf, &pbuf, 10) < 0 || pbuf == buf) return 0; /* Check if the next line matches a SRT timestamp */ if (ff_subtitles_read_line(&tr, buf, sizeof(buf)) < 0) return 0; pbuf = buf; if (buf[0] == '-') pbuf++; if (pbuf[0] >= '0' && pbuf[0] <= '9' && strstr(buf, " --> ") && sscanf(buf, "%*d:%*d:%*d%*1[,.]%*d --> %*d:%*d:%*d%*1[,.]%d", &v) == 1) return AVPROBE_SCORE_MAX; return 0; } struct event_info { int32_t x1, x2, y1, y2; int duration; int64_t pts; int64_t pos; }; static int get_event_info(const char *line, struct event_info *ei) { int hh1, mm1, ss1, ms1; int hh2, mm2, ss2, ms2; ei->x1 = ei->x2 = ei->y1 = ei->y2 = ei->duration = -1; ei->pts = AV_NOPTS_VALUE; ei->pos = -1; if (sscanf(line, "%d:%d:%d%*1[,.]%d --> %d:%d:%d%*1[,.]%d" "%*[ ]X1:%"PRId32" X2:%"PRId32" Y1:%"PRId32" Y2:%"PRId32, &hh1, &mm1, &ss1, &ms1, &hh2, &mm2, &ss2, &ms2, &ei->x1, &ei->x2, &ei->y1, &ei->y2) >= 8) { const int64_t start = (hh1*3600LL + mm1*60LL + ss1) * 1000LL + ms1; const int64_t end = (hh2*3600LL + mm2*60LL + ss2) * 1000LL + ms2; ei->duration = end - start; ei->pts = start; return 0; } return -1; } static int add_event(FFDemuxSubtitlesQueue *q, AVBPrint *buf, char *line_cache, const struct event_info *ei, int append_cache) { if (append_cache && line_cache[0]) av_bprintf(buf, "%s\n", line_cache); line_cache[0] = 0; while (buf->len > 0 && buf->str[buf->len - 1] == '\n') buf->str[--buf->len] = 0; if (buf->len) { AVPacket *sub = ff_subtitles_queue_insert(q, buf->str, buf->len, 0); if (!sub) return AVERROR(ENOMEM); av_bprint_clear(buf); sub->pos = ei->pos; sub->pts = ei->pts; sub->duration = ei->duration; if (ei->x1 != -1) { uint8_t *p = av_packet_new_side_data(sub, AV_PKT_DATA_SUBTITLE_POSITION, 16); if (p) { AV_WL32(p, ei->x1); AV_WL32(p + 4, ei->y1); AV_WL32(p + 8, ei->x2); AV_WL32(p + 12, ei->y2); } } } return 0; } static int srt_read_header(AVFormatContext *s) { SRTContext *srt = s->priv_data; AVBPrint buf; AVStream *st = avformat_new_stream(s, NULL); int res = 0; char line[4096], line_cache[4096]; int has_event_info = 0; struct event_info ei; FFTextReader tr; ff_text_init_avio(s, &tr, s->pb); if (!st) return AVERROR(ENOMEM); avpriv_set_pts_info(st, 64, 1, 1000); st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE; st->codecpar->codec_id = AV_CODEC_ID_SUBRIP; av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED); line_cache[0] = 0; while (!ff_text_eof(&tr)) { struct event_info tmp_ei; const int64_t pos = ff_text_pos(&tr); ptrdiff_t len = ff_subtitles_read_line(&tr, line, sizeof(line)); if (len < 0) break; if (!len || !line[0]) continue; if (get_event_info(line, &tmp_ei) < 0) { char *pline; if (!has_event_info) continue; if (line_cache[0]) { /* We got some cache and a new line so we assume the cached * line was actually part of the payload */ av_bprintf(&buf, "%s\n", line_cache); line_cache[0] = 0; } /* If the line doesn't start with a number, we assume it's part of * the payload, otherwise is likely an event number preceding the * timing information... but we can't be sure of this yet, so we * cache it */ if (strtol(line, &pline, 10) < 0 || line == pline) av_bprintf(&buf, "%s\n", line); else strcpy(line_cache, line); } else { if (has_event_info) { /* We have the information of previous event, append it to the * queue. We insert the cached line if and only if the payload * is empty and the cached line is not a standalone number. */ char *pline = NULL; const int standalone_number = strtol(line_cache, &pline, 10) >= 0 && pline && !*pline; res = add_event(&srt->q, &buf, line_cache, &ei, !buf.len && !standalone_number); if (res < 0) goto end; } else { has_event_info = 1; } tmp_ei.pos = pos; ei = tmp_ei; } } /* Append the last event. Here we force the cache to be flushed, because a * trailing number is more likely to be geniune (for example a copyright * date) and not the event index of an inexistant event */ if (has_event_info) { res = add_event(&srt->q, &buf, line_cache, &ei, 1); if (res < 0) goto end; } ff_subtitles_queue_finalize(s, &srt->q); end: av_bprint_finalize(&buf, NULL); return res; } static int srt_read_packet(AVFormatContext *s, AVPacket *pkt) { SRTContext *srt = s->priv_data; return ff_subtitles_queue_read_packet(&srt->q, pkt); } static int srt_read_seek(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags) { SRTContext *srt = s->priv_data; return ff_subtitles_queue_seek(&srt->q, s, stream_index, min_ts, ts, max_ts, flags); } static int srt_read_close(AVFormatContext *s) { SRTContext *srt = s->priv_data; ff_subtitles_queue_clean(&srt->q); return 0; } AVInputFormat ff_srt_demuxer = { .name = "srt", .long_name = NULL_IF_CONFIG_SMALL("SubRip subtitle"), .priv_data_size = sizeof(SRTContext), .read_probe = srt_probe, .read_header = srt_read_header, .read_packet = srt_read_packet, .read_seek2 = srt_read_seek, .read_close = srt_read_close, };