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n3.4.14
libavformat/microdvddec.c
215 строк
7 KB
Michael Niedermayer
avformat/microdvddec: use 64bit for durations
11 сен 2021, 22:23
11 сен 2021, 22:23
f59e526
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/* * MicroDVD subtitle demuxer * Copyright (c) 2010 Aurelien Jacobs <aurel@gnuage.org> * Copyright (c) 2012 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/intreadwrite.h" #include "libavutil/opt.h" #define MAX_LINESIZE 2048 typedef struct { const AVClass *class; FFDemuxSubtitlesQueue q; AVRational frame_rate; } MicroDVDContext; static int microdvd_probe(AVProbeData *p) { unsigned char c; const uint8_t *ptr = p->buf; int i; if (AV_RB24(ptr) == 0xEFBBBF) ptr += 3; /* skip UTF-8 BOM */ for (i=0; i<3; i++) { if (sscanf(ptr, "{%*d}{}%c", &c) != 1 && sscanf(ptr, "{%*d}{%*d}%c", &c) != 1 && sscanf(ptr, "{DEFAULT}{}%c", &c) != 1) return 0; ptr += ff_subtitles_next_line(ptr); } return AVPROBE_SCORE_MAX; } static int64_t get_pts(const char *buf) { int frame; char c; if (sscanf(buf, "{%d}{%c", &frame, &c) == 2) return frame; return AV_NOPTS_VALUE; } static int64_t get_duration(const char *buf) { int frame_start, frame_end; if (sscanf(buf, "{%d}{%d}", &frame_start, &frame_end) == 2) return frame_end - (int64_t)frame_start; return -1; } static const char *bom = "\xEF\xBB\xBF"; static int microdvd_read_header(AVFormatContext *s) { AVRational pts_info = (AVRational){ 2997, 125 }; /* default: 23.976 fps */ MicroDVDContext *microdvd = s->priv_data; AVStream *st = avformat_new_stream(s, NULL); int i = 0, ret; char line_buf[MAX_LINESIZE]; int has_real_fps = 0; if (!st) return AVERROR(ENOMEM); while (!avio_feof(s->pb)) { char *p; AVPacket *sub; int64_t pos = avio_tell(s->pb); int len = ff_get_line(s->pb, line_buf, sizeof(line_buf)); char *line = line_buf; int64_t pts; if (!strncmp(line, bom, 3)) line += 3; p = line; if (!len) break; line[strcspn(line, "\r\n")] = 0; if (i++ < 3) { int frame; double fps; char c; if ((sscanf(line, "{%d}{}%6lf", &frame, &fps) == 2 || sscanf(line, "{%d}{%*d}%6lf", &frame, &fps) == 2) && frame <= 1 && fps > 3 && fps < 100) { pts_info = av_d2q(fps, 100000); has_real_fps = 1; continue; } if (!st->codecpar->extradata && sscanf(line, "{DEFAULT}{}%c", &c) == 1) { st->codecpar->extradata = av_strdup(line + 11); if (!st->codecpar->extradata) { ret = AVERROR(ENOMEM); goto fail; } st->codecpar->extradata_size = strlen(st->codecpar->extradata) + 1; continue; } } #define SKIP_FRAME_ID \ p = strchr(p, '}'); \ if (!p) { \ av_log(s, AV_LOG_WARNING, "Invalid event \"%s\"" \ " at line %d\n", line, i); \ continue; \ } \ p++ SKIP_FRAME_ID; SKIP_FRAME_ID; if (!*p) continue; pts = get_pts(line); if (pts == AV_NOPTS_VALUE) continue; sub = ff_subtitles_queue_insert(µdvd->q, p, strlen(p), 0); if (!sub) { ret = AVERROR(ENOMEM); goto fail; } sub->pos = pos; sub->pts = pts; sub->duration = get_duration(line); } ff_subtitles_queue_finalize(s, µdvd->q); if (has_real_fps) { /* export the FPS info only if set in the file */ microdvd->frame_rate = pts_info; } else if (microdvd->frame_rate.num) { /* fallback on user specified frame rate */ pts_info = microdvd->frame_rate; } avpriv_set_pts_info(st, 64, pts_info.den, pts_info.num); st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE; st->codecpar->codec_id = AV_CODEC_ID_MICRODVD; return 0; fail: ff_subtitles_queue_clean(µdvd->q); return ret; } static int microdvd_read_packet(AVFormatContext *s, AVPacket *pkt) { MicroDVDContext *microdvd = s->priv_data; return ff_subtitles_queue_read_packet(µdvd->q, pkt); } static int microdvd_read_seek(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags) { MicroDVDContext *microdvd = s->priv_data; return ff_subtitles_queue_seek(µdvd->q, s, stream_index, min_ts, ts, max_ts, flags); } static int microdvd_read_close(AVFormatContext *s) { MicroDVDContext *microdvd = s->priv_data; ff_subtitles_queue_clean(µdvd->q); return 0; } #define OFFSET(x) offsetof(MicroDVDContext, x) #define SD AV_OPT_FLAG_SUBTITLE_PARAM|AV_OPT_FLAG_DECODING_PARAM static const AVOption microdvd_options[] = { { "subfps", "set the movie frame rate fallback", OFFSET(frame_rate), AV_OPT_TYPE_RATIONAL, {.dbl=0}, 0, INT_MAX, SD }, { NULL } }; static const AVClass microdvd_class = { .class_name = "microdvddec", .item_name = av_default_item_name, .option = microdvd_options, .version = LIBAVUTIL_VERSION_INT, }; AVInputFormat ff_microdvd_demuxer = { .name = "microdvd", .long_name = NULL_IF_CONFIG_SMALL("MicroDVD subtitle format"), .priv_data_size = sizeof(MicroDVDContext), .read_probe = microdvd_probe, .read_header = microdvd_read_header, .read_packet = microdvd_read_packet, .read_seek2 = microdvd_read_seek, .read_close = microdvd_read_close, .priv_class = µdvd_class, };