libavformat/microdvddec.c

   1 /*
   2  * MicroDVD subtitle demuxer
   3  * Copyright (c) 2010  Aurelien Jacobs <aurel@gnuage.org>
   4  * Copyright (c) 2012  Clément Bœsch <u pkh me>
   5  *
   6  * This file is part of FFmpeg.
   7  *
   8  * FFmpeg is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * FFmpeg is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with FFmpeg; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 #include "avformat.h"
  24 #include "demux.h"
  25 #include "internal.h"
  26 #include "subtitles.h"
  27 #include "libavutil/intreadwrite.h"
  28 #include "libavutil/opt.h"
  29
  30 #define MAX_LINESIZE 2048
  31
  32
  33 typedef struct {
  34     const AVClass *class;
  35     FFDemuxSubtitlesQueue q;
  36     AVRational frame_rate;
  37 } MicroDVDContext;
  38
  39
  40 static int microdvd_probe(const AVProbeData *p)
  41 {
  42     unsigned char c;
  43     const uint8_t *ptr = p->buf;
  44     int i;
  45
  46     if (AV_RB24(ptr) == 0xEFBBBF)
  47         ptr += 3;  /* skip UTF-8 BOM */
  48
  49     for (i=0; i<3; i++) {
  50         if (sscanf(ptr, "{%*d}{}%c",     &c) != 1 &&
  51             sscanf(ptr, "{%*d}{%*d}%c",  &c) != 1 &&
  52             sscanf(ptr, "{DEFAULT}{}%c", &c) != 1)
  53             return 0;
  54         ptr += ff_subtitles_next_line(ptr);
  55     }
  56     return AVPROBE_SCORE_MAX;
  57 }
  58
  59 static int64_t get_pts(const char *buf)
  60 {
  61     int frame;
  62     char c;
  63
  64     if (sscanf(buf, "{%d}{%c", &frame, &c) == 2)
  65         return frame;
  66     return AV_NOPTS_VALUE;
  67 }
  68
  69 static int64_t get_duration(const char *buf)
  70 {
  71     int frame_start, frame_end;
  72
  73     if (sscanf(buf, "{%d}{%d}", &frame_start, &frame_end) == 2)
  74         return frame_end - (int64_t)frame_start;
  75     return -1;
  76 }
  77
  78 static const char *bom = "\xEF\xBB\xBF";
  79
  80 static int microdvd_read_header(AVFormatContext *s)
  81 {
  82     AVRational pts_info = (AVRational){ 2997, 125 };  /* default: 23.976 fps */
  83     MicroDVDContext *microdvd = s->priv_data;
  84     AVStream *st = avformat_new_stream(s, NULL);
  85     int i = 0, ret;
  86     char line_buf[MAX_LINESIZE];
  87     int has_real_fps = 0;
  88
  89     if (!st)
  90         return AVERROR(ENOMEM);
  91
  92     while (!avio_feof(s->pb)) {
  93         char *p;
  94         AVPacket *sub;
  95         int64_t pos = avio_tell(s->pb);
  96         int len = ff_get_line(s->pb, line_buf, sizeof(line_buf));
  97         char *line = line_buf;
  98         int64_t pts;
  99
 100         if (!strncmp(line, bom, 3))
 101             line += 3;
 102         p = line;
 103
 104         if (!len)
 105             break;
 106         line[strcspn(line, "\r\n")] = 0;
 107         if (!*p)
 108             continue;
 109         if (i++ < 3) {
 110             int frame;
 111             double fps;
 112             char c;
 113
 114             if ((sscanf(line, "{%d}{}%6lf",    &frame, &fps) == 2 ||
 115                  sscanf(line, "{%d}{%*d}%6lf", &frame, &fps) == 2)
 116                 && frame <= 1 && fps > 3 && fps < 100) {
 117                 pts_info = av_d2q(fps, 100000);
 118                 has_real_fps = 1;
 119                 continue;
 120             }
 121             if (!st->codecpar->extradata && sscanf(line, "{DEFAULT}{}%c", &c) == 1) {
 122                 int size = strlen(line + 11);
 123                 ret = ff_alloc_extradata(st->codecpar, size);
 124                 if (ret < 0)
 125                     return ret;
 126                 memcpy(st->codecpar->extradata, line + 11, size);
 127                 continue;
 128             }
 129         }
 130 #define SKIP_FRAME_ID                                       \
 131     p = strchr(p, '}');                                     \
 132     if (!p) {                                               \
 133         av_log(s, AV_LOG_WARNING, "Invalid event \"%s\""    \
 134                " at line %d\n", line, i);                   \
 135         continue;                                           \
 136     }                                                       \
 137     p++
 138         SKIP_FRAME_ID;
 139         SKIP_FRAME_ID;
 140         if (!*p)
 141             continue;
 142         pts = get_pts(line);
 143         if (pts == AV_NOPTS_VALUE)
 144             continue;
 145         sub = ff_subtitles_queue_insert(&microdvd->q, p, strlen(p), 0);
 146         if (!sub)
 147             return AVERROR(ENOMEM);
 148         sub->pos = pos;
 149         sub->pts = pts;
 150         sub->duration = get_duration(line);
 151     }
 152     ff_subtitles_queue_finalize(s, &microdvd->q);
 153     if (has_real_fps) {
 154         /* export the FPS info only if set in the file */
 155         microdvd->frame_rate = pts_info;
 156     } else if (microdvd->frame_rate.num) {
 157         /* fallback on user specified frame rate */
 158         pts_info = microdvd->frame_rate;
 159     }
 160     avpriv_set_pts_info(st, 64, pts_info.den, pts_info.num);
 161     st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
 162     st->codecpar->codec_id   = AV_CODEC_ID_MICRODVD;
 163     return 0;
 164 }
 165
 166 static int microdvd_read_packet(AVFormatContext *s, AVPacket *pkt)
 167 {
 168     MicroDVDContext *microdvd = s->priv_data;
 169     return ff_subtitles_queue_read_packet(&microdvd->q, pkt);
 170 }
 171
 172 static int microdvd_read_seek(AVFormatContext *s, int stream_index,
 173                              int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
 174 {
 175     MicroDVDContext *microdvd = s->priv_data;
 176     return ff_subtitles_queue_seek(&microdvd->q, s, stream_index,
 177                                    min_ts, ts, max_ts, flags);
 178 }
 179
 180 static int microdvd_read_close(AVFormatContext *s)
 181 {
 182     MicroDVDContext *microdvd = s->priv_data;
 183     ff_subtitles_queue_clean(&microdvd->q);
 184     return 0;
 185 }
 186
 187
 188 #define OFFSET(x) offsetof(MicroDVDContext, x)
 189 #define SD AV_OPT_FLAG_SUBTITLE_PARAM|AV_OPT_FLAG_DECODING_PARAM
 190 static const AVOption microdvd_options[] = {
 191     { "subfps", "set the movie frame rate fallback", OFFSET(frame_rate), AV_OPT_TYPE_RATIONAL, {.dbl=0}, 0, INT_MAX, SD },
 192     { NULL }
 193 };
 194
 195 static const AVClass microdvd_class = {
 196     .class_name = "microdvddec",
 197     .item_name  = av_default_item_name,
 198     .option     = microdvd_options,
 199     .version    = LIBAVUTIL_VERSION_INT,
 200 };
 201
 202 const FFInputFormat ff_microdvd_demuxer = {
 203     .p.name         = "microdvd",
 204     .p.long_name    = NULL_IF_CONFIG_SMALL("MicroDVD subtitle format"),
 205     .p.priv_class   = &microdvd_class,
 206     .priv_data_size = sizeof(MicroDVDContext),
 207     .flags_internal = FF_INFMT_FLAG_INIT_CLEANUP,
 208     .read_probe     = microdvd_probe,
 209     .read_header    = microdvd_read_header,
 210     .read_packet    = microdvd_read_packet,
 211     .read_seek2     = microdvd_read_seek,
 212     .read_close     = microdvd_read_close,
 213 };