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 "internal.h"
  25 #include "subtitles.h"
  26 #include "libavutil/intreadwrite.h"
  27 #include "libavutil/opt.h"
  28
  29 #define MAX_LINESIZE 2048
  30
  31
  32 typedef struct {
  33     const AVClass *class;
  34     FFDemuxSubtitlesQueue q;
  35     AVRational frame_rate;
  36 } MicroDVDContext;
  37
  38
  39 static int microdvd_probe(AVProbeData *p)
  40 {
  41     unsigned char c;
  42     const uint8_t *ptr = p->buf;
  43     int i;
  44
  45     if (AV_RB24(ptr) == 0xEFBBBF)
  46         ptr += 3;  /* skip UTF-8 BOM */
  47
  48     for (i=0; i<3; i++) {
  49         if (sscanf(ptr, "{%*d}{}%c",     &c) != 1 &&
  50             sscanf(ptr, "{%*d}{%*d}%c",  &c) != 1 &&
  51             sscanf(ptr, "{DEFAULT}{}%c", &c) != 1)
  52             return 0;
  53         ptr += ff_subtitles_next_line(ptr);
  54     }
  55     return AVPROBE_SCORE_MAX;
  56 }
  57
  58 static int64_t get_pts(const char *buf)
  59 {
  60     int frame;
  61     char c;
  62
  63     if (sscanf(buf, "{%d}{%c", &frame, &c) == 2)
  64         return frame;
  65     return AV_NOPTS_VALUE;
  66 }
  67
  68 static int64_t get_duration(const char *buf)
  69 {
  70     int frame_start, frame_end;
  71
  72     if (sscanf(buf, "{%d}{%d}", &frame_start, &frame_end) == 2)
  73         return frame_end - (int64_t)frame_start;
  74     return -1;
  75 }
  76
  77 static const char *bom = "\xEF\xBB\xBF";
  78
  79 static int microdvd_read_header(AVFormatContext *s)
  80 {
  81     AVRational pts_info = (AVRational){ 2997, 125 };  /* default: 23.976 fps */
  82     MicroDVDContext *microdvd = s->priv_data;
  83     AVStream *st = avformat_new_stream(s, NULL);
  84     int i = 0, ret;
  85     char line_buf[MAX_LINESIZE];
  86     int has_real_fps = 0;
  87
  88     if (!st)
  89         return AVERROR(ENOMEM);
  90
  91     while (!avio_feof(s->pb)) {
  92         char *p;
  93         AVPacket *sub;
  94         int64_t pos = avio_tell(s->pb);
  95         int len = ff_get_line(s->pb, line_buf, sizeof(line_buf));
  96         char *line = line_buf;
  97         int64_t pts;
  98
  99         if (!strncmp(line, bom, 3))
 100             line += 3;
 101         p = line;
 102
 103         if (!len)
 104             break;
 105         line[strcspn(line, "\r\n")] = 0;
 106         if (i++ < 3) {
 107             int frame;
 108             double fps;
 109             char c;
 110
 111             if ((sscanf(line, "{%d}{}%6lf",    &frame, &fps) == 2 ||
 112                  sscanf(line, "{%d}{%*d}%6lf", &frame, &fps) == 2)
 113                 && frame <= 1 && fps > 3 && fps < 100) {
 114                 pts_info = av_d2q(fps, 100000);
 115                 has_real_fps = 1;
 116                 continue;
 117             }
 118             if (!st->codecpar->extradata && sscanf(line, "{DEFAULT}{}%c", &c) == 1) {
 119                 st->codecpar->extradata = av_strdup(line + 11);
 120                 if (!st->codecpar->extradata) {
 121                     ret = AVERROR(ENOMEM);
 122                     goto fail;
 123                 }
 124                 st->codecpar->extradata_size = strlen(st->codecpar->extradata) + 1;
 125                 continue;
 126             }
 127         }
 128 #define SKIP_FRAME_ID                                       \
 129     p = strchr(p, '}');                                     \
 130     if (!p) {                                               \
 131         av_log(s, AV_LOG_WARNING, "Invalid event \"%s\""    \
 132                " at line %d\n", line, i);                   \
 133         continue;                                           \
 134     }                                                       \
 135     p++
 136         SKIP_FRAME_ID;
 137         SKIP_FRAME_ID;
 138         if (!*p)
 139             continue;
 140         pts = get_pts(line);
 141         if (pts == AV_NOPTS_VALUE)
 142             continue;
 143         sub = ff_subtitles_queue_insert(&microdvd->q, p, strlen(p), 0);
 144         if (!sub) {
 145             ret = AVERROR(ENOMEM);
 146             goto fail;
 147         }
 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 fail:
 165     ff_subtitles_queue_clean(&microdvd->q);
 166     return ret;
 167 }
 168
 169 static int microdvd_read_packet(AVFormatContext *s, AVPacket *pkt)
 170 {
 171     MicroDVDContext *microdvd = s->priv_data;
 172     return ff_subtitles_queue_read_packet(&microdvd->q, pkt);
 173 }
 174
 175 static int microdvd_read_seek(AVFormatContext *s, int stream_index,
 176                              int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
 177 {
 178     MicroDVDContext *microdvd = s->priv_data;
 179     return ff_subtitles_queue_seek(&microdvd->q, s, stream_index,
 180                                    min_ts, ts, max_ts, flags);
 181 }
 182
 183 static int microdvd_read_close(AVFormatContext *s)
 184 {
 185     MicroDVDContext *microdvd = s->priv_data;
 186     ff_subtitles_queue_clean(&microdvd->q);
 187     return 0;
 188 }
 189
 190
 191 #define OFFSET(x) offsetof(MicroDVDContext, x)
 192 #define SD AV_OPT_FLAG_SUBTITLE_PARAM|AV_OPT_FLAG_DECODING_PARAM
 193 static const AVOption microdvd_options[] = {
 194     { "subfps", "set the movie frame rate fallback", OFFSET(frame_rate), AV_OPT_TYPE_RATIONAL, {.dbl=0}, 0, INT_MAX, SD },
 195     { NULL }
 196 };
 197
 198 static const AVClass microdvd_class = {
 199     .class_name = "microdvddec",
 200     .item_name  = av_default_item_name,
 201     .option     = microdvd_options,
 202     .version    = LIBAVUTIL_VERSION_INT,
 203 };
 204
 205 AVInputFormat ff_microdvd_demuxer = {
 206     .name           = "microdvd",
 207     .long_name      = NULL_IF_CONFIG_SMALL("MicroDVD subtitle format"),
 208     .priv_data_size = sizeof(MicroDVDContext),
 209     .read_probe     = microdvd_probe,
 210     .read_header    = microdvd_read_header,
 211     .read_packet    = microdvd_read_packet,
 212     .read_seek2     = microdvd_read_seek,
 213     .read_close     = microdvd_read_close,
 214     .priv_class     = &microdvd_class,
 215 };