LCOV - code coverage report
Current view: top level - libavformat - webvttdec.c (source / functions) Hit Total Coverage
Test: coverage.info Lines: 76 88 86.4 %
Date: 2017-12-18 20:14:19 Functions: 5 6 83.3 %

          Line data    Source code
       1             : /*
       2             :  * Copyright (c) 2012 Clément Bœsch
       3             :  *
       4             :  * This file is part of FFmpeg.
       5             :  *
       6             :  * FFmpeg is free software; you can redistribute it and/or
       7             :  * modify it under the terms of the GNU Lesser General Public
       8             :  * License as published by the Free Software Foundation; either
       9             :  * version 2.1 of the License, or (at your option) any later version.
      10             :  *
      11             :  * FFmpeg is distributed in the hope that it will be useful,
      12             :  * but WITHOUT ANY WARRANTY; without even the implied warranty of
      13             :  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      14             :  * Lesser General Public License for more details.
      15             :  *
      16             :  * You should have received a copy of the GNU Lesser General Public
      17             :  * License along with FFmpeg; if not, write to the Free Software
      18             :  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
      19             :  */
      20             : 
      21             : /**
      22             :  * @file
      23             :  * WebVTT subtitle demuxer
      24             :  * @see http://dev.w3.org/html5/webvtt/
      25             :  */
      26             : 
      27             : #include "avformat.h"
      28             : #include "internal.h"
      29             : #include "subtitles.h"
      30             : #include "libavutil/bprint.h"
      31             : #include "libavutil/intreadwrite.h"
      32             : #include "libavutil/opt.h"
      33             : 
      34             : typedef struct {
      35             :     const AVClass *class;
      36             :     FFDemuxSubtitlesQueue q;
      37             :     int kind;
      38             : } WebVTTContext;
      39             : 
      40        6130 : static int webvtt_probe(AVProbeData *p)
      41             : {
      42        6130 :     const uint8_t *ptr = p->buf;
      43             : 
      44        6130 :     if (AV_RB24(ptr) == 0xEFBBBF)
      45           8 :         ptr += 3;  /* skip UTF-8 BOM */
      46        6132 :     if (!strncmp(ptr, "WEBVTT", 6) &&
      47           4 :         (!ptr[6] || strchr("\n\r\t ", ptr[6])))
      48           2 :         return AVPROBE_SCORE_MAX;
      49        6128 :     return 0;
      50             : }
      51             : 
      52          54 : static int64_t read_ts(const char *s)
      53             : {
      54             :     int hh, mm, ss, ms;
      55          54 :     if (sscanf(s, "%u:%u:%u.%u", &hh, &mm, &ss, &ms) == 4) return (hh*3600LL + mm*60LL + ss) * 1000LL + ms;
      56          40 :     if (sscanf(s,    "%u:%u.%u",      &mm, &ss, &ms) == 3) return (            mm*60LL + ss) * 1000LL + ms;
      57           0 :     return AV_NOPTS_VALUE;
      58             : }
      59             : 
      60           2 : static int webvtt_read_header(AVFormatContext *s)
      61             : {
      62           2 :     WebVTTContext *webvtt = s->priv_data;
      63             :     AVBPrint header, cue;
      64           2 :     int res = 0;
      65           2 :     AVStream *st = avformat_new_stream(s, NULL);
      66             : 
      67           2 :     if (!st)
      68           0 :         return AVERROR(ENOMEM);
      69           2 :     avpriv_set_pts_info(st, 64, 1, 1000);
      70           2 :     st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
      71           2 :     st->codecpar->codec_id   = AV_CODEC_ID_WEBVTT;
      72           2 :     st->disposition |= webvtt->kind;
      73             : 
      74           2 :     av_bprint_init(&header, 0, AV_BPRINT_SIZE_UNLIMITED);
      75           2 :     av_bprint_init(&cue,    0, AV_BPRINT_SIZE_UNLIMITED);
      76             : 
      77          31 :     for (;;) {
      78             :         int i;
      79             :         int64_t pos;
      80             :         AVPacket *sub;
      81             :         const char *p, *identifier, *settings;
      82             :         int identifier_len, settings_len;
      83             :         int64_t ts_start, ts_end;
      84             : 
      85          33 :         ff_subtitles_read_chunk(s->pb, &cue);
      86             : 
      87          33 :         if (!cue.len)
      88           2 :             break;
      89             : 
      90          31 :         p = identifier = cue.str;
      91          31 :         pos = avio_tell(s->pb);
      92             : 
      93             :         /* ignore header chunk */
      94          60 :         if (!strncmp(p, "\xEF\xBB\xBFWEBVTT", 9) ||
      95          58 :             !strncmp(p, "WEBVTT", 6) ||
      96          29 :             !strncmp(p, "NOTE", 4))
      97           4 :             continue;
      98             : 
      99             :         /* optional cue identifier (can be a number like in SRT or some kind of
     100             :          * chaptering id) */
     101         331 :         for (i = 0; p[i] && p[i] != '\n' && p[i] != '\r'; i++) {
     102         327 :             if (!strncmp(p + i, "-->", 3)) {
     103          23 :                 identifier = NULL;
     104          23 :                 break;
     105             :             }
     106             :         }
     107          27 :         if (!identifier)
     108          23 :             identifier_len = 0;
     109             :         else {
     110           4 :             identifier_len = strcspn(p, "\r\n");
     111           4 :             p += identifier_len;
     112           4 :             if (*p == '\r')
     113           0 :                 p++;
     114           4 :             if (*p == '\n')
     115           4 :                 p++;
     116             :         }
     117             : 
     118             :         /* cue timestamps */
     119          27 :         if ((ts_start = read_ts(p)) == AV_NOPTS_VALUE)
     120           0 :             break;
     121          27 :         if (!(p = strstr(p, "-->")))
     122           0 :             break;
     123          27 :         p += 2;
     124          54 :         do p++; while (*p == ' ' || *p == '\t');
     125          27 :         if ((ts_end = read_ts(p)) == AV_NOPTS_VALUE)
     126           0 :             break;
     127             : 
     128             :         /* optional cue settings */
     129          27 :         p += strcspn(p, "\n\t ");
     130          66 :         while (*p == '\t' || *p == ' ')
     131          12 :             p++;
     132          27 :         settings = p;
     133          27 :         settings_len = strcspn(p, "\r\n");
     134          27 :         p += settings_len;
     135          27 :         if (*p == '\r')
     136           0 :             p++;
     137          27 :         if (*p == '\n')
     138          27 :             p++;
     139             : 
     140             :         /* create packet */
     141          27 :         sub = ff_subtitles_queue_insert(&webvtt->q, p, strlen(p), 0);
     142          27 :         if (!sub) {
     143           0 :             res = AVERROR(ENOMEM);
     144           0 :             goto end;
     145             :         }
     146          27 :         sub->pos = pos;
     147          27 :         sub->pts = ts_start;
     148          27 :         sub->duration = ts_end - ts_start;
     149             : 
     150             : #define SET_SIDE_DATA(name, type) do {                                  \
     151             :     if (name##_len) {                                                   \
     152             :         uint8_t *buf = av_packet_new_side_data(sub, type, name##_len);  \
     153             :         if (!buf) {                                                     \
     154             :             res = AVERROR(ENOMEM);                                      \
     155             :             goto end;                                                   \
     156             :         }                                                               \
     157             :         memcpy(buf, name, name##_len);                                  \
     158             :     }                                                                   \
     159             : } while (0)
     160             : 
     161          27 :         SET_SIDE_DATA(identifier, AV_PKT_DATA_WEBVTT_IDENTIFIER);
     162          27 :         SET_SIDE_DATA(settings,   AV_PKT_DATA_WEBVTT_SETTINGS);
     163             :     }
     164             : 
     165           2 :     ff_subtitles_queue_finalize(s, &webvtt->q);
     166             : 
     167           2 : end:
     168           2 :     av_bprint_finalize(&cue,    NULL);
     169           2 :     av_bprint_finalize(&header, NULL);
     170           2 :     return res;
     171             : }
     172             : 
     173          29 : static int webvtt_read_packet(AVFormatContext *s, AVPacket *pkt)
     174             : {
     175          29 :     WebVTTContext *webvtt = s->priv_data;
     176          29 :     return ff_subtitles_queue_read_packet(&webvtt->q, pkt);
     177             : }
     178             : 
     179           0 : static int webvtt_read_seek(AVFormatContext *s, int stream_index,
     180             :                             int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
     181             : {
     182           0 :     WebVTTContext *webvtt = s->priv_data;
     183           0 :     return ff_subtitles_queue_seek(&webvtt->q, s, stream_index,
     184             :                                    min_ts, ts, max_ts, flags);
     185             : }
     186             : 
     187           2 : static int webvtt_read_close(AVFormatContext *s)
     188             : {
     189           2 :     WebVTTContext *webvtt = s->priv_data;
     190           2 :     ff_subtitles_queue_clean(&webvtt->q);
     191           2 :     return 0;
     192             : }
     193             : 
     194             : #define OFFSET(x) offsetof(WebVTTContext, x)
     195             : #define KIND_FLAGS AV_OPT_FLAG_SUBTITLE_PARAM
     196             : 
     197             : static const AVOption options[] = {
     198             :     { "kind", "Set kind of WebVTT track", OFFSET(kind), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, KIND_FLAGS, "webvtt_kind" },
     199             :         { "subtitles",    "WebVTT subtitles kind",    0, AV_OPT_TYPE_CONST, { .i64 = 0 },                           INT_MIN, INT_MAX, 0, "webvtt_kind" },
     200             :         { "captions",     "WebVTT captions kind",     0, AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_CAPTIONS },     INT_MIN, INT_MAX, 0, "webvtt_kind" },
     201             :         { "descriptions", "WebVTT descriptions kind", 0, AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_DESCRIPTIONS }, INT_MIN, INT_MAX, 0, "webvtt_kind" },
     202             :         { "metadata",     "WebVTT metadata kind",     0, AV_OPT_TYPE_CONST, { .i64 = AV_DISPOSITION_METADATA },     INT_MIN, INT_MAX, 0, "webvtt_kind" },
     203             :     { NULL }
     204             : };
     205             : 
     206             : static const AVClass webvtt_demuxer_class = {
     207             :     .class_name  = "WebVTT demuxer",
     208             :     .item_name   = av_default_item_name,
     209             :     .option      = options,
     210             :     .version     = LIBAVUTIL_VERSION_INT,
     211             : };
     212             : 
     213             : AVInputFormat ff_webvtt_demuxer = {
     214             :     .name           = "webvtt",
     215             :     .long_name      = NULL_IF_CONFIG_SMALL("WebVTT subtitle"),
     216             :     .priv_data_size = sizeof(WebVTTContext),
     217             :     .read_probe     = webvtt_probe,
     218             :     .read_header    = webvtt_read_header,
     219             :     .read_packet    = webvtt_read_packet,
     220             :     .read_seek2     = webvtt_read_seek,
     221             :     .read_close     = webvtt_read_close,
     222             :     .extensions     = "vtt",
     223             :     .priv_class     = &webvtt_demuxer_class,
     224             : };

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