| /* |
| * TED Talks captions format decoder |
| * Copyright (c) 2012 Nicolas George |
| * |
| * 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 "libavutil/bprint.h" |
| #include "libavutil/log.h" |
| #include "libavutil/opt.h" |
| #include "avformat.h" |
| #include "internal.h" |
| #include "subtitles.h" |
| |
| typedef struct { |
| AVClass *class; |
| int64_t start_time; |
| FFDemuxSubtitlesQueue subs; |
| } TEDCaptionsDemuxer; |
| |
| static const AVOption tedcaptions_options[] = { |
| { "start_time", "set the start time (offset) of the subtitles, in ms", |
| offsetof(TEDCaptionsDemuxer, start_time), AV_OPT_TYPE_INT64, |
| { .i64 = 15000 }, INT64_MIN, INT64_MAX, |
| AV_OPT_FLAG_SUBTITLE_PARAM | AV_OPT_FLAG_DECODING_PARAM }, |
| { NULL }, |
| }; |
| |
| static const AVClass tedcaptions_demuxer_class = { |
| .class_name = "tedcaptions_demuxer", |
| .item_name = av_default_item_name, |
| .option = tedcaptions_options, |
| .version = LIBAVUTIL_VERSION_INT, |
| }; |
| |
| #define BETWEEN(a, amin, amax) ((unsigned)((a) - (amin)) <= (amax) - (amin)) |
| |
| #define HEX_DIGIT_TEST(c) (BETWEEN(c, '0', '9') || BETWEEN((c) | 32, 'a', 'z')) |
| #define HEX_DIGIT_VAL(c) ((c) <= '9' ? (c) - '0' : ((c) | 32) - 'a' + 10) |
| #define ERR_CODE(c) ((c) < 0 ? (c) : AVERROR_INVALIDDATA) |
| |
| static void av_bprint_utf8(AVBPrint *bp, unsigned c) |
| { |
| int bytes, i; |
| |
| if (c <= 0x7F) { |
| av_bprint_chars(bp, c, 1); |
| return; |
| } |
| bytes = (av_log2(c) - 2) / 5; |
| av_bprint_chars(bp, (c >> (bytes * 6)) | ((0xFF80 >> bytes) & 0xFF), 1); |
| for (i = bytes - 1; i >= 0; i--) |
| av_bprint_chars(bp, ((c >> (i * 6)) & 0x3F) | 0x80, 1); |
| } |
| |
| static void next_byte(AVIOContext *pb, int *cur_byte) |
| { |
| uint8_t b; |
| int ret = avio_read(pb, &b, 1); |
| *cur_byte = ret > 0 ? b : ret == 0 ? AVERROR_EOF : ret; |
| } |
| |
| static void skip_spaces(AVIOContext *pb, int *cur_byte) |
| { |
| while (*cur_byte == ' ' || *cur_byte == '\t' || |
| *cur_byte == '\n' || *cur_byte == '\r') |
| next_byte(pb, cur_byte); |
| } |
| |
| static int expect_byte(AVIOContext *pb, int *cur_byte, uint8_t c) |
| { |
| skip_spaces(pb, cur_byte); |
| if (*cur_byte != c) |
| return ERR_CODE(*cur_byte); |
| next_byte(pb, cur_byte); |
| return 0; |
| } |
| |
| static int parse_string(AVIOContext *pb, int *cur_byte, AVBPrint *bp, int full) |
| { |
| int ret; |
| |
| av_bprint_init(bp, 0, full ? AV_BPRINT_SIZE_UNLIMITED : AV_BPRINT_SIZE_AUTOMATIC); |
| ret = expect_byte(pb, cur_byte, '"'); |
| if (ret < 0) |
| goto fail; |
| while (*cur_byte > 0 && *cur_byte != '"') { |
| if (*cur_byte == '\\') { |
| next_byte(pb, cur_byte); |
| if (*cur_byte < 0) { |
| ret = AVERROR_INVALIDDATA; |
| goto fail; |
| } |
| if ((*cur_byte | 32) == 'u') { |
| unsigned chr = 0, i; |
| for (i = 0; i < 4; i++) { |
| next_byte(pb, cur_byte); |
| if (!HEX_DIGIT_TEST(*cur_byte)) { |
| ret = ERR_CODE(*cur_byte); |
| goto fail; |
| } |
| chr = chr * 16 + HEX_DIGIT_VAL(*cur_byte); |
| } |
| av_bprint_utf8(bp, chr); |
| } else { |
| av_bprint_chars(bp, *cur_byte, 1); |
| } |
| } else { |
| av_bprint_chars(bp, *cur_byte, 1); |
| } |
| next_byte(pb, cur_byte); |
| } |
| ret = expect_byte(pb, cur_byte, '"'); |
| if (ret < 0) |
| goto fail; |
| if (full && !av_bprint_is_complete(bp)) { |
| ret = AVERROR(ENOMEM); |
| goto fail; |
| } |
| return 0; |
| |
| fail: |
| av_bprint_finalize(bp, NULL); |
| return ret; |
| } |
| |
| static int parse_label(AVIOContext *pb, int *cur_byte, AVBPrint *bp) |
| { |
| int ret; |
| |
| ret = parse_string(pb, cur_byte, bp, 0); |
| if (ret < 0) |
| return ret; |
| ret = expect_byte(pb, cur_byte, ':'); |
| if (ret < 0) |
| return ret; |
| return 0; |
| } |
| |
| static int parse_boolean(AVIOContext *pb, int *cur_byte, int *result) |
| { |
| static const char * const text[] = { "false", "true" }; |
| const char *p; |
| int i; |
| |
| skip_spaces(pb, cur_byte); |
| for (i = 0; i < 2; i++) { |
| p = text[i]; |
| if (*cur_byte != *p) |
| continue; |
| for (; *p; p++, next_byte(pb, cur_byte)) |
| if (*cur_byte != *p) |
| return AVERROR_INVALIDDATA; |
| if (BETWEEN(*cur_byte | 32, 'a', 'z')) |
| return AVERROR_INVALIDDATA; |
| *result = i; |
| return 0; |
| } |
| return AVERROR_INVALIDDATA; |
| } |
| |
| static int parse_int(AVIOContext *pb, int *cur_byte, int64_t *result) |
| { |
| int64_t val = 0; |
| |
| skip_spaces(pb, cur_byte); |
| if ((unsigned)*cur_byte - '0' > 9) |
| return AVERROR_INVALIDDATA; |
| while (BETWEEN(*cur_byte, '0', '9')) { |
| val = val * 10 + (*cur_byte - '0'); |
| next_byte(pb, cur_byte); |
| } |
| *result = val; |
| return 0; |
| } |
| |
| static int parse_file(AVIOContext *pb, FFDemuxSubtitlesQueue *subs) |
| { |
| int ret, cur_byte, start_of_par; |
| AVBPrint label, content; |
| int64_t pos, start, duration; |
| AVPacket *pkt; |
| |
| next_byte(pb, &cur_byte); |
| ret = expect_byte(pb, &cur_byte, '{'); |
| if (ret < 0) |
| return AVERROR_INVALIDDATA; |
| ret = parse_label(pb, &cur_byte, &label); |
| if (ret < 0 || strcmp(label.str, "captions")) |
| return AVERROR_INVALIDDATA; |
| ret = expect_byte(pb, &cur_byte, '['); |
| if (ret < 0) |
| return AVERROR_INVALIDDATA; |
| while (1) { |
| content.size = 0; |
| start = duration = AV_NOPTS_VALUE; |
| ret = expect_byte(pb, &cur_byte, '{'); |
| if (ret < 0) |
| return ret; |
| pos = avio_tell(pb) - 1; |
| while (1) { |
| ret = parse_label(pb, &cur_byte, &label); |
| if (ret < 0) |
| return ret; |
| if (!strcmp(label.str, "startOfParagraph")) { |
| ret = parse_boolean(pb, &cur_byte, &start_of_par); |
| if (ret < 0) |
| return ret; |
| } else if (!strcmp(label.str, "content")) { |
| ret = parse_string(pb, &cur_byte, &content, 1); |
| if (ret < 0) |
| return ret; |
| } else if (!strcmp(label.str, "startTime")) { |
| ret = parse_int(pb, &cur_byte, &start); |
| if (ret < 0) |
| return ret; |
| } else if (!strcmp(label.str, "duration")) { |
| ret = parse_int(pb, &cur_byte, &duration); |
| if (ret < 0) |
| return ret; |
| } else { |
| return AVERROR_INVALIDDATA; |
| } |
| skip_spaces(pb, &cur_byte); |
| if (cur_byte != ',') |
| break; |
| next_byte(pb, &cur_byte); |
| } |
| ret = expect_byte(pb, &cur_byte, '}'); |
| if (ret < 0) |
| return ret; |
| |
| if (!content.size || start == AV_NOPTS_VALUE || |
| duration == AV_NOPTS_VALUE) |
| return AVERROR_INVALIDDATA; |
| pkt = ff_subtitles_queue_insert(subs, content.str, content.len, 0); |
| if (!pkt) |
| return AVERROR(ENOMEM); |
| pkt->pos = pos; |
| pkt->pts = start; |
| pkt->duration = duration; |
| av_bprint_finalize(&content, NULL); |
| |
| skip_spaces(pb, &cur_byte); |
| if (cur_byte != ',') |
| break; |
| next_byte(pb, &cur_byte); |
| } |
| ret = expect_byte(pb, &cur_byte, ']'); |
| if (ret < 0) |
| return ret; |
| ret = expect_byte(pb, &cur_byte, '}'); |
| if (ret < 0) |
| return ret; |
| skip_spaces(pb, &cur_byte); |
| if (cur_byte != AVERROR_EOF) |
| return ERR_CODE(cur_byte); |
| return 0; |
| } |
| |
| static av_cold int tedcaptions_read_header(AVFormatContext *avf) |
| { |
| TEDCaptionsDemuxer *tc = avf->priv_data; |
| AVStream *st; |
| int ret, i; |
| AVPacket *last; |
| |
| ret = parse_file(avf->pb, &tc->subs); |
| if (ret < 0) { |
| if (ret == AVERROR_INVALIDDATA) |
| av_log(avf, AV_LOG_ERROR, "Syntax error near offset %"PRId64".\n", |
| avio_tell(avf->pb)); |
| ff_subtitles_queue_clean(&tc->subs); |
| return ret; |
| } |
| ff_subtitles_queue_finalize(avf, &tc->subs); |
| for (i = 0; i < tc->subs.nb_subs; i++) |
| tc->subs.subs[i].pts += tc->start_time; |
| |
| last = &tc->subs.subs[tc->subs.nb_subs - 1]; |
| st = avformat_new_stream(avf, NULL); |
| if (!st) |
| return AVERROR(ENOMEM); |
| st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE; |
| st->codecpar->codec_id = AV_CODEC_ID_TEXT; |
| avpriv_set_pts_info(st, 64, 1, 1000); |
| st->probe_packets = 0; |
| st->start_time = 0; |
| st->duration = last->pts + last->duration; |
| st->cur_dts = 0; |
| |
| return 0; |
| } |
| |
| static int tedcaptions_read_packet(AVFormatContext *avf, AVPacket *packet) |
| { |
| TEDCaptionsDemuxer *tc = avf->priv_data; |
| |
| return ff_subtitles_queue_read_packet(&tc->subs, packet); |
| } |
| |
| static int tedcaptions_read_close(AVFormatContext *avf) |
| { |
| TEDCaptionsDemuxer *tc = avf->priv_data; |
| |
| ff_subtitles_queue_clean(&tc->subs); |
| return 0; |
| } |
| |
| static av_cold int tedcaptions_read_probe(AVProbeData *p) |
| { |
| static const char *const tags[] = { |
| "\"captions\"", "\"duration\"", "\"content\"", |
| "\"startOfParagraph\"", "\"startTime\"", |
| }; |
| unsigned i, count = 0; |
| const char *t; |
| |
| if (p->buf[strspn(p->buf, " \t\r\n")] != '{') |
| return 0; |
| for (i = 0; i < FF_ARRAY_ELEMS(tags); i++) { |
| if (!(t = strstr(p->buf, tags[i]))) |
| continue; |
| t += strlen(tags[i]); |
| t += strspn(t, " \t\r\n"); |
| if (*t == ':') |
| count++; |
| } |
| return count == FF_ARRAY_ELEMS(tags) ? AVPROBE_SCORE_MAX : |
| count ? AVPROBE_SCORE_EXTENSION : 0; |
| } |
| |
| static int tedcaptions_read_seek(AVFormatContext *avf, int stream_index, |
| int64_t min_ts, int64_t ts, int64_t max_ts, |
| int flags) |
| { |
| TEDCaptionsDemuxer *tc = avf->priv_data; |
| return ff_subtitles_queue_seek(&tc->subs, avf, stream_index, |
| min_ts, ts, max_ts, flags); |
| } |
| |
| AVInputFormat ff_tedcaptions_demuxer = { |
| .name = "tedcaptions", |
| .long_name = NULL_IF_CONFIG_SMALL("TED Talks captions"), |
| .priv_data_size = sizeof(TEDCaptionsDemuxer), |
| .priv_class = &tedcaptions_demuxer_class, |
| .read_header = tedcaptions_read_header, |
| .read_packet = tedcaptions_read_packet, |
| .read_close = tedcaptions_read_close, |
| .read_probe = tedcaptions_read_probe, |
| .read_seek2 = tedcaptions_read_seek, |
| }; |
