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122 lines
3.8 KiB
122 lines
3.8 KiB
/* |
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* RCWT (Raw Captions With Time) demuxer |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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/* |
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* RCWT (Raw Captions With Time) is a format native to ccextractor, a commonly |
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* used open source tool for processing 608/708 Closed Captions (CC) sources. |
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* |
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* This demuxer implements the specification as of March 2024, which has |
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* been stable and unchanged since April 2014. |
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* |
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* A free specification of RCWT can be found here: |
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* @url{https://github.com/CCExtractor/ccextractor/blob/master/docs/BINARY_FILE_FORMAT.TXT} |
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*/ |
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#include "avformat.h" |
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#include "demux.h" |
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#include "internal.h" |
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#include "subtitles.h" |
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#include "libavutil/intreadwrite.h" |
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#define RCWT_HEADER_SIZE 11 |
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typedef struct RCWTContext { |
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FFDemuxSubtitlesQueue q; |
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} RCWTContext; |
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static int rcwt_read_header(AVFormatContext *avf) |
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{ |
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RCWTContext *rcwt = avf->priv_data; |
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AVStream *st; |
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uint8_t header[RCWT_HEADER_SIZE]; |
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int ret; |
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/* read header */ |
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ret = ffio_read_size(avf->pb, header, RCWT_HEADER_SIZE); |
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if (ret < 0) |
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return ret; |
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if (AV_RB16(header + 6) != 0x0001) { |
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av_log(avf, AV_LOG_ERROR, "RCWT format version is not compatible " |
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"(only version 0.001 is known)\n"); |
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return AVERROR_INVALIDDATA; |
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} |
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av_log(avf, AV_LOG_DEBUG, "RCWT writer application: %02X version: %02x\n", |
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header[3], header[5]); |
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/* setup stream */ |
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st = avformat_new_stream(avf, NULL); |
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if (!st) |
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return AVERROR(ENOMEM); |
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st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE; |
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st->codecpar->codec_id = AV_CODEC_ID_EIA_608; |
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avpriv_set_pts_info(st, 64, 1, 1000); |
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/* demux */ |
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while (!avio_feof(avf->pb)) { |
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AVPacket *sub; |
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int64_t cluster_pos = avio_tell(avf->pb); |
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int64_t cluster_pts = avio_rl64(avf->pb); |
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int cluster_nb_blocks = avio_rl16(avf->pb); |
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if (cluster_nb_blocks == 0) |
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continue; |
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sub = ff_subtitles_queue_insert(&rcwt->q, NULL, 0, 0); |
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if (!sub) |
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return AVERROR(ENOMEM); |
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ret = av_get_packet(avf->pb, sub, cluster_nb_blocks * 3); |
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if (ret < 0) |
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return ret; |
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sub->pos = cluster_pos; |
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sub->pts = cluster_pts; |
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} |
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ff_subtitles_queue_finalize(avf, &rcwt->q); |
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return 0; |
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} |
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static int rcwt_probe(const AVProbeData *p) |
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{ |
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return p->buf_size > RCWT_HEADER_SIZE && |
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AV_RB16(p->buf) == 0xCCCC && |
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AV_RB8(p->buf + 2) == 0xED && |
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AV_RB16(p->buf + 6) == 0x0001 ? 50 : 0; |
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} |
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const FFInputFormat ff_rcwt_demuxer = { |
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.p.name = "rcwt", |
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.p.long_name = NULL_IF_CONFIG_SMALL("RCWT (Raw Captions With Time)"), |
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.p.flags = AVFMT_TS_DISCONT, |
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.priv_data_size = sizeof(RCWTContext), |
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.flags_internal = FF_INFMT_FLAG_INIT_CLEANUP, |
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.read_probe = rcwt_probe, |
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.read_header = rcwt_read_header, |
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.read_packet = ff_subtitles_read_packet, |
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.read_seek2 = ff_subtitles_read_seek, |
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.read_close = ff_subtitles_read_close |
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};
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