@ -1,6 +1,5 @@
/*
* Raw Captions With Time ( RCWT ) muxer
* Author : Marth64 < marth64 @ proxyid . net >
* RCWT ( Raw Captions With Time ) muxer
*
* This file is part of FFmpeg .
*
@ -20,16 +19,16 @@
*/
/*
* Raw Captions With Time ( RCWT ) is a format native to ccextractor , a commonly
* used open source tool for processing 608 / 708 closed caption ( CC ) sources .
* RCWT ( R aw Captions With Time ) is a format native to ccextractor , a commonly
* used open source tool for processing 608 / 708 Closed Captions ( CC ) sources .
* It can be used to archive the original , raw CC bitstream and to produce
* a source file for later CC processing or conversion . As a result ,
* it also allows for interopability with ccextractor for processing CC data
* extracted via ffmpeg . The format is simple to parse and can be used
* to retain all lines and variants of CC .
*
* This muxer implements the specification as of 2024 - 01 - 05 , which has
* been stable and unchanged for 10 years as of this writing .
* This muxer implements the specification as of March 2024 , which has
* been stable and unchanged since April 2014 .
*
* This muxer will have some nuances from the way that ccextractor muxes RCWT .
* No compatibility issues when processing the output with ccextractor
@ -40,13 +39,7 @@
* ( 1 ) This muxer will identify as " FF " as the writing program identifier , so
* as to be honest about the output ' s origin .
*
* ( 2 ) ffmpeg ' s MPEG - 1 / 2 , H264 , HEVC , etc . decoders extract closed captioning
* data differently than ccextractor from embedded SEI / user data .
* For example , DVD captioning bytes will be translated to ATSC A53 format .
* This allows ffmpeg to handle 608 / 708 in a consistant way downstream .
* This is a lossless conversion and the meaningful data is retained .
*
* ( 3 ) This muxer will not alter the extracted data except to remove invalid
* ( 2 ) This muxer will not alter the extracted data except to remove invalid
* packets in between valid CC blocks . On the other hand , ccextractor
* will by default remove mid - stream padding , and add padding at the end
* of the stream ( in order to convey the end time of the source video ) .
@ -172,7 +165,7 @@ static int rcwt_write_trailer(AVFormatContext *avf)
const FFOutputFormat ff_rcwt_muxer = {
. p . name = " rcwt " ,
. p . long_name = NULL_IF_CONFIG_SMALL ( " Raw Captions With Time " ) ,
. p . long_name = NULL_IF_CONFIG_SMALL ( " RCWT (R aw Captions With Time) " ) ,
. p . extensions = " bin " ,
. p . flags = AVFMT_GLOBALHEADER | AVFMT_VARIABLE_FPS | AVFMT_TS_NONSTRICT ,
. p . subtitle_codec = AV_CODEC_ID_EIA_608 ,