vcdimager: SVCD Subtitles
1.5.2.2 SVCD Subtitles
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There exist two major subtitle formats for SVCD's, of which only
one--"Overlay Graphics Text" or OGT--is officially supported. The
non-compliant one has it's origin in the so-called CVD format, a
competitor for the Video CD 2.0 successor. The _real_ SVCD subtitle
format is part of the Super Video Specification, wheras the CVD-style
subtitle format is not. Alas the latter one is more widely used, due to
older pre-SVCD aged software only supporting the non-compliant CVD
subtitle format.
Compliant SVCD subtitles are transported in a 'private_stream_1'
stream with only the 'private_data_id' '0x70'(1). The 'sub_stream_id'
is used to distinguish between the 4 available subtitle channels.
As of the time of writing, there is only a proof of concept
implementation (read _hack_) for creating proper SVCD subtitles. The
source code is available from the contribs download directory, but its
use is not recommended for production use. If you are searching for a
new free software project, you could take this as an idea...
---------- Footnotes ----------
(1) While AC3 tracks use the 'private_data_id' '0x80+', DVD subtitles
'0x20' onwards and CVD subtitles '0x00' and up.
Info Catalog
vcdimager: Scan Information Data
vcdimager: Super Video CD