Making SVCDs w/ Closed Captions?

[jedisb]

I have a friend with a specific need to include closed captions in his SVCDs. He has a piece of equipment called the TV Guardian (TVG) that uses the closed caption information to filter for offensive language. The TVG will then mute that part of the movie and display an alternate word in a caption. But is essential that the closed captions are included on the SVCD (as closed captions, not subs - if they are different) to get the filtering to work properly. The TVG works with the original DVD but we're just not sure how to go about getting the captions off the DVD and onto the SVCD.

We are both very new at this and I usually don't mess with subs anyway but I thought I'd ask about this for him. I discovered here (http://www.dvdrhelp.com/svcd) that there is a CAPTnn.dat file on SVCDs that contain the closed caption data. Is this the same file that hold the subs? Are subs and CCs the same or different?

Bottom line question is can DVD2SVCD create SVCDs with closed captions? If so, how?

I've already tried searching the forums, as well as several other, but can't seem to fine a direct answer to this question.

Thanks in advance.

Scott

[McPoodle]

The best place to ask caption questions is on the Subtitles forum.

Closed Captions vs. Subtitles: Captions show up on most TV shows and can be turned on and off with the TV remote, while switchable subtitles can only be turned on or off by the DVD remote. Closed captions are stored as CAPnn.DAT files in the EXT directory of the SVCD (where nn is the same number that the movie got, so if the movie turned into AVSEQ02.DAT on the SVCD, the matching captions must be named CAPT02.DAT). Subtitles on the other hand are muxed into the MPEG file with WinSubMux.

Copying captions is a relatively straightforward process:
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Use VobSub on the DVD and select the "cc" stream to extract. You will end up with a file called VTS_01_0.sub.cc.raw. There is a wizard version of this program that works better--download from here (http://gabest.org/vsrip.rar), but that program names the output VTS_01_0.cc.raw--rename to VTS_01_0.sub.cc.raw to make the next step work (at least until I get around to fixing VOBSUB2SCC).
Use the command line tool VOBSUB2SCC on the file produced in step 1--download from here (http://www.geocities.com/mcpoodle43/SCC_TOOLS/vobsub2scc.exe). This will produce the file VTS_01_0.bin.
Rename VTS_01_0.bin to CAPT02.DAT (or whatever name it needs to be).
Use VCDEasy or whatever SVCD authoring tool to put the caption file in the EXT directory (this is the last tab in VCDEasy).
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Now if you're splitting your movie onto multiple disks, you'll need to split the captions, too, plus get the timing correct for the second half, making things a bit more complicated. Download the full tools package from my website (link at the bottom of this message)--you'll be using the other output of VOBSUB2SCC (VTS_01_0.scc), which is a text file containing timecodes and hexidecimal data for each caption. Move the lines for the second half of the movie into a new file with the same header ("Scenarist_SCC V1.0"), then use the CCADJ tool to move all the timecodes in the new file back by the same amount. The tool SCC2RAW will then convert the two .scc files into .bin files, which puts you back at step 3 above. Hopefully, that should do everything you need.

--McPoodle
The SCC Tools Package (http://www.geocities.com/mcpoodle43/SCC_TOOLS/DOCS/SCC_TOOLS.HTML), complete with documentation.

[jedisb]

Thanks so much for the answer. I was beginning to wonder if I was going to get one or not. I'm assuming that if the film is split into 3 discs that the procedure for the thrid disc is pretty much the same as the second one?

[McPoodle]

That's right. Each file has to have that header line, and the timecodes need to be adjusted so they are lined up with the zero-point of each video. Captions use a counter-intuitive method for the timecodes, though, where the timecode needs to be about a second before the time you want the caption is supposed to appear.

One of the tools on my page, CCASDI, will translate the hexidecimal codes into something readable--if you run the file with the option "-a", the output file (with a .ccd extension) will have the timecodes adjusted to be when the caption appears instead of being early. You can then split the captions into three separate files, copying the header of the first file to the other two (these .ccd files have a different 2-line header compared to the .scc files, so my programs can tell them apart). You then run CCADJ on the second and third .ccd files to put the timecodes where you want them (for example, "ccadj -o-0:45:00:00 part2.ccd part2.1.ccd" will copy the file part2.ccd to part2.1.ccd, subtracting an even 45 minutes from all of the timecodes).

When you have all the .ccd files the way you want them, run CCASDI again on them with the "-a" option to turn them back into proper .scc files.

[McPoodle]

An apology to anyone who may have been following this thread. The information I posted was based on research and guesswork, not actual experience. I finally got around to following my technique for adding closed captions to a VCD, and they don't work (or maybe they did work and all the software DVD players that display captions won't do it for VCDs?). All the documentation I've seen says that the EXT/CAPTnn.DAT file contains the closed captions, but nothing says how the captions are stored, so I just assumed they were in the same format they were broadcast in. Apparently this is incorrect.

If anyone owns a VCD or SVCD with closed captions, please reply to this thread so we can get the information needed to work out this problem. A thorough search of the internet revealed that none of the major VCD dealers will tell you if their VCD's are captioned. Since it appears that all commercial VCD's nowadays are in PAL format, it may be impossible to obtain a commercial VCD with captions. Maybe one of the VCD recorders out there records captions?

[McPoodle]

Another update. The format of the CAPTnn.DAT file can be found here (http://www.icdia.org/docs_sw/vcd_on_cdi_41.pdf). I managed to get an old VCD with this file that verified the format. Implied in this document is the fact that this file can only be read by the old CD-I player.

This leaves a second mechanism. Apparently captions can be stored inside the MPEG-1 file, just like DVD captions are stored. Unfortunately, it looks like the format is different and undocumented (at least, for anyone who doesn't want to pay for it). So for the moment, VCD closed captions are still not possible. I'll update this thread yet again if I learn anything new.